Wetland Loss Research Articles

Drivers of vulnerability to wetlands in Punarbhaba river basin of India-Bangladesh

Wetland degradation and loss of wetland is one of the emerging challenges against sustaining such worthy environmental capital having plenty of goods and services. In Barind tract of India and Bangladesh, such trend of wetland conversion is highly explicit. Present paper attempted to capture such trend of wetland loss, conversion of wetland and their associated reasons behind. At present total wetlands area of the basin is 220.9 km2 and which is 35.78% lower than pre-dam wetland coverage. Flow modification triggered by Komardanga dam (34.35% for average flow and 52.24% for peak stream flow have declined) is emerged as one the major reasons behind wetlands loss. It also causes reduction of active flood prone area by 39.72% as well as inconsistent water service to wetlands. De-linking of Punarbhaba river system from Tista river system is another historical cause behind lowering of flow and flood magnitude in Punarbhaba. Loss of tie channels is also responsible for irregular water service to the wetlands. In last 30 years, about 100 km2 of wetland is transformed into agricultural land, which points out the responsibility of agricultural extension for wetland deterioration. So, periodic monitoring of wetlands, release of ecological flow and stop agricultural encroachment are necessary for sustaining wetland.

Changes in bird assemblages in a wetland ecosystem after 14 years of intensified cattle farming

AbstractHuman activities have modified wetlands all over the word. Water control structures that are frequently implemented in these ecosystems to keep lands free of flooding can decrease or degrade habitat for biodiversity. The Paraná River Delta, one of the largest wetlands in Argentina, has recently experienced rapid cattle grazing intensification facilitated by water control structures, resulting in extensive conversion of wetlands to pastures. It is unclear if this loss of wetlands has had a negative impact on the highly diverse bird community. Here, we evaluated the changes in bird assemblages in the Lower Delta of Paraná River after 14 years of cattle grazing intensification. We compared point count data from 1997 to 1999 with data collected in 2012 and 2013 using the same survey methods. We assessed the temporal changes in bird richness and composition using paired permutation tests and multivariate analysis. We related the bird composition to landscape changes to analyse if avian changes were associated with landscape dynamics. We found that after 14 years, the bird community differed greatly. In general, species richness decreased, especially in wet years. We found fewer wetland species in recent surveys; in particular we did not register saffron‐cowled blackbird (Xanthopsar flavus), a species listed as globally vulnerable. Changes in bird composition were associated with an increase in bare soil due to land‐use changes. Even though inter‐annual differences in precipitation and river stage have great effects on the species present in the surveys, the absence of many wetland species in recent wet years, that is when habitat is suitable for them, is most likely due to changes in land cover. Globally, agricultural land use makes inroads into many wetlands, eroding their quality and extent. Maintenance of wetland species requires that conservation efforts focus on these vulnerable ecosystems before full‐scale land conversion occurs.

Variación de la línea de costa en la aldea de Cedeño, y cartografía de amenaza ante marejadas y ascenso del nivel del mar

La aldea de Cedeño es altamente vulnerable al embate de los fenómenos hidro meteorológicos que periódicamente ocurren en sus playas (Marejadas), a esto se le debe sumar los efectos que producirá el cambio climático. Todo lo anterior ocasionara daños irreversibles como retroceso de la línea de costa, inundaciones debido al aumento del océano, perdida de humedales, intrusión de agua salina, y desplazamiento de personas. Los impactos negativos en el sistema territorial y por ende en la calidad de vida de sus pobladores serán grandes. El objetivo general, consistió en elaborar una línea base sobre los patrones de variabilidad de la costa de la Aldea de Cedeño (tasas de erosión/acreción), además de la cartografía de amenazas ante fenómenos naturales (Mapas de inundación marejadas/ inundación ante el ascenso del mar), que sirva de apoyo para proponer políticas de planificación y gestión del territorio adecuadas. La metodología empleada se basó en análisis geoespacial, usando herramientas de sistemas de información geográfica, teledetección, participación ciudadana y herramientas estadísticas. Los resultados evidenciaron un comportamiento erosivo en las playas de la aldea de Cedeño, así como también una gran área vulnerable a inundación ante las marejadas y escenarios de ascenso del nivel del mar.

