A classification of major natural habitats of Amazonian white-water river floodplains (várzeas)

Most countries sharing the Amazon basin have signed the Ramsar Convention on Wetlands of International Importance but still lack complete wetland inventories, classification systems, and management plans. Amazonian wetlands vary considerably with respect to hydrology, water and soil fertility, vegetation cover, diversity in plant and animal species and primary and secondary productivity. Here, we propose a classification system of major natural habitats of Amazonian white-water river floodplains (várzeas) based on hydrological, water and soil chemistry and biological parameters. The Amazonian várzea is one of the largest Amazonian wetlands. It is exceptionally rich in plant and animal species and plays important roles in landscape history, evolution, hydrology and biogeochemical cycles of the Amazon basin. Most of Amazonia??s rural population lives in or along the várzea, emphasizing the economic importance of its natural resources. Our classification indicates five major systems, which are subdivided into 10 main habitats and up to 40 functional (vegetation) units of which the most important mesohabitats are described. We understand this classification as a dynamic system, as it is open to the inclusion of future research attempts and habitats without affecting the entire classification system. Our classification may be used for scientific purposes, such as comparative studies on biomass, productivity, biogeochemical cycles and biodiversity. Also, because the classification builds on habitat types and/or vegetation and functional units already distinguished by the local population it may be especially useful in guiding intelligent use of várzea habitat for specific management activities, such as agriculture, animal husbandry, forestry, fisheries, and conservation.     

Recruitment of migratory Characiforms in the different wetland habitats of Central Amazonia: Subsidies for sustainable fisheries management

By promoting the biological recruitment of relevant natural resources, wetlands offer a major ecosystem service. This study investigates the importance of wetland habitats of the central Amazon basin as sites for spawning and/or initial development of seven of the most important commercial Characiforms fish species. In order to confirm this importance, samples of the eggs, larvae, and juveniles of these fish species were collected during the four seasonal phases of the hydrological cycles of 2010 and 2011, in different aquatic environments of the wetland ecosystem in the central Amazon. The results confirmed that the flooding phase is the most important for the spawning of these species, and that they preferred to use the marginal areas of the central Amazon as spawning grounds. The larvae of these species colonize the confluence zone of the rivers and the mouths of the floodplain channels, principally during the initial stages (pre-flexion) of their ontogenetic development. The channels that connect the lakes to the rivers are the main dispersal route for the larvae, especially those in advanced stages of development (flexion/post-flexion), towards the internal of the wetland habitats, such as the lakes and large mattresses of floating vegetation. The different wetland habitats of this region provide an extremely important ecosystem service, playing a critical role in the recruitment of commercially-valuable fish species, and thus require adequate protection and management to ensure the continuity of fisheries and natural stocks.     

The status,conservation and sustainable use of Estonian wetlands

In Estonia, as in other countries, the area of wetlands has diminished remarkably due to different utilization for economic needs. Comparatively large areas of natural wetlands have, however, been preserved. The country’s economic and political situation has changed rapidly since the regaining of independence in 1991 and accession to the European Union in 2004 brought about new challenges for the sustainable use of natural resources. This paper provides an update of conditions of wetlands in Estonia and, in part, represents an update of the relevant materials for Estonia that are described for the country when it was under the rule of the former USSR (Botch and Masing 1983, this volume). We review the diversity and status of wetlands in Estonia and describe the main problems and challenges of sustainable wetland use. Substantial progress has been achieved in Estonia in the area of wetland conservation and a significant proportion of valuable wetlands (a total of 33 wetland habitat types covering more than 300,000 ha) are legally protected and included in the integral and united system of protected areas. All Special Protection Areas and 80% of Special Conservation Areas in the Natura 2000 network represent a lesser or greater amount of wetland habitats. The main challenges of wetland preservation and use are: (1) management of drained wetland areas that have become sources of greenhouse gases; (2) attaining the sustainable use of peat resources and ensuring the restoration of cut-away peatlands; (3) maintenance of the traditional management of valuable semi-natural wetlands. In addition, the increasing pressure of various development projects and tourism on Estonia’s wetland resources need to be evaluated. Wetlands are also seen as an important basis for sustainable development and about 100 wetlands in Estonia that are used for primary or secondary treatment of wastewater. Energy production from wetland plant biomass is considered to be a promising source for small-scale heating plants.     

