岷山黑熊生境选择的初步分析

1998 年3 月末至9 月, 作者在岷山山系对黑熊的生境选择进行了研究。野外工作中共设置了40 个20 ×20 m²样方和15 个生态因子, 以此为基准进行了定量分析。黑熊生境喜好程度分析表明, 黑熊喜欢选择向阳、坡度较大、避风性适中、郁闭度在30 %～50 %之间的山嵴或山坡面, 选择乔木密度和灌木密度适中、倒木密度和树桩密度较小的生境, 其他如乔木距离、灌木距离、倒木距离和树桩距离以适中为准。主成分分析表明,影响黑熊生境选择的主要因子有5 种, 依次为: 食物丰富度因子(包括乔木密度、灌木密度、乔木距离和灌木距离) 、干扰因子(包括倒木密度、树桩密度、倒木距离和树桩距离) 、地形因子(包括郁闭度、地理性和坡位) 、气候因子(包括避风性和坡向) 和海拔因子。其最适生境状况为: 乔木密度为1 226～1 625根/ hm², 灌木密度为1 425～1 976 根/ hm², 倒木密度为120～240 根/ hm² , 树桩密度为110～230 根/ hm² , 郁闭度为3519 %～4315 % , 地理性为0.6～0.7 (山坡面) , 坡位为0.5～0.7 (中坡位) , 避风性为0.4～0.7 (适中) , 坡向为49.8°～153°(东坡) , 海拔高度为1 993～2 276 m (阔叶林和针阔混交林带) 。

Preliminary Analysis on the Habitat Selection of Black Bears in the Minshan Mountains

This paper deals with the habitat selection of black bear from the end of March to September in the Minshan Mountains in 1998. Forty samples of 20 ×20 m² and 15 factors were set up for quantitative analysis in the habitat selection of black bear.The analysis indicates that black bear chooses the peak or slope face of mountain , which is sunny and has bigger slope, moderate shelter wind and which canopy is between 30 % - 50 %. It still chooses the moderate tree and shrub densities and the smaller fallen log and tree stump densities. The selection of tree distance , shrub distance , fallen log distance and tree stump distance is based on moderation. The main component analysis shows that there are five factors affecting the habitat selection of black bears. They are the food abundant (tree density , shrub density , tree and shrub distance) , the disturbing (fallen log density , tree stump density , fallen log and tree stump distance) , the geography (canopy , geographic nature and slope site) , the climatic (shelter wind nature and aspect) and the elevation factor. The most suitable habitat of black bear is that the tree density is 1 226 - 1 625 roots/ha; the shrub density is 1 425 - 1 976 roots/ha; the fallen log density is 120 - 240 roots/ha, the tree stump density is 110- 230 roots/a; the canopy is 3519 % - 4315 %, the geographic nature is 0.6 - 0.7 (slope face) ; the slope site is 0.5 - 0.7(middle slope site) , the shelter wind nature is 0.4 - 0.7 ( moderation) ; the aspect is 49.8°- 153°(sunny slope) ; and the elevation is 1 993 - 2 276 m (The broadleaf forest and the mixed coniferous and broadleaf forest) .