Wetland Deterioration Research Articles

Assessment of wetland loss through industrialization and community expansion: a case study of the greater amanzule wetland in the Ellembelle district of Ghana

Wetland ecosystems provide numerous services to humanity and the biosphere at large. However, these services are constantly dwindling due to the massive wetland loss caused by urbanization. Urbanization-induced wetland loss is a global problem, with most developing countries experiencing it currently. Several studies on wetland loss have been conducted. However, there is a dearth of studies integrating GIS and other ecological models to estimate the periodic deterioration of wetlands in rural settings in underdeveloped nations. As a result, this study aims to determine wetland loss in a developing country’s countryside, using the Greater Amanzule Wetland in the Ellembelle District of Ghana as a case study. The study used the GIS and Remote Sensing dataset, the Normalization Difference Vegetation Index, and the InVEST-Habitat Quality model to analyze the spatial pattern of wetland loss and habitat quality variations caused by industrialization and community expansions between 2000 and 2020. Our results indicate that, from 2000 to 2015, community built-up and industrial land areas grew from 25.19 ha to 84.21 ha and 0–4.71 ha respectively, causing a wetland loss of −39.64 ha (−31.10%). Between 2015 and 2020, community built-up land grew to 78.65 ha while industrial land slightly reduced to 2.54 ha, leading to the wetland degradation of approximately −69.06 ha (−42.53%). Wetland habitat quality steadily declined, from 0.97 in 2000 to 0.93 in 2015 and 0.93 in 2020. The study findings led to policy recommendations to reduce wetland encroachment and enhance sustainability. These recommendations included conducting effective land-use plan inspections before issuing permits, coordinating effective management, and promoting the recovery of natural and artificial vegetation to sustain the wetland.

Wetland conservation legislations: global processes and China’s practices

Abstract Natural wetland areas in China have experienced a continuous decline over the past two decades, which is partly due to the lack of comprehensive wetland protection laws and regulations. Despite investing over 4.24 billion USD in wetland conservation and restoration since 2000, the deterioration of wetlands persists. This study reviews the development of global wetland protection laws and regulations, analyzes the progress of wetland legislation in China and explores the impact of economic development levels on wetland protection legislation, while also providing an in-depth interpretation of the core elements of the ‘Wetland Protection Law of the People’s Republic of China’. The results indicate that since the late 1940s, wetland protection laws and regulations have begun to emerge, with most developed countries gradually implementing related policies between the 1980s and 1990s; about 71% of wetland protection laws are concentrated in 29 countries, while 69 countries still lack specific wetland protection laws. An analysis of 962 global documents reveals that wetland protection legislation mainly focuses on the protection of water resources, species and ecosystems. China’s wetland legislation started late, with the ‘Wetland Protection Law of the People’s Republic of China’ being officially implemented only in June 2022. Furthermore, the study points out that economic development plays a crucial role in wetland legislation worldwide. Lastly, the article summarizes the key features of the ‘Wetland Protection Law of the People’s Republic of China’, including the improvement of the environmental protection legislative system, increased penalties for illegal occupation of wetlands, clearer protection goals and the assurance of the integrity and connectivity of wetland ecosystems through stringent policies.

The status of artificial wetland areas in light of climate change using Geospatial systems: Case study Ain Zada Lake (Algeria)

Climate patterns in North Africa, specifically the southern Mediterranean, have changed considerably due to global climate change. As a result, a major environmental problem has emerged: the deterioration of wetlands and associated ecosystems, which are protected under the Ramsar Convention. This study examines the state of an artificial wetland, notably the reservoir formed by the Ain Zada Dam in northeastern Algeria, from 2001 to 2021. RS, GIS, and GEE were used to analyse indices and satellite images. The study found that the reservoir’s water storage decreased significantly, from 10.5 million m3 in 2001 to 2.4 million m3 in 2021. This finding is entirely consistent with the NDWI index, which was generated from an analysis of 151 satellite images. The drop in water storage has had an extensive effect on the reservoir’s ecosystem. That decline is linked to changes in the region’s environment over the last 40 years, which has been characterized by lower water levels and higher temperatures, providing additional evidence of global warming.