湿地退化研究进展

受经济发展、城市扩张、气候变化的影响,湿地退化已经成为全球性现象,是当前国际湿地科学前沿领域的热点。从湿地退化标准、退化特征、退化分级、退化过程、退化机理、退化监测体系、退化评价指标与指标体系、退化监测新技术及其生态恢复理论与技术9个方面系统地介绍了当前湿地退化研究进展。结果表明湿地退化过程、退化机理、退化评价指标体系和退化湿地监测、恢复与重建研究是当前研究的重点,在未来相当长的时间内,全球气候变化、湿地退化的微观过程与机理、湿地生态系统的可持续利用将会是重要的研究方向。最后就我国当前湿地退化研究存在的问题进行了分析,并提出近期湿地退化研究亟待开展的11项研究工作,供我国湿地退化研究工作者参考。     

Regionalization of methane emissions in the Amazon Basin with microwave remote sensing

Wetlands of the Amazon River basin are globally significant sources of atmospheric methane. Satellite remote sensing (passive and active microwave) of the temporally varying extent of inundation and vegetation was combined with field measurements to calculate regional rates of methane emission for Amazonian wetlands. Monthly inundation areas for the fringing floodplains of the mainstem Solimões/Amazon River were derived from analysis of the 37 GHz polarization difference observed by the Scanning Multichannel Microwave Radiometer from 1979 to 1987. L‐band synthetic aperture radar data (Japanese Earth Resources Satellite‐1) were used to determine inundation and wetland vegetation for the Amazon basin (<500 m elevation) at high (May–June 1996) and low water (October 1995). An extensive set of measurements of methane emission is available from the literature for the fringing floodplains of the central Amazon, segregated into open water, flooded forest and floating macrophyte habitats. Uncertainties in the regional emission rates were determined by Monte Carlo error analyses that combined error estimates for the measurements of emission and for calculations of inundation and habitat areas. The mainstem Solimões/Amazon floodplain (54–70°W) emitted methane at a mean annual rate of 1.3 Tg C yr^?1, with a standard deviation (SD) of the mean of 0.3 Tg C yr^?1; 67% of this range in uncertainty is owed to the range in rates of methane emission and 33% is owed to uncertainty in the areal estimates of inundation and vegetative cover. Methane emission from a 1.77 million square kilometers area in the central basin had a mean of 6.8 Tg C yr^?1 with a SD of 1.3 Tg C yr^?1. If extrapolated to the whole basin below the 500 m contour, approximately 22 Tg C yr^?1 is emitted; this mean flux has a greenhouse warming potential of about 0.5 Pg C as CO₂. Improvement of these regional estimates will require many more field measurements of methane emission, further examination of remotely sensed data for types of wetlands not represented in the central basin, and process‐based models of methane production and emission.     

Aquatic carbon fluxes dampen the overall variation of net ecosystem productivity in the Amazon basin: An analysis of the interannual variability in the boundless carbon cycle

The river–floodplain network plays an important role in the carbon (C) cycle of the Amazon basin, as it transports and processes a significant fraction of the C fixed by terrestrial vegetation, most of which evades as CO₂ from rivers and floodplains back to the atmosphere. There is empirical evidence that exceptionally dry or wet years have an impact on the net C balance in the Amazon. While seasonal and interannual variations in hydrology have a direct impact on the amounts of C transferred through the river–floodplain system, it is not known how far the variation of these fluxes affects the overall Amazon C balance. Here, we introduce a new wetland forcing file for the ORCHILEAK model, which improves the representation of floodplain dynamics and allows us to closely reproduce data‐driven estimates of net C exports through the river–floodplain network. Based on this new wetland forcing and two climate forcing datasets, we show that across the Amazon, the percentage of net primary productivity lost to the river–floodplain system is highly variable at the interannual timescale, and wet years fuel aquatic CO₂ evasion. However, at the same time overall net ecosystem productivity (NEP) and C sequestration are highest during wet years, partly due to reduced decomposition rates in water‐logged floodplain soils. It is years with the lowest discharge and floodplain inundation, often associated with El Nino events, that have the lowest NEP and the highest total (terrestrial plus aquatic) CO₂ emissions back to atmosphere. Furthermore, we find that aquatic C fluxes display greater variation than terrestrial C fluxes, and that this variation significantly dampens the interannual variability in NEP of the Amazon basin. These results call for a more integrative view of the C fluxes through the vegetation‐soil‐river‐floodplain continuum, which directly places aquatic C fluxes into the overall C budget of the Amazon basin.     

