Jersey (Pearson 1959). After 7 years the area was dominated by herbaceous 

 plants, such as asters and goldenrod, and by broomsedge. Woody plants, which 

 included cedar, dogwood, bayberry, and sumac, were present only as seedlings. 

 After 16 years of abandonment broomsedge still occupied 75% of the area and 

 goldenrod-aster cover and trees and shrubs accounted for the other 25%. After 

 46 years trees and shrubs were more abundant, but broomsedge still occupied 

 most of the area. After 66 years shrub and tree cover was extensive but 

 patches of herbaceous vegetation still grew between them. Forest succession 

 on abandoned farmlands is much slower than on burned over or logged forest 

 lands because of more numerous and slower stages of succession. 



Plants and Animals 



Oldfields support a wide variety of grasses, herbaceous plants, shrubs, and 

 trees but the dominant form depends on the stage of succession. The biomass 

 of vegetation increases as succession proceeds, because more and more 

 perennial and woody species become established. Biomass in early successional 

 stages may be as low as 1.1 tons/acre (2.5 t/ha; Odum 1960). The biomass 

 sharply increases once woody vegetation begins to invade, and by the time 

 immature forests are present biomass is about 44.5 tons/acre (100 t/ha). 



Although biomass of abandoned fields is initially low, productivity (annual 

 growth increments) may be as high or higher than in forests. Values of 2.2 to 

 2.9 tons/acre/year (4.9 to 6.5 t/ha/year) have been reported for oldfields in 

 the eastern United States (Bazaaz and Metzgar 1973; and Golley 1965). 

 Productivity is usually higher the first year or two after abandonment, after 

 which it declines slightly. As each new serai stage or plant life form 

 becomes dominant, another sharp, but smaller, increase occurs in productivity. 



The most important consumers in oldfields are invertebrates (Weigert and Evans 

 1964) , although they consume only a small portion of the available net 

 productivity. A study of the trophic structure of an oldfield in Georgia 

 indicated that grasshoppers, which accounted for 9l7o of the invertebrate 

 biomass, consumed only 77o of the net production (Odum et al. 1962). They 

 estimated that all invertebrates would consume no more than 20%. 



Other primary consumers in oldfields are mice, hares, deer, woodchucks, and 

 some seed-eating birds (e.g., sparrows and other finches). Mice and birds 

 were found to consume as much as 50% of the annual seed crop in a Georgia 

 oldfield but this represented only 1% to 2% of the net annual primary 

 productivity (Odum et al. 1962). 



Secondary consumers include birds (e.g., red-winged blackbirds, meadow larks, 

 sparrows, warblers, and hawks), snakes, toads, and mammals (e.g., shrews, 

 weasels, and fox). 



MANAGEMENT PRACTICES 



The management of agricultural, developed, and abandoned lands for fish and 

 wildlife and for environmental protection in Maine is exercised in a number of 

 ways by several authorities. Some programs are mandated by law, while others 

 are only guidelines and compliance is voluntary. 



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10-80 



