EMAP-Wetlands: A sampling design with global application

The U.S. Environmental Protection Agency (EPA) initiated the Environmental Monitoring and Assessment Program (EMAP) in 1988. The wetland component (EMAP-Wetlands) is designed to provide quantitative assessments of the current status and long-term trends in the ecological condition of wetland resources. EMAP-Wetlands will develop a wetland monitoring network and will identify and evaluate indicators that describe and quantify wetland condition. The EMAP-Wetlands network will represent a probability sample of the total wetland resource. The EMAP sample is based on a triangular grid of approximately 12,600 sample points in the conterminous U.S. The triangular grid adequately samples wetland resources that are common and uniformly distributed in a region, such as the prairie pothole wetlands of the Midwest. However, the design is flexible and allows the base grid density to be increased to adequately sample wetland resources, such as the coastal wetlands of the Gulf of Mexico, which are distributed linearly along the coast. The Gulf sample network required a 49-fold increase in base grid density. EMAP-Wetlands aggregates the 56 U.S. Fish and Wildlife Service's (FWS) National Wetland Inventory (NWI) categories (Cowardin et al. 1979) into 12 functionally similar groups (Leibowitz et al. 1991). Both the EMAP sample design and aggregated wetland classes are suitable for global inventory and assessment of wetlands.The research described in this report has been funded by the U.S. Environmental Protection Agency. This document has been prepared at the EPA Environmental Research Laboratory in Corvallis, OR, through contract No. 68-C8-0006 to Man Tech Environmental Technology, Inc. This paper has been subjected to the Agency's peer and administrative review and approved for publication. Mention of trade names or commercial products does not constitute endorsement or recommendation for use.     

A conceptual model for the assessment of depressional wetlands in the prairie pothole region

The U.S. Environmental Protection Agency's (EPA's), Environmental Monitoring and Assessment Program (EMAP) is developing a landscape-level conceptual model to evaluate the condition of depressional (basin-type) wetlands in the prairie pothole region (PPR) of the United States. This effort is underway to determine the current condition of the Nation's wetlands and to track how it is improving or degrading over time, as well as to identify management priorities over major geographic areas. The depressional wetlands in the PPR were selected by EMAP both because of the importance of this region for waterfowl and because of the efforts currently being conducted by federal agencies and academic institutions in this region. The PPR provides nesting habitat for more than 15 species of ducks, and supports as much as half of the total production of dabbling and diving ducks in North America. Wetlands in this area became a vulnerable resource after extensive draineage in the 1800s. We propose a conceptual model that represents a framework for guiding the development of ecological indicators, research activities, and data collection for the evaluation of wetland conditions. In princple, this conceptual model is applicable to wetlands in any part of the world.     

Ten years primary succession on a newly created landfill at a lagoon of the Mediterranean Sea (Lake Burullus RAMSAR site)

This study was carried out on the transported bed soil dredged from the outlet of Lake Burullus to the Mediterranean Sea and deposited nearby, forming by this way new land that underwent a primary plant succession. The multi-methodological approach comprised floristic inventories, vegetation sampling and soil composition analyses of the study site in order to detect the crucial parameters controlling the plant resettlement on recently deposited soil as related to time, local micro-topography and substrate characteristics. Floristic composition was assessed for the first 10 years of primary succession (2001–2010) on 18 stands of the area, distributed on basement, slope stands and plateau of the landfill, respectively. Vegetation surveys were the basis of multivariate analyses of the vegetation and soil data using TWINSPAN, DCA and CCA. Relationships between the edaphic gradients, floristic composition and species diversity were assessed.     

Detention and mixing in free water wetlands

Mixing was studied in free water surface wetland receiving pumped river water, by measurement of the non-interacting tracer lithium. The flow pattern was found to be intermediate between plug flow and well-mixed. The nominal detention time, calculated from volume aand flow, was 50% larger than the mean tracer detention time. The peak time was found to be one-half the tracer detention time. Three models were constructed: plug flow with dispersion, tanks in series, and a series-parallel network of tanks. All proved capable of fitting the exit tracer concentration curves but the network model provided a better fit to internal measurements. Pumping frequency was high enough to allow use of an average flowrate. The degree of mixing, as characterized by the variance of the exit tracer response curve, was comparable to that found by other researchers for wetlands, ponds and rivers.     