Farmers’ perception on climate change and ecological hazards in Riu and Rapti waterbasin, Chitwan, Nepal

A survey research was done to study the farmers’ perception on climate change and ecological hazards in Riu and Rapti water basin, Chitwan, Nepal. Altogether 120 households, 60 from each water basin in Riu and Rapti were selected randomly for the study. Pre-tested interview, direct observation, focus group discussion as well as secondary data from Department of Hydrology and Meteorology (DHM), Kathmandu were used to collect the required information. Majority of the farmers’ perceived the change in climatic condition in their locality in terms of increase in hotter days, decrease in colder days, variability in the number of rainy days, decrease in rainfall duration, increase in amount and intensity of rainfall, late onset and shift of usual monsoon pattern, prolonged occurrences of dry spells, decrease water level in the river as compared to the past decades. Farmers prioritized the floods/riverbank cutting (61.7%) and drought (63.4%) hazards for obtaining immediate solution/adaptation strategies in Riu water basin; and for drought (60%) and loss of wetland and declining water source (45%) in Rapti water basin. Analysis of the climatic data (last 42 years for rainfall and last 30 years for temperature) showed the increasing trend of annual rainfall (6.83 mm per year) and those of both maximum and minimum temperature (0.019°C per year and 0.069°C per year, respectively). These analyses strongly support the farmers’ perception about the climate change and for which immediately effective adaptation mechanism is required.

Controls of carbon flux in a semi-arid grassland ecosystem experiencing wetland loss: Vegetation patterns and environmental variables

Inner Mongolia, China, contains the world’s largest grassland ecosystem. This has many areas of wetland, which provide important ecological services, especially carbon sequestration in the semi-arid terrestrial ecosystems. However, the area of wetland has decreased sharply in the past two decades. This study examined ways to recognize and extract wetland from grassland to determine the difference among net ecosystem exchange (NEE), gross primary production (GPP) and ecosystem respiration (Reco) between wetland and grassland and to evaluate the influence of wetland loss on carbon sequestration in the grassland. The eddy covariance (EC) flux technique was coupled with the Vegetation Photosynthesis and Respiration Model (VPRM) to upscale the spatial patterns of carbon flux. The results showed that the region was a carbon source in 2016, probably caused by overharvesting and degradation of forests. The value of the NEE (average: 6.63 ± 3.50 g C m−2 d−1) in grassland was apparently higher than that in wetland (average: 0.86 ± 1.69 g C m−2 d−1), which suggested that the capability of carbon sequestration in wetland was still stronger than that in grassland even in carbon loss condition. The results showed a positive relationship between aboveground biomass (AGB) and ground-based daily GPP or Reco for both wetland and grassland and a negative relationship between AGB and NEE. The ground-based daily NEE was also significantly related to soil water content (SWC) but showed no relationship with daily precipitation (PRE), which suggested that SWC was a more important impact factor than precipitation on CO2 flux exchange in the study area. The change between wetland and grassland did not influence the positive relationship between AGB or SWC and CO2 flux. Our study provides a new way to determine the spatial CO2 flux exchange and its controlling factors (environmental variables and vegetation patterns) and to successfully analyze its differences in wetland and grassland.