Response of wetland plant communities to inundation within floodplain landscapes

Summary Many floodplain wetlands in south‐eastern Australia have become isolated from the main river channel as a consequence of reduced high flows and associated flood events following river regulation. In the Central Murray region of south‐eastern Australia, many temporary wetlands would have received water once every five years or so, with large floods maintaining floodplain connectivity every decade, under natural conditions. Now, the River Murray is highly regulated and many of these wetland areas have not been flooded for periods of up to 30 years. Consequently, these wetlands are becoming degraded and the biodiversity of the area is in decline. From 2001–2003, 21 Black Box depression wetlands in the Central Murray region were each watered once. Plant communities in each wetland were monitored for changes in abundance (assessed as percentage cover) before and during the wetting and drying phases. Wetlands were watered during spring or early summer with the length of inundation ranging from 6 to 19 weeks. After watering, the percentage cover of native plant taxa and native plant functional groups in most wetlands increased. In general, there was a decrease in the percentage number of terrestrial plants present and an increase in the percentage cover of aquatic plants. Introduced species were a minor component. Although these wetlands are all located in the Central Murray region, individual wetlands developed plant communities that contained taxa specific to individual wetlands despite initial similarities. These results indicate that wetland plant biodiversity within the landscape can be promoted and maintained by ensuring there is a diversity of wetlands with varying flood regimes within the landscape.     

基于系统保护规划的黄河流域湿地优先保护格局

黄河流域湿地为我国生物多样性维持提供了重要生境.本研究基于黄河流域气候分区、地貌单元及湿地遥感数据,构建黄河流域生态地理综合湿地分类系统.在系统保护规划理论框架下,将湿地气候-地貌分类单元作为生态系统层次保护对象,结合黄河流域鸟类分布范围作为物种层次的保护对象,设定30%湿地优化目标,将公路、铁路、城镇、农村居民点、水坝等作为度量因子创建黄河流域保护代价图层,并利用系统保护规划工具--Marxan软件构建黄河流域湿地保护优化格局,识别湿地保护空缺.结果表明: 黄河流域大部分沼泽湿地集中在黄河上游区域,目前源区保护区覆盖面积大,在内蒙古、甘肃及四川部分区域一些稀有湿地类型游离在保护体系外;黄河中游湿地类型以河道和河滩湿地类型为主,保护覆盖率极低,保护空缺严重,经优化保护网络体系后,保护成效可分别得到29.1%、37.6%的提升.黄河下游湿地主要集中在黄河三角洲区域,目前保护体系完整,保护空缺面积极小.总体上,黄河流域中游河流湿地的保护空缺比例最高,亟需重视.本研究基于湿地保护格局优化结果分区分析黄河流域湿地保护模式,为黄河流域湿地的保护规划管理提供了科学性建议,从宏观层面上为黄河流域水生态保护奠定了基石.     

Resource dependence and attitudes of local people toward conservation of Kabartal wetland: a case study from the Indo-Gangetic plains

Wetlands are rapidly disappearing from the earth's surface because of agricultural conversion and other land-use changes. The Indo-Gangetic biogeographic zone is a water-surplus area and it abounds in numerous wetlands and floodplains. Kabartal is one such freshwater wetland ecosystem situated in the mid Ganges basin. The wetland not only supports a large population of migratory and residential waterfowl but also plays an equally important role in the local economy and livelihoods of people. The objective of this paper is to examine the different wetland–society linkages, resource dependence, and attitudes of the people living in the peripheral villages of Kabartal. The results indicate that 67% of people depend on the wetland for different types of subsistence and commercial goods including fodder, fuel wood, construction materials, and fish. Kabartal wetland, like many other wetlands of the region, is used simultaneously for rice cultivation, fishing, and many other uses. This has resulted in conflict between different stakeholder groups. The non-settlement of land rights in the Kabartal sanctuary area has further complicated the situation. Agriculture was rated as the most important use of the wetland and was the basic source of income in the area. This was apparent from the attitudes of people, and most of the respondents demanded draining of the water to make more land available for agriculture. The study reveals the high dependence of people in low-income groups on wetland resources. In such a scenario, although the concept of conservation is well supported, the economic conditions of people dictate otherwise. A general lack of awareness about the ecological functions of wetlands points to the need for conservation education. Managing the wetland on the basis of zone concepts and involving local people in alternative income-generating activity by use of extension programs has been suggested as a means of reducing pressure on agricultural land and also reducing the threat to Kabartal wetland.     

