Guo Qinfeng
Department of Biology, University of New Mexico, 87131, Albuquerque, NM, USA.
Oecologia. 1996 Apr;106(2):247-256. doi: 10.1007/BF00328605.
The effects of bannertail kangaroo rat (Dipodomys spectabilis) mounds and associated soil-surface disturbance on plant species composition and diversity in the Chihuahuan Desert were examined with multivariate analysis. Kangaroo rat mounds created disturbance gaps and contributed to local species diversity by creating microhabitats that supported unique plant communities. These microhabitats supported populations of species that were relatively rare in surrounding areas. The diversity observed at the whole habitat level resulted from (1) local spatial heterogeneity, because the mounds offered microenvironments with distinctive nutrient, water, and light conditions; and (2) local patterning of disturbance, because the digging and traffic of the kangaroo rats maintained high levels of soil disturbance at and near the mounds. At a finer scale, species diversity was highest in the area immediately adjacent to active and inactive mounds, and was lower on both the highly disturbed soil of the mounds and in the relatively undisturbed area between mounds. Lowest species diversity occurred on inactive mounds. Annual plant biomass was much greater on mounds than in inter-mound areas. The results support the predictions that intermediate levels of disturbance and small-scale environmental heterogeneity contribute to supporting high species diversity.
通过多变量分析，研究了旗尾更格卢鼠（Dipodomys spectabilis）土丘及相关土壤表面扰动对奇瓦瓦沙漠植物物种组成和多样性的影响。更格卢鼠土丘造成了干扰间隙，并通过创造支持独特植物群落的微生境，促进了当地物种多样性。这些微生境为周边地区相对稀有的物种提供了生存空间。在整个栖息地层面观察到的多样性源于：（1）局部空间异质性，因为土丘提供了具有独特养分、水分和光照条件的微环境；（2）局部干扰格局，因为更格卢鼠的挖掘和活动使土丘及其附近的土壤扰动程度维持在较高水平。在更精细的尺度上，物种多样性在紧邻活动和不活动土丘的区域最高，在土丘高度扰动的土壤以及土丘之间相对未受干扰的区域则较低。物种多样性最低的是不活动土丘。土丘上的一年生植物生物量比丘间区域大得多。研究结果支持了以下预测：中等程度的干扰和小规模的环境异质性有助于维持较高的物种多样性。