Global mitochondrial and chloroplast genome diversity in the threatened aquatic carnivorous plant Aldrovanda vesiculosa

The submerged aquatic carnivorous plant Aldrovanda vesiculosa (Droseraceae) is threatened by rapid deterioration of wetlands and oligotrophic lake habitats. Its native distribution spans four continents, but many historic populations are now extinct. Previous genetic studies found distinction between populations from Australia and those from the rest of the world, but due to limited genetic markers, neither detailed phylogenetic relationships nor the migration routes of A. vesiculosa populations were revealed. We used a de novo assembly of the A. vesiculosa mitochondrial genome and a previously published plastid genome as references for mapping short DNA sequence reads from 17 globally distributed populations. Phylogenetic trees were constructed based on detected polymorphisms. Genetic diversity of both the mitochondrial and plastid genome was low (Pi 0.55 × 10−4 and 0.7 × 10−4, respectively). Greater polymorphisms were found in the mitochondrial compared with the plastid genome, owing to its larger size (1.27 Mb). Australian populations formed a monophyletic clade in both plastid and mitochondrial trees, while the mitochondrial tree also distinguished populations from southern and northern Europe. Aldrovanda vesiculosa likely migrated to Australia and Africa from a southern European refuge during the last interglacial period∼100,000 years ago. When the last glaciation started, some populations could have survived in eastern Europe and moved north, when the continental glacier retreated. Aldrovanda vesiculosa experienced repeated population bottlenecks that reduced its genetic diversity.

Pond basin colonization by terrestrial vegetation indicates wetland deterioration

Abstract Efforts to conserve the pond network in the Doñana National Park are being threatened by groundwater overexploitation. The dramatic expansion of farming and tourism in nearby areas has caused a severe lowering of the water table, reducing pond hydroperiod length or even instigating pond desiccation. It is important to document the link between groundwater abstraction and pond deterioration with a view to decreasing human pressures on the park and preserving the pond network's singular biodiversity. Here, the gradual deterioration of one of the network's main ponds is described in detail by characterizing vegetation patterns within the pond's basin using orthophotos taken between 1956 and 2019. In the earliest images, the pond contained a wide central area of bare soil during its dry phase. This area was surrounded by reeds and had a line of Tamarix canariensis trees along its southern edge. Starting in 2000, the orthophotos showed the pond's gradual colonization by terrestrial vegetation. In tandem, pond hydroperiod decreased, as did the length of time the pond retained certain depths of water. In recent years, Tamarix trees finally fully invaded the pond's central area, which is surrounded by reeds and has scattered terrestrial bushes and pines. This invasion resulted from the pond's sparse inundation over recent decades, being the cover of trees related to the depth of groundwater, and is a clear sign of pond deterioration. More broadly, colonization by terrestrial vegetation has been observed in approximately 60% of the network's ponds. Colonization of temporary pond basins by terrestrial vegetation can be used as an indicator of deterioration and highlights the need for active restoration and management.

Understanding the role of surface runoff in potential flood inundation in the Kashmir valley, Western Himalayas

