The Eastern Great Lakes and Hudson Lowlands ecoregion is a glaciated region of irregular plains bordered by hills and lakes, located mostly in New York, but also extending alongside Lake Erie into Pennsylvania and Ohio and into western Vermont, including Lake Champlain (fig. 1). This ecoregion has less surface irregularity and more agricultural activity and a higher population density than the adjacent ecoregions, Northeastern Highlands (58) and Northern Appalachian Plateau and Uplands (60) (Omernik, 1987). The ecoregion covers approximately 60,591 km² (23,394 mi²) and is primarily a mix of forest, agricultural land, and developed land. Water bodies and rivers are a dominant feature of this forested ecoregion. Lake Erie and Lake Ontario form the northern boundary of the ecoregion, and Lake Champlain forms the eastern boundary.

The spodosol soils of the river valleys in the ecoregion have developed on glacial deposits. They are heavier and of better quality than soils in the higher elevations of adjacent ecoregions and provide a strong foundation for agriculture. Major crops grown in the ecoregion include apples, grapes, tart cherries, pears, plums, corn, hay, wheat, oats, barley, soybeans, cabbage, and potatoes (U.S. Department of Agriculture, 1997). Vineyards and wineries are found along the Lake Erie shore and in the Finger Lakes region as they experience a longer growing season, more winter cloudiness, and greater snowfall than the rest of the ecoregion.

Figure 1: Eastern Great Lakes and Hudson Lowlands ecoregion (83). The underlying land cover is from the 1992 National Land Cover Database (Vogelmann and others, 2001). The thirty 10 km x 10 km sample sites for the Land Cover Trends project are shown in black. Click on image to enlarge

The overall spatial change—the percentage of land area within the ecoregion where land cover changed at least once between 1973 and 2000—was fairly low in comparison to other Eastern U.S. ecoregions (fig. 2). Land cover changed on a total of 5.8 percent of the land area within the ecoregion (table 1), and of that total, 5.0 percent changed one time and 0.8 percent changed two times (table 1). Total change in each of the four time periods selected for this study was very similar, ranging between 1.3 percent and 2.1 percent (table 2). After normalizing the land cover change per period to an annual rate of change, the rates ranged from a low of 0.2 percent per year in the 1973 to 1980 period to a high of 0.4 percent per year in the 1992 to 2000 period (table 2).

Table 1: Amount of overall spatial change detected in the ecoregion and proportion of the ecoregion that experienced change during one or multiple time periods.

Table 2: Raw estimates of percent change in the ecoregion computed for each of the four time periods and associated margin of error at an 85-percent confidence level. [Estimates of change per period normalized to an annual rate of change for each of the four time periods]

Figure 2: The overall spatial change in all Eastern U.S. ecoregions. Each bar chart shows the proportion of the ecoregion that experienced change on 1, 2, 3, or 4 dates. Click on image to enlarge

Figure 3: The estimates of land cover change per time interval normalized to an annual rate of change. Click on image to enlarge

Table 3 lists the percentage of each individual land cover class during each of the five mapped dates. Forest, agriculture, and developed land account for 88 percent of the land cover in the ecoregion (table 3). The timber industry in the Adirondack region developed in the 1800s, spurred on by the ability to transport logs across Lake Champlain. During the study, the amount of forested land decreased 2.1 percent from 39.9 percent in 1973 to 38.8 percent in 2000. The Finger Lakes region in upstate New York is one of several important agricultural areas in the ecoregion. The extent of agricultural land decreased 0.6 percent, from 39.5 percent of the ecoregion in 1973 to 37.3 percent in 2000. Developed land showed the greatest change with an areal increase of 2.4 percent, from 9.1 percent in 1973 to 11.5 percent in 2000.

During the entire study period, the conversion of forest to developed land was most common (table 4). The second most common conversion was agricultural land to developed land. Developed land increased in each of the four time intervals (fig. 4). A majority of the newly developed land was converted from forest in the first two time intervals, 1973 to 1980 and 1980 to 1986, and from agricultural in the last two time intervals, 1986 to 1992 and 1992 to 2000 (table 4). This unidirectional land cover change to developed land was driven by a population increase both in and around several large urban centers including Albany, Buffalo, Rochester, Syracuse, and Utica, New York; Burlington, Vermont; Cleveland, Ohio; and Erie, Pennsylvania.

Figure 4: The percentage of land cover change by sector during each time interval. Click on image to enlarge