Browsing by Subject "Mangrove"
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Item Open Access A Systematic Review of Facilitation in Intertidal Habitats(2021-04-30) Townsend, SamanthaRecent decades have seen an increase in research on positive species interactions, and it is now known that they are ubiquitous in nature. However, these interactions were never intentionally used in beneficial ways. This changed in 2015 when a study revealed that positive species interactions could aid in salt marsh restoration. Since then, the restoration paradigm has shifted from systematically suppressing negative interactions to harnessing nature’s positive interactions, including ecological facilitation. This review investigates the facilitative interactions that have been observed in intertidal habitats, including salt marshes, mangroves, and oyster reefs. I performed a systematic review to highlight the general trends and research gaps in the study of facilitation across these three intertidal habitats. Seventy-eight studies were included in the database, and the earliest study was published in 1984 in a salt marsh. Since then, studies have increased exponentially. The majority were located in mid-latitudes but were spread across six continents and 18 countries. The 78 studies revealed 212 unique, facilitative interactions. One hundred and thirty-two of these interactions were in salt marshes, 77 were in mangroves, and only 3 were in oyster reefs. The majority of interactions involved autotrophs and lower trophic level species. In addition, the majority of facilitative interactions were direct, interspecific, non-trophic, and involved a primary foundation species. The 78 papers in this database revealed some previously unknown trends in intertidal facilitation which can actively be incorporated into restoration projects. However, this study also revealed the major research gaps in the field that need to be filled in order to more thoroughly establish facilitative theory and most effectively include facilitation in intertidal restoration design.Item Open Access An Analysis Comparing Mangrove Conditions under Different Management Scenarios in Southeast Asia(2017-04-27) Shi, CongjieMangroves in Phang Nga Bay, Thailand and in Matang Mangrove Reserve, Malaysia serve a variety of crucial ecosystem services. However, they are threatened by various natural and human-influenced factors such as tsunami damage and development in recent decades. This project provides a look at how distribution and status of mangrove forests have changed over time and how mangrove health changes over time. Selected Landsat 5 TM images from 2000 to 2010 were analyzed to classify the land use changes by object-oriented method using feature extraction and by supervised classification. The expansion in urban development and agriculture is concerning for both Thailand and Malaysia according to the literature review (Gopal and Chauhan 2006; Giri et al. 2008). The Phang Nga Bay mangroves experienced significant 6.3% decline from 2003 to 2010 according to the supervised classification with tasseled-cap transformation. The Matang mangroves experienced a 3.95% decline from 2000 to 2010 according to the supervised classification. Although these mangroves are declining at a slower rate than the reported national and global average, the rate of decrease is still concerning compare to other Southeast Asian mangroves. We also examined the overall characteristics such as EVI, NDVI, GPP, and NDWI using Google Earth Engine to compare the overall patterns in the two study areas. There is no significant difference in EVI between the two study areas. The EVI value is 0.54 for the site in Thailand and 0.52 for the site in Malaysia. NDVI is higher for mangroves in the Thai site (0.61) than the Malaysian site (0.42). Mangroves at the Malaysian site has higher GPP and NDWI. The mean GPP for the site in Malaysia is 354 kg*C/m^2, while the mean GPP is only 217 kg*C/m^2 for the site in Thailand. The trend in GPP can be fit into an ARIMA(1, 0, 1)*(1, 0, 0)46 model for the Thai site and an ARIMA(2, 0, 1)*(1, 0, 0)46 model for the Malaysia site. The NDWI values are 0.149 and 0.137 for the Malaysian site and the Thai site correspondingly. The derived indices (tasseled cap, NDVI, and SAVI) were used to classify the mangrove areas into subclasses. An EO-1 Hyperion imagery from 2014 was examined to classify mangrove types in the Thai study area. We were able to classify mangroves into edge, island, riverine, estuary, and inland types based on the good spectral bands. A spectral library for the region or field data is necessary for more exact species classification. In terms of management, the local conservation departments and national park services in Thailand need to reach out more frequently to the local community and educate the fishermen and hoteliers about the ecosystem services of mangroves. It can be worthwhile for Matang forest managers to test the mixed block method with managed and natural mangrove patches to sustain biodiversity and ecological function of mangrove forests.Item Open Access Economic Valuation of Mangrove-Fishery Linkages in Guyana and Suriname(2019-04-24) Bollini, Celeste; Millar, EmilyMangroves are among the most productive ecosystems in the word. By providing valuable ecosystem services, mangroves enhance human well-being and contribute to biodiversity conservation in the tropical and subtropical regions where they are found. Mangroves provide nursery, feeding, breeding grounds, and shelter areas for many marine species, which in turn enhances the productivity of traditional and commercial fisheries. The objective of the present study is to evaluate how mangrove ecosystems affect fisheries in Guyana and Suriname, as part of a collaborative project between the Nicholas Institute for Environmental Policy Solutions and Conservation International. The evaluation involved conducting a meta-analysis of information drawn from 21 mangrove-fishery linkage studies from around the world to estimate a general model relating fish catch to mangrove area. A benefit transfer method was then used to apply the results from the meta-analysis to recent and projected future changes in mangrove areas in Guyana and Suriname, and thereby predict the impacts on fish catch in the two countries. The first section of this report provides an overview of mangrove ecosystems, definitions of the four types of ecosystem services identified by the Millennium Ecosystem Assessment, and an outline of the ecosystem services provided exclusively