In the present study, direct runoff and Total runoff were estimated at temporal scales (2000–2018) focusing on flood potential in the catchments of Kashmir valley. The valley is recurrently prone to catastrophic floods with increased Total runoff frequency in recent decades (post-2010 periods). LANDSAT ETM+ satellite image based land use/land cover mapping exhibited the dominance of vegetation cover (46%) primarily in the peripheral hilly regions, in contrast to agricultural land (29%) and built-up (1.6%) in the elongated valley region. The high anomalous rainfall (>500 mm) in most of the catchments during 2014–2018 caused an increased runoff apparently leading to catastrophic floods inundation (as observed in 2014 with accumulated rainfall of 713 mm and cumulative Total Runoff of 55 LCM). A higher contribution towards Total Runoff in northern catchments (>56%) exhibited higher susceptibility to flood inundation as compared to the southern catchments (<42%). The study highlighted a high vulnerability in the large proportion of built-up land (148 km2) within close proximity to Jhelum river and below 1560m elevation range due to the erratic rainfall induced runoff floods. The insignificant proportion of built-up led to less contribution towards the high runoff yet increases the severity of runoff and flood inundation due to high imperviousness. The rapid built-up growth coupled with deterioration of natural wetlands in the urban-rural fringe increased the impact of catastrophic flood manifolds. The study provided a regional and comprehensive runoff assessment that can be utilized to develop adequate flood control measures at the catchment level in the valley.

A Random Forest-Based Multi-Index Classification (RaFMIC) Approach to Mapping Three-Decadal Inundation Dynamics in Dryland Wetlands Using Google Earth Engine

Australian inland riparian wetlands located east of the Great Dividing Range exhibit unique, hydroecological characteristics. These flood-dependent aquatic systems located in water-limited regions are declining rapidly due to the competitive demand for water for human activities, as well as climate change and variability. However, there exist very few reliable data to characterize inundation change conditions and quantify the impacts of the loss and deterioration of wetlands. A long-term time record of wetland inundation maps can provide a crucial baseline to monitor, assess, and assist the management and conservation of wetland ecosystems. This study presents a random forest-based multi-index classification algorithm (RaFMIC) on the Google Earth Engine (GEE) platform to efficiently construct a temporally dense, three-decadal time record of inundation maps of the southeast Australian riparian inland wetlands. The method was tested over the Macquarie Marshes located in the semiarid region of NSW, Australia. The results showed a good accuracy when compared against high-spatial resolution imagery. The total inundated area was consistent with precipitation and streamflow patterns, and the temporal dynamics of vegetation showed good agreement with the inundation maps. The inundation time record was analysed to generate inundation probability maps, which were in a good agreement with frequently flooded areas simulated by a hydrodynamic model and the distribution of flood-dependent vegetation species. The long-term, time-dense inundation maps derived from the RaFMIC method can provide key information to assess the condition and health of wetland ecosystems and have the potential to improve wetland inventory with spatially explicit water regime information. RaFMIC can be adapted over other dryland wetlands, as an effective semiautomated method of mapping long-term inundation dynamics.

Harmonizing Natural and Built Environments

At the moment urban agglomeration sees how cities grow and expand within a shorter period by overlooking the existence of natural eco-system. Natural and built components of the urban environment are the main focal point for sustainable development strategies of a city. Unfortunately, economic pressure being the major driving force of our cities development always cater for high dry-land considering wet areas like a wetland, canals, khals, lowlands, water reservoir etc. as backward and primitive. Wetland and water-related resources all over the world are given less priority which is acute in urban areas and Bangladesh is not an exception. Water and water-related resources are not maintained properly resulting continuous deterioration of wetlands and water bodies. Considering Ananya R/A, Chittagong, a developing residential area on wetland, as study site this paper aims at acknowledging some ideologies of development in a wetland which will contribute to enriching the natural environment of the area by introducing chemistry of land-water-ecology.

Spatio-temporal analysis of urban area expansion in Zimbabwe between 1990 and 2020: The case of Gweru city

