Special wetlands along Taiwan’s coasts contain extremely rich biological and landscape resources. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript. The results of EVI are consistent with those of NDVI. The following samples and information were collected: Second, from within the extracted area, a minimum distance classification program then identified the mangrove and non-mangrove areas. Mangrove degradation is a well-documented trend, but the spread of mangroves within the Siangshan Wetland in Hsinchu, Taiwan, runs contrary to that trend. A 12-months microcosm study was conducted and more than 55% of the BDE-99 in contaminated sediment was removed at the end. • 30 cm sediment core (diameter 5 cm). The crabs returned to the original habitat shortly after mangrove removal. No files have been attached to this dataset. NDVI represents reaction to photosynthetic activity; the relevant equation is NDVI = (NIR − RED)/(NIR + RED) (Schowengerdt, 1997; Kovacs et al., 2004; Matsushita et al., 2007), where NIR represents the reflectance of near-infrared radiation and RED represents the reflection of visible red radiation, as measured by a satellite radiometer. In subtropical estuarine wetlands, fishes, crabs, gastropods, prawns, and other megafauna require mudflats to serve as critical habitats. Mangroves cover a wide latitudinal range in Australia and New Zealand, so it is difficult to summarize the potential synergistic effects of climate change stressors for the entire region. Perhaps one of the most commonly identified services provided by mangrove communities is the provision of a nursery habitat for juvenile fish. The number of species within the mangrove regions increased after mangrove removal. The results showed that both the Shannon–Wiener index (H′) and Pielou’s evenness index (J) increased, indicating an increase in biodiversity after mangrove removal. The variations in the Shannon–Wiener index (H′) and Pielou’s evenness index (J) are illustrated in Fig. Results. Samples of mangrove areas and other vegetation areas from the digital aerial imagery served as training areas; mangrove boundaries were marked on the images. A high ratio indicates thriving vegetation, whereas a low ratio suggests either stressed vegetation or the absence of vegetation. – ICES Journal of Marine Science, 67: 1087–1104. "For coasts where mud supply remains limited, removal of barriers that obstruct inland migration is of utmost importance to avoid loss of mangrove forests and biodiversity.” By University of Exeter. A large-scale mangrove-removal project was undertaken by the Hsinchu City Government from October 2015 to March 2016. A reduction of mangrove trees can even increase damage caused by natural disasters (Sandilyan and Kathiresan, 2012). The following information was supplied regarding data availability: The raw data are provided in a Supplemental File. Mangrove presence increases the residence time of water, especially in flat, wide mangroves with complex waterways (Wolanski & Ridd 1986). Frequency of collection: Data collected in 2005 and 2008, www.ew.govt.nz/Publications/Technical-Reports/TR200913/, Benthic Communities (including shellfish). no more than one email per day or week based on your preferences. 1. Many rehabilitation projects are conducted by planting full-grown mangroves or seedlings. 2007, Nakahara 2007) and show similar results to studies on the island of Hawai‘i; mangroves seem to be be providing habitat for invasive fish species (e.g., poeciliids, snapper, tilapia) (Van der Veur 2006, MacKenzie et al. The fluctuations in monthly benthic density and the number of species are shown in Fig. Diverting water can harm mangroves by preventing their seeds from being dispersed via seawater, and it can kill the trees by cutting off freshwater supplies. suggesting that it would be some time, if at all, before these sites evolve to a purely sandy environment under the present-day conditions. However, a slight increase in Fe concentrations after one and two years could be associated with newly precipitated Fe oxy(hydroxide) as a result of exposure of the habitat (loss of canopy and biological … “The rate of sea-level rise keeps going up,” says Geselbracht, who was not affiliated with the study. Moanaanuanu Estuary, Whangamata Harbour. With global losses already in excess of 50%, mangroves are being lost more rapidly than tropical rainforests. The relevant equation is EVI = G × (NIR − RED)/(NIR + C1 × RED − C 2 × Blue + L) (Huete, Justice & Van Leewen, 1999), where EVI is a modified NDVI with enhanced vegetation monitoring ability, achieved by decoupling the cover background signals and the atmospheric interference (Huete, Justice & Van Leewen, 1999). The non-mangrove region had significantly higher benthic biomass than did the mangrove areas (t = 2.45, p = 0.003). (Taiwan). The expansion of mangroves often blocks the waterways. Changes of the mangroves over the study decade are shown in Fig. Abstract. Mangrove habitat is the area of low current, where impact of coastal tide gets reduced. The following information was supplied relating to field study approvals (i.e., approving body and any reference numbers): Field experiments were approved by the Environmental Protection Administration, R.O.C. The other dense region appeared in the south near Haishan Fishing Port in 2008. If you are following multiple publications then we will send you And research indicates they store four times as much carbon as other tropical forests. Uca arcuate, Uca lacteal, and Uca borealis are common in mangroves, sandy and muddy areas, and salt marshes in Siangshan Wetland. Special wetlands along Taiwan’s coasts contain extremely rich biological and landscape resources. The benthic biomass was significantly different at periods before and after mangrove removal (one-way ANOVA, F = 5.571, p = 0.022). Some studies have analyzed the effects of mangrove