Quantitative assessment of urban wetland dynamics using high spatial resolution satellite imagery between 2000 and 2013

Accurate and timely information describing urban wetland resources and their changes over time, especially in rapidly urbanizing areas, is becoming more important. We applied an object-based image analysis and nearest neighbour classifier to map and monitor changes in land use/cover using multi-temporal high spatial resolution satellite imagery in an urban wetland area (Hangzhou Xixi Wetland) from 2000, 2005, 2007, 2009 and 2013. The overall eight-class classification accuracies averaged 84.47% for the five years. The maps showed that between 2000 and 2013 the amount of non-wetland (urban) area increased by approximately 100%. Herbaceous (32.22%), forest (29.57%) and pond (23.85%) are the main land-cover types that changed to non-wetland, followed by cropland (6.97%), marsh (4.04%) and river (3.35%). In addition, the maps of change patterns showed that urban wetland loss is mainly distributed west and southeast of the study area due to real estate development, and the greatest loss of urban wetlands occurred from 2007 to 2013. The results demonstrate the advantages of using multi-temporal high spatial resolution satellite imagery to provide an accurate, economical means to map and analyse changes in land use/cover over time and the ability to use the results as inputs to urban wetland management and policy decisions.

Depressional wetlands affect watershed hydrological, biogeochemical, and ecological functions.

Depressional wetlands of the extensive U.S. and Canadian Prairie Pothole Region afford numerous ecosystem processes that maintain healthy watershed functioning. However, these wetlands have been lost at a prodigious rate over past decades due to drainage for development, climate effects, and other causes. Options for management entities to protect the existing wetlands, and their functions, may focus on conserving wetlands based on spatial location vis-à-vis a floodplain or on size limitations (e.g., permitting smaller wetlands to be destroyed but not larger wetlands). Yet the effects of such management practices and the concomitant loss of depressional wetlands on watershed-scale hydrological, biogeochemical, and ecological functions are largely unknown. Using a hydrological model, we analyzed how different loss scenarios by wetland size and proximal location to the stream network affected watershed storage (i.e., inundation patterns and residence times), connectivity (i.e., streamflow contributing areas), and export (i.e., streamflow) in a large watershed in the Prairie Pothole Region of North Dakota, USA. Depressional wetlands store consequential amounts of precipitation and snowmelt. The loss of smaller depressional wetlands (<3.0ha) substantially decreased landscape-scale inundation heterogeneity, total inundated area, and hydrological residence times. Larger wetlands act as hydrologic "gatekeepers," preventing surface runoff from reaching the stream network, and their modeled loss had a greater effect on streamflow due to changes in watershed connectivity and storage characteristics of larger wetlands. The wetland management scenario based on stream proximity (i.e., protecting wetlands 30 m and ~450 m from the stream) alone resulted in considerable landscape heterogeneity loss and decreased inundated area and residence times. With more snowmelt and precipitation available for runoff with wetland losses, contributing area increased across all loss scenarios. We additionally found that depressional wetlands attenuated peak flows; the probability of increased downstream flooding from wetland loss was also consistent across all loss scenarios. It is evident from this study that optimizing wetland management for one end goal (e.g., protection of large depressional wetlands for flood attenuation) over another (e.g., protecting of small depressional wetlands for biodiversity) may come at a cost for overall watershed hydrological, biogeochemical, and ecological resilience, functioning, and integrity.

Analysis of spatiotemporal land cover changes in Inner Mongolia using self-organizing map neural network and grid cells method

Land use has changed dramatically in the Inner Mongolia Autonomous Region because of rapid economic growth and human disturbances. However, little information is available about the medium- and long-term land use changes in this region. The effects of ecological recovery policies have also been evaluated rarely. In this study, we employed the self-organizing map neural network method to identify the land cover changes in Inner Mongolia between 2000 and 2014. MOD13Q1, Landsat, and DMSP/OLS night-time light data were used as the data resources. The dynamic change map was characterized using the grid cell method. The results showed that urban area of Inner Mongolia increased by more than five times during the 15-year study period, while the mining area also increased. In addition, 35.3% of the farmland was changed into grassland, which may have been caused by the “Grain to Green” policy. The most significant environmental issue in Inner Mongolia is the loss of wetland. >40% of the wetland was converted into other land use types between 2000 and 2014. Grassland increased by 6.05%, but areas of open water and woodland remained about the same. In terms of the geographical distribution, cropland increased in the eastern and middle parts of the region. The transformation from wetland to grassland mainly occurred in the north. Grassland degradation occurred in the west. Thus, environmental policy has resulted in some ecological improvements in Inner Mongolia. However, new environmental problems associated with rapid economic development should be addressed in a timely manner.

