CLIMATE CHANGE: POTENTIAL IMPACTS AND INTERACTIONS IN WETLANDS OF THE UNTTED STATES¹

Abstract

Wetlands exist in a transition zone between aquatic and terrestrial environments which can be altered by subtle changes in hydrology. Twentieth century climate records show that the United States is generally experiencing a trend towards a wetter, warmer climate; some climate models suggest that this trend will continue and possibly intensify over the next 100 years. Wetlands that are most likely to be affected by these and other potential changes (e.g., sea‐level rise) associated with atmospheric carbon enrichment include permafrost wetlands, coastal and estuanne wetlands, peat lands, alpine wetlands, and prairie pothole wetlands. Potential impacts range from changes in community structure to changes in ecological function, and from extirpation to enhancement. Wetlands (particularly boreal peat‐lands) play an important role in the global carbon cycle, generally sequestering carbon in the form of biomass, methane, dissolved organic material and organic sediment. Wetlands that are drained or partially dried can become a net source of methane and carbon dioxide to the atmosphere, serving as a positive biotic feedback to global warming. Policy options for minimizing the adverse impacts of climate change on wetland ecosystems include the reduction of current anthropogenic stresses, allowing for inland migration of coastal wetlands as sea‐level rises, active management to preserve wetland hydrology, and a wide range of other management and restoration options.

Possible impacts of climate change on wetlands and its biota in the Brazilian Amazon

“…Changes in the hydrological regime might also modify the physicochemical properties of the soil, directly impacting the wetland biota (Carpenter et al, 1992;Burkett and Kusler, 2000;Lake et al, 2000). Concerning floodplain environments, changes in flood pulse and the relationship between water and adjacent terrestrial systems can affect the biodiversity and the health of the system, with serious ecological and socio-economic consequences (Tundisi and Matsumura-Tundisi, 2008).…”

“…These conditions associated with increased evapotranspiration, might reduce the extent of flooded areas or convert them into drylands (Burkett and Kusler, 2000). The absence of an adequate period of flooding, in magnitude, duration and time, might cause a decline of many species which depend on flooding to complete their life cycle, and, in addition, might promote the establishment of invasive species (Poff, 2002;Döll and Zhang, 2010).…”

Biogeochemical consequences of winter flooding in brook valleys

“…Climatic change affects river catchments and their associated wetlands throughout the world by increasing extreme precipitation events (Hartig et al 1997;Mortsch 1998;Winter 2000;Burkett and Kusler 2000;Johnson et al 2005). In the Dutch stream catchments increased frequency and duration of floodings are expected during winter as a result of the larger amounts of precipitation and the more frequent extreme events (Klein Tank et al 2006).…”

Control of sediment deposition rates in two mid-Atlantic Coast tidal freshwater wetlands

“…Mean global sea level rose 1-2 mm yr ÿ1 during the last 100 years and global warming is predicted to increase this rate two to five times by the year 2100 (Cahoon & Lynch, 1997). If sea level rise outpaces vertical sediment accretion, wetland loss will result everywhere that lateral wetland migration is not possible, and salt water intrusion will cause shifts in plant community composition (Burkett & Kusler, 2000;Callaway et al, 1996;Winter, 2000). Locally, anthropogenic activity such as development of coastal areas, reservoir and water-withdrawal projects, and dam building can affect the complex interaction of sediment deposition, erosion, and subsidence that determine wetland surface elevation (Davis, 1997;Najjar et al, 2000).…”