Urbanization in Zimbabwe has become an unstoppable phenomenon since the 2000 decade. Before 2000, expansion of towns and cities in Zimbabwe was very slow and restricted by private land around them. In 2000 Zimbabwe embarked on a fast-track land reform program which changed both the rural and urban landscape in terms of land ownership as it freed most of the land that was in private hands. This triggered accelerated lateral expansion of most urban centers including Gweru. The study assessed Gweru city expansion between 1990 and 2020. The study adopted a mixed methods research design which allowed use of both quantitative and qualitative research techniques. Geographic information system and remote sensing, interviews and observations were used for data collection in this research. The study revealed that banks, building societies and some private land developers were major land development players who contributed to expansion of Gweru city between 1990 and 2020. The results of this study showed that rates of Gweru urban expansion were heterogeneous between 1990 and 2020. It was highlighted that the rates of Gweru urban expansion experienced an increasing trend from 1990 to 2020 with decade 2010 to 2020 experiencing highest rates of urban expansion followed by the 2000 to 2010 decade. The study results demonstrate that horizontal expansion of Gweru city took place at the expense of greenbelts and farmlands. Findings from this study showed that the land reform program and dollarization were the major drivers of Gweru urban expansion between 1990 and 2020. The study recommends that Gweru city council should take cognizance of the provisions of the environmental management act especially on protection of green spaces and wetland ecosystems when drawing its development plans to guard against deterioration of both green spaces and wetlands within the vicinity of Gweru urban. The study concludes that sustainable development of Gweru city can only be achieved if all developments take place according to the approved city council development plan.

Morphodynamic modeling of a low-lying barrier subject to hurricane forcing: The role of backbarrier wetlands

Along much of the world's coastline, coastal barriers serve as the first line of defense against oceanic and meteorological forces. Extreme storms cause large morphological changes on coastal barriers through high sediment transport rates, which may degrade their defensive capabilities. The understanding of morphological impacts is therefore important for coastal resiliency, but is often challenged by site-specific characteristics, such as land cover and sediment availability, and their poorly understood impacts on the governing physical processes. The Caminada Headlands, Louisiana, USA presents unique considerations for morphodynamic modeling with regard to its low-lying topography, variable land cover, nearshore muddy substrate and sand deficiency. This study investigates the effects of land cover and limited sediment supply on low-lying barrier island morphology under storm conditions by using physics-based numerical models. A high-resolution, local-scale sediment transport/morphodynamic model (XBeach) of the Caminada Headlands is verified for Hurricane Gustav's (2008) impact using pre- and post-storm LIDAR surveys. When accurate input data are used to create physics-based numerical models these tools are robust in hindcasting storm impacts and provide a wealth of information as to the governing processes, which is otherwise difficult to obtain observationally. The simulation results show that a short-duration overwash regime dominates the morphological change in this low-lying barrier and is influenced by backbarrier wetland deterioration. The morphological response to overwash is modulated by backbarrier land cover and topography, as reduced accommodation space limits landward transport during the subsequent inundation regime. An intact backbarrier marsh reduces landward washover sediment transport distances and promotes deposition at supratidal elevations. In light of these findings, simultaneous restoration/creation of backbarrier wetlands in conjunction with subaerial beach renourishment may be an effective form of increasing the resiliency of low-lying barriers subject to frequent overwashing.

Mismatch between watershed effects and local efforts constrains the success of coastal salt marsh vegetation restoration

Coastal restoration is considered a key solution to counteract coastal degradation and mitigate climate change. In recent years, China’s coastal restoration projects have multiplied, with more than one billion US dollars spent during 2016–2019. Due to the sudden die-off of marsh vegetation in the Liaohe River Estuary, local managers have spent more than 30 million dollars to restore these salt marshes since 2015. However, these projects either failed or yielded limited results. Combining long-term remote sensing data to ground-based surveys, we found that salt marshes in the Liaohe River Estuary have experienced two dramatic diebacks separated by a recovery period, and the rapid changes in vegetation canopy were primarily driven by freshwater availability, especially river discharge. We suggest that mismatch between degradation drivers at the watershed-scale and restoration efforts at the local-scale hinders the success of coastal restorations. Efforts to restore these salt marshes will always be thwarted unless freshwater availability is replenished. Therefore, we propose a watershed-based solution, incorporating water replenishment from the river basin in estuarine restoration projects. Given the declining trends in river freshwater inputs in low-middle latitude coastlines, such wetland deterioration might also occur in many world’s estuaries. Lessons from China’s large-scale coastal restoration projects can help other regions to avoid similar shortcomings, and improve our restoration practices before too many resources are lost.