Spatiotemporal Dynamics of Coastal Wetlands and Reclamation in the Yangtze Estuary During Past 50 Years (1960s–2015)

Reclamation is one of the fastest-growing land use type developed in coastal areas and has caused degradation and loss of coastal wetlands as well as serious environmental problems. This paper was aimed at monitoring the spatiotemporal patterns of coastal wetlands and reclamation in the Yangtze Estuary during the 1960s and 2015. Satellite images obtained from 1980 to 2015 and topography maps of the 1960s were employed to extract changes of reclamation and coastal wetlands. Area-weight centroids were calculated to identify the movement trend of reclamation and coastal wetlands. The results show that from the 1960s to 2015, the net area of natural wetlands declined by 574.3 km2, while man-made wetlands and reclamation increased by 553.6 and 543.9 km2, respectively. During the five study phases, the fastest areal change rate natural wetlands was–13.3 km2/yr in the period of 1990–2000, and that of man-made areas was 24.7 km2/yr in the same period, and the areal change rate of reclamation was 27.6 km2/yr in the period of 2000–2010. Conversion of coastal wetlands mainly occurred in the Chongming Island, Changshu City and the east coast of Shanghai Municipality. Reclamation was common across coastal areas, and was mainly attributed to settlement and man-made wetlands in the Chongming Island, Lianyungang City and the east coast of Shanghai Municipality. Natural wetlands turned into farmlands and settlement, and man-made wetlands gained from reclamation of farmlands. The centroid of natural wetlands generally moved towards the sea, man-made wetlands expanded equally in all directions and inland, and the centroid of reclamation migrated toward Shanghai Municipality. Sea level rise, erosion-deposition changes, and reclamation activities together determine the dynamics of the Yangtze Estuary wetlands. However, reclamation activities for construction of ports, industries and aquaculture are the key causes for the dynamics. The results from this study on the dynamics of coastal wetlands and reclamation are valuable for local government to put forward sustainable land use and land development plans.

Remote Monitoring of Expansion of Aquaculture Ponds Along Coastal Region of the Yellow River Delta from 1983 to 2015

Aquaculture ponds are one of the fastest-growing land use types in valuable and fertile coastal areas and have caused serious environmental problems. Quantitative assessment of the extent, spatial distribution, and dynamics of aquaculture ponds is of utmost importance for sustainable economic development and scientific management of land and water resources in the coastal area. An object- oriented classification approach was applied to Landsat images acquired over three decades to investigate the long-term change of aquaculture ponds in the coastal region of the Yellow River Delta. The results indicated that the aquaculture ponds in the study area undergone a sharp expansion from 40.38 km2 in 1983 to 1406.89 km2 in 2015, and the fast expansion occurred during the period of 2010–2015 and 1990–2000. Natural wetlands, especially mudflat, and cropland were main land use types contributing to the increase of aquaculture ponds. The patches of aquaculture ponds were consequently prevalence in the north of the Yellow River Estuary and landscape metrics indicated an increase of the aquaculture ponds of the study area in the quantity and complexity. The expansion of aquaculture ponds inevitably had negative effects on the coastal environment, including loss of natural wetlands, water pollution and land subsidence, etc. The results from this study provide baseline data and valuable information for efficiently planning and managing aquaculture practices and for effectively implementing adequate regulations and protection measures.

