The Study Of Fauna And Diversity Of Small Mammals In Jiajin Mountains

From September to October 2008 and September to October 2009, the small mammals were investigated by the method of pitfall and snap traps in Jiajin Mountains including the east hillside and the west hillside. We studied the relative relations that the diversity of small mammals changes with the changing of elevation and communities by comparing the composing of small mammals, number of small mammals, frequency of capturing and Shannon-Wiener et al. Results as follows:1. A total of 927 small mammals were captured in the survey region. These specimens belong to 3 orders,8 families and 38 species. In the east hillside,664 specimens belong to 3 orders,8 families and 34 species. In the west hillside, we captured 263 specimens which belong to 3 orders,6 families and 22 species. In both slopes, there are 17 common species including Nasillus gracilis, Sicista concolor and Niviventer confucianus et al.18 species are quite different,15 species in east slope (Neotetracus sinensis, Uropsilus soricipes, Scaptonyx fusicaudus, Eurocaptor longirostirs, Soriculus macrurus, Chodsigoa salenskii, Blarinella quadraticauda, Blarinella wardi, Anourosorex squamipes, Tamiops swinhoei, Micromys minutus, Apodemus chevrieri, Eothenomys eleusis, Caryomys eva and Eothenomys melanogaster), the remaining three species in west slope including Crocidura vorax, Eozapus setchuanus and Microtus limnophilus. Thus, species diversity is extremely abundant, the species of in the east hillside is relatively higher in diversity than the other side, and the species of RODENTIA is preponderant in both slopes.2. We obtained 38 species small mammals in Jiajin Mountains.28 species in this study region belong to the Oriental realm, and 10 belong to the Palearctic realm. The Oriental realm is preponderant. As viewed from species distribution types, the Himalayan-Hengduan mountains type is preponderant. In the east hillside,28 species (82.35% of captures) of small mammals belong to the Oriental realm, and the remaining six species (17.65% of captures) belong to the Palearctic realm. In the opposite hillside,13 species (account for 59.09% of captures) of small mammals belong to the Oriental realm, and nine species (40.91% of captures) belong to the Palearctic realm. The Oriental realm is preponderant and the Himalayan-Hengduan mountains type is preponderant too. The results show that the Oriental species in the east slope are significantly higher than the west slope, and the Palearctic ingredients in west slope is much higher than the opposite slope.3. According to some materials, a total of 126 small mammal species recorded in Sichuan, and 29 species in Erlang Mountains,31 species in Wanglang,34 species in Jiuzhai and 12 species in Jiuding Mountains.however, we captured 38 species in Jiajin Mountains. Compared with Erlang Mountains (the southest of Qionglai Mountains), Wanglang, Jiuzhai and Jiuding Mountains (Minjiang Mountains), the biodiversity of Jiajin Mountains is much higher.4. The lowest altitude started at 1500m in the east hillside, and 2400m in the west hillside. The interval is 300m. We divided this area into nine different elevation parts in the east slope and six various elevation parts in the west slope.The species of South China type is preponderant below 2100m elevation in the east hillside and Oriental type is preponderant below 3000m elevation in the west hillside. The Palearctic realm is dominated over 3600m elevation in both hillsides and other elevation is dominated by Himalayan-Hengduan mountains type.The number and biodiversity of small mammals is the most abundant in the middle area of Jiajin Mountains and it is lower in the lower area and the higher area in the whole survey area. The species of RODENTIA is preponderant in whole elevation category.Crop land, hardwood forest, coniferous forest and alpine shrub exist in both hillsides, and other communities are quite different.All small mammals captured in crop land in both the hillsides belong to the Oriental realm, but the distribution type is different. In crop land community (east slope), the distribution types of these small mammals are dominated by the South China type, and the Oriental type in the same community (west slope). In both two hillsides, Himalayan-Hengduan mountains type is preponderant in both hardwood forest community and coniferous forest community.In the east slope, biological diversity index is the most rich in coniferous and broad-leaved mixed forest community, and the crop land community is the lowest. In the west slope, the diversity index is the most abundant in hardwood forest community, and crop land community is also the lowest. As seen from communities, the species of RODENTIA is preponderant in whole community type.5. In both hillsides, the diversity index increases and decreases while the altitude is climbing up. Much higher index in middle altitude area, and relatively lower in others. The true reason is that plant species diversity, lesser human disturbance and vegetation being in aboriginal state in middle altitude. Higher levels of human disturbance and native vegetation deterioration in low altitude. Harsh climatic condition and single vegetation types in high altitude.Through the cluster analysis among these communities in Jiajin Mountains, four main communities exist in large scale in east slope and three main communities in other slope. The cluster dendrograms clearly show the relation between these communities.6. Finally, we discussed some species that people have been interesting. These species include Sorex minutus, Blarinella quadraticauda and Blarinella wardi, Vernaya fulva, Apodemus draco and Apodemus orestes, Pitymys sikimensis and Ochotona huangensis respectively.