The Diet Selection And Its Influence Factors Of Brand’s Vole (Lasiopodomys Bandtii)

We studied the food composition of Brand’s vole(Lasiopodomys bandtii) using feces microscopic analysis during June to September in Inner Mongolia grassland animal experiment stations. Also we investigated the plant community structure, measured the contents of protein and soluble total sugar and plants secondary compounds (simple total phenol, phenol and condensed tannins)in plants. In order to determine the factors that manage the diet selection of Brand’s vole, the GLMs(generalized linear models) models were used. We obtained the following results:1) The analysis of food habits showed that 11 plant species were grazed by Brand’s vole, which were Stipa capillata, Leymus chinensis, Cleistogenes squarrasa, Carex tristachya, Neopallasia pectinata, Paraphlomis lanceolata, Medicago sativa, Corispermum declinatum, Lepidium apetalum, Setaria viridis, Chenopodium aristatum. The first three species were the most important food sources for Brand’s vole, accounts for 93.94% of total food intake. In June and July, the highest percentage of plant intake was Leymus chinensis, accounts for 60.29%and 55.88% respectively of total food intake, followed by Stipa capillata (24.35% and 25.96% respectively) and Cleistogenes squarrasa (13.67% and 14.41% respectively). In August and September, the highest percentage of plant intake was Stipa capillata, accounts for 65.58% and 62.29% respectively of the total food intake, which was followed by Leymus chinensis (13.64% and 17.85% respectively) and Cleistogenes squarrasa (15.19% and 8.64% respectively). Results of the food preference index indicated that Brand’s voles have some food selectivity. In June and July, they preferred Leymus chinensis, In August and September, they preferred Stipa capillata, Leymus chinensis, Carex tristachya, Medicago sativa and Setaria viridis.2) The results of plants investigated showed that 23 kinds of plant species were recorded in habitats of Brand’s vole. The dominant species of plant was Stipa capillata, Leymus chinensis and Cleistogenes squarrasa. The Cleistogenes squarrasa had the highest importance value. There was no significant seasonal difference of density, biomass and coverage of Stipa capillata, Leymus chinensis and Cleistogenes squarrasa. The height of Cleistogenes squarrasa had significant seasonal difference, however no differences were found for Stipa capillata, Leymus chinensis.3) The results of nutrient contents analysis showed that there was higher crude protein contents of plants in the early stage of plant growth, and it decreased seasonally. The soluble total sugar content was lower in the early stage of plant growth, and increased while the plant grows, and then decreased during the perish period. There were significantly seasonal variations for the crude protein contents and soluble total sugar of the three dominant plants which was the food resource of Brand’s vole.4) The results of secondary compounds analysis showed that the contents of plants for total phenol, simple phenol and condense tannins were lower in the early stage of plant growth, and increased while the plant grows, and the lowest in the perish period, The main food plant of Brand’s vole had significant differences in total phenol and condense tannins contents of plants, where was significant difference in simple phenol contents of Leymus chinensis, Cleistogenes squarrasa.5) GLMS analysis showed that coverage, height, importance value, total soluble sugar contents and total phenol contents were factors that affected food choice of Brand’s vole. The liner regression analysis showed that frequency of food intake increased with increasing of coverage, height, biomass, importance value and decreased with increasing of total soluble sugar contents, total phenol contents and simple phenol contents. The height, total phenol contents, soluble total sugar contents, simple phenol contents of plant and interaction between soluble total sugar contents and simple phenol contents of plant mainly affected food choice of Brand’s vole in June. The height and soluble total phenol contents and simple phenol contents of plant mainly affected food choice of Brand’s vole in July. The coverage, height, biomass, importance value and total phenol contents of plant mainly affected food choice of Brand’s vole in August. The coverage,height,and phenol contents of plant mainly affected food choice of Brand’s vole in September.Above all, we believe that Brand’s vole is a euryphagous animal, the diet character is changing alongside the month. Coverage, height, importance of plant, soluble total sugar contents of plant and total phenol contents of plant affect the diet choice. This study has proved that the food availability and food quality decide food selection pattern of small herbivorous rodents.