基于选择实验的三江平原湿地生态系统服务功能价值评价及偏好异质性研究

维持与保护生态系统服务功能是实现可持续发展的基础,定量评价湿地生态系统服务功能的经济价值已成为当前生态学领域研究的前沿课题。以三江平原湿地为研究对象,应用选择实验法,选取湿地面积、生物多样性、水源涵养和自然景观等4项湿地属性,运用随机参数Logit模型(RPL)对其进行货币化评价,并结合潜在分类模型(LCM)证实并解释公众对湿地生态系统服务功能的偏好异质性。研究结果显示:湿地生态系统服务功能的价值依次为水源涵养湿地面积生物多样性自然景观。对于维持当前各项湿地生态系统服务功能的总价值为14.61亿元/a,改善价值为98.58亿元/a。此外,研究发现受访者可分为资源偏好型、景观偏好型和价格敏感型等3个潜在类别,不同类型的群体对湿地生态系统服务功能存在不同偏好;女性和更高学历的受访者更偏好于资源保护,高收入和到景区旅游次数多的受访者更偏好于景观保护,而教育和收入水平越低的受访者更倾向于选择价格较低的湿地管理方案。研究有助于湿地可持续管理政策的优化设计,为相关环境政策的制定提供理论依据。     

Total economic value of wetland conservation in Sri Lanka identifying use and non-use values

In tropical regions, mangroves, clean (unpolluted) water-bodies and fish are important aspects of wetland areas, which are considered as the basic requirement for livelihood improvement in local communities. Particularly, their conservation is very important to both inland as well as inshore fisheries. However, conservation of such areas is dependent on the perceptions of key stakeholders in the area. A novel approach of a one and one-half bound based contingent valuation method (CVM) was implemented to measure the stakeholder willingness to pay (WTP) towards the conservation of fish, mangroves and water in a Sri Lankan wetland area. Estimated median WTP is Rs. 264.26, which is thought reliable when considering average income in the community. The analytic hierarchy process (AHP) was used to separate use and non-use values from the total value. Results show that non-use values are a significant component in the elicited WTP value, of between 45-55%. In the past such commodities have been assigned zero or low values due to difficulties involved in assigning economic values.     

Development of a multimetric plant-based index of biotic integrity for assessing the ecological state of forested,urban and agricultural natural wetlands of Jimma Highlands,Ethiopia

Wetlands are vital natural resources thereby providing ecological and socio-economic benefits to the people. However, anthropogenic activities have seriously changed the ecological conditions of wetlands worldwide, especially in developing nations like Ethiopia. Predominantly, the absence of biomonitoring tool greatly hampers the protection and management of wetlands. Therefore, the objective of this research is to develop a plant-based index of biological integrity for facilitating the management of wetlands. Accordingly, 122 plant species belonging to 37 families were collected and identified from forested, urban and agricultural wetland types and included in the analysis of the plant metrics. Initially, we reviewed and screened 35 potential metrics. Then, we selected four core metrics (% cover of native species, sensitive plant species richness, tolerant plant species richness and% of shrub species richness) using the decrease or increase responses to human disturbances, Mann-Whitney U test and redundant metric test. A trisect-quartile range system using box plots of the reference or impaired sites of wetlands was established to provide values for each core metrics. Then after, we combined the core metrics to develop the plant-based index of biological integrity. Finally, we validated the index by comparing the index response to different wetland types. Additionally, the index was validated based on the measured environmental variables that characterize the human disturbance gradient of wetlands. We found that the plant-based index is robust to discriminate the reference wetlands from impaired wetlands and can also be used as an effective tool for evaluating the long term natural wetland conditions of the Eastern African wetlands in the future.     

