1
|
Deboelpaep E, Partoens L, Koedam N, Vanschoenwinkel B. Highway(s) overhead: Strong differences in wetland connectivity and protected status challenge waterbird migration along the four Palearctic‐Afrotropical flyways. DIVERS DISTRIB 2022. [DOI: 10.1111/ddi.13508] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022] Open
Affiliation(s)
- Evelien Deboelpaep
- Vrije Universiteit Brussel Ecology & Biodiversity Research Group Community Ecology Lab Brussels Belgium
- Vrije Universiteit Brussel Ecology & Biodiversity Research Group Plant Biology & Nature Management Brussels Belgium
| | - Lisa Partoens
- Vrije Universiteit Brussel Ecology & Biodiversity Research Group Community Ecology Lab Brussels Belgium
- Vrije Universiteit Brussel Ecology & Biodiversity Research Group Plant Biology & Nature Management Brussels Belgium
| | - Nico Koedam
- Vrije Universiteit Brussel Ecology & Biodiversity Research Group Plant Biology & Nature Management Brussels Belgium
| | - Bram Vanschoenwinkel
- Vrije Universiteit Brussel Ecology & Biodiversity Research Group Community Ecology Lab Brussels Belgium
- Centre for Environmental Management University of the Free State Bloemfontein South Africa
| |
Collapse
|
2
|
Jenoh EM, Traoré M, Kosore C, Koedam N. Biochemical response of Sonneratia alba Sm. branches infested by a wood boring moth (Gazi Bay, Kenya). PLoS One 2021; 16:e0259261. [PMID: 34727136 PMCID: PMC8562821 DOI: 10.1371/journal.pone.0259261] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2021] [Accepted: 10/18/2021] [Indexed: 11/29/2022] Open
Abstract
Infestation by a moth woodborer species is causing mortality of Sonneratia alba Sm. mangrove by tunneling through the inner bark, cambium and conductive tissue. Infestation leads to death of some infested branches, whereas in other cases infested branches have been observed to recover from infestation. We have used Fourier transform infrared spectroscopy (FTIR) to investigate the differences in macromolecule (polysaccharide and lignin) content present in branches that died (D) of the infestation, those that recovered (R) from the infestation and control branches (C) that were not subject to any infestation. Wood samples were taken from four sampling plots (A, B, C and D) in Gazi Bay (Kenya). From each of the four plots, 15 S. alba branches were taken from five trees, from which 1 cm thick discs were cut from each of these branches to be used as samples. To identify the most characteristic FTIR bands for the three groups of samples, Principal Component Analysis (PCA) was applied on the transposed data matrix. Furthermore, canonical discriminant analysis was applied on the data considering the main FTIR band that would be identified through the PCA factors. Finally, One-way ANOVA and post hoc test were used to verify the significance of the observed trends. Branches that recovered from infestation had higher relative abundance of lignified cells. We conclude that insect-infested S. alba undergo changes related to the lignocellulosic contents. The infestation induces a decrease of the proportion of the polysaccharide content and an increase of the proportion of the lignin contents.
Collapse
Affiliation(s)
- Elisha Mrabu Jenoh
- Kenya Marine and Fisheries Research Institute (KMFRI), Mombasa, Kenya
- Laboratory of Plant Biology and Nature Management (APNA), Ecology & Biodiversity, Vrije Universiteit Brussel, Brussels, Belgium
- * E-mail:
| | - Mohamed Traoré
- Department of Geology and Mines, Ecole Nationale d’Ingénieur–Abderhamane Baba Touré, Bamako, Mali
| | - Charles Kosore
- Kenya Marine and Fisheries Research Institute (KMFRI), Mombasa, Kenya
| | - Nico Koedam
- Laboratory of Plant Biology and Nature Management (APNA), Ecology & Biodiversity, Vrije Universiteit Brussel, Brussels, Belgium
| |
Collapse
|
3
|
Ngeve MN, Koedam N, Triest L. Genotypes of Rhizophora Propagules From a Non-mangrove Beach Provide Evidence of Recent Long-Distance Dispersal. Front Conserv Sci 2021. [DOI: 10.3389/fcosc.2021.746461] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Dispersal plays a crucial role in the connectivity of established mangrove populations and in species range dynamics. As species ranges shift in response to climate change, range expansions can occur from incremental short-distance dispersal events and from stochastic long-distance dispersal events. Most population genetic research dealt with historically accumulated events though evidence of actual propagule dispersal allows to estimate genotypic features and origin of founders. In this study, we aim to disentangle a contemporary dispersal event. Using microsatellite markers, we genotyped 60 Rhizophora racemosa drift propagules obtained on a bare unforested coastal area in southern Cameroon, estimated their relationship to 109 adult trees from most proximate sites (which were 3–85 km away), and assessed their relative difference with 873 trees of major mangrove areas (> 300 km) along the Cameroonian coastline. Proximate mangrove populations were considered as potential source populations in assignment tests. However, drift propagules could not be assigned to any of the Cameroonian mangrove sites and were genetically isolated from Cameroonian populations. Drift propagules showed higher levels of genetic diversity and private alleles giving a higher relatedness to each other than to any putative source population. Chloroplast sequences were used to confirm the identity of drift propagules as R. racemosa. We postulate that a complex interaction of ocean currents, estuarine geomorphology, and tidal patterns explain drift propagule dispersal to an area. Most likely the investigated cohort of propagules originated from more southern mangrove areas of the West African range beyond the Cameroonian border. This study unraveled the allelic, genetic, and genotypic features of stranded propagules following a stochastic long-distance dispersal. Transboundary dispersal of these propagules highlights the need for intergovernmental efforts in the management of biodiversity.
Collapse
|
4
|
Triest L, Van der Stocken T, De Ryck D, Kochzius M, Lorent S, Ngeve M, Ratsimbazafy HA, Sierens T, van der Ven R, Koedam N. Expansion of the mangrove species Rhizophora mucronata in the Western Indian Ocean launched contrasting genetic patterns. Sci Rep 2021; 11:4987. [PMID: 33654151 PMCID: PMC7925526 DOI: 10.1038/s41598-021-84304-8] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2020] [Accepted: 02/11/2021] [Indexed: 12/14/2022] Open
Abstract
Estimates of population structure and gene flow allow exploring the historical and contemporary processes that determine a species’ biogeographic pattern. In mangroves, large-scale genetic studies to estimate gene flow have been conducted predominantly in the Indo-Pacific and Atlantic region. Here we examine the genetic diversity and connectivity of Rhizophora mucronata across a > 3,000 km coastal stretch in the Western Indian Ocean (WIO) including WIO islands. Based on 359 trees from 13 populations and using 17 polymorphic microsatellite loci we detected genetic breaks between populations of the (1) East African coastline, (2) Mozambique Channel Area (3) granitic Seychelles, and (4) Aldabra and northern Madagascar. Genetic structure, diversity levels, and patterns of inferred connectivity, aligned with the directionality of major ocean currents, driven by bifurcation of the South Equatorial Current, northward into the East African Coastal Current and southward into the Mozambique Channel Area. A secondary genetic break between nearby populations in the Delagoa Bight coincided with high inbreeding levels and fixed loci. Results illustrate how oceanographic processes can connect and separate mangrove populations regardless of geographic distance.
Collapse
Affiliation(s)
- Ludwig Triest
- Ecology and Biodiversity, Vrije Universiteit Brussel, Pleinlaan 2, 1050, Elsene, Brussels, Belgium.
| | - Tom Van der Stocken
- Ecology and Biodiversity, Vrije Universiteit Brussel, Pleinlaan 2, 1050, Elsene, Brussels, Belgium
| | - Dennis De Ryck
- Ecology and Biodiversity, Vrije Universiteit Brussel, Pleinlaan 2, 1050, Elsene, Brussels, Belgium
| | - Marc Kochzius
- Marine Biology, Vrije Universiteit Brussel, Pleinlaan 2, 1050, Elsene, Brussels, Belgium
| | - Sophie Lorent
- Ecology and Biodiversity, Vrije Universiteit Brussel, Pleinlaan 2, 1050, Elsene, Brussels, Belgium
| | - Magdalene Ngeve
- Ecology and Biodiversity, Vrije Universiteit Brussel, Pleinlaan 2, 1050, Elsene, Brussels, Belgium.,Department of Plant Sciences and Landscape Architecture, University of Maryland, College Park, MD, 20742, USA
| | - Hajaniaina Andrianavalonarivo Ratsimbazafy
- Ecology and Biodiversity, Vrije Universiteit Brussel, Pleinlaan 2, 1050, Elsene, Brussels, Belgium.,Marine Biology, Vrije Universiteit Brussel, Pleinlaan 2, 1050, Elsene, Brussels, Belgium.,Laboratory of Systems Ecology and Resource Management, Département de Biologie Des Organismes, Université Libre de Bruxelles - ULB, Av. F.D. Roosevelt 50, CPi 264/1, 1050, Brussels, Belgium
| | - Tim Sierens
- Ecology and Biodiversity, Vrije Universiteit Brussel, Pleinlaan 2, 1050, Elsene, Brussels, Belgium
| | - Rosa van der Ven
- Marine Biology, Vrije Universiteit Brussel, Pleinlaan 2, 1050, Elsene, Brussels, Belgium.,Marine Animal Ecology Group, Wageningen University, Wageningen, The Netherlands
| | - Nico Koedam
- Ecology and Biodiversity, Vrije Universiteit Brussel, Pleinlaan 2, 1050, Elsene, Brussels, Belgium
| |
Collapse
|
5
|
Triest L, Van der Stocken T, Allela Akinyi A, Sierens T, Kairo J, Koedam N. Channel network structure determines genetic connectivity of landward-seaward Avicennia marina populations in a tropical bay. Ecol Evol 2020; 10:12059-12075. [PMID: 33209270 PMCID: PMC7663977 DOI: 10.1002/ece3.6829] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2020] [Revised: 09/01/2020] [Accepted: 09/04/2020] [Indexed: 12/31/2022] Open
Abstract
Mangrove ecosystems along the East African coast are often characterized by a disjunct zonation pattern of seaward and landward Avicennia marina trees. This disjunct zonation may be maintained through different positions in the tidal frame, yielding different dispersal settings. The spatial configuration of the landscape and coastal processes such as tides and waves is expected to largely influence the extent of propagule transport and subsequent regeneration. We hypothesized that landward sites would keep a stronger genetic structure over short distances in comparison with enhanced gene flow among regularly flooded seaward fringes. We tested this hypothesis from densely vegetated A. marina transects of a well-documented mangrove system (Gazi Bay, Kenya) and estimated local gene flow and kinship-based fine-scale genetic structure. Ten polymorphic microsatellite markers in 457 A. marina trees revealed no overall significant difference in levels of allele or gene diversities between sites that differ in hydrological proximity. Genetic structure and connectivity of A. marina populations however indicated an overall effect of geographic distance and revealed a pronounced distinction between channels and topographic setting. Migration models allowed to infer gene flow directionality among channels, and indicated a bidirectional steppingstone between seaward and nearest located landward stands. Admixed gene pools without any fine-scale structure were found within the wider and more exposed Kidogoweni channel, suggesting open systems. Elevated kinship values and structure over 5 to 20 m distance were only detected in two distant landward and seaward transects near the mouth of the Mkurumuji River, indicating local retention and establishment. Overall, our findings show that patterns of A. marina connectivity are explained by hydrological proximity, channel network structure, and hydrokinetic energy, rather than just their positioning as disjunct landward or seaward zones.
Collapse
Affiliation(s)
- Ludwig Triest
- Research Group Plant Biology and Nature ManagementVrije Universiteit BrusselBrusselsBelgium
| | - Tom Van der Stocken
- Research Group Plant Biology and Nature ManagementVrije Universiteit BrusselBrusselsBelgium
| | - Abbie Allela Akinyi
- Research Group Plant Biology and Nature ManagementVrije Universiteit BrusselBrusselsBelgium
| | - Tim Sierens
- Research Group Plant Biology and Nature ManagementVrije Universiteit BrusselBrusselsBelgium
| | - James Kairo
- Department of Oceanography and HydrographyKenya Marine and Fisheries Research InstituteMombasaKenya
| | - Nico Koedam
- Research Group Plant Biology and Nature ManagementVrije Universiteit BrusselBrusselsBelgium
| |
Collapse
|
6
|
Jenoh EM, de Villiers EP, de Villiers SM, Okoth S, Jefwa J, Kioko E, Kaimenyi D, Hendrickx M, Dahdouh-Guebas F, Koedam N. Infestation mechanisms of two woodborer species in the mangrove Sonneratia alba J. Smith in Kenya and co-occurring endophytic fungi. PLoS One 2019; 14:e0221285. [PMID: 31585459 PMCID: PMC6777984 DOI: 10.1371/journal.pone.0221285] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2019] [Accepted: 08/02/2019] [Indexed: 11/18/2022] Open
Abstract
Insect damage on trees can severely affect the quality of timber, reduce the fecundity of the host and render it susceptible to fungal infestation and disease. Such pathology weakens or eventually kills the host. Infestation by two insect woodborer species (a moth and a beetle) is causing mortality of Sonneratia alba, a wide-ranging pioneer mangrove species of the Indo-Pacific. Establishing the infestation mechanism of the two insect woodborer species is an initial and essential step towards understanding their ecological role in the mangroves and in determining sustainable management priorities and options. Our main objectives were to investigate the infestation mechanism employed by the two insect woodborers which infest S. alba trees, to establish the occurrence of secondary infestation by endophytic fungi in the infested S. alba branches, and to explore a control management option to the woodborer infestation. We conducted an external inspection of infested branches in two large embayments in Kenya, Gazi Bay and Mida Creek, and by splitting infested branches we determined the respective internal infestation mechanisms. Infested wood samples from Gazi Bay and Mida Creek were incubated at 28±1°C for 3–5 days to establish the presence of fungi. A survey was conducted in both Gazi Bay and Mida Creek to ascertain the presence of ants on S. alba. The infestation characteristics of the two insect woodborer species were different. It took 6–8 months for the beetle to kill a branch of 150 cm—200 cm long. For the moth to kill a branch, it depended upon several factors including the contribution by multiple species, other than the moth infestation alone. A total of 15 endophytic fungal species were identified. Two ant species Oecophylla longipoda and a Pheidole sp. inhabited 62% and 69% respectively of sampled S. alba trees in Gazi Bay whereas only Pheidole sp. inhabited 17% of the sampled S. alba trees in Mida Creek. In summary, we have documented the time it takes each woodborer species to kill a branch, the infestation mechanism of the two insect woodborers, and we hypothesized on the role of two ant species. The presence of several different fungal species was ascertained, and we discussed their possible role in the infested wood. Our results cannot unambiguously associate the woodborers and identified fungi. We recommend further studies to investigate the presence or absence, and if present, the nature of fungi in the gut of the woodborers.