Geospatial Analysis of Wetlands Degradation in Makurdi, Nigeria

Abstract. Globally, the amount of wetlands have being on the decline due to the fragile nature of these ecosystems and unplanned land consumption practices. This has created pressure on suitable land for cultivation in most developing countries where most of the growing food demand originates. Previous studies revealed that wetlands and agricultural landuse dominated the landscape of Makurdi. However, the trend is changing in recent times. Makurdi has undergone tremendous transformation in its landuse/landcover due to rapid urbanization since 1976 when it became the capital city of Benue State. To estimate the land cover change in Makurdi, Landsat ETM, ETM+ and OLI satellite data for 1996, 2006 and 2016, respectively were utilised. The study adapted the Kappa index for assessing accuracy of the land use/cover maps generated from the analysis to improve the accuracy of results. An accuracy level of 80 to 91 % was achieved. The results reveal an overall significant increase in built-up area and other land uses at the expense of wetlands from 26.3 % in 1996 to 18.1 % in 2016. Further analysis includes the land consumption rate (LCR) and land absorption coefficient (LAC) which reveals the role of population expansion in the recorded levels of wetland losses recorded in this study. The study projects a further decline of wetland cover by 33.15 km2 (or by 22.57 %) in 2026 if steps are not instituted to control the rate of decline. Suggestions are made to align with and incorporate into policy the strategic need to adopt the provisions of the SDGs at local levels if we intend to avert the massive failure recorded by the now rested MDGs.

Potential carbon loss associated with post-settlement wetland conversion in southern Ontario, Canada

BackgroundNatural wetlands can mitigate ongoing increases in atmospheric carbon by storing any net balance of organic carbon (peat) between plant production (carbon uptake) and microbial decomposition (carbon release). Efforts are ongoing to quantify peat carbon stored in global wetlands, with considerable focus given to boreal/subarctic peatlands and tropical peat swamps. Many wetlands in temperate latitudes have been transformed to anthropogenic landscapes, making it difficult to investigate their natural/historic carbon balance. The remaining temperate swamps and marshes are often treated as mineral soil wetlands and assumed to not accumulate peat. Southern Ontario in the Laurentian Great Lakes drainage basin was formerly a wetland-rich region that has undergone significant land use change since European settlement.ResultsThis study uses southern Ontario as a case study to assess the degree to which temperate regions could have stored substantial carbon if it had not been for widespread anthropogenic land cover change. Here, we reconstruct the full extent and distribution of natural wetlands using two wetland maps, one for pre-settlement conditions (prior to 1850 CE) and the other for modern-day patterns of land use (2011 CE). We found that the pre-settlement wetland cover decreased by about 56% with the loss most significant for marshes as only 11% of predicted pre-settlement marshland area remains today. We estimate that pre-settlement wetlands held up to ~ 3.3 Pg of carbon relative to ~ 1.3 Pg for present-day (total across all wetland classes).ConclusionsBy not considering the recent carbon loss of temperate wetlands, we may be underestimating the wetland carbon sink in the pre-industrial carbon cycle. Future work is needed to better track the conversion of natural wetlands globally and the associated carbon stock change.

Conversions between natural wetlands and farmland in China: A multiscale geospatial analysis

Agricultural activity is widely recognized as a leading driver of natural wetland loss in many parts of the world. However, little is known about the spatiotemporal patterns of conversion between natural wetlands and farmland in China. This information deficiency has limited decision-making for the sustainable management of natural wetland ecosystems. In this study, we explicitly quantified bidirectional natural wetland-farmland conversions during the periods of 1990–2000 and 2000–2010 at multiple spatiotemporal scales. Our results revealed that about 60% (15,765km2) of China's lost natural wetlands were due to agricultural encroachment for grain production, 74.7% (11,778km2) of which occurred from 1990 to 2000. Natural wetland conversion to farmland was highest in Northeast China (13,467km2 or 85.4%), whereas the natural wetlands in Northwest China demand extra attention because of a notable increase of agricultural encroachment. Natural wetlands in the humid zone experienced tremendous agricultural encroachment, leading to a loss of 10,649km2, accounting for 67.5% of the total agriculture-induced natural wetland loss in China. On the other hand, a total of 1369km2 of natural wetlands were restored from farmland, with 66.3% of this restoration occurring between 2000 and 2010, primarily in Northeast China and the humid zone. Although a series of national policies and population pressure resulted in agricultural encroachment into natural wetlands, there are also policies and management measures protecting and restoring natural wetlands in China. The spatial differences in natural wetland-farmland conversions among different geographic regions and climatic zones suggest that China must develop place-based sustainable management policies and plans for natural wetlands. This study provides important scientific information necessary for developing such policies and implementation plans.

