1
|
Agarwal A, Wahajuddin M, Chaturvedi S, Singh SK, Rashid M, Garg R, Chauhan DI, Sultana N, Gayen JR. Formulation and Characterization of Phytosomes as Drug Delivery System of Formononetin: An Effective Anti-Osteoporotic Agent. Curr Drug Deliv 2024; 21:261-270. [PMID: 36734892 DOI: 10.2174/1567201820666230124114906] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2022] [Revised: 11/16/2022] [Accepted: 11/25/2022] [Indexed: 02/04/2023]
Abstract
BACKGROUND Formononetin (FNT), a methoxy isoflavone, is a potential phytoconstituent utilized for refurbishing fractures in bone tissue. Conceding to its involvement in first-pass metabolism followed by glucuronidation, its absorption efficacy is limited. Hence, it belongs to the BCS class II classification. OBJECTIVE We designed the present work to enhance FNT oral bioavailability by using Phospholipids (PL) as a promising carrier. Formononetin Phospholipid Complex (FNT-PC) was prepared by the solvent evaporation method and characterized. METHODS FNT-PC was prepared by solvent evaporation method and characterization (FNT-PC) was performed using aqueous/n-octanol solubility and partition coefficient, FTIR, NMR, SEM, and in vivo pharmacokinetic study in female SD rats at 50 mg/kg. RESULTS Physicochemical properties like aqueous/n-octanol solubility and partition coefficient were enhanced in FNT-PC. The FTIR spectrum confirmed there was no involvement of functional groups in the preparation of FNT-PC. Whereas, the NMR study resulted in the attachment of carbon (C-8) position of FNT by replacing the quaternary amine of PL to form FNT-PC. When scrutinized for its surface morphology, the FNT-PC exhibited the amorphous geometry that remarkably enhanced the dissolution of FNT (p<0.05) from its pure form. This dissolution effect was also affirmed by the per-oral administration of FNT-PC in female Sprague Dawley (SD) rats at 50 mg/kg dose. The pharmacokinetic profile showed the free FNT levels were markedly increased, correspondingly decreasing the conjugated FNT levels in rat plasma. CONCLUSION To summarize, FNT-PC could substantially reduce the first-pass metabolism with enhanced free concentration, improving oral bioavailability for therapeutic use.
Collapse
Affiliation(s)
- Arun Agarwal
- Pharmaceutics and Pharmacokinetics Division, CSIR-Central Drug Research Institute, Lucknow-226031, India
- Academy of Scientific and Innovative Research (AcSIR), Ghaziabad-201002, India
| | - Muhammad Wahajuddin
- Pharmaceutics and Pharmacokinetics Division, CSIR-Central Drug Research Institute, Lucknow-226031, India
- Academy of Scientific and Innovative Research (AcSIR), Ghaziabad-201002, India
- Institute of Cancer Therapeutics, School of Pharmacy and Medical Sciences, Faculty of Life Sciences, University of Bradford, Richmond Road, Bradford BD7 1DP, United Kingdom
| | - Swati Chaturvedi
- Pharmaceutics and Pharmacokinetics Division, CSIR-Central Drug Research Institute, Lucknow-226031, India
- Academy of Scientific and Innovative Research (AcSIR), Ghaziabad-201002, India
| | - Sandeep K Singh
- Pharmaceutics and Pharmacokinetics Division, CSIR-Central Drug Research Institute, Lucknow-226031, India
- Academy of Scientific and Innovative Research (AcSIR), Ghaziabad-201002, India
| | - Mamunur Rashid
- Pharmaceutics and Pharmacokinetics Division, CSIR-Central Drug Research Institute, Lucknow-226031, India
| | - Richa Garg
- Pharmaceutics and Pharmacokinetics Division, CSIR-Central Drug Research Institute, Lucknow-226031, India
- Academy of Scientific and Innovative Research (AcSIR), Ghaziabad-201002, India
| | - DIvya Chauhan
- Pharmaceutics and Pharmacokinetics Division, CSIR-Central Drug Research Institute, Lucknow-226031, India
- Academy of Scientific and Innovative Research (AcSIR), Ghaziabad-201002, India
| | - Nazneen Sultana
- Pharmaceutics and Pharmacokinetics Division, CSIR-Central Drug Research Institute, Lucknow-226031, India
| | - Jiaur R Gayen
- Pharmaceutics and Pharmacokinetics Division, CSIR-Central Drug Research Institute, Lucknow-226031, India
- Academy of Scientific and Innovative Research (AcSIR), Ghaziabad-201002, India