by mangroves. This section also highlights some of the main global drivers of mangrove loss. Lastly, it provides the main objectives of this project, an overview of Guyana and Suriname, and estimates of the areas and trends in mangroves in both countries. Mangrove area change was calculated using the average of estimates from two sources for each country. The estimated changes in mangrove area during 2000-2017 were -1.96% per year in Guyana and -0.76% per year in Suriname. The second section of this report describes the methods used to determine how these trends have affected fisheries in Guyana and Suriname. After providing an overview of the meta-analysis and benefit transfer methods, this section explains the variables selected for the meta-analysis. Variables were selected to capture essential characteristics of the study sites and the studies themselves. Finally, the equation estimated by the meta-analysis is defined. This equation relates the impacts of mangrove area reported by the studies to the selected variables. Observations were included in the dataset for estimating this equation only if a study included sufficient information for calculating the reported impact as an elasticity, which can be explained as follows: denoting the elasticity by Ɛ, a 1% increase in mangrove area increases fish catch by Ɛ%. The third section of this report applies the results from the meta-analysis to calculate the benefit transfer estimates for each country. There are two final models: a shellfish model and a finfish model. The shellfish model was used to generate the estimate for Guyana, while the finfish model was used to generate the estimate for Suriname. For Guyana, the predicted elasticity (Ɛ) is 0.924, which implies a 1.81% loss in shellfish catch per year resulting from the recent loss of mangroves in that country. For Suriname, the predicted elasticity (Ɛ) is 1.77, which implies a 1.34% loss in finfish catch per year resulting from that country’s recent loss of mangroves. These estimated losses in fish catch were calculated by multiplying each country’s elasticity by the observed changes in mangrove area noted previously. The fourth section of this study provides a discussion of the analysis and estimates the benefits of mangrove restoration in each country. If the estimated loss in mangrove area had not occurred in Guyana, the Guyanese fishery would have gained $586,440 in revenue net of costs. Similarly, if the estimated loss in mangrove area had not occurred in Suriname, the fishery in that country would have gained $180,900 in revenue net of costs. This section also provides a comparison to previous mangrove-fishery linkage studies. This is followed by a discussion of limitations of the present study, including the wide variation in mangrove area and mangrove area change estimates found in different sources. Lastly, recommendations for future data collection are provided. The final section of this study provides an insight into mangrove-fishery linkages within the countries of Guyana and Suriname for specific fisheries as well as the associated monetary gains resulting from conserving mangrove area. These estimates are insufficient for determining the total value of conserving mangrove area, but a more complete estimate of total value could be determined by applying valuation methods, similar to those used in this study, to additional ecosystem services.Item Open Access Evidence Mapping: Investigating the Social and Ecological Impacts of Conservation in Mangrove Ecosystems(2019-04-26) Brooks, Willa; Manz, Amy; Woolston, ColyerThe global extent of mangrove forests has been rapidly declining in recent decades, raising concerns about the loss of the ecological and social services they provide. There is an increasing urgency to understand best approaches to conserve mangrove forests given their decline. This project seeks to identify literature that addresses the question: What is the extent and occurrence of evidence for ecological and social impacts of conservation interventions within mangrove ecosystems? Following systematic mapping standards, we develop and apply a search strategy to identify relevant literature that evaluates the impacts of conservation in mangrove forests. Our research culminates in a structured matrix, organizing our findings by interventions and outcomes of interest. We find that of the 39 included studies, the majority of the evidence base examined linkages between conservation interventions and ecological outcomes, with a noticeable dearth in studies evaluating social outcomes; specifically, awareness raising, and education and training outcomes. We conclude with recommendations for how to use our systematic map geared towards conservation researchers, policy makers, and practitioners.Item Open Access GIS Project to Categorize and Map Smalltooth Sawfish (Pristis pectinata) Shoreline and Nearshore Habitat Features in Southwest Florida(2022-04-22) Dar, RabiyaThis project was conducted in cooperation with NOAA Fisheries to support the management of smalltooth sawfish (Pristis pectinata) in Charlotte Harbor, Florida. Smalltooth sawfish have experienced a serious decline in their range due to commercial and recreational fishing, entanglement, illegal trade, and coastal development. In the United States, they once ranged from Texas to North Carolina, but are now only found in parts of southern Florida. NOAA Fisheries manages smalltooth sawfish under the purview of the Endangered Species Act and has designated Charlotte Harbor and the Ten Thousand Islands/Everglades as critical habitat units for the U.S. distinct population of this species. These areas were chosen as they have an abundance of mangroves in shallow, euryhaline water which is prime nursery habitat for sawfish. This project focuses on the Charlotte Harbor unit of critical habitat and utilizes ArcGIS to categorize the shoreline with emphasis on classifying and analyzing mangroves to identify priority sawfish habitat. A supervised classification using the maximum likelihood classification method is used to categorize the shoreline into three classes: mangrove, other vegetation, and non-vegetation. Classified mangroves are then analyzed to identify contiguous mangrove patches, mangrove distance to shoreline, and mangrove neighborhood density. The products from this project will be combined with other datasets to develop a sawfish distribution model. Such a model could be useful in predicting sawfish abundance across seascapes to promote better management of this endangered species.