Persistent use of a shorebird staging site in the Yellow Sea despite severe declines in food resources implies a lack of alternatives

SummaryMany shorebird populations are in decline along the East Asian-Australasian Flyway. The rapid loss of coastal wetlands in the Yellow Sea, which provide critical stop-over sites during migration, is believed to be the cause of the alarming trends. The Yalu Jiang coastal wetland, a protected area in the north Yellow Sea, supports the largest known migratory staging populations of Bar-tailed Godwits Limosa lapponica (menzbieri and baueri subspecies) and Great Knots Calidris tenuirostris. Monitoring of the macrozoobenthos food for these shorebirds from 2011 to 2016 showed declines of over 99% in the densities of the bivalve Potamocorbula laevis, the major food here for both Bar-tailed Godwits and Great Knots. The loss of the bivalve might be caused by any combination of, but not limited to: (1) change in hydrological conditions and sediment composition due to nearby port construction, (2) run-off of agrochemicals from the extensive shoreline sea cucumber farms, and (3) parasitic infection. Surprisingly, the numbers of birds using the Yalu Jiang coastal wetland remained stable during the study period, except for the subspecies of Bar-tailed Godwit L. l. menzbieri, which exhibited a 91% decline in peak numbers. The lack of an overall decline in the number of bird days in Great Knots and in the peak numbers of L. l. baueri, also given the published simultaneous decreases in their annual survival, implies a lack of alternative habitats that birds could relocate to. This study highlights that food declines at staging sites could be an overlooked but important factor causing population declines of shorebirds along the Flyway. Maintaining the quality of protected staging sites is as important in shorebird conservation as is the safeguarding of staging sites from land claim. Meanwhile, it calls for immediate action to restore the food base for these beleaguered migrant shorebirds at Yalu Jiang coastal wetland.

Enhanced land subsidence in Galveston Bay, Texas: Interaction between sediment accumulation rates and relative sea level rise

Galveston Bay is the second largest estuary along the northern Gulf of Mexico coast, with a watershed containing one of largest concentrations of petroleum and chemical industries globally, as well as Houston, the fifth largest metropolitan area in the USA. Throughout the last century, extensive groundwater extraction to support these industries and an expanding population has resulted in significantly enhanced land subsidence (0.6–3.0 cm yr−1). The highest subsidence rates observed in the bay are within the lower 15 km of the San Jacinto River/Houston Ship Channel region (SJR/HSC), with distal areas in East and West Galveston Bays having subsidence rates on the order of 0.2 cm yr−1. In order to investigate the impacts of subsidence on sedimentation, a series of 22 vibracores were collected throughout the bay, and 210Pb and 137Cs radioisotope geochronologies and grain size distributions were determined. Sediment accumulation rates are highest (1.9 ± 0.5 cm yr−1) in the SJR/HSC, and decrease (<0.6 cm yr−1) both seaward and towards low subsidence regions. These results indicate sedimentation rates are significantly (p < 0.01) higher in areas with elevated Relative Sea Level Rise (RSLR). However, throughout most of Galveston Bay sedimentation rates are lower (as much as 50%) than estimated RSLR, indicating a sediment accretionary deficit. In areas (e.g., Scott Bay) within the SJR/HSC, the bay has deepened by more than 1.5 m, suggesting that sediment accumulation cannot keep pace with RSLR. Ultimately, this has resulted in a loss of coastal wetlands and a conversion of marine habitats from relatively shallow to deeper water settings.

