A Study Of Multi-scale On The Disturbance Effects Of The Rodent Community Patterns In Alashan Desert Region

The four kinds of study areas under different human disturbance were selected in the typical region in Alashan desert of Inner Mongolia from 2002 to 2004, i.e. farmland area, rotational grazing area, over-grazing area and forbidden grazing area. The rodent communities in the four kinds of study areas were investigated by using trap-day and mark-recapture methods on three scales: 1hm~2, 10hm~2 and 40hm~2. The data on three scales was analyzed on composition pattern, diversity, evenness, similarity, niche characteristics, the correspondence between rodent species and different disturbance, the correspondence between rodent species and scales and the relationship between rodent species and habitats. The results are as following: (1) Scale effects on the rodent communities in Alashan desert region varied with different disturbance, scales and analyzing points of view. (2) There was a point of scale transition between 1hm~2 and 10hm~2 on the disturbance effects of the rodent communities in Alashan desert region. 10hm~2 and 40hm~2 belong to the same scale domain. Furthermore, the disturbance effects on 10hm~2 and 40hm~2 are greatly better than on 1hm~2 in the reflection of the disturbance effects of the rodent communities in Alashan desert region. (3) Meriones meridianus and Cricetulus barabensis adapted to the habitats under the farming disturbance and forbidden grazing disturbance very well; Phodopus roborovskii adapted to the habitat under the rotational grazing disturbance very well, and Dipus sagitta adapted to the habitat under the over-grazing disturbance very well. Moreover,the numeral dynamic of Phodopus roborovskii and Dipus sagitta have an indicative function to the grazing intensity in Alashan desert ecosystem. (4) Dipus sagitta has greater tolerance than Meriones meridianus and Allactaga sibirica in the process of habitat fragmentation in Alashan desert, despite Dipus sagitta having a narrow niche breadth and Meriones meridianus and Allactaga sibirica having a wide niche breadth. (5) The niche characteristics on different scales show a hierarchical scale effect and a dynamically inlaying pattern on the rodent communities in Alashan desert region.