| |
Collapse
|
2
|
Martin N, Robinson TB, Clusella-Trullas S. Warmer and more acidic conditions enhance performance of an endemic low shore gastropod. J Exp Biol 2023:308997. [PMID: 37158127 DOI: 10.1242/jeb.245423] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2022] [Accepted: 05/02/2023] [Indexed: 05/10/2023]
Abstract
Changing ocean temperatures are predicted to challenge marine organisms, especially when combined with other factors, such as ocean acidification. Acclimation, as a form of phenotypic plasticity, can however, moderate the consequences of changing environments for biota. Our understanding of how altered temperature and acidification together influence species acclimation responses is, however, limited compared to responses to single stressors. This study investigated how temperature and acidification affected the thermal tolerance and righting speed of the Girdled Dogwhelk, Trochia cingulata (Linnaeus, 1771). Whelks were acclimated for two weeks to combinations of three temperatures (11°C: cold, 13°C: moderate and 15°C: warm) and two pH regimes (8.0: moderate and 7.5: acidic). We measured the temperature sensitivity of righting response by generating thermal performance curves from individual data collected at seven test temperatures and determined critical thermal minima (CTmin) and maxima (CTmax). We found that T. cingulata has a broad basal thermal tolerance range (∼38°C) and after acclimation to the warm temperature regime, both the optimal temperature for maximum righting speed and CTmax increased. Contrary to predictions, acidification did not narrow this population's thermal tolerance but increased CTmax. These plastic responses are likely driven by the predictable exposure to temperature extremes measured in the field which originate from the local tidal cycle and the periodic acidification associated with ocean upwelling in the region. This acclimation ability suggests that T. cingulata has at least some capacity to buffer the thermal changes and increased acidification predicted to occur with climate change.
Collapse
Affiliation(s)
- Nicole Martin
- Department of Botany and Zoology, Centre for Invasion Biology, Stellenbosch University, Stellenbosch, South Africa
| | - Tamara B Robinson
- Department of Botany and Zoology, Centre for Invasion Biology, Stellenbosch University, Stellenbosch, South Africa
| | - Susana Clusella-Trullas
- Department of Botany and Zoology, Centre for Invasion Biology, Stellenbosch University, Stellenbosch, South Africa
| |
Collapse
|
3
|
Vimercati G, Probert AF, Volery L, Bernardo-Madrid R, Bertolino S, Céspedes V, Essl F, Evans T, Gallardo B, Gallien L, González-Moreno P, Grange MC, Hui C, Jeschke JM, Katsanevakis S, Kühn I, Kumschick S, Pergl J, Pyšek P, Rieseberg L, Robinson TB, Saul WC, Sorte CJB, Vilà M, Wilson JRU, Bacher S. The EICAT+ framework enables classification of positive impacts of alien taxa on native biodiversity. PLoS Biol 2022; 20:e3001729. [PMID: 35972940 PMCID: PMC9380921 DOI: 10.1371/journal.pbio.3001729] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [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] [Indexed: 11/18/2022] Open
Abstract
Species introduced through human-related activities beyond their native range, termed alien species, have various impacts worldwide. The IUCN Environmental Impact Classification for Alien Taxa (EICAT) is a global standard to assess negative impacts of alien species on native biodiversity. Alien species can also positively affect biodiversity (for instance, through food and habitat provisioning or dispersal facilitation) but there is currently no standardized and evidence-based system to classify positive impacts. We fill this gap by proposing EICAT+, which uses 5 semiquantitative scenarios to categorize the magnitude of positive impacts, and describes underlying mechanisms. EICAT+ can be applied to all alien taxa at different spatial and organizational scales. The application of EICAT+ expands our understanding of the consequences of biological invasions and can inform conservation decisions.
