Eastern Great Lakes and Hudson Lowlands

By Janis L. Taylor ¹

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Ecoregion Description

 

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 (fig. 2). 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) (fig. 3). 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.

 

Change from 1973 to 2000

 

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. 4). Land cover changed on a total of 5.8 percent of the land area within the ecoregion (table 1), and of that total, 4.7 percent changed one time and 0.9 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) (fig. 5). 

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 (fig. 6). 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. 7). 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.

Populated places across this ecoregion have long been tied to waterways, as these waterways have been important traffic arteries, providing easy passage between the Atlantic Ocean and the Great Lakes (fig. 8). For example, the New York State Canal System, which replaced the Erie Canal in the early 1900s, links together many of the lakes and rivers in the region. In addition to being transportation routes, the Hudson River, St. Lawrence River, Mohawk River, Black River, and Niagara River are also scenic and tourist attractions, as well as sources of hydroelectric power.

The third most common conversion overall was the conversion of agriculture to the grassland/shrub class. The largest conversion of this type occurred from 1986 to 1992, when 220 km² of agricultural land was converted to grassland/shrubland (table 4). In the interval from 1980 to 1986, 121 km² of agricultural land was converted to grassland/shrubland (table 4). This type of conversion is driven by either agricultural abandonment, or it is a step in the transition to developed land.

 

References

 

Omernik, J.M. 1987.  Ecoregions of the conterminous United States: Annals of the Association of American Geographers v. 77, n. 1, p. 118-125.

 

US Department of Agriculture, 1997, Census of Agriculture, <http://www.usda.gov/nass/pubs/agr97/acro97.htm>.

 

Vogelmann, J.E, Howard, S.M., Yang, L., Larson, C.R., Wylie, B.K., and Van Driel, N., 2001, Completion of the 1990s National Land Cover Data set for the conterminous United States from Landsat Thematic Mapper data and ancillary data sources: Photogrammetric Engineering & Remote Sensing, v. 61, p. 650-662.

 

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

 

	Overall	Number of changes
	spatial change	1	2	3	4
Percent of ecoregion	5.8	4.9	0.8	0.0	0.0

 

 

 

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]

 

	Period
	1973-1980	1980-1986	1986-1992	1992-2000
Total change (% of ecoregion)	1.2%	1.5%	2.2%	1.8%
Margin of error (85% confidence level)	+/-0.3%	+/-0.4%	+/-0.6%	+/-0.5%
Average annual rate of change (%/year)	0.2%	0.2%	0.4%	0.2%

 

 

 

Table 3.  Proportion of the ecoregion covered by each land cover class during each of the five mapped dates

 

	1973		1980		1986		1992		2000		Net change 1973-2000
Land-use/land-cover class	km²	%	km²	%	km²	%	km²	%	km²	%	km²	%
Water	2501	4.2	2508	4.3	2531	4.3	2558	4.3	2567	4.4	66	0.1
Developed	5574	9.5	5767	9.8	6068	10.3	6515	11.1	7022	11.9	1448	2.5
Mechanically disturbed	15	0.0	74	0.1	47	0.1	110	0.2	63	0.1	48	0.1
Mining	233	0.4	249	0.4	253	0.4	259	0.4	267	0.5	34	0.1
Barren	1	0.0	1	0.0	1	0.0	1	0.0	1	0.0	0	0.0
Forest	23824	40.4	23730	40.3	23593	40.0	23599	40.0	23558	40.0	-266	-0.5
Grassland/Shrubland	310	0.5	322	0.5	382	0.6	454	0.8	452	0.8	141	0.2
Agriculture	24112	40.9	23921	40.6	23714	40.2	23113	39.2	22694	38.5	-1418	-2.4
Wetland	2374	4.0	2369	4.0	2353	4.0	2334	4.0	2319	3.9	-54	-0.1
Non-mechanically disturbed	0	0	0	0	0	0.0	0	0.0	0	0.0	0	0.0

 

 

Table 4.  Leading land cover conversions from 1973 to 2000 ranked by greatest to least area changed

 

			Area changed	% of all
Period	From class	To class	(km2)	changes
1973-1980	Agriculture	Forest	164	23
	Forest	Developed	157	22
	Forest	Agriculture	146	20
	Agriculture	Developed	59	8
	Grassland/Shrubland	Forest	57	8
	Other classes	Other classes	132	18
			715	100
1980-1986	Forest	Developed	152	17
	Agriculture	Grassland/Shrubland	142	16
	Forest	Agriculture	139	16
	Grassland/Shrubland	Forest	89	10
	Agriculture	Forest	89	10
	Other classes	Other classes	261	30
			872	100
1986-1992	Agriculture	Developed	262	20
	Agriculture	Grassland/Shrubland	247	19
	Grassland/Shrubland	Forest	198	15
	Forest	Developed	144	11
	Agriculture	Forest	122	9
	Other classes	Other classes	352	27
			1,325	100
1992-2000	Agriculture	Developed	216	20
	Forest	Developed	177	16
	Grassland/Shrubland	Forest	163	15
	Agriculture	Grassland/Shrubland	161	15
	Mechanically disturbed	Developed	92	8
	Other classes	Other classes	280	26
			1,089	100
Overall:
1973-2000	Forest	Developed	630	16
	Agriculture	Developed	620	15
	Agriculture	Grassland/Shrubland	591	15
	Grassland/Shrubland	Forest	507	13
	Forest	Agriculture	442	11
	Other classes	Other classes	1,211	30
			4,001	100

 

 

 

 

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.

 

 

 

Figure 2.  Homes and farm fields on the hills surrounding Otisco Lake, east of Auburn, New York.

 

 

 

Figure 3.  Corn field surrounded by forest near Cambridge, New York.

 

 

Figure 4.  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.

 

 

 

Figure 5.  The estimates of land cover change per time interval normalized to an annual rate of change.

 

 

Figure 6.  Dairy farm near Conesus Lake in Livingston County, New York.

 

 

 

Figure 7.  The percentage of land cover change by sector during each time interval.

 

 

 

Figure 8.  New subdivision southeast of Buffalo, New York.