Distribution and abundance of small mammals along a subtropical elevational gradient in central Taiwan

The elevational distribution of small mammals was surveyed by three transects during 1989–90 at Yushan National Park in subtropical central Taiwan. As a result of this survey, a sample of 1205 animals was obtained. Based on the sample, the sampling regime and elevational distribution of these species is reported with consideration of the spatial and temporal components. To detect the presence of all species and to estimate their relative abundances at any elevational site, one must trap consecutively for a minimum of five days.‘Trap competition’is common in trap lines, resulting in a few traps being responsible for all the captures. Besides, common and rare species at each elevation have different trap responses. The elevational distribution of small mammals shows substantial seasonal and spatial variation. Furthermore, the plant succession is demonstrated to influence the species composition and relative abundances of the small mammal community at the same elevation. Despite the variation, some general patterns of elevational distribution emerge. Tamiops muritimus occurs above 2000 m and is common at 2000–3000 m. Apodemus semotus is widely distributed from 1400 to 3700 m, but becomes rare below 1500 m and above 3600 m. The congeneric A. ugrurius is known only from lowlands in Taiwan and reaches no higher than 1000 m. Niviventer culturutus occurs at about 2000–3000 m, whereas N. coxingi occurs no higher than 2000 m and is common below 1300 m. Two species of microtine also show replacement in elevational distribution. Eothenomys melunoguster occurs from 1400 to 3000 m and Microtus kikuchii becomes abundant only above 3000 m. Two shrews, Anourosorex squumipes and Soriculus fumidus, are widely distributed at different elevations, but their distribution seems to be little related to elevation. 1994 The Zoological Society of London