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Das A, Choudhury KM, Choudhury AK. An assessment of mangrove vegetation changes in reference to cyclone impacted climatic alterations at land-ocean interface of Indian Sundarbans with application of remote sensing-based analytical tools. ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH INTERNATIONAL 2023; 30:89311-89335. [PMID: 37452248 DOI: 10.1007/s11356-023-28486-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/28/2022] [Accepted: 06/24/2023] [Indexed: 07/18/2023]
Abstract
Mangrove ecoregions of the Indian Sundarbans (IS) are highly productive ecosystems in the Bengal delta of the Indian subcontinent. These mangroves are crucial in reducing the negative consequences of extreme environmental events like excessive wave movements and periodic storm surges, in addition to serving as an important habitat for a variety of distinct flora and animals. The Bay of Bengal has been increasingly affected by climatic changes like increase in sea surface temperature (SST), salinization, and sediment loads, a decrease in freshwater intake, and sea level rise. In the last two decades (2000-2020), these climatic phenomena have increased the frequency of tropical cyclones. From 2000 to 2020, the loss of landmass has been attributed to exposure to these climate changes. According to open-source satellite imaging data, such losses in land area have also led to a decrease in the amount of mangrove vegetation. Thus, to monitor the health of mangrove vegetation, Landsat-based health indicators like normalized difference vegetation index (NDVI), enhanced vegetation index (EVI), and combined mangrove recognition index (CMRI) have been considered in this study. CMRI, as a mangrove-specific index, was measured on the basis of the difference of NDVI and normalized difference water index for remote sensing of vegetation liquid water from space (NDWI_Gao). Furthermore, datasets for abiotic variables have been extrapolated from remotely sensed data for the said period using specific formulae. Both long-term and short-term temporal trends have been considered to better envisage the impact of episodic cyclonic events on mangrove health (1990-2020). Our findings indicate that cyclones altered the habitat with respect to land area and salinization status which would possibly render the dominance of more halotolerant forms with loss of freshwater mangrove biodiversity. Even though plantation efforts have shown the recovery of mangroves in this area, sudden storm surges and concomitant salinization of habitat put the plantation efforts in vain. A combination of factors like salinization, rise in SST, rainfall reduction in pre- and post-monsoon periods and episodic cyclonic events would probably lead to further deterioration of mangrove health in this area. Since the IS is suffering the most from climatic change and intermittent cyclonic occurrences, it is crucial to consider this when making policy decisions. Appropriate actions must be taken along with stronger conservation techniques, to protect this vulnerable environment. Better conservation tactics and ongoing plantation efforts would stop the loss of mangrove vegetation and its habitat, even though the growing frequency of episodic storm occurrences cannot be stopped.
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Affiliation(s)
- Arghadeep Das
- Phycology Lab, Department of Botany, Ramakrishna Mission Vivekananda Centenary College, Rahara, Kolkata, West Bengal, 700118, India
| | | | - Avik Kumar Choudhury
- Phycology Lab, Department of Botany, Ramakrishna Mission Vivekananda Centenary College, Rahara, Kolkata, West Bengal, 700118, India.
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Bird rookery nutrient over-enrichment as a potential accelerant of mangrove cay decline in Belize. Oecologia 2021; 197:771-784. [PMID: 34626271 DOI: 10.1007/s00442-021-05056-w] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2021] [Accepted: 09/28/2021] [Indexed: 10/20/2022]
Abstract
Coastal eutrophication is an issue of serious global concern and although nutrient subsidies can enhance primary productivity of coastal wetlands, they can be detrimental to their long-term maintenance. By supplying nutrients to coastal ecosystems at levels comparable to intensive agriculture practices, roosting colonial waterbirds provide a natural experimental design to examine the impacts of anthropogenic nutrient enrichment in these systems. We tested the hypothesis that long-term nutrient enrichment from bird guano deposition is linked to declines in island size, which may subsequently decrease the stability and resilience of mangrove cays in Belize. We combined remote sensing analysis with field- and lab-based measurements of forest structure, sediment nutrients, and porewater nutrients on three pairs of rookery and control cays in northern, central, and southern Belize. Our results indicate that rookery cays are disappearing approximately 13 times faster than cays without seasonal or resident seabird populations. Rookery cays were associated with a significantly higher concentration of nitrogen (N) in mangrove leaves and greater aboveground biomass, suggesting that eutrophication from bird guano contributes to increased aboveground productivity. Sediments of rookery cays also had lower percentages of soil organic matter and total N and carbon (C) than control islands, which suggests that eutrophication accelerates organic matter decomposition resulting in lower total C stocks on rookery cays. Our results indicate that coastal eutrophication can reduce ecosystem stability by contributing to accelerated cay loss, with potential consequences for mangrove resilience to environmental variability under contemporary and future climatic scenarios.