Collapse
Affiliation(s)
- Giovanni Vimercati
- Department of Biology, University of Fribourg, Fribourg, Switzerland
- * E-mail:
| | - Anna F. Probert
- Department of Biology, University of Fribourg, Fribourg, Switzerland
| | - Lara Volery
- Department of Biology, University of Fribourg, Fribourg, Switzerland
| | - Ruben Bernardo-Madrid
- Department of Integrated Biology, Estación Biológica de Doñana (EBD), CSIC, Sevilla, Spain
| | - Sandro Bertolino
- Department of Life Sciences and Systems Biology, University of Turin, Torino, Italy
| | - Vanessa Céspedes
- Laboratory of Aquatic Ecology, Estación Biológica de Doñana (EBD), CSIC, Sevilla, Spain
| | - Franz Essl
- Bioinvasions, Global Change, Macroecology-Group, Department of Botany and Biodiversity Research, University of Vienna, Vienna, Austria
| | - Thomas Evans
- Ecologie Systématique et Evolution, Université Paris-Saclay, Gif-sur-Yvette, France
- Institute of Biology, Freie Universität Berlin, Berlin, Germany
- Leibniz Institute of Freshwater Ecology and Inland Fisheries (IGB), Berlin, Germany
- Berlin-Brandenburg Institute of Advanced Biodiversity Research (BBIB), Berlin, Germany
| | | | - Laure Gallien
- Univ. Grenoble Alpes, Univ. Savoie Mont Blanc, CNRS, LECA, Grenoble, France
| | | | | | - Cang Hui
- Centre for Invasion Biology, Department of Mathematical Sciences, Stellenbosch University, Stellenbosch, South Africa
- Biodiversity Informatics Unit, African Institute for Mathematical Sciences, Cape Town, South Africa
| | - Jonathan M. Jeschke
- Institute of Biology, Freie Universität Berlin, Berlin, Germany
- Leibniz Institute of Freshwater Ecology and Inland Fisheries (IGB), Berlin, Germany
- Berlin-Brandenburg Institute of Advanced Biodiversity Research (BBIB), Berlin, Germany
| | | | - Ingolf Kühn
- Department Community Ecology, Helmholtz Centre for Environmental Research—UFZ, Halle, Germany
- Department of Geobotany and Botanical Garden, Martin Luther University Halle-Wittenberg, Halle, Germany
- German Centre for Integrative Biodiversity Research (iDiv) Halle-Jena-Leipzig, Leipzig, Germany
| | - Sabrina Kumschick
- Centre for Invasion Biology, Department of Botany and Zoology, Stellenbosch University, Stellenbosch, South Africa
- Kirstenbosch Research Centre, South African National Biodiversity Institute, Cape Town, South Africa
| | - Jan Pergl
- Department of Invasion Ecology, Institute of Botany, Czech Academy of Sciences, Průhonice, Czech Republic
| | - Petr Pyšek
- Department of Invasion Ecology, Institute of Botany, Czech Academy of Sciences, Průhonice, Czech Republic
- Department of Ecology, Faculty of Science, Charles University, Prague, Czech Republic
| | - Loren Rieseberg
- Department of Botany and Biodiversity Research Centre, University of British Columbia, Vancouver, Canada
| | - Tamara B. Robinson
- Centre for Invasion Biology, Department of Botany and Zoology, Stellenbosch University, Stellenbosch, South Africa
| | - Wolf-Christian Saul
- Institute of Biology, Freie Universität Berlin, Berlin, Germany
- Leibniz Institute of Freshwater Ecology and Inland Fisheries (IGB), Berlin, Germany
- Berlin-Brandenburg Institute of Advanced Biodiversity Research (BBIB), Berlin, Germany
| | - Cascade J. B. Sorte
- Department of Ecology and Evolutionary Biology, University of California, Irvine, California, United States of America
| | - Montserrat Vilà
- Department of Integrated Biology, Estación Biológica de Doñana (EBD), CSIC, Sevilla, Spain
- Department of Plant Biology and Ecology, University of Sevilla, Sevilla, Spain
| | - John R. U. Wilson
- Centre for Invasion Biology, Department of Botany and Zoology, Stellenbosch University, Stellenbosch, South Africa
- Kirstenbosch Research Centre, South African National Biodiversity Institute, Cape Town, South Africa
| | - Sven Bacher
- Department of Biology, University of Fribourg, Fribourg, Switzerland
| |
Collapse
|
4
|
