Research On Genetic Diversity, Nest-site Selection And Home Range Of Xinjiang Beaver, Castor Fiber Birulai

Xinjiang beaver is one subspecies of Eurasian beaver(Castor fiber), and the largest size animal of rodents animals in Eurasia, also the only representative of beaver families. Eurasian beaver once widely distributed in early history, because of human hunting and habitat degradation, their population number dramatically reducing, now only survives in some remote areas and isolated from each other.Xinjiang beaver is the first class national protected animals, only distributed in the Ulungur River and it's upstream of the Green River, Bulgan River, which are located in the northeast of Xinjiang, China. The existing survey shows that there are only472-700 Xinjiang beaver. The number of their population scarcity and the limitation and remoteness of their population distribution led to the current study on Xinjiang beaver is little. In our study, based on the investigation and research on the habitat selection, home ranges and genetic diversities of Xinjiang beaver, the basic data and scientific evidence are hoped to provided for the future better conservation and management, and give useful protection methods combined the reality.2014.11-2016.1, the genetic diversities and population structure of Asiatic beaver(Castor fiber) in Xinjiang was investigated by analyzing the HV-?sequences of the mitochondrial DNA control region(D-loop), and the Castor fiber birulai nest-site selection and its characters in cold and hot seasons in the Ulungur watershed of Xinjiang were investigated by the methods of line transect and plot sampling, and the home range of Castor fiber birulai was also investigated by the methods of trace method and camera trapping, combined the radio telemetry technology.What the main results showed are as follows:1. The length of mtDNA D-loop HV-?sequence of Xinjiang beaver was 569 bp.Xinjiang beaver population had two unique haplotypes, whose haplotype diversity(Hd) ? nucleotide diversity(Pi) and average number of nucleotide differences(K) were 0.233�0.01578?0.00123�0.0159 and 0.700, indicating a low levelof genetic diversity, deeply related to its limited environment and human factors.Xinjiang beaver and Mongolia beaver were in one cluster by phylogenetic analyses based on the open mtDNA D-loop HV- ? sequence of beaver in other regions on GenBank, suggesting Xinjiang beaver also belonged to the subspecies of C. f. birulai.2. 2014.11-12,2015.4 and 2015.11, there were 160?158 and 152 Xinjiang beaver nests and winter food heap were found respectively. Chi-square test showed there were no significant differences in the choice of in the nest location(x2=0.001, df=1,P=0.976) and the dominant plants(x2=0.001, df=2, P=0.999) between warm and cold season. Mann-Whitey U test also showed there were no significant differences in the choice of other factors(P>0.05) except for the water area, water depth, river width and slope significantly outside(Z=9.005, Z=7.558, Z=8.919, Z=4.289, P<0.01)between warm and cold season. Regardless of temperature changes between warm and cold season and the impact of water level influenced by the temperature, the Xinjiang beaver's nest habitat selection between cold and warm seasons showed no differences.3. After 17 environmental variables possibly pertaining to the beaver nest-site selection in winter measured and analyzed, the results showed that the Xinjiang beaver nest-sites were mainly located in a high elevation(P>0.05), the near water area with a high river bank(P>0.05), steep slope(P>0.05), deep water(P>0.05),and its water width and area were fit. The environment of beaver nest-sites were covert, whose vegetation characteristics were high crown and tree density, low shrub density and height. The beaver nest-sites were usually in the opposite river bank of the near human road and house. What's more, the vast majority of beaver nest-sites were in the willow wood of trees with a high density, and near the food cache.4. One sophisticated non-invasive trapping method for catching live Xinjiang beaver was presented, whose capture success rate was over 75%.5. There were differences in the same home range size of Xinjiang beaver beforeand after the use of radio telemetry, which showed radio telemetry techniques can be helped to get the actual home range.6. The maximum width, length and area of beaver family A in autumn was138.147 m, 1573.656 m and 1.943�105m2 respectively, while it only moved near it's winter nest and food cache sites. The autumn and winter beaver family home range showed differences. The maximum width, length and area of beaver family B in autumn was 152.566 m, 687.759 m and 0.799�105m2 respectively. The home range of difference beaver family also have differences, and was influenced by season(temperature), nutritional requirements, habitat characteristics and competitive effects with other beaver family.7. We proposed protection and management measures for C. f. birulai.