Population Dynamics And Habitat Selection Of Siberian Chipmunk In The Broad-leaved And Korean Pine Mixed Forest

Siberian chipmunk (Eutamias sibiricus) is one of important rodent populations in broad-leaved and Korean pine mixed forest of Xiaoxing’anling region. Chipmunks take part in hoarding a variety of plant seeds and their hoarding tree seeds play a crucial role in seedling establishment. They consume many different kinds of fungi, and are an important vector for dispersal of the spores of subterranean sporocarps (truffles) which have co-evolved with these and other mycophagous mammals and thus lost the ability to disperse their spores through the air. They directly affect the dispersion of Korean pine seeds and ecological process of broad-leaved and Korean pine mixed forest.Tracking observation, line transect method, quadrat method and mark-recapture method were used to investigate population dynamics and habitat selection and to explain seasonal fluctuations of population of Siberian chipmunk from October,2011to October,2012in Liangshui national nature reserve in Heilongjiang province, China.A200m x400m rectangular sample area was set in block19in the reserve.3225m×25m quadrats were set in the sample area forming an8x4matrix. Center-center spacing of adjacent quadrats was50m. All of population dynamics research and part of habitat selection research were finished in these fixed quadrats.4live traps(10cm×10cm×25cm) were set10m away from the center in the four directions, north and south, east and west in each quadrat. Traps were baited with locally picked cones, opened in the morning, checked twice during the day, and closed at the end of the second check. PIT tags were used to mark and identify individuals.Our results were listed as below:1. Seventy-two chipmunks were marked in autumn,2011, more than50%of which were recaptured in spring,2012. All recaptured chipmunks exhibited no significant decrease in body weight.2. Chipmunks exhibited a clumped distribution pattern in autumn and uniform pattern in spring. The average population density of chipmunks in the Korean pine forests of the Reserve was4.98±0.86per hectare in autumn,2011,8.90±2.53per hectare in spring,2012and9.16±2.09per hectare in autumn,2012. The percentage of situ-recapture of chipmunks was61.29%in autumn,2011,30.91%in spring,2012and21.43%in autumn,2012.3. The average maximum movement diameter of Siberian chipmunks was44.94±4.29m. The result of principal component analysis showed that Korean pine coverage, log coverage, shrub coverage, distance from forest edge and disturbance intensity had significant influence on wintering habitat selection of Siberian chipmunks (P<0.05). The catch and number of burrows of Siberian chipmunks in the microhabitat with high Korean pine coverage (0.4-0.5), high log coverage (0.3), high shrub coverage (0.7-1.0), high disturbance intensity (picking) and far away from forest edge (>10m) was high.4. Chipmunk would scatter hoarded a small number of seeds nearby foraging site. The chipmunks which were back to their burrows during our excavation would bury food in their cheek pouches in the earth provisionally. There were461.9±161.4g shelled pine seeds and56.6±30.4g shellless pine seeds in average in the burrows we excavated in October,2011and2012.Most of chipmunk burrows were located in north-face slopes in mixed forests with entrances near logs or tree roots. The excavated burrows were338±19cm in length and104±7cm in depth in average. A burrow consisted of a nest chamber, several storage chambers and chambers for the waste, and sometimes a blind tunnel. There was about75.4±15.2g leaves in each burrow.The results showed that:1. PIT tags are safe in marking chipmunks, and are mainly useful in small mammal ecology.2. Chipmunks in Korean pine forest tended to active in situ in autumn and move outward in spring.3. A chipmunk had its own territory and there were prominent overlaps among their home ranges. They preferred the microhabitat with high Korean pine coverage, high log coverage, high shrub coverage, high disturbance intensity and far away from forest edge.4. Siberian chipmunks acted as larder hoarders more than scatter hoarders in hoarding Korean pine seeds. Their burrows were well-concealed, strong defensive, waterproof and easy for chipmunks to forage. Chipmunks stored leaves as nest material.We hope our research can provide theoretical foundation in controlling chipmunk population and offer positive suggestions in biodiversity conservation and management of broad-leaved and Korean pine mixed forest.