du Plessis NS, Rebelo AJ, Richardson DM, Esler KJ. Guiding restoration of riparian ecosystems degraded by plant invasions: Insights from a complex social-ecological system in the Global South. Ambio 2022; 51:1552-1568. [PMID: 34962641 PMCID: PMC8713150 DOI: 10.1007/s13280-021-01691-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 06/03/2021] [Revised: 08/27/2021] [Accepted: 12/03/2021] [Indexed: 06/14/2023]
Abstract
Restoring riparian ecosystems in human-dominated landscapes requires attention to complexity, and consideration of diverse drivers, social actors, and contexts. Addressing a Global North bias, this case study uses a mixed-method approach, integrating historical data, remote sensing techniques and stakeholder perceptions to guide restoration of a river in the Western Cape, South Africa. An analysis of aerial photographs of the riparian zone from 1953 to 2016 revealed that although anthropogenic land conversion happened primarily before the 1950s, several land use and land cover classes showed marked increases in area, including: waterbodies (+ 1074%), urban areas (+ 316%), alien weeds (+ 311%) and terrestrial alien trees (+ 79%). These changes have likely been driven by land fragmentation, disturbance, and agricultural intensification. Stakeholder interviews revealed that despite the clear need for restoration, several barriers exist to successful implementation; these stem from inadequate financial resources, inappropriate funding models, institutional challenges, and a lack of techno-scientific knowledge. We give several recommendations to overcome these barriers.
Collapse
Affiliation(s)
- Nicola S. du Plessis
- Department of Conservation Ecology and Entomology, Stellenbosch University, Private Bag X1, Matieland, 7602 South Africa
| | - Alanna J. Rebelo
- Department of Conservation Ecology and Entomology, Stellenbosch University, Private Bag X1, Matieland, 7602 South Africa
| | - David M. Richardson
- Centre for Invasion Biology, Stellenbosch University, Private Bag X1, Matieland, 7602 South Africa
- Department of Botany and Zoology, Stellenbosch University, Private Bag X1, Matieland, 7602 South Africa
| | - Karen J. Esler
- Department of Conservation Ecology and Entomology, Stellenbosch University, Private Bag X1, Matieland, 7602 South Africa
- Centre for Invasion Biology, Stellenbosch University, Private Bag X1, Matieland, 7602 South Africa
| |
Collapse
|
5
|
Muzondiwa D, Hlanze H, Reva ON. The Epistatic Landscape of Antibiotic Resistance of Different Clades of Mycobacterium tuberculosis. Antibiotics (Basel) 2021; 10:857. [PMID: 34356778 PMCID: PMC8300818 DOI: 10.3390/antibiotics10070857] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2021] [Revised: 07/08/2021] [Accepted: 07/13/2021] [Indexed: 11/16/2022] Open
Abstract
Drug resistance (DR) remains a global challenge in tuberculosis (TB) control. In order to develop molecular-based diagnostic methods to replace the traditional culture-based diagnostics, there is a need for a thorough understanding of the processes that govern TB drug resistance. The use of whole-genome sequencing coupled with statistical and computational methods has shown great potential in unraveling the complexity of the evolution of DR-TB. In this study, we took an innovative approach that sought to determine nonrandom associations between polymorphic sites in Mycobacterium tuberculosis (Mtb) genomes. Attributable risk statistics were applied to identify the epistatic determinants of DR in different clades of Mtb and the possible evolutionary pathways of DR development. It was found that different lineages of Mtb exploited different evolutionary trajectories towards multidrug resistance and compensatory evolution to reduce the DR-associated fitness cost. Epistasis of DR acquisition is a new area of research that will aid in the better understanding of evolutionary biological processes and allow predicting upcoming multidrug-resistant pathogens before a new outbreak strikes humanity.