removal, but few have evaluated the effects of large-scale removal efforts. Rehabilitation projects are most effective when they are appropriate to the environmental conditions (Friess et al., 2012). Climate change also affects their survival. Worldwide, mangrove rehabilitation projects are undertaken primarily to revive forest cover and habitat functions (Katon et al., 2000; Barbier, 2006). The muddy intertidal zone is a breeding ground for large numbers of shrimp, crabs, shellfish, and benthic organisms, and it attracts a variety of protected bird species (National Important Wetland Conservation Project, 2014). Stokes, D. 2009: Assessment of Physical Changes after Mangrove Removal: Whangamata Harbour 2008. The loss of mangroves contributes to nearly one-fifth of global emissions from deforestation. However, some areas have been cut down and their mangroves have been removed to construct aquaculture farms, for coastal development purposes, or by local residents to acquire firewood and other products (Diop, 2003). The smallest number of species was found in February 2016 and the largest in August 2016. “The rate of sea-level rise keeps going up,” says Geselbracht, who was not affiliated with the study. These results showed that the benthic density and species change seasonally in Siangshan Wetland, decreasing in winter and spring and increasing in summer. To calculate the area of mangrove cover, NDVI and EVI were used. To solve the problem of mangrove overspreading, a large-scale removal project was planned by the Hsinchu Municipal Government in October 2015. Two crab species, Uca arcuata and Uca vocans borealis, were observed at the sampling sites within the mangrove area before mangrove removal. Furthermore, the density of bivalve species in the two different regions (mangrove: A1, A5; and non-mangrove: B1, B5) were compared (Fig. The results showed that mangrove removal might be a feasible approach for coastal management and ecological restoration. Lower density was measured in the mangrove region than in the non-mangrove region. Multitemporal FORMOSAT-2 satellite images were analyzed to identify mangrove vegetation areas and nonvegetation areas. These results showed that the benthic density and the number of species increased after mangrove removal. Mangrove forests are coastal plant communities that are part of a larger coastal ecosystem that typically includes mud flats, seagrass meadows, tidal marshes, salt barrens and even coastal upland forests and freshwater wetlands (i.e. Journal Reference Hard and strong coastal engineering methods have often been used to protect the rapidly developing coastal zones (Chu et al., 2007). The density of crustacean species varied from month to month (Fig. Density was estimated as the count of individual organisms (N) per unit area; the total number of species (S) was applied to quantify species richness. These ecosystems provide habitat, shelter and food for numerous organisms, including some species that support important nearshore fisheries. Species density of tide crabs at A1, B1, A5 and B5 in October 2015 (A); species density of tide crabs at A1, B1, A5 and B5 in February 2016 (B); species density of tide crabs at A1, B1, A5 and B5 in June 2016 (C); species density of tide crabs at A1, B1, A5 and B5 in August 2016 (D). and will receive updates in the daily or weekly email digests if turned on. 1998, Rönnbäck et al. Effects of mangrove removal on benthic organisms in the Siangshan Wetland in Hsinchu, Taiwan. Bottlenecks, thresholds and knowledge gaps to mangrove and salt marsh ecosystems, Structure and regeneration status of mangrove patches along the estuarine and coastal stretches of Kerala, India, Remote sensing handbook for tropical coastal management, Restoration of shorebird-roosting mudflats by partial removal of estuarine mangroves in Northern Taiwan, MODIS vegetation index (MOD13) algorithm theoretical basis document, Rehabilitating the mangrove resources of Cogtong Bay, Philippines: a co-management perspective, Estimating leaf area index of a degraded mangrove forest using high spatial resolution satellite data, Mapping disturbances in a mangrove forest using multi-date Landsat TM imagery, Mapping mangrove leaf area index at the species level using IKONOS and LAI-2000 sensors for the Agua Brava Lagoon, Mexican Pacific, Impacts of vegetation changes on the hydraulic and sediment transport characteristics in Guandu mangrove wetland, Applying remote sensing techniques to monitor shifting wetland vegetation: a case study of Danshui River estuary mangrove communities, Taiwan. Mangrove forests are among the world's most vulnerable subtropical and tropical habitats. Mangroves cover a wide latitudinal range in Australia and New Zealand, so it is difficult to summarize the potential synergistic effects of climate change stressors for the entire region. Alfaro (2010) also reported that mangrove removal in temperate region in the north of New Zealand had particular effects on sediment characteristics and benthic communities. Mangroves are beneficial for aquaculture and agriculture; mangroves can provide firewood and building material, medicines, and for other local subsistence items (Alongi, 2002; Walters et al., 2008). In this study, we used satellite telemetry and biological investigation to monitor the situation before and after mangrove removal. Vascular plants have a strong influence on coastal community structure, function, and successional patterns (Bertness, 1991, 1992; Snelgrove et al., 2000; Bortolus et al., 2002; Levin and Talley, 2002). After mangrove removal, the values for individuals, number of species, and indicators of benthic organisms increased significantly. In 2001, Siangshan Wetland was officially named the Hsinchu City Coastal Wildlife Sanctuary. After mangrove removal, the benthic density rose to 2 to 25 ind./m2 and the species range increased to between two and seven. Our promise You can also choose to receive updates via daily or weekly email digests. 