Wetland Plant Community Responses to the Interactive Effects of Simulated Nutrient and Sediment Loading: Implications for Coastal Restoration Using Mississippi River Diversions

The Mississippi River Delta Complex (MRDC) has experienced extensive wetland loss in the last century due, in part, to flood control levees that have isolated the lower Mississippi River and its sediment resource from adjacent wetlands. Reconnecting the River to these wetlands through diversions is being used and proposed on a larger scale for the future, to reduce wetland loss rates. However, some currently operating diversions (e.g., Caernarvon and Davis Pond) have been implicated in causing negative impacts on wetland ecosystem structure and function due to increased nutrient loads in diverted Mississippi River water combined with insufficient sediment delivery. Initial assessments of these concerns were carried out in a greenhouse setting where six nutrient enrichment treatment levels (control, NO3, NH4, PO4, SO4, and Combo [NO3 + NH4 + PO4 + SO4]) were applied with and without sediment addition to 60 marsh sods from a Sagittaria lancifolia-dominated oligohaline wetland at rates simulating the Davis Pond Diversion of the Mississippi River. After 25 months, independent enrichment with N (regardless of form) and sediment was generally beneficial to wetland structure and function, while SO4 enrichment had the opposite effect, regardless of sediment addition. Simultaneous application of N and P (i.e., the Combo treatment level) ameliorated the negative impacts of SO4-loading, but the concurrent application of sediment did not, likely because the loading rate was based on a diversion that was designed to deliver water and not to maximize sediment input. Nonetheless, sediment input is critical to the sustainability of MRDC wetlands experiencing high rates of deterioration. Thus, optimizing future diversions to maximize sediment delivery, along with continued surveillance of negative nutrient effects, are recommended management decisions.

Wetland Conservation and Protection; Implications for Sustainable Flood Disaster Management in a Critical Urban Fringe Area of Port Harcourt

The study investigated the perception of indigenous people to wetland conservation and protection in Rumuagholu community in Obio/Akpor L.G.A of Rivers State. Experimental and survey research design were adopted in the study. Three hundred and sixty two respondents were randomly selected as the sample size for the study. Data for the study were collected using questionnaire while field measurements were obtained through satellite imagery as to ascertain the extent of wetlands in the community before and presently. Tables were used in the presentation of the result of the study. The study revealed that the people in the area do not practice wetland conservation and protection, Wetland distribution in Rumuagholu community has both spatial and temporal variation. It also revealed that wetland within the period of the study lost 10.64% its original state moving from 11km2 to 6km2 and that Loss of biodiversity in the Rumuagholu Community is a major effect of wetland loss. The study recommended the need to encourage effective urban planning mechanism that will help curtail the excessive use of wetlands, and that Government should as a matter of urgency buy up the remaining wetlands to forestall its conversion to other uses because of its role in flood management and water provision as well as eco tourism.

Hydrodynamic storm surge model simplification via application of land to water isopleths in coastal Louisiana