Collapse
Affiliation(s)
- Elisha Mrabu Jenoh
- Kenya Marine and Fisheries Research Institute (KMFRI), Mombasa, Kenya
- Laboratory of Systems Ecology and Resource Management, Département de Biologie des Organismes, Université Libre de Bruxelles (ULB), Brussels, Belgium
- Laboratory of Plant Biology and Nature Management (APNA), Ecology & Biodiversity, Vrije Universiteit Brussel, Brussels, Belgium
- * E-mail:
| | | | | | - Sheila Okoth
- University of Nairobi (UoN), Centre for Biotechnology and Bioinformatics (CEBIB), Nairobi, Kenya
| | - Joyce Jefwa
- National Museums of Kenya (NMK), Nairobi, Kenya
| | | | - Davies Kaimenyi
- Pwani University Department of Biochemistry and Biotechnology, Kilifi Kenya
| | - Marijke Hendrickx
- BCCM/IHEM: Scientific Institute of Public Health, Mycology and Aerobiology Section, Brussels, Belgium. Rue Juliette Wytsmanstraat, Brussels, Belgium
| | - Farid Dahdouh-Guebas
- Laboratory of Systems Ecology and Resource Management, Département de Biologie des Organismes, Université Libre de Bruxelles (ULB), Brussels, Belgium
| | - Nico Koedam
- Laboratory of Plant Biology and Nature Management (APNA), Ecology & Biodiversity, Vrije Universiteit Brussel, Brussels, Belgium
| |
Collapse
|
7
|
Van der Stocken T, Wee AKS, De Ryck DJR, Vanschoenwinkel B, Friess DA, Dahdouh-Guebas F, Simard M, Koedam N, Webb EL. A general framework for propagule dispersal in mangroves. Biol Rev Camb Philos Soc 2019; 94:1547-1575. [PMID: 31058451 DOI: 10.1111/brv.12514] [Citation(s) in RCA: 34] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2018] [Revised: 03/19/2019] [Accepted: 03/27/2019] [Indexed: 12/29/2022]
Abstract
Dispersal allows species to shift their distributions in response to changing climate conditions. As a result, dispersal is considered a key process contributing to a species' long-term persistence. For many passive dispersers, fluid dynamics of wind and water fuel these movements and different species have developed remarkable adaptations for utilizing this energy to reach and colonize suitable habitats. The seafaring propagules (fruits and seeds) of mangroves represent an excellent example of such passive dispersal. Mangroves are halophytic woody plants that grow in the intertidal zones along tropical and subtropical shorelines and produce hydrochorous propagules with high dispersal potential. This results in exceptionally large coastal ranges across vast expanses of ocean and allows species to shift geographically and track the conditions to which they are adapted. This is particularly relevant given the challenges presented by rapid sea-level rise, higher frequency and intensity of storms, and changes in regional precipitation and temperature regimes. However, despite its importance, the underlying drivers of mangrove dispersal have typically been studied in isolation, and a conceptual synthesis of mangrove oceanic dispersal across spatial scales is lacking. Here, we review current knowledge on mangrove propagule dispersal across the various stages of the dispersal process. Using a general framework, we outline the mechanisms and ecological processes that are known to modulate the spatial patterns of mangrove dispersal. We show that important dispersal factors remain understudied and that adequate empirical data on the determinants of dispersal are missing for most mangrove species. This review particularly aims to provide a baseline for developing future research agendas and field campaigns, filling current knowledge gaps and increasing our understanding of the processes that shape global mangrove distributions.
Collapse
Affiliation(s)
- Tom Van der Stocken
- Earth Science Section, Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA, 91109, U.S.A.,Radar Science and Engineering Section, Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA, 91109, U.S.A.,Ecology and Biodiversity, Vrije Universiteit Brussel, Brussels, 1050, Belgium
| | - Alison K S Wee
- Department of Biological Sciences, National University of Singapore, Singapore, 117543, Singapore.,Key Laboratory of Forest Ecology and Conservation, College of Forestry, Guangxi University, Nanning, Guangxi, 530004, China
| | - Dennis J R De Ryck
- Ecology and Biodiversity, Vrije Universiteit Brussel, Brussels, 1050, Belgium
| | | | - Daniel A Friess
- Department of Geography, National University of Singapore, Singapore, 117570, Singapore
| | - Farid Dahdouh-Guebas
- Ecology and Biodiversity, Vrije Universiteit Brussel, Brussels, 1050, Belgium.,Systems Ecology and Resource Management, Université Libre de Bruxelles, Brussels, 1050, Belgium
| | - Marc Simard
- Radar Science and Engineering Section, Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA, 91109, U.S.A
| | - Nico Koedam
- Ecology and Biodiversity, Vrije Universiteit Brussel, Brussels, 1050, Belgium
| | - Edward L Webb
- Department of Biological Sciences, National University of Singapore, Singapore, 117543, Singapore
| |
Collapse
|
8
|
Benitez-Capistros F, Camperio G, Hugé J, Dahdouh-Guebas F, Koedam N. Emergent conservation conflicts in the Galapagos Islands: Human-giant tortoise interactions in the rural area of Santa Cruz Island. PLoS One 2018; 13:e0202268. [PMID: 30208033 PMCID: PMC6135374 DOI: 10.1371/journal.pone.0202268] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2017] [Accepted: 07/31/2018] [Indexed: 11/25/2022] Open
Abstract
The conservation of biodiverse areas around the world has contributed to the protection and recovery of endangered species. This has been the case for 11 species of Galapagos giant tortoises (Chelonoidis spp.) that today are successfully maintained over six islands: Española, Santiago, Pinzon, Isabela, San Cristobal and Santa Cruz. A favourable state of conservation will depend however on future development in the islands. In Santa Cruz Island the development of the agricultural areas has encroached on the migratory routes of the southwestern species C. porteri and may be an emergent conflict for tortoise conservation. We investigated the social and ecological inter-linkages using two methods framed under a participatory rural appraisal (PRA) approach: semi-structured interviews and questionnaires to study farmers’ perceptions and attitudinal factors regarding giant tortoises; as well as the associated socio-economic impacts of the conflict. Moreover, we coupled the PRA approach with an ecological assessment of giant tortoises’ population density by performing transect counts during the two yearly phases of giant tortoises’ migration to the lowlands (January to June) and back to the highlands (July to December). Our results indicate that farmers reporting damage and cultivating crops have higher odds of taking actions (fencing and physical actions) towards giant tortoises; regardless of having (or not) a negative perception towards the species. The economic losses for crops and fences averaged 2.8 USD/m2 and 13USD/m, respectively, and provide an initial step to further analyse and characterise the direct and indirect damage costs. Finally, we estimated a density of 76 and 185 individuals of giant tortoises per km2 in the rural area for the lowland and highland migratory phases, respectively. Our approach provides grounded scientific social and ecological information to effectively inform and aid managers, policy and decision makers in the selection of adequate social and ecological criteria to implement the best available options in the resolution of this emergent conservation conflict.
Collapse
Affiliation(s)
- Francisco Benitez-Capistros
- Central University of Ecuador, Biomedicine Research Institute (INBIOMED), Quito, Ecuador
- Vrije Universiteit Brussel, Department of Biology, Laboratory of Plant Biology and Nature Management (APNA), Ecology & Biodiversity, Brussels, Belgium
- Université Libre de Bruxelles, Department of Organism Biology, Laboratory of Systems Ecology and Resource Management (SERM), Brussels, Belgium
- * E-mail: (FBC); (GC)
| | - Giorgia Camperio
- Université Libre de Bruxelles, Department of Organism Biology, Laboratory of Systems Ecology and Resource Management (SERM), Brussels, Belgium
- ETH Zürich, Department of Earth Sciences, Zürich, Switzerland
- Eawag, Department of Surface Waters Research & Management, Dübendorf, Switzerland
- * E-mail: (FBC); (GC)
| | - Jean Hugé
- Vrije Universiteit Brussel, Department of Biology, Laboratory of Plant Biology and Nature Management (APNA), Ecology & Biodiversity, Brussels, Belgium
- Université Libre de Bruxelles, Department of Organism Biology, Laboratory of Systems Ecology and Resource Management (SERM), Brussels, Belgium
- University of Hasselt, Centre for Environmental Science, Hasselt, Belgium
- University of Ghent, Centre for Sustainable Development, Ghent, Belgium
| | - Farid Dahdouh-Guebas
- Université Libre de Bruxelles, Department of Organism Biology, Laboratory of Systems Ecology and Resource Management (SERM), Brussels, Belgium
- ETH Zürich, Department of Earth Sciences, Zürich, Switzerland
| | - Nico Koedam
- Université Libre de Bruxelles, Department of Organism Biology, Laboratory of Systems Ecology and Resource Management (SERM), Brussels, Belgium
| |
Collapse
|
9
|
Deboelpaep E, Keleman PJ, Vanschoenwinkel B, Koedam N. Gallant geese, fearful flocks? Flock size and heterospecifics alter the escape behaviour of an invasive goose. BELG J ZOOL 2018. [DOI: 10.26496/bjz.2018.23] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
While escape responses are shown to differ in areas with varying levels of human disturbance, it is not known to what extent these reactions depend on the composition of local species assemblages. We investigated variation in three flight response metrics for the invasive Canada Goose (Branta canadensis) in Belgium in three locations with different human accessibility. Results indicate that heterospecific birds and flock size affected flight initiation distances of the Canada Goose, but that these effects are location-specific. Escape responses were most pronounced in the nature reserve with the lowest human accessibility, and highly reduced in the recreational park. This study illustrates that, when buffer zones are being developed, generalising escape behaviour of birds may lead to potentially dangerous overestimations of their tolerance to human disturbance.
Collapse
|
10
|
Ruwaimana M, Satyanarayana B, Otero V, M. Muslim A, Syafiq A. M, Ibrahim S, Raymaekers D, Koedam N, Dahdouh-Guebas F. The advantages of using drones over space-borne imagery in the mapping of mangrove forests. PLoS One 2018; 13:e0200288. [PMID: 30020959 PMCID: PMC6051606 DOI: 10.1371/journal.pone.0200288] [Citation(s) in RCA: 60] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2017] [Accepted: 06/22/2018] [Indexed: 11/19/2022] Open
Abstract
Satellite data and aerial photos have proved to be useful in efficient conservation and management of mangrove ecosystems. However, there have been only very few attempts to demonstrate the ability of drone images, and none so far to observe vegetation (species-level) mapping. The present study compares the utility of drone images (DJI-Phantom-2 with SJ4000 RGB and IR cameras, spatial resolution: 5cm) and satellite images (Pleiades-1B, spatial resolution: 50cm) for mangrove mapping-specifically in terms of image quality, efficiency and classification accuracy, at the Setiu Wetland in Malaysia. Both object- and pixel-based classification approaches were tested (QGIS v.2.12.3 with Orfeo Toolbox). The object-based classification (using a manual rule-set algorithm) of drone imagery with dominant land-cover features (i.e. water, land, Avicennia alba, Nypa fruticans, Rhizophora apiculata and Casuarina equisetifolia) provided the highest accuracy (overall accuracy (OA): 94.0±0.5% and specific producer accuracy (SPA): 97.0±9.3%) as compared to the Pleiades imagery (OA: 72.2±2.7% and SPA: 51.9±22.7%). In addition, the pixel-based classification (using a maximum likelihood algorithm) of drone imagery provided better accuracy (OA: 90.0±1.9% and SPA: 87.2±5.1%) compared to the Pleiades (OA: 82.8±3.5% and SPA: 80.4±14.3%). Nevertheless, the drone provided higher temporal resolution images, even on cloudy days, an exceptional benefit when working in a humid tropical climate. In terms of the user-costs, drone costs are much higher, but this becomes advantageous over satellite data for long-term monitoring of a small area. Due to the large data size of the drone imagery, its processing time was about ten times greater than that of the satellite image, and varied according to the various image processing techniques employed (in pixel-based classification, drone >50 hours, Pleiades <5 hours), constituting the main disadvantage of UAV remote sensing. However, the mangrove mapping based on the drone aerial photos provided unprecedented results for Setiu, and was proven to be a viable alternative to satellite-based monitoring/management of these ecosystems. The improvements of drone technology will help to make drone use even more competitive in the future.
Collapse
Affiliation(s)
- Monika Ruwaimana
- Systems Ecology and Resource Management, Université libre de Bruxelles (ULB), Brussels, Belgium
- Ecology and Biodiversity (APNA), Vrije Universiteit Brussel (VUB), Brussels, Belgium
- Department of Biology, Universitas Atma Jaya Yogyakarta, Yogyakarta, Indonesia
| | - Behara Satyanarayana
- Systems Ecology and Resource Management, Université libre de Bruxelles (ULB), Brussels, Belgium
- Mangrove Research Unit (MARU), Institute of Oceanography and Environment, Universiti Malaysia Terengganu (UMT), Kuala Terengganu, Malaysia
| | - Viviana Otero
- Systems Ecology and Resource Management, Université libre de Bruxelles (ULB), Brussels, Belgium
| | - Aidy M. Muslim
- Mangrove Research Unit (MARU), Institute of Oceanography and Environment, Universiti Malaysia Terengganu (UMT), Kuala Terengganu, Malaysia
| | - Muhammad Syafiq A.
