Cumming David H M, Cumming Graeme S
Tropical Resource Ecology Programme, Department of Biological Sciences, University of Zimbabwe, P.O. Box MP167, Mount Pleasant, Harare, Zimbabwe.
Oecologia. 2003 Mar;134(4):560-8. doi: 10.1007/s00442-002-1149-4. Epub 2003 Jan 30.
A wide range of bioenergetic, production, life history and ecological traits scale with body size in vertebrates. However, the consequences of differences in community body-size structure for ecological processes have not been explored. We studied the scaling relationships between body mass, shoulder height, hoof area, stride length and daily ranging distance in African ungulates ranging in size from the 5 kg dik-dik to the 5,000 kg African elephant, and the implications of these relationships on the area trampled by single and multispecies herbivore communities of differing structure. Hoof area, shoulder height and stride length were strongly correlated with body mass (Pearson's r >0.98, 0.95 and 0.90, respectively). Hoof area scaled linearly to body mass with a slope of unity, implying that the pressures exerted on the ground per unit area by a small antelope and an elephant are identical. Shoulder height and stride length scaled to body mass with similar slopes of 0.32 and 0.26, respectively; larger herbivores have relatively shorter legs and take relatively shorter steps than small herbivores, and so trample a greater area of ground per unit distance travelled. We compared several real and hypothetical single- and multi-species ungulate communities using exponents of between 0.1 and 0.5 for the body mass to daily ranging distance relationship and found that the estimated area trampled was greater in communities dominated by larger animals. The impacts of large herbivores are not limited to trampling. Questions about the ecological implications of community body-size structure for such variables as foraging and food intake, dung quality and deposition rates, methane production, and daily travelling distances remain clear research priorities.
脊椎动物的多种生物能量、生产、生活史和生态特征都与体型大小相关。然而，群落体型结构差异对生态过程的影响尚未得到探究。我们研究了体重从5千克的犬羚到5000千克的非洲象不等的非洲有蹄类动物的体重、肩高、蹄面积、步幅和日活动范围之间的比例关系，以及这些关系对不同结构的单物种和多物种食草动物群落践踏面积的影响。蹄面积、肩高和步幅与体重密切相关（皮尔逊相关系数r分别>0.98、0.95和0.90）。蹄面积与体重呈线性比例关系，斜率为1，这意味着小羚羊和大象对单位面积地面施加的压力是相同的。肩高和步幅与体重的比例关系斜率分别为0.32和0.26；大型食草动物的腿相对较短，步幅也相对较短，因此每移动单位距离践踏的地面面积更大。我们使用体重与日活动范围关系的指数在0.1到0.5之间，比较了几个真实的和假设的单物种和多物种有蹄类动物群落，发现由大型动物主导的群落中估计的践踏面积更大。大型食草动物的影响不仅限于践踏。关于群落体型结构对觅食和食物摄入量、粪便质量和沉积速率、甲烷产生以及日活动距离等变量的生态影响的问题，仍然是明确的研究重点。
