Larsen Eric
Department of Ecology and Evolutionary Biology, University of Arizona, 85721, Tucson, AZ, USA.
Oecologia. 1986 May;69(2):231-237. doi: 10.1007/BF00377627.
Competitive release among desert rodents on sand dunes of differing species richness was examined in the Great Basin and Mohave Deserts, USA. Expansions in microhabitat use were exhibited by the kangaroo rats Dipodomys ordii and D. merriami (granivorous heteromyid rodents, weighing 49 and 42 g, respectively) as the number of coexisting heteromyid species decreased geographically. Perognathus longimembris, the only common small heteromyid species (7 g) exhibited no competitive release. This may be due either to the absence of competitive interactions that affect the use of space by P. longimembris or to an unacceptable increase in risk of predation that precludes the use of more open microhabitats even in the absence of kangaroo rats. The breadth of microhabitat use of an omnivorous cricetid, Peromyscus maniculatus, decreased as the density of Perognathus longimembris increased, and increased as the density of conspecifics increased. The evidence for competitive release in Dipodomys and not in Perognathus is consistent with the hypothesis that species in the same guild and of similar size compete more intensely than species of disparate size.
在美国大盆地和莫哈韦沙漠，研究了不同物种丰富度沙丘上沙漠啮齿动物之间的竞争释放情况。随着共存异鼠科物种数量在地理上减少， Ordii更格卢鼠和Merriami更格卢鼠（均为食谷的异鼠科啮齿动物，体重分别为49克和42克）在微生境利用上出现了扩展。长耳侏鼠是唯一常见的小型异鼠科物种（7克），未表现出竞争释放。这可能是由于不存在影响长耳侏鼠空间利用的竞争相互作用，或者是由于捕食风险不可接受地增加，即使在没有更格卢鼠的情况下也排除了使用更开阔微生境的可能性。杂食性仓鼠科动物鹿鼠的微生境利用广度随着长耳侏鼠密度增加而减小，随着同种个体密度增加而增大。更格卢鼠有竞争释放而长耳侏鼠没有这一证据，与同一功能群中大小相似的物种比大小不同的物种竞争更激烈这一假设相符。