2. A large-scale removal project was undertaken from October 2015 to March 2016. In Louisiana, for example, the effect of rising water is compounded by land sinking due to water removal and sediment compaction. Sediment texture and colour changes along the core were recorded. Mangroves stabilize coasts, reducing erosion and the damaging effects of hurricanes and tsunamis. The results of the study indicated that surface sediments in the 2005 cleared mown site are similar in 2008 to those in the existing mangrove habitat, with over 50% Mangrove and seagrass ecosystems are widespread coastal and estuarine environments found in tropical and subtropical latitudes. The crab species included Uca arcuata, Uca lacteal, and Helice formosensis. 2. The types of mangroves, bare land, and water were analyzed using Erdas Imagine Software. The results showed that the concentrations of heavy metals at all sediment depths in the S. apetala site were significantly higher than that in K. obovata.The geo-accumulation index and potential ecological risk … After mangrove removal, speciesreturnedtotheiroriginalhabitatsandnoteworthybiologicalvaluessignificantly increasedinthemangroveregions.Thisstudypresentsevidencetoarguethatmangrove removal benefits benthic organisms. No Bivalvia species were found. They also investigated the consequences of mangrove removal on benthic organisms and adjacent habitats from October 2015 to September 2016, and the density, species count, Shannon–Wiener index (H′), and Pielou’s evenness index (J′) of the mangrove and non-mangrove regions were compared. Rehabilitation and restoration differ in their meaning: the latter refers to partly or completely replacing the structure or functional aspects of an affected ecosystem, whereas the former attempts to return the ecosystem to its original characteristics (Field, 1999). Summary. Because of the continuous spreading of the mangrove in the coastal areas, the effects seen included habitat singularity, decline of species abundance, decline of biodiversity, infilling of estuaries, flooding, and small black mosquito breeding. Functional differences between the major and minor claws of fiddler crabs (Uca, family Ocypodidae, order Decapoda, Subphylum Crustacea): a result of selection or developmental constraint? H′ varied from 0 to 1.04, while J varied from 0 to 0.95 before mangrove removal, whereas after mangrove removal, the H’ varied from 0.69 to 1.72, and J varied from 0.77 to 1.00. The Shannon–Wiener index was applied to evaluate species diversity (H′, log) (Shannon & Weaver, 1963), whereas evenness (J′) was estimated by the method of Pielou (1966). The dominant mangrove species on the tidal flats are Kandelia candel, Avicennia marina, and Rhizophora mucronata. The juveniles of few species of crustaceans, such as banana prawns Penaeus merguiensis and P. indicus ), are found exclusively in mangrove ecosystem (Staples et al. Generally, scholars think that natural coast habitats provide healthier ecosystems than those that are artificially constructed. 4. Core stratigraphy revealed silty sands to depths below 12 cm at all cleared sites, Coastal sediment redeposition after resuspension events may change the sediment capacity to sequester pollutants after the formation of new sediment-water interfaces. The primary threats to all mangrove species are habitat destruction and removal of mangrove areas for conversion to aquaculture, agriculture, urban and coastal development, and overexploitation. "Following" is like subscribing to any updates related to a publication. WMC: recently cleared habitat This region could shed light on such synergistic effects when studied at the latitudinal boundary of mangrove extent in south Australia and north New Zealand. Analyses of temporal trends in the data indicate that benthic invertebrate abundance and diversity are increasing with time and that the disparity in population structure between the mangrove site and the cleared site may decrease as time goes on. Analysis of the 2005 samples was reported by Felsing (2006) and a comparison of the 2005 and 2006 results was discussed in a report by Stokes (2008). The results indicate that the benthic communities at the cleared sites have not recovered within the observation period (2005 – 2008). This provides the small juvenile fishes benign physical environment to settle. The difference in mangrove decomposition rate between O'ahu and the native range may be due to differences in flow conditions, methodology, effects of mangrove removal, and/or macrofaunal diversity. 4. Three studies were subsequently undertaken by Environment Waikato to investigate 3. The present study compared accumulation of heavy metals in a mangrove swamp dominated by Kandelia obovata with that by Sonneratia apetala in Pearl River Estuary, China. After mangrove removal, the composition of the sediment changed from a muddy to a sandier habitat, and clams began to appear (Young, 2013). “It is essential to secure or restore mud delivery to coasts to counter negative effects of sea-level rise. Ju-Der Wei performed the experiments, approved the final draft. Effects of mangrove removal on benthic communities and sediment characteristics at Mangawhai Harbour, northern New Zealand. Satellite telemetry is a technique increasingly being adopted to efficiently observe, quantify, and survey vegetation (Green, Clark & Edwards, 2000; Kovacs, Wang & Blanco-Correa, 2001; Kovacs et al., 2004; Kovacs, Wang & Flores-Verdugo, 2005; Satyanarayana et al., 2011). The high mud content and below ground biomass documented at one of the cleared sites highlights the importance of considering the intertidal position and hydrodynamics of a site before planning the removal of any coastal vegetation. 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