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Wetland Types (wetland + type)

Distribution by Scientific Domains

Life Sciences	62%

Selected Abstracts

Connecting Atmosphere and Wetland: Trace Gas Exchange

GEOGRAPHY COMPASS (ELECTRONIC), Issue 2 2009
Peter M. Lafleur
This article reviews the exchange of carbon dioxide (CO2) and methane (CH4) gases between wetland and atmosphere, with a primary emphasis on ecosystem-scale fluxes and their environmental controls. It is intended to complement a previous review of wetland energy and water exchanges (Lafleur 2008). It is shown that wetland exchanges of these gases are greatly variable in space and time, especially CH4. Most wetlands appear to be sinks for atmospheric CO2, while almost all are emitters of CH4. The strongest environmental control on the CO2 flux is drought, which often determines whether a wetland will be a net sink or source for atmospheric CO2. Due to complex biochemistry and transport mechanisms, methane efflux from wetlands often ranges over several orders of magnitude within a single wetland and among wetlands, making it difficult to quantify the environmental controls on this flux. The magnitude of gas fluxes is not strongly related to wetland type, which implies that modelling of these fluxes should consider wetlands a continuum and attempt to address processes as they vary along this continuum instead of as discrete entities. Although more research is required into the magnitude, variation and controls on trace gas fluxes in all wetland types, some wetlands (tropical and temperate marshes) are particularly understudied. [source]

Connecting Atmosphere and Wetland: Energy and Water Vapour Exchange

GEOGRAPHY COMPASS (ELECTRONIC), Issue 4 2008
Peter M. Lafleur
Wetlands are ubiquitous over the globe, comprise a vast array of ecosystem types and are of great ecological and social importance. Their functioning is intimately tied to the atmosphere by the energy and mass exchanges that take place across the wetland,atmosphere boundary. This article examines recent research into these exchanges, with an emphasis on the water vapour exchange. Although broad classes of wetland type, such as fen, bog and marsh, can be defined using ecological or hydrologic metrics, distinct difference in energy exchanges between the classes cannot be found. This arises because there are many factors that control the energy exchanges and interplay of these factors is unique to every wetland ecosystem. Wetlands are more similar in their radiation balances than in the partitioning of this energy into conductive and turbulent heat fluxes. This is especially true of evapotranspiration (ET) rates, which vary considerably among and within wetland classes. A global survey of wetland ET studies shows that location has little to do with ET rates and that variation in rates is largely determined by local climate and wetland characteristics. Recent modelling studies suggest that although wetlands occupy a small portion of the global land surface, their water and energy exchanges may be important in regional and global climates. Although the number of studies of wetland,atmosphere interactions has increased in recent years more research is needed. Five key areas of study are identified: (i) the importance of moss covers, (ii) lack of study in tropical systems, (iii) inclusion of wetlands in global climate models, (iv) importance of microforms in wetlands and their scaling to the whole ecosystem, and (v) the paucity of annual ET measurements. [source]

Priority Wetland Invertebrates as Conservation Surrogates

CONSERVATION BIOLOGY, Issue 2 2010
S. J. ORMEROD
agua dulce; caracoles; conservación; especies paraguas; especies sustitutas; gasterópodos Abstract:,Invertebrates are important functionally in most ecosystems, but seldom appraised as surrogate indicators of biological diversity. Priority species might be good candidates; thus, here we evaluated whether three freshwater invertebrates listed in the U.K. Biodiversity Action Plan indicated the richness, composition, and conservation importance of associated wetland organisms as defined respectively by their alpha diversity, beta diversity, and threat status. Sites occupied by each of the gastropods Segmentina nitida, Anisus vorticulus, and Valvata macrostoma had greater species richness of gastropods and greater conservation importance than other sites. Each also characterized species assemblages associated with significant variations between locations in alpha or beta diversity among other mollusks and aquatic macrophytes. Because of their distinct resource requirements, conserving the three priority species extended the range of wetland types under management for nature conservation by 18% and the associated gastropod niche-space by around 33%. Although nonpriority species indicated variations in richness, composition, and conservation importance among other organisms as effectively as priority species, none characterized such a wide range of high-quality wetland types. We conclude that priority invertebrates are no more effective than nonpriority species as indicators of alpha and beta diversity or conservation importance among associated organisms. Nevertheless, conserving priority species can extend the array of distinct environments that are protected for their specialized biodiversity and environmental quality. We suggest that this is a key role for priority species and conservation surrogates more generally, and, on our evidence, can best be delivered through multiple species with contrasting habitat requirements. Resumen:,Los invertebrados son funcionalmente importantes en la mayoría de los ecosistemas, pero raramente son valorados como indicadores sustitutos de la diversidad biológica. Las especies prioritarias pueden ser buenos candidatos; por lo tanto, aquí evaluamos sí tres especies de invertebrados enlistados en el Plan de Acción para la Biodiversidad del Reino Unido eran indicadores de la riqueza, la composición e importancia para la conservación de organismos de humedal asociados definida por su diversidad alfa, diversidad beta y estatus de amenaza respectivamente. Los sitios ocupados por cada uno de los gasterópodos Segmentina nitida, Anisus vorticulus and Valvata macrostoma tuvieron una mucho mayor riqueza de gasterópodos y mayor importancia para la conservación que otros sitios. Cada uno también caracterizó a los ensambles asociados con variaciones significativas entre localidades en la diversidad alfa o entre otros moluscos y macrofitas acuáticas en la diversidad beta. Debido a sus diferentes requerimientos de recursos, la conservación de las tres especies prioritarias se amplió la extensión de todos los tipos de humedal bajo manejo para la conservación de la naturaleza en 18% y el nicho-espacio de los gasterópodos asociados se amplió alrededor de 33%. Aunque las especies no prioritarias indicaron variaciones en riqueza, composición e importancia de conservación entre otros organismos tan efectivamente como las especies prioritarias, ninguna caracterizó un rango tan amplio de humedales de alta calidad. Concluimos que los invertebrados prioritarios no son más efectivos que las especies no prioritarias como indicadores de la diversidad alfa y beta ni de la importancia para la conservación entre organismos asociados. Sin embargo, la conservación de especies prioritarias puede ampliar el conjunto de ambientes diferentes que son protegidos por su biodiversidad especializada y calidad ambiental. Sugerimos que este es un papel clave para las especies prioritarias y, más generalmente, para los sustitutos de conservación, y, con base en nuestra evidencia, puede ser desarrollado mediante múltiples especies con requerimientos de hábitat contrastantes. [source]