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Peel JR, Golubov J, Mandujano MC, López‐Portillo J. Phenology and floral synchrony of
Rhizophora mangle
along a natural salinity gradient. Biotropica 2019. [DOI: 10.1111/btp.12644] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
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Bhomia RK, MacKenzie RA, Murdiyarso D, Sasmito SD, Purbopuspito J. Impacts of land use on Indian mangrove forest carbon stocks: Implications for conservation and management. ECOLOGICAL APPLICATIONS : A PUBLICATION OF THE ECOLOGICAL SOCIETY OF AMERICA 2016; 26:1396-1408. [PMID: 27755754 DOI: 10.1890/15-2143] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/05/2015] [Accepted: 12/18/2015] [Indexed: 06/06/2023]
Abstract
Globally, mangrove forests represents only 0.7% of world's tropical forested area but are highly threatened due to susceptibility to climate change, sea level rise, and increasing pressures from human population growth in coastal regions. Our study was carried out in the Bhitarkanika Conservation Area (BCA), the second-largest mangrove area in eastern India. We assessed total ecosystem carbon (C) stocks at four land use types representing varying degree of disturbances. Ranked in order of increasing impacts, these sites included dense mangrove forests, scrub mangroves, restored/planted mangroves, and abandoned aquaculture ponds. These impacts include both natural and/or anthropogenic disturbances causing stress, degradation, and destruction of mangroves. Mean vegetation C stocks (including both above- and belowground pools; mean ± standard error) in aquaculture, planted, scrub, and dense mangroves were 0, 7 ± 4, 65 ± 11 and 100 ± 11 Mg C/ha, respectively. Average soil C pools for aquaculture, planted, scrub, and dense mangroves were 61 ± 8, 92 ± 20, 177 ± 14, and 134 ± 17 Mg C/ha, respectively. Mangrove soils constituted largest fraction of total ecosystem C stocks at all sampled sites (aquaculture [100%], planted [90%], scrub [72%], and dense mangrove [57%]). Within BCA, the four studied land use types covered an area of ~167 km2 and the total ecosystem C stocks were 0.07 Tg C for aquaculture (~12 km2 ), 0.25 Tg C for planted/ restored mangrove (~24 km2 ), 2.29 teragrams (Tg) Tg C for scrub (~93 km2 ), and 0.89 Tg C for dense mangroves (~38 km2 ). Although BCA is protected under Indian wildlife protection and conservation laws, ~150 000 people inhabit this area and are directly or indirectly dependent on mangrove resources for sustenance. Estimates of C stocks of Bhitarkanika mangroves and recognition of their role as a C repository could provide an additional reason to support conservation and restoration of Bhitarkanika mangroves. Harvesting or destructive exploitation of mangroves by local communities for economic gains can potentially be minimized by enabling these communities to avail themselves of carbon offset/conservation payments under approved climate change mitigation strategies and actions.
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Affiliation(s)
- R K Bhomia
- Department of Fisheries and Wildlife, Oregon State University, Corvallis, Oregon 97331, USA
- Center for International Forestry Research (CIFOR), Jalan CIFOR, Situgede, Bogor 16115, Indonesia
| | - R A MacKenzie
- USDA Forest Service, Pacific Southwest Research Station, Institute of Pacific Islands Forestry, Hilo, Hawaii 96720, USA
| | - D Murdiyarso
- Center for International Forestry Research (CIFOR), Jalan CIFOR, Situgede, Bogor 16115, Indonesia
- Department of Geophysics and Meteorology, Bogor Agricultural University, Darmaga Campus, Bogor 16152, Indonesia
| | - S D Sasmito
- Center for International Forestry Research (CIFOR), Jalan CIFOR, Situgede, Bogor 16115, Indonesia
| | - J Purbopuspito
- Soil Science Department, Sam Ratulangi University, Kampus Kleak-Bahu, Manado 95115, Indonesia
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Goessens A, Satyanarayana B, Van der Stocken T, Quispe Zuniga M, Mohd-Lokman H, Sulong I, Dahdouh-Guebas F. Is Matang Mangrove Forest in Malaysia sustainably rejuvenating after more than a century of conservation and harvesting management? PLoS One 2014; 9:e105069. [PMID: 25144689 PMCID: PMC4140741 DOI: 10.1371/journal.pone.0105069] [Citation(s) in RCA: 82] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2014] [Accepted: 07/17/2014] [Indexed: 11/18/2022] Open
Abstract
Matang Mangrove Forest Reserve (MMFR) in Peninsular Malaysia is under systematic management since 1902 and still considered as the best managed mangrove forest in the world. The present study on silvimetrics assessed the ongoing MMFR forest management, which includes a first thinning after 15 years, a second thinning after 20 years and clear-felling of 30-year old forest blocks, for its efficiency and productivity in comparison to natural mangroves. The estimated tree structural parameters (e.g. density, frequency) from three different-aged mangrove blocks of fifteen (MF15), twenty (MF20), and thirty (MF30) years old indicated that Bruguiera and Excoecaria spp. did not constitute a significant proportion of the vegetation (<5%), and hence the results focused majorly on Rhizophora apiculata. The density of R. apiculata at MF15, MF20 and MF30 was 4,331, 2,753 and 1,767 stems ha(-1), respectively. In relation to ongoing practices of the artificial thinnings at MMFR, the present study suggests that the first thinning could be made earlier to limit the loss of exploitable wood due to natural thinning. In fact, the initial density at MF15 was expected to drop down from 6,726 to 1,858 trees ha(-1) before the first thinning. Therefore the trees likely to qualify for natural thinning, though having a smaller stem diameter, should be exploited for domestic/commercial purposes at an earlier stage. The clear-felling block (MF30) with a maximum stem diameter of 30 cm was estimated to yield 372 t ha(-1) of the above-ground biomass and suggests that the mangrove management based on a 30-year rotation is appropriate for the MMFR. Since Matang is the only iconic site that practicing sustainable wood production, it could be an exemplary to other mangrove locations for their improved management.