- Mangrove Research Unit (MARU), Institute of Oceanography and Environment, Universiti Malaysia Terengganu (UMT), Kuala Terengganu, Malaysia
| | - Sulong Ibrahim
- Mangrove Research Unit (MARU), Institute of Oceanography and Environment, Universiti Malaysia Terengganu (UMT), Kuala Terengganu, Malaysia
| | - Dries Raymaekers
- Vlaamse Instelling voor Technologisch Onderzoek (VITO), Mol, Belgium
| | - Nico Koedam
- Ecology and Biodiversity (APNA), Vrije Universiteit Brussel (VUB), Brussels, Belgium
| | - Farid Dahdouh-Guebas
- Systems Ecology and Resource Management, Université libre de Bruxelles (ULB), Brussels, Belgium
- Ecology and Biodiversity (APNA), Vrije Universiteit Brussel (VUB), Brussels, Belgium
| |
Collapse
|
11
|
Gillerot L, Vlaminck E, De Ryck DJR, Mwasaru DM, Beeckman H, Koedam N. Inter- and intraspecific variation in mangrove carbon fraction and wood specific gravity in Gazi Bay, Kenya. Ecosphere 2018. [DOI: 10.1002/ecs2.2306] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022] Open
Affiliation(s)
- Loïc Gillerot
- Ecology and Biodiversity, Plant Biology and Nature Management; Vrije Universiteit Brussel; Pleinlaan 2 B-1050 Brussels Belgium
| | - Ellen Vlaminck
- Ecology and Biodiversity, Plant Biology and Nature Management; Vrije Universiteit Brussel; Pleinlaan 2 B-1050 Brussels Belgium
| | - Dennis J. R. De Ryck
- Ecology and Biodiversity, Plant Biology and Nature Management; Vrije Universiteit Brussel; Pleinlaan 2 B-1050 Brussels Belgium
| | | | - Hans Beeckman
- Laboratory of Wood Biology and Xylarium; Royal Museum for Central Africa (RMCA); Leuvensesteenweg 13 B-3080 Tervuren Belgium
| | - Nico Koedam
- Ecology and Biodiversity, Plant Biology and Nature Management; Vrije Universiteit Brussel; Pleinlaan 2 B-1050 Brussels Belgium
| |
Collapse
|
12
|
Van der Stocken T, Vanschoenwinkel B, De Ryck D, Koedam N. Caught in transit: offshore interception of seafaring propagules from seven mangrove species. Ecosphere 2018. [DOI: 10.1002/ecs2.2208] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Affiliation(s)
- Tom Van der Stocken
- Department of Biology Vrije Universiteit Brussel Pleinlaan 2 B‐1050 Brussels Belgium
| | - Bram Vanschoenwinkel
- Department of Biology Vrije Universiteit Brussel Pleinlaan 2 B‐1050 Brussels Belgium
| | - Dennis De Ryck
- Department of Biology Vrije Universiteit Brussel Pleinlaan 2 B‐1050 Brussels Belgium
| | - Nico Koedam
- Department of Biology Vrije Universiteit Brussel Pleinlaan 2 B‐1050 Brussels Belgium
| |
Collapse
|
13
|
Kodikara KAS, Mukherjee N, Jayatissa LP, Dahdouh-Guebas F, Koedam N. Have mangrove restoration projects worked? An in-depth study in Sri Lanka. Restor Ecol 2017. [DOI: 10.1111/rec.12492] [Citation(s) in RCA: 103] [Impact Index Per Article: 14.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Affiliation(s)
- Kodikara Arachchilage Sunanda Kodikara
- Department of Botany; University of Ruhuna; Wellamadama Matara 81000 Sri Lanka
- Laboratory of Plant Biology and Nature Management, Ecology and Biodiversity; Vrije Universiteit Brussel - VUB; Pleinlaan 2 B-1050 Brussels Belgium
| | - Nibedita Mukherjee
- Conservation Science Group, Department of Zoology; University of Cambridge; Cambridge CB23EJ U.K
- Laboratory of Systems Ecology and Resource Management, Department of Organism Biology, Faculty of Sciences; Université Libre de Bruxelles - ULB; Av. F.D. Roosevelt 50, CPI 264/1 B-1050 Brussels Belgium
| | | | - Farid Dahdouh-Guebas
- Laboratory of Plant Biology and Nature Management, Ecology and Biodiversity; Vrije Universiteit Brussel - VUB; Pleinlaan 2 B-1050 Brussels Belgium
- Laboratory of Systems Ecology and Resource Management, Department of Organism Biology, Faculty of Sciences; Université Libre de Bruxelles - ULB; Av. F.D. Roosevelt 50, CPI 264/1 B-1050 Brussels Belgium
| | - Nico Koedam
- Laboratory of Plant Biology and Nature Management, Ecology and Biodiversity; Vrije Universiteit Brussel - VUB; Pleinlaan 2 B-1050 Brussels Belgium
| |
Collapse
|
14
|
Hugé J, Vande Velde K, Benitez-Capistros F, Japay JH, Satyanarayana B, Nazrin Ishak M, Quispe-Zuniga M, Mohd Lokman BH, Sulong I, Koedam N, Dahdouh-Guebas F. Mapping discourses using Q methodology in Matang Mangrove Forest, Malaysia. J Environ Manage 2016; 183:988-997. [PMID: 27692515 DOI: 10.1016/j.jenvman.2016.09.046] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/19/2015] [Revised: 08/16/2016] [Accepted: 09/15/2016] [Indexed: 06/06/2023]
Abstract
The sustainable management of natural resources requires the consideration of multiple stakeholders' perspectives and knowledge claims, in order to inform complex and possibly contentious decision-making dilemmas. Hence, a better understanding of why people in particular contexts do manage natural resources in a particular way is needed. Focusing on mangroves, highly productive tropical intertidal forests, this study's first aim is to map the diversity of subjective viewpoints among a range of stakeholders on the management of Matang Mangrove Forest in peninsular Malaysia. Secondly, this study aims to feed the reflection on the possible consequences of the diversity of perspectives for the future management of mangroves in Malaysia and beyond. The use of the semi-quantitative Q methodology allowed us to identify three main discourses on mangrove management: i. the optimization discourse, stressing the need to improve the current overall satisfactory management regime; ii. the 'change for the better' discourse, which focuses on increasingly participatory management and on ecotourism; and iii. the conservative 'business as usual' discourse. The existence of common points of connection between the discourses and their respective supporters provides opportunities for modifications of mangrove management regimes. Acknowledging this diversity of viewpoints, reflecting how different stakeholders see and talk about mangrove management, highlights the need to develop pro-active and resilient natural resource management approaches.
Collapse
Affiliation(s)
- Jean Hugé
- Systems Ecology & Resource Management Unit, Université Libre de Bruxelles (ULB), Brussels, Belgium.
| | - Katherine Vande Velde
- Systems Ecology & Resource Management Unit, Université Libre de Bruxelles (ULB), Brussels, Belgium
| | - Francisco Benitez-Capistros
- Systems Ecology & Resource Management Unit, Université Libre de Bruxelles (ULB), Brussels, Belgium; Laboratory of Plant Biology and Nature Management, Vrije Universiteit Brussel - VUB, Brussels, Belgium
| | - Jan Harold Japay
- Systems Ecology & Resource Management Unit, Université Libre de Bruxelles (ULB), Brussels, Belgium
| | - Behara Satyanarayana
- Mangrove Research Unit (MARU), Institute of Oceanography and Environment (INOS), Universiti Malaysia Terengganu - UMT, Kuala Terengganu, Malaysia
| | - Mohammad Nazrin Ishak
- Mangrove Research Unit (MARU), Institute of Oceanography and Environment (INOS), Universiti Malaysia Terengganu - UMT, Kuala Terengganu, Malaysia
| | - Melissa Quispe-Zuniga
- Systems Ecology & Resource Management Unit, Université Libre de Bruxelles (ULB), Brussels, Belgium; Zentrum für Entwicklungsforschung (ZEF), University of Bonn, Germany
| | - Bin Husain Mohd Lokman
- Mangrove Research Unit (MARU), Institute of Oceanography and Environment (INOS), Universiti Malaysia Terengganu - UMT, Kuala Terengganu, Malaysia
| | - Ibrahim Sulong
- Mangrove Research Unit (MARU), Institute of Oceanography and Environment (INOS), Universiti Malaysia Terengganu - UMT, Kuala Terengganu, Malaysia
| | - Nico Koedam
- Laboratory of Plant Biology and Nature Management, Vrije Universiteit Brussel - VUB, Brussels, Belgium
| | - Farid Dahdouh-Guebas
- Systems Ecology & Resource Management Unit, Université Libre de Bruxelles (ULB), Brussels, Belgium; Laboratory of Plant Biology and Nature Management, Vrije Universiteit Brussel - VUB, Brussels, Belgium
| |
Collapse
|
15
|
Benitez-Capistros F, Hugé J, Dahdouh-Guebas F, Koedam N. Exploring conservation discourses in the Galapagos Islands: A case study of the Galapagos giant tortoises. Ambio 2016; 45:706-24. [PMID: 27010556 PMCID: PMC5012995 DOI: 10.1007/s13280-016-0774-9] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/24/2015] [Revised: 12/13/2015] [Accepted: 03/08/2016] [Indexed: 05/24/2023]
Abstract
Conservation discourses change rapidly both at global and local scales. To be able to capture these shifts and the relationships between humans and nature, we focused on a local and iconic conservation case: the Galapagos giant tortoises (Chelonoidis spp.). We used the Q methodology to contextualize conservation for science and decision making and to explore the multidimensionality of the conservation concept in Galapagos. The results indicate four prevailing discourses: (1) Multi-actor governance; (2) giant tortoise and ecosystems conservation; (3) community governance; and (4) market and tourism centred. These findings allow us to identify foreseeable points of disagreement, as well as areas of consensus, and to discuss the implication of the findings to address socio-ecological conservation and sustainability challenges. This can help the different involved stakeholders (managers, scientists and local communities) to the design and apply contextualized conservation actions and policies to contribute to a better sustainable management of the archipelago.
Collapse
Affiliation(s)
- Francisco Benitez-Capistros
- Laboratory of Plant Biology and Nature Management (APNA), Faculty of Sciences and Bio-engineering Sciences, Vrije Universiteit Brussel, Pleinlaan 2, 1050 Brussels, Belgium
- Laboratory of Systems Ecology and Resource Management, Department of Organism Biology, Faculty of Sciences, Université Libre de Bruxelles, Av. F.D. Roosevelt 50, 1050 Brussels, Belgium
| | - Jean Hugé
- Laboratory of Systems Ecology and Resource Management, Department of Organism Biology, Faculty of Sciences, Université Libre de Bruxelles, Av. F.D. Roosevelt 50, 1050 Brussels, Belgium
| | - Farid Dahdouh-Guebas
- Laboratory of Plant Biology and Nature Management (APNA), Faculty of Sciences and Bio-engineering Sciences, Vrije Universiteit Brussel, Pleinlaan 2, 1050 Brussels, Belgium
- Laboratory of Systems Ecology and Resource Management, Department of Organism Biology, Faculty of Sciences, Université Libre de Bruxelles, Av. F.D. Roosevelt 50, 1050 Brussels, Belgium
| | - Nico Koedam
- Laboratory of Plant Biology and Nature Management (APNA), Faculty of Sciences and Bio-engineering Sciences, Vrije Universiteit Brussel, Pleinlaan 2, 1050 Brussels, Belgium
| |
Collapse
|
16
|
Affiliation(s)
- Sandrine Godefroid
- Botanic Garden Meise; Nieuwelaan 38 1860 Meise Belgium
- Fédération Wallonie-Bruxelles; rue A. Lavallée 1 1080 Brussels Belgium
- Laboratory of Plant Biology and Nature Management (APNA); Vrije Universiteit Brussel; Pleinlaan 2 1050 Brussels Belgium
- Laboratory of Plant Ecology and Biogeochemistry; Université libre de Bruxelles; CP 244, Boulevard du Triomphe 1050 Brussels Belgium
| | - Ugo Sansen
- Laboratory of Plant Biology and Nature Management (APNA); Vrije Universiteit Brussel; Pleinlaan 2 1050 Brussels Belgium
| | - Nico Koedam
- Laboratory of Plant Biology and Nature Management (APNA); Vrije Universiteit Brussel; Pleinlaan 2 1050 Brussels Belgium
| |
Collapse
|
17
|
Lechthaler S, Robert EMR, Tonné N, Prusova A, Gerkema E, Van As H, Koedam N, Windt CW. Rhizophoraceae Mangrove Saplings Use Hypocotyl and Leaf Water Storage Capacity to Cope with Soil Water Salinity Changes. Front Plant Sci 2016; 7:895. [PMID: 27446125 PMCID: PMC4921503 DOI: 10.3389/fpls.2016.00895] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/16/2016] [Accepted: 06/07/2016] [Indexed: 05/08/2023]
Abstract
Some of the most striking features of Rhizophoraceae mangrove saplings are their voluminous cylinder-shaped hypocotyls and thickened leaves. The hypocotyls are known to serve as floats during seed dispersal (hydrochory) and store nutrients that allow the seedling to root and settle. In this study we investigate to what degree the hypocotyls and leaves can serve as water reservoirs once seedlings have settled, helping the plant to buffer the rapid water potential changes that are typical for the mangrove environment. We exposed saplings of two Rhizophoraceae species to three levels of salinity (15, 30, and 0-5‰, in that sequence) while non-invasively monitoring changes in hypocotyl and leaf water content by means of mobile NMR sensors. As a proxy for water content, changes in hypocotyl diameter and leaf thickness were monitored by means of dendrometers. Hypocotyl diameter variations were also monitored in the field on a Rhizophora species. The saplings were able to buffer rapid rhizosphere salinity changes using water stored in hypocotyls and leaves, but the largest water storage capacity was found in the leaves. We conclude that in Rhizophora and Bruguiera the hypocotyl offers the bulk of water buffering capacity during the dispersal phase and directly after settlement when only few leaves are present. As saplings develop more leaves, the significance of the leaves as a water storage organ becomes larger than that of the hypocotyl.