Determination of Trace Element Stability in Sediments Using Redox Gel Probes: Probe Construction and Theoretical Performance

A simple and inexpensive technique is described that can be used to assess the stability of redox-sensitive compounds in the sediments of wetlands and other shallow water environments. In this method, solid redox-sensitive compounds, such as manganese dioxide (MnO 2 ), are incorporated into agar gels held in rigid plastic holders. One surface of the gel remains exposed along the length of the resulting probe. The probes are pushed vertically into sediments and are left in situ for a period of time (days to weeks), after which they are visually inspected and chemically analyzed. The diffusion of nonreactive solutes (e.g., sulfate) in 2% (wt/vol) agar was unaffected by the presence of immobilized MnO 2 particles. The rate of dissolution of particulate MnO 2 in agar gels in the presence of an external diffusing reductant (L-ascorbic acid) could be quantified by digital analysis of pixel density on gel images. Redox gel probes incubated in the sediment of a wetland built to remove manganese from circumneutral pH coal mine drainage demonstrated different patterns of depth-dependent MnO 2 stability along a 15-m transect. MnO 2 gel probe results were consistent with data obtained using sediment cores and porewater diffusion samplers.     

Understory vegetation as an indicator for floodplain forest restoration in the Mississippi River Alluvial Valley,U.S.A.

In the Mississippi River Alluvial Valley (MAV), complete alteration of river‐floodplain hydrology allowed for widespread conversion of forested bottomlands to intensive agriculture, resulting in nearly 80% forest loss. Governmental programs have attempted to restore forest habitat and functions within this altered landscape by the methods of tree planting (afforestation) and local hydrologic enhancement on reclaimed croplands. Early assessments identified factors that influenced whether planting plus tree colonization could establish an overstory community similar to natural bottomland forests. The extent to which afforested sites develop typical understory vegetation has not been evaluated, yet understory composition may be indicative of restored site conditions. As part of a broad study quantifying the ecosystem services gained from restoration efforts, understory vegetation was compared between 37 afforested sites and 26 mature forest sites. Differences in vegetation attributes for species growth forms, wetland indicator classes, and native status were tested with univariate analyses; floristic composition data were analyzed by multivariate techniques. Understory vegetation of restoration sites was generally hydrophytic, but species composition differed from that of mature bottomland forest because of young successional age and differing responses of plant growth forms. Attribute and floristic variation among restoration sites was related to variation in canopy development and local wetness conditions, which in turn reflected both intrinsic site features and outcomes of restoration practices. Thus, understory vegetation is a useful indicator of functional progress in floodplain forest restoration.     

Persistence of Water within Perched Basins of the Peace-Athabasca Delta, Northern Canada

The Peace-Athabasca Delta (PAD) is one of the world’s largest freshwater deltas. Many of its shallow (<1.5 m) lakes and wetlands are perched above surrounding waterways. The delta has experienced a number of wetting and drying intervals. The latest drying trend ended in 1996 when high waters, generated under ice-jam and open-water conditions, recharged a number of the perched basins. The objective of this study was to determine the relative importance of hydroclimatic components on the persistence of water. A water-balance model was developed to simulate water-level responses following a flood event. Basin response was tested against a range of historical hydroclimatic conditions that have occurred in the delta during the 20th century. Ponded water duration in a 0.8 m deep perched basin was 5 years for the cool-dry period of the 1920s, slightly longer for the post-1974 flood era, and up to 9 years for the wet conditions of the 1940s and 1950s. Water drawdown occurred in almost every year and was almost exclusively due to evaporation exceeding precipitation. Net groundwater flux was minimal. Given the overlying importance of the floodwater component in the water balance of perched basins, the next step is to investigate the causes, spatial sources and frequency of flooding. This water balance model presented in this paper offers a useful tool for the management of the duration of water in perched wetlands of the PAD, which can help preserve essential habitat for wildlife.