Results of seawater intrusion in Mediterranean Spain and the Spanish islands according to the SASMIE report

Groundwater salinization of the Spanish aquifers by seawater has been known for decades. However, in only a few cases has this been managed to control the damage, as salinization affects small territories and involves water rights that in practice remain largely in the private domain. Groundwater salinization affects many people and industrial, tourist and agricultural activities. The greatest problems appeared in the last decades of the 20th century. Some of them still persist but others have been dwindling as water from other origins rather than local ones has been made available to substitute existing pumped wells. The abandonment of part of the coastal aquifers as a freshwater resource is an important hydraulic inheritance loss and especially a decrease in the guarantee of water availability if other costly and environmentally less friendly structures are not incorporated. Global and climatic change may modify the current situation. Coastal aquifers can be recovered if the cost is proportionate. Seawater intrusion implies an impairment to general wellbeing due to enhanced corrosion, negative effects on agriculture, deterioration of wetlands, and a decrease in the ecologically important continental freshwater outflow to the ocean. All this goes beyond the scope of the aquifer good status of coastal groundwater bodies to be achieved according to the European Water Framework Directive. Long-term manag ement action is needed, both structural and non–structural. The current experience in Spain has been synthetized in the SASMIE (2017) report, developed by the Technical University of Catalonia with the support of SUEZ-Spain and the overview of CETAQUA, which centers on the Mediterranean and island areas of Spain. Some of the most relevant situations here are considered, based on the available data.

Drivers of a habitat shift by critically endangered Siberian cranes: Evidence from long-term data.

Many waterbird populations have become increasingly dependent on agricultural habitats for feeding. While habitat destruction has been proposed as a key reason forcing waterbirds to move from natural habitats to agricultural habitats, few have used long‐term data to test this hypothesis. The Siberian crane (Leucogeranus leucogeranus) is an IUCN Critically Endangered species. About 98% of its global population winters at Poyang Lake, China. Recently, many cranes shifted from feeding in natural wetlands to agricultural habitats. Here, we integrate bird surveys, Vallisneria tuber (the traditional food of cranes in natural wetlands) surveys, water level data, and remotely sensed images from 1999 to 2016 to explore the drivers of this habitat shift. Changes in Siberian crane numbers in natural wetlands and agricultural fields indicated that the habitat shift occurred in the winters of 2015–2016. Analyses using generalized linear mixed models suggested that crane numbers in natural wetlands were positively related to tuber density and the interaction between dry season (October–March) water level and tuber density. The changes in tuber density and dry season water level in 2015–2016 indicated that tuber disappearance may have been the primary driver of the habitat shift, with a smaller effect of high water level. Submerged plants at Poyang Lake have degraded seriously in the past two decades. The plant degradation at Shahu Lake, a sublake of Poyang Lake, may have been caused by high spring water, high winter temperature, and low summer temperature. However, the drivers of tuber disappearance at Poyang Lake may not be restricted to these variables. Because Poyang Lake is an important refuge for many waterbirds in the Yangtze River floodplain, it is urgent to take effective measures to restore its submerged plants and ecosystem health. Agricultural fields can be important refuges for Siberian cranes, mitigating the negative impacts of wetland deterioration.