The Mississippi River Delta ranks the seventh largest delta in the world. It provides a habitat for the Louisiana seafood industry, navigation canals and rivers that support five of the 15 largest cargo ports by volume in the United States, and hurricane storm surge protection for coastal cities and oil and gas industry infrastructure that facilitates 90% of the outer continental oil and gas extraction. Due to substantial coastal wetland loss since 1900, the risk of damage to these industries and infrastructure has increased through time. The goal of this research is to develop a methodology to analyze the historical and future evolution of coastal hazards, such as hurricane storm surge, across a complex, low-lying coastal landscape. To accomplish this task, the change in coastal hazards is analyzed through historical changes in coastal wetlands. Specifically, isopleths, defined as lines on a map indicating a constant value of a given variable, are developed to describe areas of constant values of the ratio of land to water (L:W) across coastal Louisiana.In this analysis, a methodology is developed that utilizes land to water (L:W) isopleths to simplify the modern day Louisiana coastal landscape as represented in a state-of-the-art high resolution storm surge model. L:W isopleths are derived for the year 2010 and used to construct 36 storm surge models, each featuring variations of three distinct coastal zones: “High” (i.e. high wetland), “Intermediate” (i.e. wetland), and “Submersed” (i.e. region between open water and wetland). The ADvanced CIRCulation (ADCIRC) code is used to compute water surface elevations and depth-averaged currents forced by hurricane wind and pressures from Hurricanes Rita, Gustav, and Katrina for each model. Peak water levels and volume of inundation are quantified within hydrologic unit code watersheds (HUC12) in order to compare storm surge models featuring high resolution and simplified coastal landscapes.A L:W isopleth permutation of 99%–90%–40%–1% with areas labeled “High” (99%–90%), “Intermediate” (90%–40%) and “Submersed” (40%–1%) is found to best represent simulated storm surge that most closely reproduces the high resolution storm surge model. Simulation results reveal the methodology developed in this analysis is effective in identifying an isopleth permutation that accurately simplifies a high resolution storm surge model. This result may lead to future analyses of the historical evolution of storm surge attenuation in the Mississippi River Delta (MRD) as well as other complex, low-lying deltas. These possibilities include developing storm surge models for the years 1930 and 1970, for instance, with the same isopleth permutation to examine the changes in storm surge attenuation through time. This analysis could also be applied in other similar low-lying coastal regions to conduct past and future analyses of the evolution of coastal hazards.

Benefits of adapting to sea level rise: the importance of ecosystem services in the French Mediterranean sandy coastline

12 This article proposes an innovative approach to assess the benefits of adapting to sea level rise (SLR) in a coastal 13 area on a regional scale. The valuation framework integrates coastal ecosystem services, together with urban and 14 agricultural assets. We simulate the impacts of a progressive 1 m rise in sea level in the 21 st century and an extreme 15 flooding event in 2100 for four contrasted adaptation scenarios (Denial, Laissez-faire , Protection and Retreat). 16 The assessment involves coupling the results of hazard-modelling approaches with different economic valuation 17 methods, including direct damage functions and methods used in environmental economics. The framework is 18 applied to the French Mediterranean sandy coastline. SLR will result in major land-use changes at the 2100 time 19 horizon: relocation or densification of urban areas, loss of agricultural land, increase in lagoon areas and 20 modification of wetlands (losses, migration or extension of ecosystems). Total benefits of public adaptation options 21 planned in advance could reach €31.2 billion for the period 2010-2100, i.e. €69,000 per inhabitant (in the study 22 area) in 2010 or €135 million/km of coastline. Our results highlight the importance of (i) raising awareness to 23 ensure that public services and coastal managers can anticipate the consequences of SLR and (ii) incorporating 24 coastal ecosystems into the assessment of the adaptation options. Our findings could provide a basis for 25 participatory foresight approaches to build coastline adaptation pathways. 26 27

Review of Rapid Transformation of Floodplain Wetlands in Northeast China: Roles of Human Development and Global Environmental Change

Northeast China is the region with the largest area of wetlands in China. The Sanjiang Plain and the Songnen Plain are large freshwater marsh distribution regions that are affected by climate warming and by the increasing frequency and density of extreme weather and are the regions most subject to disturbances by human activities in Northeast China. The wetlands of the Sanjiang Plain and the Songnen Plain have shrunk severely in the past 60 years, and wetland functions have been reduced substantially because of climate change, unreasonable land use, fire episodes, engineering and construction works and urbanization. Large-scale agricultural development started in the 1950s has been the most important driving factor for wetland loss and degradation in the Sanjiang Plain. Water shortage has been the most important factor for degradation and fragmentation of wetlands in the Songnen Plain. To mitigate wetland degradation and better protect wetlands, special regulations, long-term mechanisms and technical support of wetland protection should be established. A wetland compensation program should be implemented, and technologies for increasing the adaptive capacity of wetlands should be developed. Moreover, it is most important to find the balanced threshold between agricultural development and wetland protection.