. Animal Ecology. Animal ecology. FIG. 9 3 Forest-edge at Wil and herbs in foreground, bri am Trelease Woods, University of Illinois rs and shrubs in nniddle, forest in backgr meter destroyed enough forage on three acres during one month to support one cow for a month ( Stoddart and Smith 1943). Rodents and rabbits consume very considerable amounts of grasses and other herbs and cause great damage at times of high populations. In a study per- formed in Arizona (Taylor 1930), grazing by Gunnison's prairie dogs alone consumed 87 per cent of the total grass production and grazing by cattle and ro
. Animal Ecology. Animal ecology. FIG. 9 3 Forest-edge at Wil and herbs in foreground, bri am Trelease Woods, University of Illinois rs and shrubs in nniddle, forest in backgr meter destroyed enough forage on three acres during one month to support one cow for a month ( Stoddart and Smith 1943). Rodents and rabbits consume very considerable amounts of grasses and other herbs and cause great damage at times of high populations. In a study per- formed in Arizona (Taylor 1930), grazing by Gunnison's prairie dogs alone consumed 87 per cent of the total grass production and grazing by cattle and rodents combined, 95 per cent. In California, Beechey's ground squirrels eliminated 35 per cent of the green forage by the end of the season, pocket gophers 25 per cent, and kangaroo rats 16 per cent (Fitch and Bentley 1949). Since these various rodents have food preferences of grass species simi- lar to those of cattle, there is obviously severe com- petition between them, especially in times of drought. When rodents are not overly abundant, they have some beneficial effects in fertilizing, aerating, and mixing the soil. Among big-game mammals, bison and wapiti are largely grass-eaters, especially during the summer season. Food consumption of bison is about equal to that of cattle, but wapiti eat only about half as much per individual. In Yellowstone Park it has been esti- mated that wapiti may utilize 67 per cent of the avail- TABLE 9-5 Carrying capacity of grasslands for big game and livestock (fr. sources, compiled by Petrides 1956). Location Game or livestock Number/mi* Biomass/mi ( km^) Pounds Kg Oregon Tanganyilca, Africa Montana Arizona Western Western Nairobi Nat. Pk., Africa Nairobi Nat. Pk., Africa Antelope (64%), mule deer (36%) 9 1,000 454 Bush country game 10 3,300 1,498 Bison (50%), mule deer, elk, bighorn 21 14,000 6,356 Bison 17 17,000 7,718 Cattle, ave. all grassland types 20 20,000 9,080 Cattle, tall grass prairie 28 28,000 12,712 (1) herbivorous b
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Keywords: ., bookcentury1900, bookcollectionbiodive, booksubjectanimalecology