Connecting Atmosphere and Wetland: Trace Gas Exchange

Ecosystem,atmosphere exchange of CH4 and N2O and ecosystem respiration in wetlands in the Sanjiang Plain, Northeastern China

GLOBAL CHANGE BIOLOGY, Issue 3 2009
CHANGCHUN SONG
Abstract Natural wetlands are critically important to global change because of their role in modulating atmospheric concentrations of CO2, CH4, and N2O. One 4-year continuous observation was conducted to examine the exchanges of CH4 and N2O between three wetland ecosystems and the atmosphere as well as the ecosystem respiration in the Sanjiang Plain in Northeastern China. From 2002 to 2005, the mean annual budgets of CH4 and N2O, and ecosystem respiration were 39.40 ± 6.99 g C m,2 yr,1, 0.124 ± 0.05 g N m,2 yr,1, and 513.55 ± 8.58 g C m,2 yr,1 for permanently inundated wetland; 4.36 ± 1.79 g C m,2 yr,1, 0.11 ± 0.12 g N m,2 yr,1, and 880.50 ± 71.72 g C m,2 yr,1 for seasonally inundated wetland; and 0.21 ± 0.1 g C m,2 yr,1, 0.28 ± 0.11 g N m,2 yr,1, and 1212.83 ± 191.98 g C m,2 yr,1 for shrub swamp. The substantial interannual variation of gas fluxes was due to the significant climatic variability which underscores the importance of long-term continuous observations. The apparent seasonal pattern of gas emissions associated with a significant relationship of gas fluxes to air temperature implied the potential effect of global warming on greenhouse gas emissions from natural wetlands. The budgets of CH4 and N2O fluxes and ecosystem respiration were highly variable among three wetland types, which suggest the uncertainties in previous studies in which all kinds of natural wetlands were treated as one or two functional types. New classification of global natural wetlands in more detailed level is highly expected. [source]

The development of vegetative zonation patterns in restored prairie pothole wetlands

JOURNAL OF APPLIED ECOLOGY, Issue 1 2003
Eric W. Seabloom
Summary 1The spatial structure of plant communities can have strong impacts on ecosystem functions and on associated animal communities. None the less, spatial structure is rarely used as a measure of restoration success. 2The restoration of hundreds of wetlands in the prairie pothole region in the mid-western USA provided an excellent opportunity to determine whether the re-establishment of abiotic conditions is sufficient to restore structure, composition and spatial patterning of the vegetation. 3We mapped the topography and vegetative distributions in 17 restored and nine natural wetlands. We used these data to compare the composition and spatial structure of the vegetation in both wetlands types. 4The composition of the plant communities differed between restored and natural wetlands; the restored wetlands lacked the well-developed sedge-meadow community found in most natural wetlands. However, the spatial heterogeneity was similar, although the zonation patterns were less well-developed in the restored wetlands. 5Although the overall structure was similar, species distributions differed among wetland types, such that species were found more than 10 cm higher in restored wetlands than in natural wetlands. 6Synthesis and applications. This study illustrates that restored plant community composition and spatial structure may converge on their targets at different rates. Evaluations of restoration success should consider spatial structure of communities along with compositional and functional metrics. [source]