Collapse
Affiliation(s)
- Silvia Lechthaler
- Department of Territorio e Sistemi Agro-Forestali, University of Padova, PadovaItaly
- Laboratory of Plant Biology and Nature Management, Department of Biology, Vrije Universiteit Brussel, BrusselsBelgium
| | - Elisabeth M. R. Robert
- Laboratory of Plant Biology and Nature Management, Department of Biology, Vrije Universiteit Brussel, BrusselsBelgium
- Laboratory of Wood Biology and Xylarium, Department of Wood Biology, Royal Museum for Central AfricaTervuren, Belgium
| | - Nathalie Tonné
- Laboratory of Plant Biology and Nature Management, Department of Biology, Vrije Universiteit Brussel, BrusselsBelgium
- Laboratory of Wood Biology and Xylarium, Department of Wood Biology, Royal Museum for Central AfricaTervuren, Belgium
| | - Alena Prusova
- Laboratory of Biophysics and Wageningen NMR Centre, Department of Agrotechnology & Food Sciences, Wageningen University, WageningenNetherlands
| | - Edo Gerkema
- Laboratory of Biophysics and Wageningen NMR Centre, Department of Agrotechnology & Food Sciences, Wageningen University, WageningenNetherlands
| | - Henk Van As
- Laboratory of Biophysics and Wageningen NMR Centre, Department of Agrotechnology & Food Sciences, Wageningen University, WageningenNetherlands
| | - Nico Koedam
- Laboratory of Plant Biology and Nature Management, Department of Biology, Vrije Universiteit Brussel, BrusselsBelgium
| | - Carel W. Windt
- IBG-2: Plant Sciences, Institute for Bio- and Geosciences, Forschungszentrum Jülich, JülichGermany
| |
Collapse
|
18
|
Jenoh EM, Robert EMR, Lehmann I, Kioko E, Bosire JO, Ngisiange N, Dahdouh-Guebas F, Koedam N. Wide Ranging Insect Infestation of the Pioneer Mangrove Sonneratia alba by Two Insect Species along the Kenyan Coast. PLoS One 2016; 11:e0154849. [PMID: 27171470 PMCID: PMC4865246 DOI: 10.1371/journal.pone.0154849] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2015] [Accepted: 04/20/2016] [Indexed: 11/18/2022] Open
Abstract
Insect infestation of mangroves currently threatens mangrove forest health and management. In the Western Indian Ocean region, little is known about insect damage to mangroves despite the fact that numerous infestations have occurred. In Kenya, infestations of Sonneratia alba have persisted for almost two decades, yet the taxonomic identity of the infesting pest(s), the extent of infestation, the pests’ biology, the impacts of infestation on host and the ecosystem, the host’s defensive strategies to the infestation are poorly understood. S. alba is a ubiquitous, pioneer mangrove species of the Indo-Pacific, occurring along the waterfront in a variety of mangrove ecosystem settings. Our main objectives were to identify the pest(s) responsible for the current dieback of S. alba in Kenya, and to determine the extent of infestation. To identify the pests responsible for infestation, we trapped emergent insects and reared larvae in the laboratory. To determine the overall extent of infestation within the S. alba zone, we assessed nine sites along the entire Kenyan coastline for the presence or absence of infested mangroves. Insect infestation in two mangrove embayments (Gazi and Mida) was quantified in depth. Two wood-boring insects were identified: a metarbelid moth (Lepidoptera, Cossoidea) of undescribed genus and the beetle Bottegia rubra (Cerambycidae, Lamiinae).The metarbelid moth infests mangroves in both northern (from Ngomeni to Kiunga) and southern regions (from Vanga to Mtwapa) of the Kenyan coast. B. rubra appeared in low density in Gazi, and in high density in Mida, Kilifi, and Ngomeni, with densities gradually decreasing northward. Insect infestation levels reached 18% in Gazi and 25% of S. alba stands in Mida. Our results indicate that B. rubra has the ability to infest young mangrove trees and expand its range, posing a danger to rehabilitation efforts where plantations have been established. Thus, there is great need for forest managers to address the recent increased levels of infestation in Kenyan mangroves; apart from the ecological interest such plant-herbivore relations bring in this ecosystem.
Collapse
Affiliation(s)
- Elisha Mrabu Jenoh
- Kenya Marine and Fisheries Research Institute (KMFRI), P.O. Box 81651, Mombasa, Kenya
- Laboratory of Plant Biology and Nature Management (APNA), Vrije Universiteit Brussel, Pleinlaan 2, B-1050, Brussels, Belgium
- Laboratory of Systems Ecology and Resource Management, Département de Biologie des Organismes, Université Libre de Bruxelles (ULB), CP 169, Avenue Franklin D. Roosevelt 50, CPI 264/1, B-1050, Brussels, Belgium
- * E-mail:
| | - Elisabeth M. R. Robert
- Laboratory of Plant Biology and Nature Management (APNA), Vrije Universiteit Brussel, Pleinlaan 2, B-1050, Brussels, Belgium
- Laboratory for Wood Biology and Xylarium, Royal Museum for Central Africa (RMCA), Leuvensesteenweg 13, 3080, Tervuren, Belgium
| | - Ingo Lehmann
- University of Bonn, Zoological Research Museum, Alexander Koenig (ZFMK) Adenauerallee 160, 53113, Bonn, Germany
| | - Esther Kioko
- National Museums of Kenya (NMK), P.O. Box 40658–00100, Nairobi, Kenya
| | - Jared O. Bosire
- Kenya Marine and Fisheries Research Institute (KMFRI), P.O. Box 81651, Mombasa, Kenya
| | - Noah Ngisiange
- Kenya Marine and Fisheries Research Institute (KMFRI), P.O. Box 81651, Mombasa, Kenya
| | - Farid Dahdouh-Guebas
- Laboratory of Plant Biology and Nature Management (APNA), Vrije Universiteit Brussel, Pleinlaan 2, B-1050, Brussels, Belgium
- Laboratory of Systems Ecology and Resource Management, Département de Biologie des Organismes, Université Libre de Bruxelles (ULB), CP 169, Avenue Franklin D. Roosevelt 50, CPI 264/1, B-1050, Brussels, Belgium
| | - Nico Koedam
- Laboratory of Plant Biology and Nature Management (APNA), Vrije Universiteit Brussel, Pleinlaan 2, B-1050, Brussels, Belgium
| |
Collapse
|
19
|
Ngeve MN, Van der Stocken T, Menemenlis D, Koedam N, Triest L. Contrasting Effects of Historical Sea Level Rise and Contemporary Ocean Currents on Regional Gene Flow of Rhizophora racemosa in Eastern Atlantic Mangroves. PLoS One 2016; 11:e0150950. [PMID: 26964094 PMCID: PMC4786296 DOI: 10.1371/journal.pone.0150950] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2015] [Accepted: 02/22/2016] [Indexed: 11/18/2022] Open
Abstract
Mangroves are seafaring taxa through their hydrochorous propagules that have the potential to disperse over long distances. Therefore, investigating their patterns of gene flow provides insights on the processes involved in the spatial genetic structuring of populations. The coastline of Cameroon has a particular geomorphological history and coastal hydrology with complex contemporary patterns of ocean currents, which we hypothesize to have effects on the spatial configuration and composition of present-day mangroves within its spans. A total of 982 trees were sampled from 33 transects (11 sites) in 4 estuaries. Using 11 polymorphic SSR markers, we investigated genetic diversity and structure of Rhizophora racemosa, a widespread species in the region. Genetic diversity was low to moderate and genetic differentiation between nearly all population pairs was significant. Bayesian clustering analysis, PCoA, estimates of contemporary migration rates and identification of barriers to gene flow were used and complemented with estimated dispersal trajectories of hourly released virtual propagules, using high-resolution surface current from a mesoscale and tide-resolving ocean simulation. These indicate that the Cameroon Volcanic Line (CVL) is not a present-day barrier to gene flow. Rather, the Inter-Bioko-Cameroon (IBC) corridor, formed due to sea level rise, allows for connectivity between two mangrove areas that were isolated during glacial times by the CVL. Genetic data and numerical ocean simulations indicated that an oceanic convergence zone near the Cameroon Estuary complex (CEC) presents a strong barrier to gene flow, resulting in genetic discontinuities between the mangrove areas on either side. This convergence did not result in higher genetic diversity at the CEC as we had hypothesized. In conclusion, the genetic structure of Rhizophora racemosa is maintained by the contrasting effects of the contemporary oceanic convergence and historical climate change-induced sea level rise.
Collapse
Affiliation(s)
- Magdalene N. Ngeve
- Laboratory of Plant Biology and Nature Management (APNA), Department of Biology, Vrije Universiteit Brussel (VUB), Pleinlaan 2, B-1050, Brussels, Belgium
- * E-mail: ;
| | - Tom Van der Stocken
- Laboratory of Plant Biology and Nature Management (APNA), Department of Biology, Vrije Universiteit Brussel (VUB), Pleinlaan 2, B-1050, Brussels, Belgium
| | - Dimitris Menemenlis
- Earth Sciences Division, Jet Propulsion Laboratory, California Institute of Technology, Pasadena, California, United States of America
| | - Nico Koedam
- Laboratory of Plant Biology and Nature Management (APNA), Department of Biology, Vrije Universiteit Brussel (VUB), Pleinlaan 2, B-1050, Brussels, Belgium
| | - Ludwig Triest
- Laboratory of Plant Biology and Nature Management (APNA), Department of Biology, Vrije Universiteit Brussel (VUB), Pleinlaan 2, B-1050, Brussels, Belgium
| |
Collapse
|
20
|
Hubin E, Vanschoenwinkel B, Broersen K, De Deyn PP, Koedam N, van Nuland NA, Pauwels K. Could ecosystem management provide a new framework for Alzheimer's disease? Alzheimers Dement 2015; 12:65-74.e1. [PMID: 26341147 DOI: 10.1016/j.jalz.2015.07.491] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2015] [Revised: 03/20/2015] [Accepted: 07/01/2015] [Indexed: 10/23/2022]
Abstract
Alzheimer's disease (AD) is a progressive neurodegenerative brain disorder that involves a plethora of molecular pathways. In the context of therapeutic treatment and biomarker profiling, the amyloid-beta (Aβ) peptide constitutes an interesting research avenue that involves interactions within a complex mixture of Aβ alloforms and other disease-modifying factors. Here, we explore the potential of an ecosystem paradigm as a novel way to consider AD and Aβ dynamics in particular. We discuss the example that the complexity of the Aβ network not only exhibits interesting parallels with the functioning of complex systems such as ecosystems but that this analogy can also provide novel insights into the neurobiological phenomena in AD and serve as a communication tool. We propose that combining network medicine with general ecosystem management principles could be a new and holistic approach to understand AD pathology and design novel therapies.
Collapse
Affiliation(s)
- Ellen Hubin
- Nanobiophysics Group, MIRA Institute for Biomedical Technology and Technical Medicine, Faculty of Science and Technology, University of Twente, Enschede, The Netherlands; Structural Biology Brussels, Department of Biotechnology (DBIT), Vrije Universiteit Brussel (VUB), Brussels, Belgium; Structural Biology Research Center, VIB, Brussels, Belgium
| | - Bram Vanschoenwinkel
- Plant Biology and Nature Management (APNA), Department of Biology (DBIO), Vrije Universiteit Brussel (VUB), Brussels, Belgium
| | - Kerensa Broersen
- Nanobiophysics Group, MIRA Institute for Biomedical Technology and Technical Medicine, Faculty of Science and Technology, University of Twente, Enschede, The Netherlands
| | - Peter P De Deyn
- Department of Physiotherapy (REVAKI), Faculty of Medicine and Health Sciences, University of Antwerp, Antwerp, Belgium; Department of Neurology and Memory Clinic, Middelheim General Hospital (Ziekenhuis Netwerk Antwerpen), University of Antwerp, Antwerp, Belgium; Laboratory of Neurochemistry and Behaviour, Institute Born-Bunge, University of Antwerp, Antwerp, Belgium; Department of Neurology and Alzheimer Research Center, University of Groningen, University Medical Center Groningen (UMCG), Groningen, The Netherlands
| | - Nico Koedam
- Plant Biology and Nature Management (APNA), Department of Biology (DBIO), Vrije Universiteit Brussel (VUB), Brussels, Belgium
| | - Nico A van Nuland
- Structural Biology Brussels, Department of Biotechnology (DBIT), Vrije Universiteit Brussel (VUB), Brussels, Belgium; Structural Biology Research Center, VIB, Brussels, Belgium
| | - Kris Pauwels
- Structural Biology Brussels, Department of Biotechnology (DBIT), Vrije Universiteit Brussel (VUB), Brussels, Belgium; Structural Biology Research Center, VIB, Brussels, Belgium.
| |
Collapse
|
21
|
Merken R, Deboelpaep E, Teunen J, Saura S, Koedam N. Wetland suitability and connectivity for trans-Saharan migratory waterbirds. PLoS One 2015; 10:e0135445. [PMID: 26258590 PMCID: PMC4530951 DOI: 10.1371/journal.pone.0135445] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2014] [Accepted: 07/22/2015] [Indexed: 11/28/2022] Open
Abstract
To complete their life cycle waterbirds rely on patchily distributed and often ephemeral wetlands along their migration route in a vast unsuitable matrix. However, further loss and degradation of remaining wetland habitats might lead to a configuration and size of stopovers that is no longer sufficient to ensure long-term survival of waterbird populations. By identifying optimal conservation targets to maintain overall habitat availability en route, we can accommodate an as yet absent functional connectivity component in larger management frameworks for migratory waterbirds, such as the Ramsar Convention and the EU Natura 2000 Network. Using a graph-based habitat availability metric (Equivalent Connected Area) we determine the functional connectivity of wetland networks for seven migratory waterbirds with divergent habitat requirements. Analyses are performed at two spatial extents both spanning the Mediterranean Sea and centered around Greece (Balkan-Cyrenaica and Greece-Cyrenaica). We create species-specific suitable habitat maps and account for human disturbance by species-specific disturbance buffers, based on expert estimates of Flight Initiation Distances. At both spatial extents we quantitatively determine the habitat networks’ overall functional connectivity and identify wetland sites that are crucial for maintaining a well-connected network. We show that the wetland networks for both spatial extents are relatively well connected and identify several wetland sites in Greece and Libya as important for maintaining connectivity. The application of disturbance buffers results in wetland site-specific reduction of suitable habitat area (0.90–7.36%) and an overall decrease of the network’s connectivity (0.65–6.82%). In addition, we show that the habitat networks of a limited set of species can be combined into a single network which accounts for their autoecological requirements. We conclude that targeted management in few but specific wetland complexes could benefit migratory waterbird populations. Deterioration of these vital wetland sites in Greece and Libya will have disproportionate consequences to the waterbird populations they support.
