青藏高原东缘高寒森林小型兽类地表洞穴选择与生境特征

Small mammals burrow selection and habitat characteristics in an alpine forest of eastern Tibet Plateau,China

高寒森林地表的小型兽类洞穴是生态系统重要的景观特征,对于认识小型兽类的分布格局及其生态功能具有重要意义.为此,以青藏高原东缘典型高寒森林生态系统小型兽类洞穴为对象,于2015年夏季(7—9月)研究了其地表分布与生境特征.结果表明:小型兽类洞穴平均洞口密度为182.8个·hm^(-2),不同森林植被类型显著影响洞穴密度,表现为针叶林(328.6个·hm^(-2))>针阔混交林(160.0个·hm^(-2))>灌木林(125.0个·hm(-2))>阔叶林(81.5个·hm^(-2))>竹林(66.7个·hm^(-2)).Mann-Whitney U Test和主成分分析表明,小型兽类栖息样地的乔木郁闭度、乔木均高、乔木胸径、乔木密度、地表植被盖度、倒木密度、倒木覆盖度、灌木均高都显著大于非栖息样地;乔木因子是决定小型兽类生境选择的首要因子,贡献率最大(44.8%),其次是倒木因子(23.2%)和灌草丛因子(13.9%).说明高寒森林地表有明显的小型兽类洞穴分布,其分布格局主要受植被和倒木的影响.

The burrows of small mammals are one of the obvious landscapes in the forest floor,and play important roles in understanding the distribution patterns of small mammals and their ecological functions in the high-frigid regions. Therefore,the burrow selection and habitat characteristics of small mammals were investigated in an alpine forest of eastern Tibet Plateau from July to September in 2015. The results indicated that the average density of small mammals burrow was 182. 8 entrances per hectare. Forest vegetation had significant effects on burrow entrances density,which showed the order of coniferous vegetation（ 328.6 burrow entrances per hectare） broad-leaved and coniferous mixed vegetation（ 160.0 burrow entrances per hectare） shrubbery（ 125.0 burrow entrances per hectare） broad-leaved vegetation（ 81.5 burrow entrances per hectare） bamboo vegetation（ 66.7 burrow entrances per hectare）. Mann-Whitney U Test and PCA analysis displayed that the arbor canopy,arbor height,arbor DBH,arbor density,ground-plant cover,fallen log cover,fallen log density and shrub height in the small mammals utilized habitat plots were significantly higher than those in other habitat plots（ P 0.05）. Compared with other factors,arbor was the primary factor in dominating the selection of small mammal burrows,showing the contribution rate with 44. 8%. The following dominant factors were fallen log and shrub,with the contribution rates being 23.2% and 13.9%,respectively. In summary,there were numerous small mammal burrows in the alpine forest floor,which were primarily dominated by vegetation and fallen logs.