Population Ecology Of Callosciueus Erythraeus And Its Damage To Artificial Forests At Hongya Forestry Farm

Red-bellied squirrels (Callosciueus erythraeus) have made great damage to artificial forests in Sichuan by debarking trees,mainly Crypotomeria fortune! and Cunninghami lanceolata,in these years. Debarking retards the normal growth of trees,and even causes some trees dead. In order to develop an efficient and feasible method to protect the artificial forestry from harm of squirrel's,we have conducted field studies of population ecology of red-bellied squirrels and its damage dynamics at Hongya Forestry Farm for 2 years and 5 months. We selected 6 research plots on the basis of habitat condition.We observe behavior and monitor damage rates of trees by the red-bellied squirrel in 6 plots located on different habitats monthly,and dissect individuals to characterize morphology,stomach contents and reproduction conditions.Because the body size of the red-bellied squirrel is large and has strong movement ability,so some typical study methods on rodents are not feasible for this species of animal. Our observation reveals that different individuals leave different dental marks on barks. We assume that width between the upper incisor of the red-bellied squirrel is individually specialized. Then one-way ANOVA is applied to distinguish width of upper dental marks. If the difference is significant,a multiple comparison (Newman-Keuls) to group upper dental marks and one individual is responsible for one group,in this way the number of squirrels is estimated.The red-bellied squirrel is a diurnal animal and its activity shows apparent daily cycle:more active in the morning and evening. The results of the one-sample Kolmogorov-Smirnov suggest that 5 morphological parameters are all normally distributed. The 95% confidence intervals of morphological measuresare as follows:body weight [256.6,451.8] g,body length [192.4,235.9]mm,tail length [154.3,233.5] mm,ear length [13.7,22.7] mm,hind foot length [32.6,56.9] mm. Analyses of stomach contents in different month reveal that the red-bellied squirrel is feeding on plants mostly,but insects occasionally. Diet composition of the red-bellied squirrel shows seasonal changes:very simple in spring (mainly composed with buds and bark),more complex in summer and autumn (eat many kinds of fruits and tree cores),then become simple again in winter.The results of the monthly survey on fluctuation of the damage rate and the dental marks suggest that:l) when the damage rate is higher,the number of squirrel is larger,2) the damage rates are higher from February to April with a peak in March,but are decreasing in May and June. There are no damages at all from July to November. The squirrels begin debark trees from December to next January and damage become serious again in February and March.Many factors,including changes of habits,shortage of food supply and increase of population,may lead to damages to trees by red-bellied squirrels. Our study results can provide some biological bases to develop an effective strategy to control the red-bellied squirrel's damage.