Conservation strategies for coastal wetlands in the Gulf of California,Mexico

Wetlands worldwide, the fisheries they support, and the communities that depend on them are threatened by habitat modification. We describe strategies being used for wetland conservation in the Gulf of California, Mexico, their effectiveness, and challenges for implementation. We base our analysis on the authors’ experience working for local environmental non-governmental organizations and available literature. The strategies discussed include public and private policy instruments such as Environmental Impact Evaluations, environmental land easements, concessions and transfer agreements, Natural Protected Areas, and international agreements such as the Ramsar convention and the North American Wetlands Conservation Act. We present examples from the Gulf of California that highlight some of the challenges to wetland conservation. These challenges range from governmental failure to enforce existing environmental legislation, lack of verification of requirements for development projects, to low economic penalties for wetland modification or destruction. We found that in the Gulf of California successful conservation of coastal wetlands required a combination of policy instruments and relied on integrating science, management, and public participation through partnerships between non-governmental institutions, academic institutions, community stakeholders, and government agencies.     

基于遥感的湿地景观格局季相分析

以中国东北地区三江平原北部为研究区域,利用2012年多季相遥感影像作为数据源,结合野外调查数据,应用面向对象的分类方法,根据影像的物候、时相等特征,提取不同月份的湿地信息,进行景观格局季相分析。结果表明:(1)研究区湿地面积、类型格局在同一年不同季节不同月份会有不同幅度的变化,总体呈现缓增骤减的态势。湿地主要分布在低洼地区,主要湿地类型为草本沼泽,其次为河流,其他湿地占总面积比例较小。(2)研究区各阶段湿地都有转化,主要发生在湿地和非湿地之间,多数表现在草本沼泽和草地之间的转化。(3)湿地分布和湿地转化面积主要集中在低海拔区域和低坡度区域,其中海拔100 m和坡度5°以下范围内的湿地分布面积和湿地转化面积占湿地总面积及湿地转化面积的绝大部分。(4)年内季节性湿地转化与降水、温度和湿地植被物候关系密切。     

Perceived benefits of littoral wetlands in Uganda: a focus on the Nabugabo wetlands

Wetlands, commonly called swamps in Uganda, are estimated to cover about 13% of the total land surface area (about 30,000 km²) of the country and represent a considerable ecological, social and economic value. In 1989, the Ugandan government formerly recognised that wetlands need to be conserved and contribute considerably to the National economy and rural livelihood. The present analysis is focused on the Nabugabo wetland ecosystem. Located in Central Uganda, it is an important part of the extensive system of wetlands that surround Lake Victoria. The Nabugabo wetland is a source of important resources that are basic to the local economy, including fishing, water utilization, agriculture, livestock, wetland plants for construction and more recently, tourism. Investment in the area is low and a large percentage of the local community depends on the wetland resources for basic sustenance needs. After achieving Ramsar status, demarcation and conservation activities were initiated by the local and national leaders. However, these conservation efforts have provoked conflicts between the land owners and the policy makers, in particular to the demarcation of areas for conservation In the present analysis, we examine the benefits, perceived by local leaders and community members, of the wetland and its services, as well as views towards its conservation and management. The results show that differences between the community leaders and member exist regarding the perceived benefits of the wetlands. Tourism, while providing some opportunities for local persons is not always viewed positively. Conservation activities are viewed positively but some questions remain as to whether such efforts help or hinder the local population, in particular regarding access to basic resources.     

黄河流域湿地水鸟多样性保护对策

黄河是中华文明的发源地, 被誉为母亲河, 是两岸社会经济发展的保障, 切实保护好黄河流域湿地生态系统, 事关中华民族伟大复兴的千秋大计。黄河流域湿地总面积为391万ha, 其中80.4%分布在上游, 中游和下游分别仅12.5%和7.1%。黄河流域是东亚-澳大利西亚候鸟迁徙路线和中亚候鸟迁徙路线上水鸟的关键栖息地, 一些迁徙水鸟最关键的栖息地均分布在黄河流域, 如黑颈鹤(Grus nigricollis)、白鹤(G. leucogeranus)、丹顶鹤(G. japonensis)、斑头雁(Anser indicus)、大鸨(Otis tarda)、东方白鹳(Ciconia boyciana)、大天鹅(Cygnus cygnus)、疣鼻天鹅(C. olor)、青头潜鸭(Aythya baeri)等。尽管黄河流域湿地提供的水资源仅占全国的2%, 但维持着全国12%的人口饮水安全和15%的耕地用水, 湿地生态系统的脆弱性较高。截至2017年底, 黄河流域已建立各类湿地自然保护地230处, 其中国家公园2处、国家级自然保护区9处、地方级自然保护区68处、国家湿地公园145处、省级湿地公园6处, 湿地保护率达到65%, 高于我国湿地保护53%的平均水平。然而, 流域尺度现有水鸟生物多样性保护仍然面临不少挑战, 包括全球气候变化、水资源过度利用、水环境污染、栖息地丧失等。为此, 我们提出了建立以国家公园为主体的湿地保护地体系、开展濒危候鸟栖息地修复和强化黄河流域综合管理的体制机制建设等建议。     