Collapse
Affiliation(s)
| | | | - Oleg N. Reva
- Centre for Bioinformatics and Computational Biology, Department of Biochemistry, Genetics and Microbiology, University of Pretoria, Pretoria 0002, South Africa; (D.M.); (H.H.)
| |
Collapse
|
6
|
Iyemosolo BM, Chivese T, Esterhuizen TM. A comparison of the prevalence of sexually transmitted infections among circumcised and uncircumcised adult males in Rustenburg, South Africa: a cross-sectional study. BMC Public Health 2021; 21:656. [PMID: 33823828 PMCID: PMC8022379 DOI: 10.1186/s12889-021-10509-1] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2020] [Accepted: 02/25/2021] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND South Africa has a persistent burden of sexually transmitted infections (STIs). Male circumcision has been shown to be effective in preventing HIV and STIs, but data are scarce on the protective effect of circumcision in high-risk populations such as migrant miners. The objective of this study was to assess the effect of medical and traditional circumcision on the prevalence of STIs after adjusting for other risk factors in Rustenburg, a mining town in North West Province, South Africa. METHODS This cross-sectional study used baseline data collected from a cohort study. Adult males in a mining town were assessed for STIs (gonorrhea, chlamydia, and trichomoniasis) using syndromic assessment. Data on circumcision status and other risk factors for STI syndromes were collected using an interviewer-administered questionnaire. The following symptoms were assessed; penile discharge, painful urination, dyspareunia or penile sores. These symptoms indicate sexually transmitted infection in general since laboratory tests were not performed. Multivariable log binomial regression was used to assess the independent effect of circumcision on STI presence after adjusting for confounders. RESULTS A total of 339 participants with a median age of 25 years (IQR 22-29) were included in the study, of whom 116 (34.2%) were circumcised. The overall STIs prevalence was 27.4% (95% CI 22.8 to 32.6%) and was lower in the circumcised participants compared with those who were uncircumcised (15.5% vs 33.6%, respectively, p < 0.001). Both medical (OR 0.57, 95% CI 0.34-0.95, p = 0.030) and traditional circumcision (OR 0.34, 95% CI 0.13-0.86, p = 0.022) were strongly associated with a lower risk of STIs after adjustment for employment and condom use. CONCLUSION In this high-risk population in a mining town in South Africa, with a relatively high prevalence of STIs, and where one third of males are circumcised, both medical and traditional circumcision appear to be protective against STIs.
Collapse
Affiliation(s)
- Blanchard Mbay Iyemosolo
- Department of Global Health, Division of Epidemiology and Biostatistics, Faculty of Medicine and Health Sciences, University of Stellenbosch, Cape Town, South Africa
| | - Tawanda Chivese
- Department of Population Medicine, College of Medicine, QU Health, Qatar University, Doha, Qatar
| | - Tonya M. Esterhuizen
- Department of Global Health, Division of Epidemiology and Biostatistics, Faculty of Medicine and Health Sciences, University of Stellenbosch, Cape Town, South Africa
| |
Collapse
|
7
|
Nunes AL, Fill JM, Davies SJ, Louw M, Rebelo AD, Thorp CJ, Vimercati G, Measey J. A global meta-analysis of the ecological impacts of alien species on native amphibians. Proc Biol Sci 2019; 286:20182528. [PMID: 30963838 PMCID: PMC6408899 DOI: 10.1098/rspb.2018.2528] [Citation(s) in RCA: 38] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2018] [Accepted: 02/01/2019] [Indexed: 01/02/2023] Open
Abstract
The exponential increase in species introductions during the Anthropocene has brought about a major loss of biodiversity. Amphibians have suffered large declines, with more than 16% considered to be threatened by invasive species. We conducted a global meta-analysis of the impacts of alien species on native amphibians to determine which aspects of amphibian ecology are most affected by plant, invertebrate, fish, amphibian, reptile, or mammal introductions. Measures of fitness were most strongly affected; amphibian performance was consistently lower in the presence of alien species. While exposure to alien species caused a significant decrease in amphibian behavioural activity when compared with a no species control, this response was stronger towards a control of native impacting species. This indicates a high degree of prey naiveté towards alien species and highlights the importance of using different types of controls in empirical studies. Alien invertebrates had the greatest overall impact on amphibians. This study sets a new agenda for research on biological invasions, highlighting the lack of studies investigating the impacts of alien species on amphibian terrestrial life-history stages. It also emphasizes the strong ecological impacts that alien species have on amphibian fitness and suggests that future introductions or global spread of alien invertebrates could strongly exacerbate current amphibian declines.