Monitoring wetland deterioration in a coastal protected area in central Italy: implications for management

A wetland is a complex ecosystem with high biodiversity; in some situations, the productivity of a wetland is comparable to those of a rain forest or coral reef. The stability of wetlands is under threat due to human activities. The study area of the work described here was Palo Laziale (Province of Rome), a characteristic Mediterranean woodland and wetland area in central Italy. Agricultural activities and urbanisation have considerably reduced this habitat. The first evidence of stress on the area’s tree species was detected at the end of 1995, and this stress has gradually resulted in the complete collapse of the woodland habitat, with the deaths of more than 4000 individual trees. Physicochemical data, 87Sr/86Sr isotope data and saturation indices have been used to explore the trends in the characteristics of the aquifer over 15 years. We compared geochemical data from 2002 with new data collected in 2010 and 2016, which confirmed the brackish nature of the aquifer. The similarity of the 2010 and 2016 datasets and a comparison of those datasets with the 2002 dataset show that the system is resilient—it strongly buffers modifications without presenting any major alterations in function. The results demonstrate that the application of a hydrogeochemical approach emphasises the strong relationship between the level of wetland exposure and the nature of the wetland area at the monitoring scale applied.

The Role of Wetlands for Climate Change Mitigation and Biodiversity Conservation

Wetland is crucial in supporting biodiversity conservation and climate change regulation. A wetland ecosystem has been influenced by anthropogenic driven climate change. The main objective of this paper is to analyze the role of wetlands for climate change mitigation and biodiversity conservation through literature review. Wetland is vulnerable to climate change through alterations of hydrological regimes that lead to changes in quantity and quality of water. Climate change is undoubtedly the most pervasive, complex and challenging of the global environmental issues facing contemporary society and it affects all aspects of development. Wetlands play a key role in hydrological and biogeochemical cycles, and provide a wide range of ecosystem goods and services to humankind. In spite of these facts, wetlands are considered as wastelands in the past, which contributes for deterioration of wetlands in several places. Thus, strong environmental policy is required for the conservation of wetland ecosystem.Keywords: carbon sequestration, climate change, climate change mitigation, biodiversity conservation, wetlands

English

Obviously, there is land-use/cover change with multifaceted driving factors and associated adverse impacts out there in different parts of Ethiopia. Evidence from published journals justifies this fact but not yet compiled in a manner to convey information on the trend of change and its criticality with the aim to handle the problems. Thus, filing up all the driving factors and its adverse out come from different corners of Ethiopia together under one reviewed journal would help for policy measures and management aspects. In view of this, critical driving factors of land-use/cover change and all its possible consequences bridged together by reviewing highly relevant published journals. Deforestation, high human and livestock population, investment (coffee, tea plantations), agricultural activities ranging from small-scale subsistence agriculture to large-scale commercial agricultural schemes, urban sprawling, charcoal production, woodland collection, poor law enforcement, land rotation searching for better grazing land, resettlement (spontaneous and planned), prevalence of drought, were the leading drivers of land-use/cover change in Ethiopia. In response to these driving factors, the following are major identified adverse effects such as loss of biodiversity and ecosystem service degradation, deterioration of wetlands, creation of new landscape, rainfall variability, reduction in stream flow, increase frequent extreme in weather, conflicts of interest due to resource scrambling, soil and land degradation, prevalence of drought, increase in runoff and sedimentations, increased risk of desertification and woody land cover reduction. In general, these systematic reviews hopefully uncover all the existing scenarios and give mental picture of wide range driving factors of land-use/cover change and associated problems for stakeholders across the country as they might develop ways to end/reduce further vulnerabilities. Key words: Land-use/cover change, driving factors, adverse impacts, Ethiopia.

Assessment of impact of land use change on the wetland in Makhitha village, Limpopo province, South Africa.

Wetlands are essential for the natural function of an ecosystem, by regulating floods and remaining as a source of water supply. However, land use changes are the main forces behind wetland deterioration worldwide, including South Africa. In this article, we report on the impact of land use changes at the Makhitha wetland, Limpopo province, South Africa. The data was collected using techniques such as ecological survey, socio-economic survey and interpretation of satellite images obtained between 1978 and 2004. The study findings revealed that factors such as poverty and population growth were the driving forces behind wetland mismanagement. The cultivation of crops, grazing of livestock and road construction were the main land use activities that were practised in the wetland, which contributed to wetland deterioration, a disaster that can be mitigated. The study then recommended strategies such as environmental education, fencing and land use planning to resolve the problem of land use changes, in order to contribute to sustainable wetland management.