Collapse
Affiliation(s)
- Ronny Merken
- Laboratory of Plant Science and Nature Management, Vrije Universiteit Brussel, Brussels, Belgium
| | - Evelien Deboelpaep
- Laboratory of Plant Science and Nature Management, Vrije Universiteit Brussel, Brussels, Belgium
- * E-mail:
| | - Joachim Teunen
- Laboratory of Plant Science and Nature Management, Vrije Universiteit Brussel, Brussels, Belgium
| | - Santiago Saura
- Department of Natural Systems and Resources, Polytechnic University of Madrid, Ciudad Universitaria s/n, Madrid, Spain
| | - Nico Koedam
- Laboratory of Plant Science and Nature Management, Vrije Universiteit Brussel, Brussels, Belgium
| |
Collapse
|
22
|
Mukherjee N, Hugé J, Sutherland WJ, McNeill J, Van Opstal M, Dahdouh‐Guebas F, Koedam N. The Delphi technique in ecology and biological conservation: applications and guidelines. Methods Ecol Evol 2015. [DOI: 10.1111/2041-210x.12387] [Citation(s) in RCA: 155] [Impact Index Per Article: 17.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Affiliation(s)
- Nibedita Mukherjee
- Conservation Science Group Department of Zoology University of Cambridge Cambridge CB2 3EJ UK
- Plant Biology & Nature Management Vrije Universiteit Brussel Pleinlaan 2 1050 Brussels Belgium
- Laboratory of Systems Ecology and Resource Management Université Libre de Bruxelles CP 264/1, Avenue F.D. Roosevelt 50 1050 Brussels Belgium
| | - Jean Hugé
- Laboratory of Systems Ecology and Resource Management Université Libre de Bruxelles CP 264/1, Avenue F.D. Roosevelt 50 1050 Brussels Belgium
- Centre for Sustainable Development Ghent University Poel 16 9000 Gent Belgium
| | - William J. Sutherland
- Conservation Science Group Department of Zoology University of Cambridge Cambridge CB2 3EJ UK
| | - Jeffrey McNeill
- School of People, Environment and Planning Massey University Private Bag 11222 Palmerston North New Zealand
| | - Maarten Van Opstal
- Laboratory of Systems Ecology and Resource Management Université Libre de Bruxelles CP 264/1, Avenue F.D. Roosevelt 50 1050 Brussels Belgium
- Center of Cultural Anthropology Université Libre de Bruxelles CP 124, Avenue F.D Roosevelt 501050 Brussels Belgium
- Public Health Department Vrije Universiteit Brussel Laarbeeklaan 103 1090 Brussels Belgium
| | - Farid Dahdouh‐Guebas
- Plant Biology & Nature Management Vrije Universiteit Brussel Pleinlaan 2 1050 Brussels Belgium
- Laboratory of Systems Ecology and Resource Management Université Libre de Bruxelles CP 264/1, Avenue F.D. Roosevelt 50 1050 Brussels Belgium
| | - Nico Koedam
- Plant Biology & Nature Management Vrije Universiteit Brussel Pleinlaan 2 1050 Brussels Belgium
| |
Collapse
|
23
|
Van der Stocken T, Vanschoenwinkel B, De Ryck DJR, Bouma TJ, Dahdouh-Guebas F, Koedam N. Interaction between water and wind as a driver of passive dispersal in mangroves. PLoS One 2015; 10:e0121593. [PMID: 25811191 PMCID: PMC4374773 DOI: 10.1371/journal.pone.0121593] [Citation(s) in RCA: 38] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2014] [Accepted: 02/11/2015] [Indexed: 11/19/2022] Open
Abstract
Although knowledge on dispersal patterns is essential for predicting long-term population dynamics, critical information on the modalities of passive dispersal and potential interactions between vectors is often missing. Here, we use mangrove propagules with a wide variety of morphologies to investigate the interaction between water and wind as a driver of passive dispersal. We imposed 16 combinations of wind and hydrodynamic conditions in a flume tank, using propagules of six important mangrove species (and genera), resulting in a set of dispersal morphologies that covers most variation present in mangrove propagules worldwide. Additionally, we discussed the broader implications of the outcome of this flume study on the potential of long distance dispersal for mangrove propagules in nature, applying a conceptual model to a natural mangrove system in Gazi Bay (Kenya). Overall, the effect of wind on dispersal depended on propagule density (g l-1). The low-density Heritiera littoralis propagules were most affected by wind, while the high-density vertically floating propagules of Ceriops tagal and Bruguiera gymnorrhiza were least affected. Avicennia marina, and horizontally floating Rhizophora mucronata and C. tagal propagules behaved similarly. Morphological propagule traits, such as the dorsal sail of H. littoralis, explained another part of the interspecific differences. Within species, differences in dispersal velocities can be explained by differences in density and for H. littoralis also by variations in the shape of the dorsal sail. Our conceptual model illustrates that different propagule types have a different likelihood of reaching the open ocean depending on prevailing water and wind currents. Results suggest that in open water, propagule traits (density, morphology, and floating orientation) appear to determine the effect of water and wind currents on dispersal dynamics. This has important implications for inter- and intraspecific variation in dispersal patterns and the likelihood of reaching suitable habitat patches within a propagule's viable period.
Collapse
Affiliation(s)
- Tom Van der Stocken
- Laboratory of Plant Biology and Nature Management, Vrije Universiteit Brussel (VUB), Brussels, Belgium
- Laboratory of Systems Ecology and Resource Management, Université Libre de Bruxelles (ULB), Brussels, Belgium
- * E-mail:
| | - Bram Vanschoenwinkel
- Laboratory of Plant Biology and Nature Management, Vrije Universiteit Brussel (VUB), Brussels, Belgium
| | - Dennis J. R. De Ryck
- Laboratory of Plant Biology and Nature Management, Vrije Universiteit Brussel (VUB), Brussels, Belgium
- Laboratory of Systems Ecology and Resource Management, Université Libre de Bruxelles (ULB), Brussels, Belgium
| | - Tjeerd J. Bouma
- Department of Spatial Ecology, Royal Netherlands Institute for Sea Research (NIOZ), Yerseke, the Netherlands
| | - Farid Dahdouh-Guebas
- Laboratory of Plant Biology and Nature Management, Vrije Universiteit Brussel (VUB), Brussels, Belgium
- Laboratory of Systems Ecology and Resource Management, Université Libre de Bruxelles (ULB), Brussels, Belgium
| | - Nico Koedam
- Laboratory of Plant Biology and Nature Management, Vrije Universiteit Brussel (VUB), Brussels, Belgium
| |
Collapse
|
24
|
Mukherjee N, Dahdouh-Guebas F, Koedam N, Shanker K. An interdisciplinary framework to evaluate bioshield plantations: Insights from peninsular India. Acta Oecologica 2015. [DOI: 10.1016/j.actao.2014.01.005] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
|
25
|
Van Nedervelde F, Cannicci S, Koedam N, Bosire J, Dahdouh-Guebas F. What regulates crab predation on mangrove propagules? Acta Oecologica 2015. [DOI: 10.1016/j.actao.2014.11.006] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
|
26
|
Mukherjee N, Sutherland WJ, Dicks L, Hugé J, Koedam N, Dahdouh-Guebas F. Ecosystem service valuations of mangrove ecosystems to inform decision making and future valuation exercises. PLoS One 2014; 9:e107706. [PMID: 25243852 PMCID: PMC4171500 DOI: 10.1371/journal.pone.0107706] [Citation(s) in RCA: 94] [Impact Index Per Article: 9.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2014] [Accepted: 08/21/2014] [Indexed: 11/18/2022] Open
Abstract
The valuation of ecosystem services is a complex process as it includes several dimensions (ecological, socio-cultural and economic) and not all of these can be quantified in monetary units. The aim of this paper is to conduct an ecosystem services valuation study for mangroves ecosystems, the results of which can be used to inform governance and management of mangroves. We used an expert-based participatory approach (the Delphi technique) to identify, categorize and rank the various ecosystem services provided by mangrove ecosystems at a global scale. Subsequently we looked for evidence in the existing ecosystem services literature for monetary valuations of these ecosystem service categories throughout the biogeographic distribution of mangroves. We then compared the relative ranking of ecosystem service categories between the monetary valuations and the expert based analysis. The experts identified 16 ecosystem service categories, six of which are not adequately represented in the literature. There was no significant correlation between the expert based valuation (the Delphi technique) and the economic valuation, indicating that the scope of valuation of ecosystem services needs to be broadened. Acknowledging this diversity in different valuation approaches, and developing methodological frameworks that foster the pluralism of values in ecosystem services research, are crucial for maintaining the credibility of ecosystem services valuation. To conclude, we use the findings of our dual approach to valuation to make recommendations on how to assess and manage the ecosystem services provided by mangrove ecosystems.
Collapse
Affiliation(s)
- Nibedita Mukherjee
- Laboratory of Systems Ecology and Resource Management, Université Libre de Bruxelles, Brussels, Belgium; Laboratory of Plant Biology and Nature Management, Vrije Universiteit Brussel, Brussels, Belgium
| | - William J Sutherland
- Conservation Science Group, Department of Zoology, University of Cambridge, Cambridge, England, United Kingdom
| | - Lynn Dicks
- Conservation Science Group, Department of Zoology, University of Cambridge, Cambridge, England, United Kingdom
| | - Jean Hugé
- Laboratory of Systems Ecology and Resource Management, Université Libre de Bruxelles, Brussels, Belgium; Centre for Sustainable Development, Ghent University, Gent, Belgium
| | - Nico Koedam
- Laboratory of Plant Biology and Nature Management, Vrije Universiteit Brussel, Brussels, Belgium
| | - Farid Dahdouh-Guebas
- Laboratory of Systems Ecology and Resource Management, Université Libre de Bruxelles, Brussels, Belgium; Laboratory of Plant Biology and Nature Management, Vrije Universiteit Brussel, Brussels, Belgium
| |
Collapse
|
27
|
Wang'ondu VW, Bosire JO, Kairo JG, Kinyamario JI, Mwaura FB, Dahdouh-Guebas F, Koedam N. Litter Fall Dynamics of Restored Mangroves (Rhizophora mucronataLamk. andSonneratia albaSm.) in Kenya. Restor Ecol 2014. [DOI: 10.1111/rec.12149] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Virginia W. Wang'ondu
- School of Biological Sciences; University of Nairobi; Nairobi Kenya
- Laboratory of Plant Biology and Nature Management Mangrove Management Group; Vrije Universiteit Brussels VUB; Pleinlaan 2 1050 Brussels Belgium
| | - Jared O. Bosire
- Kenya Marine and Fisheries Research Institute; Department of Mangrove Research; Mambasa Kenya
| | - James G. Kairo
- Kenya Marine and Fisheries Research Institute; Department of Mangrove Research; Mambasa Kenya
| | | | | | - Farid Dahdouh-Guebas
- Laboratory of Systems Ecology and Resource Management, Département de Biologie des Organismes, Faculté de Science; Université Libre de Bruxelles - ULB CP 169; Avenue F. D. Roosevelt 50 B-1050 Bruxelles Belgium
| | - Nico Koedam
- Laboratory of Plant Biology and Nature Management Mangrove Management Group; Vrije Universiteit Brussels VUB; Pleinlaan 2 1050 Brussels Belgium
| |
Collapse
|
28
|
Okello JA, Robert EMR, Beeckman H, Kairo JG, Dahdouh-Guebas F, Koedam N. Effects of experimental sedimentation on the phenological dynamics and leaf traits of replanted mangroves at Gazi bay, Kenya. Ecol Evol 2014; 4:3187-200. [PMID: 25473472 PMCID: PMC4222206 DOI: 10.1002/ece3.1154] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2013] [Revised: 05/12/2014] [Accepted: 06/03/2014] [Indexed: 11/07/2022] Open
Abstract
Sedimentation results in the creation of new mudflats for mangroves to colonize among other benefits. However, large sediment input in mangrove areas may be detrimental to these forests. The dynamics of phenological events of three mangrove tree species (Avicennia marina, Ceriops tagal, and Rhizophora mucronata) were evaluated under experimental sediment burial simulating sedimentation levels of 15, 30, and 45 cm.While there was generally no shift in timing of phenological events with sedimentation, the three mangrove tree species each responded differently to the treatments.Partially buried A. marina trees produced more leaves than the controls during the wet season and less during the dry season. Ceriops tagal on the other hand had higher leaf loss and low replacement rates in the partially buried trees during the first 6 months of the experiment but adapted with time, resulting in either equal or higher leaf emergence rates than the controls.Rhizophora mucronata maintained leaf emergence and loss patterns as the unaffected controls but had a higher fecundity and productivity in the 15-cm sedimentation level.The results suggest that under incidences of large sedimentation events (which could be witnessed as a result of climate change impacts coupled with anthropogenic disturbances), mangrove trees may capitalize on "advantages" associated with terrestrial sediment brought into the biotope, thus maintaining the pattern of phenological events.
Collapse
Affiliation(s)
- Judith A Okello
- Kenya Marine and Fisheries Research Institute (KMFRI) Mombasa, Kenya ; Laboratory of Plant Biology and Nature Management (APNA), Vrije Universiteit Brussel B-1050, Brussels, Belgium ; Laboratory of Wood Biology and Xylarium, Royal Museum for Central Africa (RMCA) B-3080, Tervuren, Belgium ; Laboratory of Systems Ecology and Resource Management, Université libre de Bruxelles B-1050, Brussels, Belgium
| | - Elisabeth M R Robert
- Laboratory of Plant Biology and Nature Management (APNA), Vrije Universiteit Brussel B-1050, Brussels, Belgium
| | - Hans Beeckman
- Laboratory of Wood Biology and Xylarium, Royal Museum for Central Africa (RMCA) B-3080, Tervuren, Belgium
| | - James G Kairo
- Kenya Marine and Fisheries Research Institute (KMFRI) Mombasa, Kenya
| | - Farid Dahdouh-Guebas
- Laboratory of Plant Biology and Nature Management (APNA), Vrije Universiteit Brussel B-1050, Brussels, Belgium ; Laboratory of Systems Ecology and Resource Management, Université libre de Bruxelles B-1050, Brussels, Belgium
| | - Nico Koedam
- Laboratory of Plant Biology and Nature Management (APNA), Vrije Universiteit Brussel B-1050, Brussels, Belgium
| |
Collapse
|
29
|
Mukherjee N, Sutherland WJ, Khan MNI, Berger U, Schmitz N, Dahdouh-Guebas F, Koedam N. Using expert knowledge and modeling to define mangrove composition, functioning, and threats and estimate time frame for recovery. Ecol Evol 2014; 4:2247-62. [PMID: 25360265 PMCID: PMC4201438 DOI: 10.1002/ece3.1085] [Citation(s) in RCA: 40] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2013] [Revised: 03/04/2014] [Accepted: 03/25/2014] [Indexed: 11/28/2022] Open
Abstract
Mangroves are threatened worldwide, and their loss or degradation could impact functioning of the ecosystem. Our aim was to investigate three aspects of mangroves at a global scale: (1) their constituents (2) their indispensable ecological functions, and (3) the maintenance of their constituents and functions in degraded mangroves. We focused on answering two questions: “What is a mangrove ecosystem” and “How vulnerable are mangrove ecosystems to different impacts”? We invited 106 mangrove experts globally to participate in a survey based on the Delphi technique and provide inputs on the three aspects. The outputs from the Delphi technique for the third aspect, i.e. maintenance of constituents and functions were incorporated in a modeling approach to simulate the time frame for recovery. Presented here for the first time are the consensus definition of the mangrove ecosystem and the list of mangrove plant species. In this study, experts considered even monospecific (tree) stands to be a mangrove ecosystem as long as there was adequate tidal exchange, propagule dispersal, and faunal interactions. We provide a ranking of the important ecological functions, faunal groups, and impacts on mangroves. Degradation due to development was identified as having the largest impact on mangroves globally in terms of spatial scale, intensity, and time needed for restoration. The results indicate that mangroves are ecologically unique even though they may be species poor (from the vegetation perspective). The consensus list of mangrove species and the ranking of the mangrove ecological functions could be a useful tool for restoration and management of mangroves. While there is ample literature on the destruction of mangroves due to aquaculture in the past decade, this study clearly shows that more attention must go to avoiding and mitigating mangrove loss due to coastal development (such as building of roads, ports, or harbors).