Collapse
Affiliation(s)
- Ana L. Nunes
- Centre for Invasion Biology, Department of Botany and Zoology, Stellenbosch University, Stellenbosch, South Africa
- South African National Biodiversity Institute, Kirstenbosch Research Centre, Cape Town, South Africa
| | - Jennifer M. Fill
- Centre for Invasion Biology, Department of Botany and Zoology, Stellenbosch University, Stellenbosch, South Africa
| | - Sarah J. Davies
- Centre for Invasion Biology, Department of Botany and Zoology, Stellenbosch University, Stellenbosch, South Africa
| | - Marike Louw
- Centre for Invasion Biology, Department of Botany and Zoology, Stellenbosch University, Stellenbosch, South Africa
| | - Alexander D. Rebelo
- Centre for Invasion Biology, Department of Botany and Zoology, Stellenbosch University, Stellenbosch, South Africa
| | - Corey J. Thorp
- Centre for Invasion Biology, Department of Botany and Zoology, Stellenbosch University, Stellenbosch, South Africa
| | - Giovanni Vimercati
- Centre for Invasion Biology, Department of Botany and Zoology, Stellenbosch University, Stellenbosch, South Africa
| | - John Measey
- Centre for Invasion Biology, Department of Botany and Zoology, Stellenbosch University, Stellenbosch, South Africa
| |
Collapse
|
8
|
Strydom M, Veldtman R, Ngwenya MZ, Esler KJ. Invasive Australian Acacia seed banks: Size and relationship with stem diameter in the presence of gall-forming biological control agents. PLoS One 2017; 12:e0181763. [PMID: 28813440 PMCID: PMC5558976 DOI: 10.1371/journal.pone.0181763] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.1] [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: 04/03/2017] [Accepted: 07/06/2017] [Indexed: 11/19/2022] Open
Abstract
Australian Acacia are invasive in many parts of the world. Despite significant mechanical and biological efforts to control their invasion and spread, soil-stored seed banks prevent their effective and sustained removal. In response South Africa has had a strong focus on employing seed reducing biological control agents to deal with Australian Acacia invasion, a programme that is considered as being successful. To provide a predictive understanding for their management, seed banks of four invasive Australian acacia species (Acacia longifolia, A. mearnsii, A. pycnantha and A. saligna) were studied in the Western Cape of South Africa. Across six to seven sites for each species, seed bank sizes were estimated from dense, monospecific stands by collecting 30 litter and soil samples. Average estimated seed bank size was large (1017 to 17261 seed m-2) as was annual input into the seed bank, suggesting that these seed banks are not residual but are replenished in size annually. A clear relationship between seed bank size and stem diameter was established indicating that mechanical clearing should be conducted shortly after fire-stimulated recruitment events or within old populations when seed banks are small. In dense, monospecific stands seed-feeding biological control agents are not effective in reducing seed bank size.
Collapse
Affiliation(s)
- Matthys Strydom
- Department of Conservation Ecology and Entomology, Stellenbosch University, Matieland, South Africa
- Centre of Excellence for Invasion Biology, Stellenbosch University, Matieland, South Africa
| | - Ruan Veldtman
- Department of Conservation Ecology and Entomology, Stellenbosch University, Matieland, South Africa
- South African National Biodiversity Institute, Kirstenbosch National Botanical Garden, Cape Town, South Africa
| | | | - Karen J. Esler
- Department of Conservation Ecology and Entomology, Stellenbosch University, Matieland, South Africa
- Centre of Excellence for Invasion Biology, Stellenbosch University, Matieland, South Africa
| |
Collapse
|