Small Mammal Energetics in Grassland Ecosystems

摘要: Results of quantitative sampling small mammal populations at different grassland sites for a 3-yr period are compared to evaluate the energy requirements and con- sumption, according trophic levels, total communities all seasons in years. The purpose was search patterns food utilization by these consumers sites. This picture bioenergetics over wide range constructed from extensive US/IBP Grassland Biome diet population data physiological information out literature. work rep- resents one step process understanding role ecosystem. No species occurs strategies predominate among mammals each site: Microtines (herbivores) dominate tallgrass prairie, sciurids (om- nivores) northern shortgrass heteromyids (granivores) bunchgrass desert grasslands. Other groups occur vary their importance. At midgrass largely dependent on herbage consumption, while southern prairie rodent fauna is invertebrates. most uniform distribution resource this component consumer community site, where herbage, seeds, animal matter utilized. Relative amount sumable available (that actually utilized population), only slightly (from fraction few percent available). Animal matter, invertebrates, highly may fact be limiting factor populations. consumed greatest average annual consumption 172 X 10' kcal/ha (= 720 MJ/ha). How- ever, efficiency biomass support 32 x 10 134 MJ/ha) supported proportionately more (277 g live wt./ha) animals than site (935 g/ha). estimates presented here compare well with other estimates. These results emphasize great between year variability, how- ever. Daily respiration summer as little 14 large 1,038 kcal ha-' - day-'. Highest occurred (3,075 (2,304 g/ha) sites, lowest (14 site. Within study, stable variable ecosystems remains incompletely defined. A broader view relation resources required.