Collapse
Affiliation(s)
- Nibedita Mukherjee
- Laboratory of Systems Ecology and Resource Management, Université Libre de Bruxelles CP 169, Avenue F.D. Roosevelt 50, B-1050, Brussels, Belgium ; Laboratory of Plant Biology and Nature Management, Vrije Universiteit Brussel Pleinlaan 2, B-1050, Brussels, Belgium
| | - William J Sutherland
- Conservation Science Group, Department of Zoology, University of Cambridge CB2 3EJ, Cambridge, UK
| | - Md Nabiul I Khan
- Laboratory of Systems Ecology and Resource Management, Université Libre de Bruxelles CP 169, Avenue F.D. Roosevelt 50, B-1050, Brussels, Belgium
| | - Uta Berger
- Institute of Forest Growth and Forest Computer Sciences TU Dresden, P.O. 1117, 01735, Tharandt, Germany
| | - Nele Schmitz
- Institute of Botany, BOKU Vienna Gregor Mendel Str. 33, 1180, Vienna, Austria
| | - Farid Dahdouh-Guebas
- Laboratory of Systems Ecology and Resource Management, Université Libre de Bruxelles CP 169, Avenue F.D. Roosevelt 50, B-1050, Brussels, Belgium ; Laboratory of Plant Biology and Nature Management, Vrije Universiteit Brussel Pleinlaan 2, B-1050, Brussels, Belgium
| | - Nico Koedam
- Laboratory of Plant Biology and Nature Management, Vrije Universiteit Brussel Pleinlaan 2, B-1050, Brussels, Belgium
| |
Collapse
|
30
|
Robert EMR, Jambia AH, Schmitz N, De Ryck DJR, De Mey J, Kairo JG, Dahdouh-Guebas F, Beeckman H, Koedam N. How to catch the patch? A dendrometer study of the radial increment through successive cambia in the mangrove Avicennia. Ann Bot 2014; 113:741-52. [PMID: 24510216 PMCID: PMC3936594 DOI: 10.1093/aob/mcu001] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/25/2013] [Accepted: 11/26/2013] [Indexed: 05/13/2023]
Abstract
BACKGROUND AND AIMS Successive vascular cambia are involved in the secondary growth of at least 200 woody species from >30 plant families. In the mangrove Avicennia these successive cambia are organized in patches, creating stems with non-concentric xylem tissue surrounded by internal phloem tissue. Little is known about radial growth and tree stem dynamics in trees with this type of anatomy. This study aims to (1) clarify the process of secondary growth of Avicennia trees by studying its patchiness; and (2) study the radial increment of Avicennia stems, both temporary and permanent, in relation to local climatic and environmental conditions. A test is made of the hypothesis that patchy radial growth and stem dynamics enable Avicennia trees to better survive conditions of extreme physiological drought. Methods Stem variations were monitored by automatic point dendrometers at four different positions around and along the stem of two Avicennia marina trees in the mangrove forest of Gazi Bay (Kenya) during 1 year. KEY RESULTS Patchiness was found in the radial growth and shrinkage and swelling patterns of Avicennia stems. It was, however, potentially rather than systematically present, i.e. stems reacted either concentrically or patchily to environment triggers, and it was fresh water availability and not tidal inundation that affected radial increment. CONCLUSIONS It is concluded that the ability to develop successive cambia in a patchy way enables Avicennia trees to adapt to changes in the prevailing environmental conditions, enhancing its survival in the highly dynamic mangrove environment. Limited water could be used in a more directive way, investing all the attainable resources in only some locations of the tree stem so that at least at these locations there is enough water to, for example, overcome vessel embolisms or create new cells. As these locations change with time, the overall functioning of the tree can be maintained.
Collapse
Affiliation(s)
- Elisabeth M. R. Robert
- Laboratory of Plant Biology and Nature Management (APNA), Vrije Universiteit Brussel, B-1050 Brussels, Belgium
- Laboratory of Wood Biology and Xylarium, Royal Museum for Central Africa (RMCA), B-3080 Tervuren, Belgium
| | | | - Nele Schmitz
- Laboratory of Plant Biology and Nature Management (APNA), Vrije Universiteit Brussel, B-1050 Brussels, Belgium
- Laboratory of Wood Biology and Xylarium, Royal Museum for Central Africa (RMCA), B-3080 Tervuren, Belgium
| | - Dennis J. R. De Ryck
- Laboratory of Plant Biology and Nature Management (APNA), Vrije Universiteit Brussel, B-1050 Brussels, Belgium
- Laboratory of Wood Biology and Xylarium, Royal Museum for Central Africa (RMCA), B-3080 Tervuren, Belgium
- Laboratory of Systems Ecology and Resource Management, Université libre de Bruxelles, B-1050 Brussels, Belgium
| | - Johan De Mey
- Radiology, Universitair Ziekenhuis Brussel, B-1090 Brussels, Belgium
| | - James G. Kairo
- Kenya Marine and Fisheries Research Institute (KMFRI), Mombasa, Kenya
| | - Farid Dahdouh-Guebas
- Laboratory of Plant Biology and Nature Management (APNA), Vrije Universiteit Brussel, B-1050 Brussels, Belgium
- Laboratory of Systems Ecology and Resource Management, Université libre de Bruxelles, B-1050 Brussels, Belgium
| | - Hans Beeckman
- Laboratory of Wood Biology and Xylarium, Royal Museum for Central Africa (RMCA), B-3080 Tervuren, Belgium
| | - Nico Koedam
- Laboratory of Plant Biology and Nature Management (APNA), Vrije Universiteit Brussel, B-1050 Brussels, Belgium
| |
Collapse
|
31
|
Hijbeek R, Koedam N, Khan MNI, Kairo JG, Schoukens J, Dahdouh-Guebas F. An Evaluation of Plotless Sampling Using Vegetation Simulations and Field Data from a Mangrove Forest. PLoS One 2013; 8:e67201. [PMID: 23826233 PMCID: PMC3695089 DOI: 10.1371/journal.pone.0067201] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2012] [Accepted: 05/15/2013] [Indexed: 11/21/2022] Open
Abstract
In vegetation science and forest management, tree density is often used as a variable. To determine the value of this variable, reliable field methods are necessary. When vegetation is sparse or not easily accessible, the use of sample plots is not feasible in the field. Therefore, plotless methods, like the Point Centred Quarter Method, are often used as an alternative. In this study we investigate the accuracy of different plotless sampling methods. To this end, tree densities of a mangrove forest were determined and compared with estimates provided by several plotless methods. None of these methods proved accurate across all field sites with mean underestimations up to 97% and mean overestimations up to 53% in the field. Applying the methods to different vegetation patterns shows that when random spatial distributions were used the true density was included within the 95% confidence limits of all the plotless methods tested. It was also found that, besides aggregation and regularity, density trends often found in mangroves contribute to the unreliability. This outcome raises questions about the use of plotless sampling in forest monitoring and management, as well as for estimates of density-based carbon sequestration. We give recommendations to minimize errors in vegetation surveys and recommendations for further in-depth research.
Collapse
Affiliation(s)
- Renske Hijbeek
- Laboratory of Plant Biology and Nature Management, Vrije Universiteit Brussel, Brussels, Belgium
- Plant Production Systems, Wageningen University and Research Centre, Wageningen, The Netherlands
- * E-mail:
| | - Nico Koedam
- Laboratory of Plant Biology and Nature Management, Vrije Universiteit Brussel, Brussels, Belgium
| | - Md Nabiul Islam Khan
- Laboratory of Plant Biology and Nature Management, Vrije Universiteit Brussel, Brussels, Belgium
- Laboratory of Systems Ecology and Resource Management, Université Libre de Bruxelles, Brussels, Belgium
| | - James Gitundu Kairo
- Mombasa Research Centre, Kenya Marine and Fisheries Research Institute, Mombasa, Kenya
| | - Johan Schoukens
- Department of Fundamental Electricity and Instrumentation, Vrije Universiteit Brussel, Brussels, Belgium
| | - Farid Dahdouh-Guebas
- Laboratory of Plant Biology and Nature Management, Vrije Universiteit Brussel, Brussels, Belgium
- Laboratory of Systems Ecology and Resource Management, Université Libre de Bruxelles, Brussels, Belgium
| |
Collapse
|
32
|
Satyanarayana B, Bhanderi P, Debry M, Maniatis D, Foré F, Badgie D, Jammeh K, Vanwing T, Farcy C, Koedam N, Dahdouh-Guebas F. A socio-ecological assessment aiming at improved forest resource management and sustainable ecotourism development in the mangroves of Tanbi Wetland National Park, The Gambia, West Africa. Ambio 2012; 41:513-26. [PMID: 22351596 PMCID: PMC3390577 DOI: 10.1007/s13280-012-0248-7] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/21/2011] [Revised: 10/20/2011] [Accepted: 01/12/2012] [Indexed: 05/15/2023]
Abstract
Although mangroves dominated by Avicennia germinans and Rhizophora mangle are extending over 6000 ha in the Tanbi Wetland National Park (TWNP) (The Gambia), their importance for local populations (both peri-urban and urban) is not well documented. For the first time, this study evaluates the different mangrove resources in and around Banjul (i.e., timber, non-timber, edible, and ethnomedicinal products) and their utilization patterns, including the possibility of ecotourism development. The questionnaire-based results have indicated that more than 80% of peri-urban population rely on mangroves for timber and non-timber products and consider them as very important for their livelihoods. However, at the same time, urban households demonstrate limited knowledge on mangrove species and their ecological/economic benefits. Among others, fishing (including the oyster-Crassostrea cf. gasar collection) and tourism are the major income-generating activities found in the TWNP. The age-old practices of agriculture in some parts of the TWNP are due to scarcity of land available for agriculture, increased family size, and alternative sources of income. The recent focus on ecotourism (i.e., boardwalk construction inside the mangroves near Banjul city) received a positive response from the local stakeholders (i.e., users, government, and non-government organizations), with their appropriate roles in sharing the revenue, rights, and responsibilities of this project. Though the guidelines for conservation and management of the TWNP seem to be compatible, the harmony between local people and sustainable resource utilization should be ascertained.
Collapse
Affiliation(s)
- Behara Satyanarayana
- Laboratory of Systems Ecology and Resource Management (Complexity and Dynamics of Tropical Systems), Département de Biologie des Organismes, Faculté des Sciences, Université Libre de Bruxelles—ULB, Avenue Franklin D. Roosevelt 50, 1050 Brussels, Belgium
- Laboratory of Plant Biology and Nature Management, Mangrove Management Group, Vrije Universiteit Brussel—VUB, Pleinlaan 2, 1050 Brussels, Belgium
- Institute of Oceanography, University Malaysia Terengganu—UMT, 21030 Kuala, Terengganu Malaysia
| | - Preetika Bhanderi
- Laboratory of Plant Biology and Nature Management, Mangrove Management Group, Vrije Universiteit Brussel—VUB, Pleinlaan 2, 1050 Brussels, Belgium
- African Conservation Centre, P.O. Box 15289-00509, Nairobi, Kenya
| | - Mélanie Debry
- Forest, Nature and Society Research Group, Université Catholique de Louvain—UCL, Louvain-la-Neuve, Belgium
| | - Danae Maniatis
- Laboratory of Plant Biology and Nature Management, Mangrove Management Group, Vrije Universiteit Brussel—VUB, Pleinlaan 2, 1050 Brussels, Belgium
- School of Geography and the Environment, Environmental Change Institute, University of Oxford, Dyson Perrins Building, South Parks Road, Oxford, OX1 3QY UK
| | - Franka Foré
- Laboratory of Plant Biology and Nature Management, Mangrove Management Group, Vrije Universiteit Brussel—VUB, Pleinlaan 2, 1050 Brussels, Belgium
- Sociaal Culturele Agogiek, Vrije Universiteit Brussel—VUB, Pleinlaan 2, 1050 Brussels, Belgium
| | - Dawda Badgie
- National Environment Agency (NEA), Banjul, The Gambia
| | - Kawsu Jammeh
- Department of Parks & Wildlife Management, Abuko, The Gambia
| | - Tom Vanwing
- Sociaal Culturele Agogiek, Vrije Universiteit Brussel—VUB, Pleinlaan 2, 1050 Brussels, Belgium
| | - Christine Farcy
- Forest, Nature and Society Research Group, Université Catholique de Louvain—UCL, Louvain-la-Neuve, Belgium
| | - Nico Koedam
- Laboratory of Plant Biology and Nature Management, Mangrove Management Group, Vrije Universiteit Brussel—VUB, Pleinlaan 2, 1050 Brussels, Belgium
| | - Farid Dahdouh-Guebas
- Laboratory of Systems Ecology and Resource Management (Complexity and Dynamics of Tropical Systems), Département de Biologie des Organismes, Faculté des Sciences, Université Libre de Bruxelles—ULB, Avenue Franklin D. Roosevelt 50, 1050 Brussels, Belgium
- Laboratory of Plant Biology and Nature Management, Mangrove Management Group, Vrije Universiteit Brussel—VUB, Pleinlaan 2, 1050 Brussels, Belgium
| |
Collapse
|
33
|
Schrijver EJM, Deenik W, Chon H, Koedam N, Spoelstra-de Man AME. An unusual case of abdominal arterial thrombosis in a young woman using desmopressin. Clin Biochem 2011; 45:165-7. [PMID: 22155434 DOI: 10.1016/j.clinbiochem.2011.11.011] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2011] [Revised: 11/04/2011] [Accepted: 11/17/2011] [Indexed: 01/14/2023]
Abstract
We report an unusual case of severe abdominal arterial thrombosis in a young woman using oral desmopressin. Only a few cases with cerebrovascular accidents and coronary syndromes have been described so far, which could be attributed to intravenous administration of desmopressin. Because extensive diagnostic and laboratory investigations for (un)common coagulation disorders could not identify an alternative explanation associated with arterial thrombosis, we hypothesise that desmopressin in an oral dose of at least 200 ug once daily must have been sufficient to cause this dramatic vascular complication. Supportive of our hypothesis, we found remarkably high levels of factor VIII activity, Von Willebrand factor (vWF) antigen and vWF ristocetin cofactor activity (268%, 740%, 590% respectively). To the best of the authors' knowledge, this is the first report suggesting a relationship between oral desmopressin use and life-threatening abdominal arterial thrombosis.
