Rowe Rebecca J
Committee on Evolutionary Biology, University of Chicago, Chicago, Illinois 60637, USA.
Am Nat. 2007 Aug;170(2):242-57. doi: 10.1086/518948. Epub 2007 Jun 11.
Climate warming will continue alongside human modification of the landscape. Therefore, studying systems modified by land use may highlight factors that mitigate or exacerbate predicted biological responses to ongoing climate warming. Using historical museum specimen records and recent field surveys, I examine temporal patterns in the ecological dynamics of the small mammal fauna on five mountain ranges in central Utah over time intervals of 27-53 years during the past century. This landscape was heavily modified by livestock grazing early in the twentieth century and since then has witnessed a steady decline in grazing intensity. In general, at regional and landscape scales, species preferring mesic habitats increased in percent abundance, rank abundance, and rank occurrence over time. This result is opposite that predicted from regional climate trends and probably represents the recovery of forest conditions following a release over time from earlier periods of severe overgrazing. Decreased grazing intensity may thus mitigate the predicted biological effects of climatically driven environmental change for small mammals. This work also illustrates that abundance data gleaned from natural history collections can be an appropriate tool for assessing temporal changes in composition, especially when comparisons are drawn using time- and space-averaged data sets.
随着人类对景观的改变，气候变暖将持续下去。因此，研究受土地利用影响的系统可能会凸显出减轻或加剧对当前气候变暖预测的生物反应的因素。利用历史博物馆标本记录和近期的实地调查，我研究了过去一个世纪中，在27至53年的时间间隔内，犹他州中部五个山脉小型哺乳动物群落生态动态的时间模式。在20世纪早期，这片土地因过度放牧而受到严重影响，从那时起，放牧强度持续下降。总体而言，在区域和景观尺度上，偏好中生栖息地的物种的相对丰度、优势度等级和出现频率随时间增加。这一结果与区域气候趋势预测的相反，可能代表着随着时间推移，从早期严重过度放牧中恢复后的森林状况。因此，放牧强度的降低可能会减轻气候驱动的环境变化对小型哺乳动物预测的生物影响。这项研究还表明，从自然历史收藏中收集的丰度数据可以作为评估物种组成随时间变化的合适工具，特别是当使用时间和空间平均数据集进行比较时。