Road building, land use and climate change: prospects for environmental governance in the Amazon

Some coupled land-climate models predict a dieback of Amazon forest during the twenty-first century due to climate change, but human land use in the region has already reduced the forest cover. The causation behind land use is complex, and includes economic, institutional, political and demographic factors. Pre-eminent among these factors is road building, which facilitates human access to natural resources that beget forest fragmentation. While official government road projects have received considerable attention, unofficial road building by interest groups is expanding more rapidly, especially where official roads are being paved, yielding highly fragmented forest mosaics. Effective governance of natural resources in the Amazon requires a combination of state oversight and community participation in a 'hybrid' model of governance. The MAP Initiative in the southwestern Amazon provides an example of an innovative hybrid approach to environmental governance. It embodies a polycentric structure that includes government agencies, NGOs, universities and communities in a planning process that links scientific data to public deliberations in order to mitigate the effects of new infrastructure and climate change.     

Use of seasonal freshwater wetlands by fishes in a temperate river floodplain

This study examined the use of freshwater wetland restoration and enhancement projects ( i.e . non-estuarine wetlands subject to seasonal drying) by fish populations. To quantify fish use of freshwater emergent wetlands and assess the effect of wetland enhancement ( i.e . addition of water control structures), two enhanced and two unenhanced emergent wetlands were compared, as well as two oxbow habitats within the Chehalis River floodplain. Eighteen fish species were captured using fyke nets and emigrant traps from January to the beginning of June, with the most abundant being three-spined stickleback Gasterosteus aculeatus and Olympic mudminnow Novumbra hubbsi . Coho salmon Oncorhynchus kisutch was the dominant salmonid at all sites. Enhanced wetlands, with their extended hydroperiods, had significantly higher abundances of yearling coho salmon than unenhanced wetlands. Both enhanced and unenhanced emergent wetlands yielded higher abundances of non-game native fishes than oxbow habitats. Oxbow habitats, however, were dominated by coho salmon. Fish survival in the wetland habitats was dependent on emigration to the river before dissolved oxygen concentrations decreased and wetlands became isolated and stranding occurred. This study suggests that wetland enhancement projects with an outlet to the river channel appear to provide fishes with important temporary habitats if they have the opportunity to leave the wetland as dissolved oxygen levels deteriorate.     

Managed flooding can augment the benefits of natural flooding for native wetland vegetation

Managed flooding is increasingly being used to maintain and restore the ecological values of floodplain wetlands. However, evidence for its effectiveness is sometimes inconsistent and water available for environmental purposes often limited. We experimentally inundated a floodplain wetland (or “billabong”) in late spring by pumping water from its adjacent creek, aiming to promote the native wetland flora and suppress terrestrial exotics. Vegetation was surveyed before (spring) and after (late summer) the managed flood in the experimental billabong and in three control billabongs. Floodplain water levels were continuously monitored. Wet conditions caused two of the control billabongs to also flood, but to a lesser extent than the experimental billabong. We therefore assessed vegetation changes relative to flooding duration. With increasing flooding duration, the cover of wetland vegetation (amphibious and aquatic species) increased and the cover of terrestrial and exotic vegetation decreased, with these effects largest in the deliberately flooded billabong. Flooding durations greater than 20 days generally resulted in increased cover of wetland plants and restricted the growth of terrestrial plants. Reinstatement of more appropriate flooding regimes can thus promote native wetland plants, while suppressing terrestrial exotic species. Our study also provides evidence for the use of modest water allocations to augment the benefits of natural flooding in the maintenance and restoration of native wetland plant communities.     