Landscape Metrics and Conservation Status of Five Mangrove Wetlands in the Eastern Gulf of California Margin

Millán-Aguilar, O.; Nettel-Hernanz, A.; Hurtado-Oliva, M.Á.; Dodd, R.S.; Flores-Cárdenas, F., and Manzano-Sarabia, M., 2020. Landscape metrics and conservation status of five mangrove wetlands in the eastern Gulf of California margin. Journal of Coastal Research, 36(1), 94–102. Coconut Creek (Florida), ISSN 0749-0208.Ecological significance and relevance of mangrove wetlands has been widely highlighted worldwide. Nevertheless, human-derived impacts and climate variability are increasing threats to these ecosystems in the last decades. Mangroves from Sinaloa (Mexico) integrate a large wetland corridor and provide several ecosystem services; however, diverse stressors could be increasing their vulnerability and associated biodiversity. The conservation status of five mangrove wetlands in this region was assessed through remote sensing techniques, landscape metrics, official databases and in situ records. In general, a decrease on mangrove cover was observed, excepting Estero de Urías and Ceuta, while aquaculture increased in all sites, with a greatest coverage in Santa María-La Reforma (increased 2057 ha in 18 years). The largest annual rate of change was observed in Huizache-Caimanero (–0.99%). Although conservation programs exist, there are signs of deterioration of mangrove wetlands according to this study.

Comparing carbon accumulation in restored and natural wetland soils of coastal Louisiana

Louisiana's chronic wetland deterioration has resulted in massive soil organic matter loss and subsequent carbon release through oxidation. To combat these losses, and reestablish ecosystem function, goods, and services, many restoration projects have been constructed or planned throughout coastal Louisiana. There are significant data gaps and conflicting results regarding wetland contributions to global warming, especially related to carbon sequestration in restored wetlands. An exceptionally large data set was used to derive carbon accumulation rates from key soil characteristics and processes. Assessments and comparisons of bulk density, organic matter, total carbon, vertical accretion (short- and longer-term), and carbon accumulation rates were made across time (chronosequence) and space (i.e., coastwide, watershed basins, and vegetation zones). Carbon accumulation rates in the Louisiana coastal zone were generally correlated to hydrogeomorphology, with higher rates occurring in zones of high river connectivity or in swamp or higher salinity tolerant marsh. On average, naturally occurring wetlands had higher carbon accumulation rates than restoration sites. Although some restoration measures were higher, and most showed increasing carbon accumulation rates over time. Results demonstrate that although wetland restoration provides many ecosystem benefits, the associated carbon sequestration may also provide useful measures for climate change management.

Assessing coastal erosion and accretion trends along two contrasting subtropical rivers based on remote sensing data

The temporal shoreline position is a key indicator of coastal development and provides information on beach dynamics. Previous studies have indicated that there is a strong relationship between riverine sediment fluxes and beach volume. As such, worldwide hydroelectric projects and the associated damming infrastructure have decreased suspended sediment loads, and consequently increasing coastal erosion and deterioration of wetlands. The study was conducted along the coastline of the San Pedro River and the Santiago River on the Pacific coast of Mexico. Both rivers discharge into the ocean separated by 12 km of coastline, however the San Pedro River does not present dams through its watershed. Contrary, six dams had been constructed along the Santiago River since 1976. Results indicated that after 45 years, the San Pedro River coastline presented minimum variability and a total of 379 ha of accretion. Contrary, the Santiago River coastline showed major erosion trends with a total of 669 ha of beach and wetland losses. Our study highlights the feasibility of combining historical remote sensing data and GIS analysis in order to assess coastal variability trends when field-based surveys are not available.