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Affiliation(s)
- Arnaud Goessens
- Laboratory of Systems Ecology and Resource Management, Université Libre de Bruxelles - ULB, CPI 264/1, Brussels, Belgium
- Mangrove Research Unit (MARU), Institute of Oceanography and Environment (INOS), Universiti Malaysia Terengganu - UMT, Kuala Terengganu, Malaysia
| | - Behara Satyanarayana
- Laboratory of Systems Ecology and Resource Management, Université Libre de Bruxelles - ULB, CPI 264/1, Brussels, Belgium
- Mangrove Research Unit (MARU), Institute of Oceanography and Environment (INOS), Universiti Malaysia Terengganu - UMT, Kuala Terengganu, Malaysia
- Laboratory of Plant Biology and Nature Management, Vrije Universiteit Brussel - VUB, Brussels, Belgium
- * E-mail:
| | - Tom Van der Stocken
- Laboratory of Systems Ecology and Resource Management, Université Libre de Bruxelles - ULB, CPI 264/1, Brussels, Belgium
- Laboratory of Plant Biology and Nature Management, Vrije Universiteit Brussel - VUB, Brussels, Belgium
| | - Melissa Quispe Zuniga
- Laboratory of Systems Ecology and Resource Management, Université Libre de Bruxelles - ULB, CPI 264/1, Brussels, Belgium
- Laboratory of Plant Biology and Nature Management, Vrije Universiteit Brussel - VUB, Brussels, Belgium
| | - 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
| | - Farid Dahdouh-Guebas
- Laboratory of Systems Ecology and Resource Management, Université Libre de Bruxelles - ULB, CPI 264/1, Brussels, Belgium
- Laboratory of Plant Biology and Nature Management, Vrije Universiteit Brussel - VUB, Brussels, Belgium
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Lipset D. The tides: masculinity and climate change in coastal Papua New Guinea. JOURNAL OF THE ROYAL ANTHROPOLOGICAL INSTITUTE 2011. [DOI: 10.1111/j.1467-9655.2010.01667.x] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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Shearman PL. Recent change in the extent of mangroves in the northern Gulf of Papua, Papua New Guinea. AMBIO 2010; 39:181-9. [PMID: 20653280 PMCID: PMC3357694 DOI: 10.1007/s13280-010-0025-4] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/16/2023]
Abstract
Existing at the interface of land and sea, in regions of low topographic relief, mangroves are likely to be some of the first ecosystems that undergo spatial modification due to sea-level rise. The mangrove ecosystems of the Gulf of Papua New Guinea are some of the largest and most pristine in the Asia-Pacific region; they have not been subject to clearance for crustacean farming nor suffered from land reclamation projects. This article establishes through analysis of a time series of aerial photography and satellite imagery from the period 1973-2007, that there have been substantial changes in the distribution of mangroves in this region. These changes include the seaward progradation of the Purari Delta and the regression of the Kikori Delta by an average of 43 m year(-1) at its most seaward point. While these findings are likely to be continuations of long-term trends, it is probable that they can be explained by a variety of interacting factors including climate change, sea-level rise, subsistence in the northern Gulf of Papua and changes in sediment dynamics.
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Affiliation(s)
- Philip L Shearman
- Biology Department, University of Papua New Guinea, Waigani, Port Moresby, Papua New Guinea.
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