Identifying nascent wetland forest conversion in the Democratic Republic of the Congo

Wetlands cover large areas in the Democratic Republic of the Congo. However, their extent and distribution have not been accurately mapped. While wetland forests remain largely undisturbed, increasing threats by anthropogenic activities have been observed in areas with high population density per arable or exploitable land. The scarcity of terra firma forests in some territories of the Democratic Republic of the Congo has forced local communities to develop cropping methods that allow for cultivation in periodically flooded areas. Assessing wetlands extent and status is critical for long term conservation of these highly vulnerable ecosystems. In this study, we use multi-source and multi-resolution optical and radar remotely sensed data and elevation derived indices to map the wetlands of the Democratic Republic of the Congo. Results showed that wetlands are a significant part of the landscape in the country, covering an estimated 440,000 km² or 19.2 % of the total country area. By combining the wetlands map with a previously produced land cover depiction of the Democratic Republic of the Congo, a map including forested wetlands as a thematic class was derived. We investigated whether high terra firma population density and low percent remaining terra firma forest are related at the lowest administrative level (Sector); specifically, we tested these two variables as predictors of wetland forest cover loss. A polynomial regression relating population and primary terra firma forest to wetland forest cover loss yielded an r ² of 0.76, illustrating a nascent and significant land cover change dynamic. Areas most at risk for future wetland forest loss lie in the western Cuvette, and include (north–south) the Sud-Ubangi, Mongala, Equateur and Mai-Ndombe Districts. By quantifying available upland forest resources and overlaying with population density, it was possible to identify stressed areas inside of the forest domain (traditionally known for having generically high levels of forest resources). Results illustrate the need for addressing issues of wetland forest management and protection in the Democratic Republic of the Congo, especially where increasing populations are exhausting primary terra firma forest resources.     

海河流域湿地生态系统服务功能价值评价

摘要：海河流域湿地生态系统给人类提供了许多重要的产品和服务,但在社会经济发展的过程中,这些服务并没有完全被认识到,给海河流域社会经济的可持续发展造成了一定的影响。本研究结合海河流域湿地生态系统的特征、结构及过程,将海河流域湿地生态系统服务功能划分为提供产品功能、调节功能、支持功能及文化服务功能4大类,以2005年为基准年,评价了海河流域湿地生态系统所提供的12类生态系统服务,将这12类服务功能划分为具有直接使用价值的产品和具有间接使用价值的服务。结果表明,海河流域湿地生态系统提供的12类生态系统服务的总价值为4123.66?108元,其中直接使用价值和间接使用价值分别为257.46?108元和3866.20?108元,间接使用价值是直接使用价值的15.02倍。海河流域单位面积的湿地生态系统提供的生态系统服务功能价值为47.05?104元/hm2,高于单位面积的GDP产值8.10?104元/hm2。研究认为海河流域湿地生态系统对支持和保护人类社会具有重要的作用,为管理者和决策者有效的保护和管理湿地提供了重要的信息。     

An evaluation of the first inventory of South American wetlands

Thanks to the efforts of the International Waterfowl Research Bureau, during 1982–1984, geographic and biotic data from 368 wetlands across South America were gathered. However, the conservation impact of this inventory has not been as striking as expected because of two reasons. First, since most contributors did not work for governmental agencies, the major points stressed in the document have been overlooked by local authorities. Second, because of logistic limitations of the inventory, large wetlands (i.e. those across the Amazon basin), were not inventoried using the IWRB criteria and thus considered as one large wetland. A critical, comparative, review of the results of the inventory revealed that in addition, the reliability of the inventory is questionable because of the differential effort put into the compilation of the information. Several countries appear to contain only a small percentage of South American wetlands, while in fact they have as many wetlands of international importance as countries that have many times their estimated area of wetlands.     

Characteristic community structure of Florida’s subtropical wetlands: the Florida wetland condition index for depressional marshes, depressional forested, and flowing water forested wetlands

Land use and land cover change has a marked affect on wetland condition, and different wetland types are affected differentially depending on many abiotic and biotic variables. To assess wetland condition, we have developed a Florida wetland condition index (FWCI) composed of indicators of community structure in the diatom, macrophyte, and macroinvertebrate assemblages for 216 wetlands (n = 74 depressional marsh, n = 118 depressional forested, n = 24 flowing water forested wetlands). Depressional wetlands located along a human disturbance gradient throughout Florida were sampled for each assemblage. Forested flowing water wetlands were sampled for macrophytes only. The landscape development intensity index (LDI) was used to quantify the human disturbance gradient. In general, human disturbance in adjacent areas had the greatest impact on depressional herbaceous wetlands, followed by depressional forested wetlands. Forested flowing water wetlands (i.e., forested strands and floodplain wetlands) were less affected by local conditions, with most of their changes in wetland condition correlated with alterations at the larger watershed scale. Strong correlations between the FWCIs and LDI index scores suggest that changes in community structure can be detected along a gradient of human land use activities adjacent to wetland ecosystems.