Status And Trends Of Freshwater Wetlands In NYS

How Much Wetland Does New York Have and How Has it Changed in Recent Years?

It is estimated that as of the mid-1990s, there are approximately 2.4 million acres of wetlands in New York. Some areas, like the Adirondacks and the Lake Plains of western New York contain more wetlands because there are larger expanses of flat topography. Other areas, like the Appalachian Highlands, the Hudson Valley, and Long Island, contain relatively fewer wetlands.

DEC began a study in the mid-1990s to assess the current status and trends in the freshwater wetlands resource in New York. The Wetland Status and Trend Analysis of New York State Study (PDF)(2.3 MB) compared mid-1980s and mid-1990s aerial photography for a sample of quadrangles in five ecological zones of the state to determine the amount of wetlands; gains, losses or changes in covertype; and to what those changes could be attributed. Following are some of the highlights of that study.

Characteristics and Distribution of Wetlands in New York
Ecological Zone State Total
Lake Plains Appalachian Highlands Adirondack Hudson Valley Coastal Lowlands
Estimated acres of wetland
in this ecoregion		 883,000 423,000 904,000 170,000 21,000 2,401,000
% of area in wetland
in this ecoregion		 12.3 3.6 12.4 4.4 2.3 7.2
% of total number of wetlands
in New York state
that fall within this ecoregion		 36.8 17.6 37.6 7.1 0.9
% of wetlands that are
forested covertype		 75.4 57.5 72 61.9 65.3 69.9
% of wetlands that are
shrub/scrub covertype		 14.2 22.4 13.8 20.9 3.1 15.9
% of wetlands that are
emergent covertype		 7.9 11.8 9.4 11.6 8.3 9.1
% of wetlands that are
open water covertype		 3.3 8.3 4.7 5.6 23.3 5.1

Highlights of the Freshwater Wetlands Status and Trends Study

New York has an estimated 2.4 million acres of wetlands. The wettest ecoregions are the Lake Plains and the Adirondacks. Together they encompass 74% of the wetlands in New York state.

The most common wetland covertype is forested (70%), followed by shrub/scrub (16%), emergent (9%), and wetland open water (5%). We are gaining forested and wetland open water as covertypes. We are losing shrub/scrub and emergent wetlands as covertypes.

Between the mid-80s and mid-90s, there was a net gain of approximately 15,500 acres of freshwater wetlands.

Net gains occurred mostly in the Lake Plains (+15,200 acres), with more minor gains in the Appalachian Highlands (+2,200 acres), and the Adirondacks (+900 acres). The Coastal Lowlands remained about the same (+70 acres). There was net loss of wetlands in the Hudson Valley (-2,900 acres).

There was a gross gain of approximately 37,900 acres of freshwater wetlands. Most gains occurred in the Lake Plains ecozone (+26,300 acres). Most gains resulted from agricultural reversion (+28,800 acres) and from modified hydrology (increased run-off) (+8,600 acres).

There was a gross loss of approximately 22,500 acres of wetlands. Most losses occurred in the Lake Plains (-11,100 acres) and the Appalachian Highlands (-5,700 acres). Most losses resulted from agricultural conversion (-11,100 acres) and urbanization and its associated impacts, such as road construction (-11,300 acres).

Changes in the Freshwater Wetlands Resource between the Mid-1980s and the Mid-1990s
Cause of Change Estimated Acreage Based on Projections from Study Sample
Acres Gained Acres Lost Acres with Covertype Change
Agriculture 28,800 11,100 2,100
Urbanization 0 8,200 200
Linear Development 30 900 500
Sand and Gravel Mining 250 2,200 20
Increased Runoff 8600 50 17,200
Beaver Activity 150 0 7,900
Plant Succession 80 0 119,900
Total 37,910 22,450 147,820