Document Actions
Wetlands
Temperature rises will have severe impacts on wetland birds.
|
|
||
|
Noteworthy A third of the 165 wetland breeding species in the United States show medium or high vulnerability to climate change. Wetlands are susceptible to even minor changes in precipitation and temperature and may be degraded or eliminated if no action is taken to counteract climate change impacts. Shallow breeding wetlands (potholes) and wetland-dependent breeding birds that use them appear acutely threatened, especially in the north-central states. Wetland breeding birds are primarily vulnerable because of the water level and distribution impacts of climate change on breeding habitats. |
||
| Image: Northern Pintail by John Bedell |
Observations and Predictions
Projected temperature rises without comparable increases in
precipitation will have severe impacts on wetland ecosystems,
especially related to loss of water inputs, reduced storage
capacity, timing of wetland recharge, and frequency of drought.
The extent of semi-permanent and seasonal wetlands may be further
reduced by increases in evaporation and reduced summer soil moisture,
particularly in the prairie regions of the United States.
Impacts will probably be high on mountainous wetlands where
temperature-sensitive plants and animals will be unable to move
upslope. Wetlands that depend on snowmelt will diminish or disappear.
An increase in the severity of storms and tornadoes will increase the
incidence of flashflood erosion events or alter the length of time that
a wetland holds water.
Carbon stores in wetland soils in the U.S. may be released following
wetland drainage or if permafrost wetlands melt. Bacteria which live in
aerated conditions will oxidize the carbon and return it to the
atmosphere.
 |
| Northern Pintail courtesy USFWS |
Slightly more than one-third (36%) of the 165 wetland breeding species
in the United States show medium or high vulnerability to climate
change. Wetland breeding birds such as Western and Clark’s grebe and
Northern Pintail are primarily vulnerable to changes in water level and
distribution that affect breeding habitats. Thirty-two wetland breeding
bird species exhibiting medium or high vulnerability are currently not
considered of conservation concern including Sabine’s Gull, Pomarine
Jaeger, and Arctic Loon.
Excessive chemicals, nutrients, and sediments from unsustainable agriculture can disrupt the function of wetlands, dramatically reducing clean water and other environmental benefits, and eliminating critical areas needed by wetland birds.
 |
Of 165 wetland breeding species, 36% show medium or high vulnerability to climate change. |
 |
| Marsh Wren by Amy Liest |
Wetland-dependent breeding birds are at risk because the shallow wetlands (potholes) where they breed appear to be acutely threatened, especially in the north-central United States. The distribution of birds is influenced by the surrounding landscape and the birds’ ability to find suitable habitat. It is possible that changes in climate and habitat conditions will make areas uninhabitable for some species.
Warming temperatures and storms, droughts, and floods of greater frequency and severity will cause unpredictable changes in wetland water levels, plant communities, and prey abundance and, ultimately, the abundance of wetland birds. The effects of climate change may cause birds to shift to areas with lower quality wetland habitats that may only partially fulfill their needs during critical portions of their annual cycle.
Key Steps
Carbon sequestration incentives can help to mitigate the
effects of climate change and protect wetlands for birds as well as for
the environmental goods and services that wetlands provide to people.
Federal land management programs can help increase the amount of carbon
stored, including programs that retire farmland from crop production
and convert it back into grasslands or wetlands. During droughts small
wetlands should receive special protection because of their
vulnerability to conversion to agriculture at these times.
 |
| King Rail courtesy USFWS |
The 2008 Farm Bill included another million acres in the Wetland
Reserve Program that could provide more reliable wintering habitats for
wetland dependent birds. In 2010, Congress appropriated a record $47
million to the North American Wetland Conservation Act (NAWCA) to
promote wetland conservation efforts. Organizations such as Ducks
Unlimited conserve and restore some of the most critical habitat needed
for waterfowl.
A wetland landscape simulator (WETLANDSCAPE) is now being developed to calculate the effect of climate variability simultaneously on wetlands and other water resources within a landscape. This next-generation model is expected to reflect regional differences that may exist in wetland water depth across the Prairie Potholes. The WETLANDSCAPE model can be used to evaluate which farming practices can reduce the impacts of climate change by producing more favorable water budgets for prairie wetlands.
