Rapid response of a grassland ecosystem to an experimental manipulation of a keystone rodent and domestic livestock
Rapid response of a grassland ecosystem to an experimental manipulation of a keystone rodent and domestic livestock
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DOI：
10.1890/09-1277.1
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发表时间：
2010-11-01
期刊：
影响因子：
4.8
通讯作者：
Ceballos, Gerardo
中科院分区：
文献类型：
--
作者：
Davidson, Ana D.;Ponce, Eduardo;Ceballos, Gerardo
大型食草动物和小型穴居哺乳动物在全球草原生态系统中共存，并发挥着重要的功能作用。草食动物这两个功能群在形成草地生态系统结构和功能中的相互作用尚不清楚。在北美中部草原，家牛（Bos taurus）已经取代了美洲野牛（bison bison），现在与土拨鼠（Cynomys spp.）共存，土拨鼠是一种重要的穴居啮齿动物。了解牛与草原土拨鼠之间的生态关系及其相互独立和相互作用，对于理解影响北美草原生态系统的生态学和重要保护问题至关重要。为了满足这些需求，我们建立了一个长期的操纵性实验，使用232因子设计将土拨鼠和牛的独立和互动效应分开。我们的研究位于墨西哥奇瓦瓦州西北部的Janos-Casas Grandes地区，该地区是现存最大的黑尾草原犬鼠（C. ludovicianus）群之一。两年的处理后数据显示，在有牛放牧的地块上，草原土拨鼠的数量比没有牛放牧的地块增加了近两倍。牛对草原土拨鼠的这种积极作用在一起发生时产生了协同效应。两种植物共存的样地植被高度显著低于两种植物均不存在的样地。这些处理还显著影响了其他草原动物物种的丰度和组成，包括蚱蜢和旗尾袋鼠鼠（Dipodomys spectabili）。结果表明，穴居哺乳动物和家畜这两个不同功能类群对草地生态系统的结构和功能具有独特的协同影响。
Megaherbivores and small burrowing mammals commonly coexist and play important functional roles in grassland ecosystems worldwide. The interactive effects of these two functional groups of herbivores in shaping the structure and function of grassland ecosystems are poorly understood. In North America's central grasslands, domestic cattle (Bos taurus) have supplanted bison (Bison bison), and now coexist with prairie dogs (Cynomys spp.), a keystone burrowing rodent. Understanding the ecological relationships between cattle and prairie dogs and their independent and interactive effects is essential to understanding the ecology and important conservation issues affecting North American grassland ecosystems. To address these needs, we established a long-term manipulative experiment that separates the independent and interactive effects of prairie dogs and cattle using a 232 factorial design. Our study is located in the Janos-Casas Grandes region of northwestern Chihuahua, Mexico, which supports one of the largest remaining complexes of black-tailed prairie dogs (C. ludovicianus). Two years of posttreatment data show nearly twofold increases in prairie dog abundance on plots grazed by cattle compared to plots without cattle. This positive effect of cattle on prairie dogs resulted in synergistic impacts when they occurred together. Vegetation height was significantly lower on the plots where both species co-occurred compared to where either or both species was absent. The treatments also significantly affected abundance and composition of other grassland animal species, including grasshoppers and banner-tailed kangaroo rats (Dipodomys spectabilis). Our results demonstrate that two different functional groups of herbivorous mammals, burrowing mammals and domestic cattle, have distinctive and synergistic impacts in shaping the structure and function of grassland ecosystems.