Collapse
Affiliation(s)
- E J M Schrijver
- Tergooiziekenhuizen Hilversum, Department of Intensive Care, Van Riebeeckweg 212, 1213 XZ Hilversum, the Netherlands.
| | | | | | | | | |
Collapse
|
34
|
Nfotabong-Atheull A, Din N, Essomè Koum LG, Satyanarayana B, Koedam N, Dahdouh-Guebas F. Assessing forest products usage and local residents' perception of environmental changes in peri-urban and rural mangroves of Cameroon, Central Africa. J Ethnobiol Ethnomed 2011; 7:41. [PMID: 22146073 PMCID: PMC3261808 DOI: 10.1186/1746-4269-7-41] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/31/2011] [Accepted: 12/06/2011] [Indexed: 05/25/2023]
Abstract
BACKGROUND Deforestation is one of the most ubiquitous forms of land degradation worldwide. Although remote sensing and aerial photographs can supply valuable information on land/use cover changes, they may not regularly be available for some tropical coasts (e.g., Cameroon estuary) where cloud cover is frequent. With respect to mangroves, researchers are now employing local knowledge as an alternative means of understanding forest disturbances. This paper was primarily aimed at assessing the mangrove forest products usage, along with the local people's perceptions on environmental changes, between Littoral (Cameroon estuary) and Southern (mouth of the Nyong River and Mpalla village) regions of Cameroon. METHODS The data from both locations were obtained through conducting household interviews and field observations. RESULTS In the Cameroon estuary (Littoral region), 69.23% of respondents (mostly elders) could distinguish two to four mangrove plants, whereas the informants (65.45%) in the mouth of the Nyong River and Mpalla village (mostly young people interviewed from the Southern region) are familiar with only one or two commonly found mangroves. Also, more respondents from the Cameroon estuary are depending on mangroves for fuelwood (Rhizophora spp.) and housing (Rhizophora spp., Avicennia germinans (L.) Stearn and Nypa fruticans (Thumb.) Wurmb.) purposes, in contrast to Nyong River mouth and Mpalla village. Although local people perceived wood extraction as a greater disruptive factor, there are several causes for mangrove depletion in the Cameroon estuary. Among others, over-harvesting, clear-felled corridors, sand extraction and housing were found important. Furthermore, a decline in mangrove fauna composition (in terms of fishery products) was recorded in the Littoral as well as Southern regions. However, the causes of such perceived negative changes were not similar in both cases. CONCLUSIONS Findings of this study highlight the need to improve sustainable management of the mangrove ecosystems through afforestation (in large impacted areas), selective removal of senescent tree stems and branches (in little damage stands), regulating sand extraction and housing activities, and creating awareness and law enforcement.
Collapse
Affiliation(s)
- Adolphe Nfotabong-Atheull
- Laboratory of Systems Ecology and Resource Management, Département de Biologie des Organismes, Faculté des Sciences, Université Libre de Bruxelles-ULB, Avenue Franklin D. Roosevelt 50, CPI 169, B-1050 Brussels, Belgium
- The University of Douala, Faculty of Science, Department of Botany, P.O. Box 8948 Douala, Cameroon
- University of Yaoundé I, Faculty of Science, Department of Plant Biology, P.O. Box 812 Yaoundé, Cameroon
| | - Ndongo Din
- The University of Douala, Faculty of Science, Department of Botany, P.O. Box 8948 Douala, Cameroon
| | - Léopold G Essomè Koum
- The University of Douala, Faculty of Science, Department of Botany, P.O. Box 8948 Douala, Cameroon
| | - Behara Satyanarayana
- Laboratory of Systems Ecology and Resource Management, Département de Biologie des Organismes, Faculté des Sciences, Université Libre de Bruxelles-ULB, Avenue Franklin D. Roosevelt 50, CPI 169, B-1050 Brussels, Belgium
- Laboratory of Plant Biology and Nature Management, Mangrove Management Group, Vrije Universiteit Brussel-VUB, Pleinlaan 2, B-1050 Brussels, Belgium
- Institute of Oceanography, Universiti Malaysia Terengganu - UMT, 21030 Kuala Terengganu, Malaysia
| | - Nico Koedam
- Laboratory of Plant Biology and Nature Management, Mangrove Management Group, Vrije Universiteit Brussel-VUB, Pleinlaan 2, B-1050 Brussels, Belgium
| | - Farid Dahdouh-Guebas
- Laboratory of Systems Ecology and Resource Management, Département de Biologie des Organismes, Faculté des Sciences, Université Libre de Bruxelles-ULB, Avenue Franklin D. Roosevelt 50, CPI 169, B-1050 Brussels, Belgium
- Laboratory of Plant Biology and Nature Management, Mangrove Management Group, Vrije Universiteit Brussel-VUB, Pleinlaan 2, B-1050 Brussels, Belgium
| |
Collapse
|
35
|
Bortels L, Chan JCW, Merken R, Koedam N. Long-term monitoring of wetlands along the Western-Greek Bird Migration Route using Landsat and ASTER satellite images: Amvrakikos Gulf (Greece). J Nat Conserv 2011. [DOI: 10.1016/j.jnc.2011.01.004] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
|
36
|
Robert EMR, Schmitz N, Boeren I, Driessens T, Herremans K, De Mey J, Van de Casteele E, Beeckman H, Koedam N. Successive cambia: a developmental oddity or an adaptive structure? PLoS One 2011; 6:e16558. [PMID: 21304983 PMCID: PMC3031581 DOI: 10.1371/journal.pone.0016558] [Citation(s) in RCA: 51] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2010] [Accepted: 12/27/2010] [Indexed: 11/19/2022] Open
Abstract
BACKGROUND Secondary growth by successive cambia is a rare phenomenon in woody plant species. Only few plant species, within different phylogenetic clades, have secondary growth by more than one vascular cambium. Often, these successive cambia are organised concentrically. In the mangrove genus Avicennia however, the successive cambia seem to have a more complex organisation. This study aimed (i) at understanding the development of successive cambia by giving a three-dimensional description of the hydraulic architecture of Avicennia and (ii) at unveiling the possible adaptive nature of growth by successive cambia through a study of the ecological distribution of plant species with concentric internal phloem. RESULTS Avicennia had a complex network of non-cylindrical wood patches, the complexity of which increased with more stressful ecological conditions. As internal phloem has been suggested to play a role in water storage and embolism repair, the spatial organisation of Avicennia wood could provide advantages in the ecologically stressful conditions species of this mangrove genus are growing in. Furthermore, we could observe that 84.9% of the woody shrub and tree species with concentric internal phloem occurred in either dry or saline environments strengthening the hypothesis that successive cambia provide the necessary advantages for survival in harsh environmental conditions. CONCLUSIONS Successive cambia are an ecologically important characteristic, which seems strongly related with water-limited environments.
Collapse
Affiliation(s)
- Elisabeth M R Robert
- Laboratory for Plant Biology and Nature Management, APNA, Vrije Universiteit Brussel, VUB, Brussels, Belgium.
| | | | | | | | | | | | | | | | | |
Collapse
|
37
|
Mukherjee N, Dahdouh-Guebas F, Kapoor V, Arthur R, Koedam N, Sridhar A, Shanker K. From bathymetry to bioshields: a review of post-tsunami ecological research in India and its implications for policy. Environ Manage 2010; 46:329-339. [PMID: 20640420 DOI: 10.1007/s00267-010-9523-1] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/19/2009] [Accepted: 06/18/2010] [Indexed: 05/27/2023]
Abstract
More than half a decade has passed since the December 26th 2004 tsunami hit the Indian coast leaving a trail of ecological, economic and human destruction in its wake. We reviewed the coastal ecological research carried out in India in the light of the tsunami. In addition, we also briefly reviewed the ecological research in other tsunami affected countries in Asia namely Sri Lanka, Indonesia, Thailand and Maldives in order to provide a broader perspective of ecological research after tsunami. A basic search in ISI Web of Knowledge using keywords "tsunami" and "India" resulted in 127 peer reviewed journal articles, of which 39 articles were pertaining to ecological sciences. In comparison, Sri Lanka, Indonesia, Thailand and Maldives had, respectively, eight, four, 21 and two articles pertaining to ecology. In India, bioshields received the major share of scientific interest (14 out of 39) while only one study (each) was dedicated to corals, seagrasses, seaweeds and meiofauna, pointing to the paucity of research attention dedicated to these critical ecosystems. We noted that very few interdisciplinary studies looked at linkages between pure/applied sciences and the social sciences in India. In addition, there appears to be little correlation between the limited research that was done and its influence on policy in India. This review points to gap areas in ecological research in India and highlights the lessons learnt from research in other tsunami-affected countries. It also provides guidance on the links between science and policy that are required for effective coastal zone management.
Collapse
Affiliation(s)
- Nibedita Mukherjee
- Laboratory of Plant Biology and Nature Management, Faculty of Sciences and Bio-Engineering Sciences, Vrije Universiteit Brussel (VUB), Brussels, Belgium.
| | | | | | | | | | | | | |
Collapse
|
38
|
Affiliation(s)
- Ronny Merken
- Vrije Universiteit Brussel, Departement of Biology, Plant Biology and Nature Management, Brussels, Belgium
| | - Faidra Bazigou
- Vrije Universiteit Brussel, Departement of Biology, Plant Biology and Nature Management, Brussels, Belgium
- EC Joint Research Centre, Institute for Environment and Sustainability, Rural, Water and Ecosystem Resources Ispra, Italy
| | - Nico Koedam
- Vrije Universiteit Brussel, Departement of Biology, Plant Biology and Nature Management, Brussels, Belgium
| |
Collapse
|
39
|
Feagin RA, Mukherjee N, Shanker K, Baird AH, Cinner J, Kerr AM, Koedam N, Sridhar A, Arthur R, Jayatissa L, Lo Seen D, Menon M, Rodriguez S, Shamsuddoha M, Dahdouh-Guebas F. Shelter from the storm? Use and misuse of coastal vegetation bioshields for managing natural disasters. Conserv Lett 2010. [DOI: 10.1111/j.1755-263x.2009.00087.x] [Citation(s) in RCA: 111] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022] Open
|
40
|
Bouillon S, Moens T, Koedam N, Dahdouh-Guebas F, Baeyens W, Dehairs F. Variability in the origin of carbon substrates for bacterial communities in mangrove sediments. FEMS Microbiol Ecol 2009; 49:171-9. [PMID: 19712412 DOI: 10.1016/j.femsec.2004.03.004] [Citation(s) in RCA: 46] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022] Open
Abstract
Organic carbon in mangrove sediments originates from both local sources (mangroves, microphytobenthos) and tidal inputs (e.g. phytoplankton, seagrass-derived material). The relative inputs of these sources may vary strongly, both within and between different mangrove sites. We combined elemental (TOC/TN) and bulk delta13C analysis on sediment cores from various mangrove sites with delta13C data of bacteria-specific phospholipid fatty acids (PLFA) in order to identify the dominant carbon substrates used by in situ bacterial communities. delta13C values of each of these markers showed a range of 10% or more across the different sites and sampling depths, but generally followed the delta13C trend observed in bulk organic carbon. Several sediment cores show a strong vertical gradient in PLFA delta13C, suggesting a selectivity for algal-derived carbon in the surface layers. Our data demonstrate that the origin of bacterial carbon substrates varies widely across different mangrove sites, and imply that data on mineralization of organic matter cannot be directly incorporated in ecosystem carbon budgets without an estimation of the contribution of various sources.
Collapse
Affiliation(s)
- Steven Bouillon
- Department of Analytical and Environmental Chemistry, Mangrove Management Group, Vrije Universiteit Brussel, Pleinlaan 2, B-1050 Brussels, Belgium.
| | | | | | | | | | | |
Collapse
|
41
|
Atheull AN, Din N, Longonje SN, Koedam N, Dahdouh-Guebas F. Commercial activities and subsistence utilization of mangrove forests around the Wouri estuary and the Douala-Edea reserve (Cameroon). J Ethnobiol Ethnomed 2009; 5:35. [PMID: 19919680 PMCID: PMC2785752 DOI: 10.1186/1746-4269-5-35] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/15/2009] [Accepted: 11/17/2009] [Indexed: 05/27/2023]
Abstract
BACKGROUND Worldwide there is growing research interest in the ethnobiology of mangrove forests. Notwithstanding that, little information has been published about ethnobiology of mangrove forests in Cameroon. The aims of this study were a) to analyze the harvesting methods and the local selling of mangrove wood products by loggers in the vicinity of Wouri estuary and b) to investigate the patterns of subsistence uses of mangrove wood products around the Douala-Edea reserve. METHODS Semi-structured interviews were conducted with 120 active mangrove loggers in 23 Douala wood markets and 103 households located in three villages (Mbiako, Yoyo I and Yoyo II) close to Douala-Edea reserve. In each of the three densely populated villages, every second household was chosen for sampling while in all markets, mangrove loggers were chosen randomly. In addition, log diameters were measured in each market using a wooden foldable tape measure. A post hoc analysis (Newman-Keuls test) was performed in order to detect the common wood class diameter sold in the Douala wood markets. RESULTS The analysis of the loggers' survey data has shown that large logs of Rhizophora with diameter greater than 40 cm were common in the Douala wood markets and were more closely associated with loggers who used chainsaws. In addition to the general mangroves wood products selling, the analysis on a subsistence level (households' survey) suggests the local population's dependence on mangroves, with multiple uses of Rhizophora racemosa Meyer, R. harrisonii Leechman, Avicennia germinans L. Stearn., Laguncularia racemosa Gaertn. f. and Conocarpus erectus L. timbers for furniture, fences, smoking fish, and fuelwood. Finally, Nypa fruticans (Thunb.) Wurmb. leaves were used as thatching material for house walls and roofs. CONCLUSION Our findings revealed that big logs of Rhizophora were commonly sold by the loggers. A majority of loggers (60%) reported that mangrove marketed wood constitute a principal source of income. Most of the villagers (85.83%) often depend on mangroves for subsistence needs and for them there is no substitute for mangrove wood. Therefore, more efforts should be undertaken at the national level to implement conservation, management and sustainable use of these coastal forests.
