| Because of strong diffuse, animal community is always an important content of ecological studies, and rodents, being the most species, wide distribution, easy sampling etc. advantages, becomes an important species of research small mammals’ community. Hoarding behavior, small rodents are a major pest of agroforestry production, in addition, rodents can spread diseases, such as scrub typhus, schistosomiasis. It poses a great threat to human health, so the study of rodent community structure and population dynamics is essential, and the ecological research of dominant species can well reflect the population dynamics. Shennongjia Nature Reserve is located in Hubei Province and Chongqing City between the Yangtze and Han River. Four seasons are distinct, typical northern subtropical humid monsoon climate, and climate vertical zoning is obvious and natural vegetation is well, so it is rich in animal resources. In view of the above reasons, this study selected Shennongjia Nature Reserve’s small mammals as the research object, and we carry forward research on the community structure and ecology research on dominant species.July to August2011, October2011, December2011, March to June2012, July to August2012, using Trap-day method and Pitfall trap for sampling small mammals, survey scope covers the whole area (six protection stations), and each protection station set1or2sites for investigation. The habitat includes farmland, residential area, grassland and coniferous forest, broad-leaved forest, mixed broadleaf-conifer forest, shrub, etc., and the elevation spans from400m to2700m.The investigation, after nearly five months, placed10,307Trap-days, was recorded small mammals including Rodentia, Lagomorpha Ochotona, and Soricomorpha in7Families,25Genus, and41species. Sorex bedfordiae and Ochotona dauurica are new records in Hubei province. Habitat:capture rate is highest in shrub (3.95%), mixed broadleaf-conifer forest (3.81%) is followed by; to capture species number, the highest is grass (15species), broad-leaved forest (11species), take the second place; Clustering analysis shows that the seven habitats can be clustered into two obvious branches, reflecting the degree of complexity of the environment, broadleaf forests, shrub, meadow and mixed broadleaf-conifer forest as one branch, coniferous forest, farmland and residential area as the other one. Altitudinal gradient:the overall number of species captured, the capture rate and the Shannon-Wiener diversity index announced the trend: higher in middle altitude, but low in high and low altitude. This is another powerful evidence of the "Mid-domain Effect" hypothesis.According to Hernandez’s standard, Niviventer confucianus, it’s the only dominant species. In each habitat and altitude, the proportion is higher, and distributed in a variety of habitat’s altitude, therefore, it was selected as the dominant species and was studied. The study told us that there are obviously biased in favor of male sexual dimorphism in terms of morphological measurements, and that its weight fatness and carcass weight fatness are very significant differences (p=0.000) between the genders. Male is significantly higher than female, but female is higher than male (t=3.7039, p=0.000) at the organ index. Carcass weight was significantly different between the sexes (t=5.18, p=0.000), and therefore the carcass weight as the standard for identify age should be carried out independently between genders. The standards for each age group carcass weight divided:Male:Juvenile group(Ⅰ)<44g,44g<Sub-adult group(Ⅱ)<52g,52g<Adult group(Ⅲ)<60g, Senior group(IV)>60g; Female:Juvenile group(Ⅰ)<29g,29g <Sub-adult group(Ⅱ)<36g,36g<Adult group(Ⅲ)<42g, Senior group(Ⅳ)>42g. By the analysis of carcass weight’s variance in the different age groups, the results were highly significant differences (♀:F=118.843,p=0.000;♂:F=45.990, p=0.000), the result of t-est analysis of the adjacent two age groups among age groups within the gender’s difference was extremely significant, judgment carcass weight determination method is feasible.Studies have also shown that Niviventer confucianus’s weight, body length and tail length are growing with age, but the coefficient of variation of weight, body length in juvenile group is the largest, so baby set of weight, body length of the fastest growing stage, and the male and female’s tail length are differences significantly in juvenile and sub-adult group, but sub-adult and adult group as well as the senior group’s differences are not significant, instructions that enter the sub-adult body group the tail’s growth rate was significantly slower than the growth rate of carcass weight. The study of reproductive aspects clarifies that, the ratio of male with increasing age is sharply reduced. Female’s main breeding stage is adult and senior group, whereas male’s in the adult and sub-adult group. In this region, at main breeding stage, its gender ratio approximates to be1:1. Reproductive index was1.09; the index is at a lower level. The age structure is a recession-type. Comprehensive reproductive characteristics, sex ratio, age structure and other factors speculated Shennongjia Nature Reserve’s rodent population is remained stable or gradually reduced. There is no outbreak trend in a short period of time. |
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