Kerley Graham I H, Whitford Walter G, Kay Fenton R
Terrestrial Ecology Research Unit, Department of Zoology, University of Port Elizabeth, PO Box 1600, Port Elizabeth 6000, South Africa e-mail:
U.S. Environmental Protection Agency, National Exposure Research Laboratory, Characterization Research Division, P O Box 93478, Las Vegas, NV 89196, USA, , , , , , US.
Oecologia. 1997 Jul;111(3):422-428. doi: 10.1007/s004420050254.
Graminivory by kangaroo rats (Dipodomys spp.) was investigated as a potential mechanism for the keystone role of these rodents in the dynamics of desert grasslands. Experiments confirmed that Ord's kangaroo rats (Dipodomys ordii) cut and consumed a large proportion of the tillers of three Chihuahuan Desert tussock-forming grass species. Field observations indicated that the characteristically cut grass tillers were absent from all-rodent and medium-sized kangaroo rat exclosures, but were frequent in large-sized kangaroo rat and rabbit exclosures, indicating that the medium-sized kangaroo rats (D. ordii, D. merriami) were responsible for grass cutting. Tiller waste as a percentage of peak standing crop ranged from 7% in grassland habitats to 0.7% in Flourensia cernua shrubland. Of the 13 species of perennial, tussock-forming grasses measured, only one, Muhlenbergia porteri, had no tillers cut by kangaroo rats. This study demonstrates that the keystone role of kangaroo rats in Chihuahuan Desert grassland ecosystems is probably the result of their graminivory.
袋鼠鼠（更格卢鼠属）对草的啃食被作为这些啮齿动物在沙漠草原动态中扮演关键角色的一种潜在机制进行了研究。实验证实，奥德氏更格卢鼠（Ord's kangaroo rats，Dipodomys ordii）切断并消耗了三种奇瓦瓦沙漠丛生草本植物的大部分分蘖。野外观察表明，在所有啮齿动物和中型袋鼠鼠的围栏中没有典型的被切断的草分蘖，但在大型袋鼠鼠和兔子的围栏中很常见，这表明中型袋鼠鼠（D. ordii、D. merriami）是造成草被切断的原因。分蘖废弃物占高峰期现存作物的百分比从草原栖息地的7%到弗洛伦西亚蒿属灌木地的0.7%不等。在测量的13种多年生丛生草本植物中，只有一种，即波特穆伦伯格草（Muhlenbergia porteri）没有被袋鼠鼠切断分蘖。这项研究表明，袋鼠鼠在奇瓦瓦沙漠草原生态系统中的关键作用可能是它们食草行为的结果。