Collapse
Affiliation(s)
- Adolphe Nfotabong Atheull
- Laboratoire de Complexité et Dynamique des Systèmes Tropicaux, Département de Biologie des Organismes, Faculté des Sciences, Université Libre de Bruxelles - ULB, CP 169, Avenue F.D. Roosevelt 50, B-1050 Bruxelles, Belgium
- The University of Douala, Faculty of Science, Department of Botany, PO Box 8948 Douala, Cameroon
| | - Ndongo Din
- The University of Douala, Faculty of Science, Department of Botany, PO Box 8948 Douala, Cameroon
| | - Simon N Longonje
- Biocomplexity Research Focus c/o Laboratory of Plant Biology and Nature Management, Faculteit Wetenschappen, Vrije Universiteit Brussel - VUB, Pleinlaan 2, B-1050 Brussels, Belgium
| | - Nico Koedam
- Biocomplexity Research Focus c/o Laboratory of Plant Biology and Nature Management, Faculteit Wetenschappen, Vrije Universiteit Brussel - VUB, Pleinlaan 2, B-1050 Brussels, Belgium
| | - Farid Dahdouh-Guebas
- Laboratoire de Complexité et Dynamique des Systèmes Tropicaux, Département de Biologie des Organismes, Faculté des Sciences, Université Libre de Bruxelles - ULB, CP 169, Avenue F.D. Roosevelt 50, B-1050 Bruxelles, Belgium
- Biocomplexity Research Focus c/o Laboratory of Plant Biology and Nature Management, Faculteit Wetenschappen, Vrije Universiteit Brussel - VUB, Pleinlaan 2, B-1050 Brussels, Belgium
| |
Collapse
|
42
|
Robert EMR, Koedam N, Beeckman H, Schmitz N. A safe hydraulic architecture as wood anatomical explanation for the difference in distribution of the mangrovesAvicenniaandRhizophora. Funct Ecol 2009. [DOI: 10.1111/j.1365-2435.2009.01551.x] [Citation(s) in RCA: 51] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
|
43
|
Schmitz N, Koch G, Schmitt U, Beeckman H, Koedam N. Intervessel pit structure and histochemistry of two mangrove species as revealed by cellular UV microspectrophotometry and electron microscopy: intraspecific variation and functional significance. Microsc Microanal 2008; 14:387-397. [PMID: 18793483 DOI: 10.1017/s143192760808077x] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/26/2023]
Abstract
Intervessel pits play a key role in trees' water transport, lying at the base of drought-induced embolism, and in the regulation of hydraulic conductivity via hydrogels bordering pit canals. Recently, their microstructure has been the focus of numerous studies, but the considerable variation, even within species and the histochemistry of pit membranes, remains largely unexplained. In the present study, intervessel pits of the outermost wood were examined for Avicennia marina, of dry and rainy season wood separately for Rhizophora mucronata. The thickness of the pit membranes was measured on transmission electron micrographs while their topochemical nature was also analyzed via cellular UV microspectrophotometry. Pit membranes of R. mucronata were slightly thicker in dry season wood than in rainy season wood, but their spectra showed for both seasons a lignin and a yet unidentified higher wavelength absorbing component. It was suggested to be a derivative of the deposits, regularly filling pit canals. The vestures of A. marina chemically resembled pit membranes rather than cell walls.
Collapse
Affiliation(s)
- Nele Schmitz
- Royal Museum for Central Africa, Laboratory for Wood Biology and Xylarium, Leuvensesteenweg 13, 3080 Tervuren, Belgium.
| | | | | | | | | |
Collapse
|
44
|
Schmitz N, Robert EMR, Verheyden A, Kairo JG, Beeckman H, Koedam N. A patchy growth via successive and simultaneous cambia: key to success of the most widespread mangrove species Avicennia marina? Ann Bot 2008; 101:49-58. [PMID: 18006508 PMCID: PMC2701843 DOI: 10.1093/aob/mcm280] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/04/2007] [Revised: 08/14/2007] [Accepted: 09/20/2007] [Indexed: 05/08/2023]
Abstract
BACKGROUND AND AIMS Secondary growth via successive cambia has been intriguing researchers for decades. Insight into the mechanism of growth layer formation is, however, limited to the cellular level. The present study aims to clarify secondary growth via successive cambia in the mangrove species Avicennia marina on a macroscopic level, addressing the formation of the growth layer network as a whole. In addition, previously suggested effects of salinity on growth layer formation were reconsidered. METHODS A 1-year cambial marking experiment was performed on 80 trees from eight sites in two mangrove forests in Kenya. Environmental (soil water salinity and nutrients, soil texture, inundation frequency) and tree characteristics (diameter, height, leaf area index) were recorded for each site. Both groups of variables were analysed in relation to annual number of growth layers, annual radial increment and average growth layer width of stem discs. KEY RESULTS Between trees of the same site, the number of growth layers formed during the 1-year study period varied from only part of a growth layer up to four growth layers, and was highly correlated to the corresponding radial increment (0-5 mm year(-1)), even along the different sides of asymmetric stem discs. The radial increment was unrelated to salinity, but the growth layer width decreased with increasing salinity and decreasing tree height. CONCLUSIONS A patchy growth mechanism was proposed, with an optimal growth at distinct moments in time at different positions around the stem circumference. This strategy creates the opportunity to form several growth layers simultaneously, as observed in 14 % of the studied trees, which may optimize tree growth under favourable conditions. Strong evidence was provided for a mainly endogenous trigger controlling cambium differentiation, with an additional influence of current environmental conditions in a trade-off between hydraulic efficiency and mechanical stability.
Collapse
Affiliation(s)
- Nele Schmitz
- Vrije Universiteit Brussel (VUB), Laboratory for General Botany and Nature Management, (APNA), Pleinlaan 2, 1050 Brussels, Belgium.
| | | | | | | | | | | |
Collapse
|
45
|
Schmitz N, Jansen S, Verheyden A, Kairo JG, Beeckman H, Koedam N. Comparative anatomy of intervessel pits in two mangrove species growing along a natural salinity gradient in Gazi bay, Kenya. Ann Bot 2007; 100:271-81. [PMID: 17565970 PMCID: PMC2735318 DOI: 10.1093/aob/mcm103] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/06/2007] [Accepted: 04/04/2007] [Indexed: 05/04/2023]
Abstract
BACKGROUND AND AIMS According to the air-seeding hypothesis, embolism vulnerability in xylem elements is linked directly to bordered pit structure and functioning. To elucidate the adaptive potential of intervessel pits towards fluctuating environmental conditions, two mangrove species with a distinct ecological distribution growing along a natural salinity gradient were investigated. METHODS Scanning and transmission electron microscopic observations were conducted to obtain qualitative and quantitative characteristics of alternate intervessel pits in A. marina and scalariform intervessel pits in Rhizophora mucronata. Wood samples from three to six trees were collected at seven and five sites for A. marina and R. mucronata, respectively, with considerable differences between sites in soil water salinity. KEY RESULTS Vestured pits without visible pores in the pit membrane were observed in A. marina, the mangrove species with the widest geographical distribution on global as well as local scale. Their thick pit membranes (on average 370 nm) and minute pit apertures may contribute to reduced vulnerability to cavitation of this highly salt-tolerant species. The smaller ecological distribution of R. mucronata was in accordance with wide pit apertures and a slightly higher pitfield fraction (67 % vs. 60 % in A. marina). Nonetheless, its outer pit apertures were observed to be funnel-shaped shielding non-porous pit membranes. No trends in intervessel pit size were observed with increasing soil water salinity of the site. CONCLUSIONS The contrasting ecological distribution of two mangrove species was reflected in the geometry and pit membrane characteristics of their intervessel pits. Within species, intervessel pit size seemed to be independent of spatial variations in environmental conditions and was only weakly correlated with vessel diameter. Further research on pit formation and function has to clarify the large variations in intervessel pit size within trees and even within single vessels.
Collapse
Affiliation(s)
- Nele Schmitz
- Vrije Universiteit Brussel, Laboratory for General Botany and Nature Management (APNA), Pleinlaan 2, 1050 Brussels, Belgium.
| | | | | | | | | | | |
Collapse
|
46
|
Duke NC, Meynecke JO, Dittmann S, Ellison AM, Anger K, Berger U, Cannicci S, Diele K, Ewel KC, Field CD, Koedam N, Lee SY, Marchand C, Nordhaus I, Dahdouh-Guebas F. A World Without Mangroves? Science 2007; 317:41-2. [PMID: 17615322 DOI: 10.1126/science.317.5834.41b] [Citation(s) in RCA: 397] [Impact Index Per Article: 23.4] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/02/2022]
|
47
|
Schmitz N, Verheyden A, Beeckman H, Kairo JG, Koedam N. Influence of a salinity gradient on the vessel characters of the mangrove species Rhizophora mucronata. Ann Bot 2006; 98:1321-30. [PMID: 17062590 PMCID: PMC2803579 DOI: 10.1093/aob/mcl224] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/08/2023]
Abstract
BACKGROUND AND AIMS Although mangroves have been extensively studied, little is known about their ecological wood anatomy. This investigation examined the potential use of vessel density as a proxy for soil water salinity in the mangrove species Rhizophora mucronata (Rhizophoraceae) from Kenya. METHODS In a time-standardized approach, 50 wood discs from trees growing in six salinity categories were investigated. Vessel densities, and tangential and radial diameters of rainy and dry season wood of one distinct year, at three positions on the stem discs, were measured. A repeated-measures ANOVA with the prevailing salinity was performed. KEY RESULTS Vessel density showed a significant increase with salinity, supporting its use as a prospective measure of salinity. Interestingly, the negative salinity response of the radial diameter of vessels was less striking, and tangential diameter was constant under the varying environmental conditions. An effect of age or growth rate or the presence of vessel dimorphism could be excluded as the cause of the absence of any ecological trend. CONCLUSIONS The clear trend in vessel density with salinity, together with the absence of a growth rate and age effect, validates the potential of vessel density as an environmental proxy. However, it can only be used as a relative measure of salinity given that other environmental variables such as inundation frequency have an additional influence on vessel density. With view to a reliable, absolute proxy, future research should focus on finding wood anatomical features correlated exclusively with soil water salinity or inundation frequency. The plasticity in vessel density with differing salinity suggests a role in the establishment of a safe water transport system. To confirm this hypothesis, the role of inter-vessel pits, their relationship to the rather constant vessel diameter and the underlying physiology and cell biology needs to be examined.
Collapse
Affiliation(s)
- Nele Schmitz
- Vrije Universiteit Brussel, Laboratory for General Botany and Nature Management (APNA) Pleinlaan 2, 1050 Brussels, Belgium.
| | | | | | | | | |
Collapse
|
48
|
Dahdouh-Guebas F, Collin S, Lo Seen D, Rönnbäck P, Depommier D, Ravishankar T, Koedam N. Analysing ethnobotanical and fishery-related importance of mangroves of the East-Godavari Delta (Andhra Pradesh, India) for conservation and management purposes. J Ethnobiol Ethnomed 2006; 2:24. [PMID: 16681845 PMCID: PMC1475843 DOI: 10.1186/1746-4269-2-24] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 02/03/2006] [Accepted: 05/08/2006] [Indexed: 05/09/2023]
Abstract
Mangrove forests, though essentially common and wide-spread, are highly threatened. Local societies along with their knowledge about the mangrove also are endangered, while they are still underrepresented as scientific research topics. With the present study we document local utilization patterns, and perception of ecosystem change. We illustrate how information generated by ethnobiological research can be used to strengthen the management of the ecosystem. This study was conducted in the Godavari mangrove forest located in the East-Godavari District of the state Andhra Pradesh in India, where mangroves have been degrading due to over-exploitation, extensive development of aquaculture, and pollution from rural and urbanized areas (Kakinada).One hundred interviews were carried out among the fisherfolk population present in two mangrove zones in the study area, a wildlife sanctuary with strong conservation status and an adjacent zone. Results from the interviews indicated that Avicennia marina (Forsk.) Vierh., a dominant species in the Godavari mangroves, is used most frequently as firewood and for construction. Multiple products of the mangrove included the bark of Ceriops decandra (Griff.) Ding Hou to dye the fishing nets and improve their durability, the bark of Aegiceras corniculatum (L.) Blanco to poison and catch fish, and the leaves of Avicennia spp. and Excoecaria agallocha L. as fodder for cattle. No medicinal uses of true mangrove species were reported, but there were a few traditional uses for mangrove associates. Utilization patterns varied in the two zones that we investigated, most likely due to differences in their ecology and legal status. The findings are discussed in relation with the demographic and socio-economic traits of the fisherfolk communities of the Godavari mangroves and indicate a clear dependency of their livelihood on the mangrove forest.Reported changes in the Godavari mangrove cover also differed in the two zones, with significantly less perceptions of a decrease in the protected area, as compared to the adjacent non-protected area. A posteriori comparisons between sequential satellite imagery (retrospective till 1977) and respondents that were at least 15 years back then, revealed a mangrove decrease which was however perceived to different extents depending on the area with which the fishermen were familiar. While local needs had not been incorporated in the existing policy, we created a framework on how data on ethnobotanical traditions, fishery-related activities and local people's perceptions of change can be incorporated into management strategies.
Collapse
Affiliation(s)
- F Dahdouh-Guebas
- Biocomplexity Research Team, c/o, Mangrove Management Group, Vrije Universiteit Brussel, Pleinlaan 2, B-1050 Brussels, Belgium
| | - S Collin
- Biocomplexity Research Team, c/o, Mangrove Management Group, Vrije Universiteit Brussel, Pleinlaan 2, B-1050 Brussels, Belgium
| | - D Lo Seen
- Institut Français de Pondichéry, Rue St. Louis 11, BP 33, 605001 Pondicherry, India
| | - P Rönnbäck
- Department of Systems Ecology, University of Stockholm, Frescati Backe, S-106 91 Stockholm, Sweden
| | - D Depommier
- Institut Français de Pondichéry, Rue St. Louis 11, BP 33, 605001 Pondicherry, India
| | - T Ravishankar
- M.S. Swaminathan Research Foundation, Regional Office, 7-5A-2/1 Gopalakrishna Street, Ramaraopet, 533004 Kakinada, Andhra Pradesh, India
| | - N Koedam
- Laboratory of General Botany and Nature Management, Mangrove Management Group, Vrije Universiteit Brussel, Pleinlaan 2, B-1050 Brussels, Belgium
| |
Collapse
|
49
|
|
50
|
Abstract
Whether or not mangroves function as buffers against tsunamis is the subject of in-depth research, the importance of which has been neglected or underestimated before the recent killer tsunami struck. Our preliminary post-tsunami surveys of Sri Lankan mangrove sites with different degrees of degradation indicate that human activity exacerbated the damage inflicted on the coastal zone by the tsunami.
Collapse
Affiliation(s)
- F Dahdouh-Guebas
- Biocomplexity Research Team, c/o General Botany and Nature Management, Mangrove Management Group, Vrije Universiteit Brussel, Pleinlaan 2, B-1050 Brussels, Belgium
| | | | | | | | | | | |
Collapse
|