wetland status and trends

Wetland status and trends

Wetland trends

Wetlands covered an estimated 221 million acres of the lower 48 states in colonial days. As previously mentioned, as of 1997 only 105.5 million acres of wetlands remained. Thus more than half (53%) of the original wetlands acreage has been lost. Between the mid 1950s and the mid 1970s an estimated 458,000 acres of wetlands were lost each year. Fortunately, the amount of wetlands lost is down substantially from that figure. Between 1986 and 1997, the loss of wetlands was down to 58,500 acres/year. Most of these losses (98%) were to freshwater wetlands. However, total wetland acreage lost only provides part of the picture.

Certain wetland types are lost at higher rates than others. During this same 1986 to 1997 period, freshwater emergent wetlands (-4.6%) and freshwater forested wetlands (-2.3%) each declined by about 1.2 million acres. These losses were offset by gains in open water ponds (+13%) and freshwater shrub (+6.6 %) wetlands. Since the 1950s, freshwater emergent wetlands declined by 8 million acres (-24%). Many of the most important vegetated wetland types for wildlife (emergent and forested) historically and to a lesser extent more recently have suffered the largest declines. Wetland losses also vary by state. Several states have lost more than 80% of their original wetland acreage including California (-91%), Ohio (-90%), Iowa (-89), Indiana (-87%), Missouri (-87%), Illinois (-85%), and Kentucky (-81%).

It is heartening to know that the rate of wetland loss has declined substantially between the 1990s and the 1950s. Much of this decline can be attributed to a change in society’s views regarding the importance of wetlands and the implementation of various conservation programs. Unfortunately, some of the decline in wetland losses occurred because the most easily filled and drained wetlands have already been drained and filled. A number of factors are responsible for wetland losses. Freshwater wetland losses between 1986 and 1997 were due to the following activities:

Urban Development
Agriculture
Forestry
Rural Development

30%
26%
23%
21%