四川唐家河自然保护区黑腹绒鼠对夏季生境的选择

Summer Habitat Selection by Eothenomys melanogaster in Tangjiahe Nature Reserve,Sichuan Province

为揭示影响黑腹绒鼠夏季空间分布的生态因素,采用样线法和样方取样法,于2009年6～8月在四川省唐家河国家级自然保护区对该物种夏季生境选择进行了研究。野外工作期间,共调查生境样方和对照样方各58个。在21个生境变量中,海拔、坡度、坡向等16个变量在生境样方和对照样方间存在显著差异,表明该地黑腹绒鼠对夏季生境的利用具有明显的选择性。该地黑腹绒鼠夏季频繁出现的生境为:坡向朝南,偏好选择处于较早植被演替阶段,海拔较低,乔木和竹子较矮,离水源较近,乔木层郁闭度、乔木胸径、竹子盖度、竹子密度和落叶层盖度较小,而草本层较高,草本盖度、密度及灌木密度均较大。Logistic回归分析表明坡向和草本盖度是影响该地黑腹绒鼠夏季生境选择的主要生态因子,可能反映了来自食物丰富度和捕食两方面的选择压力决定着该物种空间分布。在此基础上构建了黑腹绒鼠夏季生境资源选择函数logit(P)=8.027+2.792×草本盖度+0.325×坡向,其对生境的选择概率为P=elogit(P)/(1+elogit(P)),可用于预测夏季黑腹绒鼠在该保护区内的空间分布。

Habitat selection research is one of the important elements in wildlife management.From June to August 2009,we studied the habitat selection of Eothenomys melanogaster using line transects and systematic sampling in Tangjiahe Nature Reserve,Sichuan province,China.Twenty-one environmental variables potentially influencing microhabitat selection by the animal were measured,which included altitude,slope,and vegetation.In univariate analysis,16 variables were significantly different between the habitat and control plots,which indicated a significant habitat preference of E.melanogaster.E.melanogaster preferred a southerly aspect,an earlier stage of vegetative succession,lower altitude,shorter trees and bamboo,nearby water source,lower tree canopy,smaller diameters of trees,lower densities of bamboo and lower coverage of forest floor;however,higher herb,herbaceous cover,density and shrub density were larger habitats in the summer.However,only 2 variables were entered into the logistic regression equation,namely grass cover and slope aspect,which indicated that they are the best indicators to discriminate habitat plots from control ones.Food abundance and predation pressures were perhaps the two primary factors that determined microhabitat selection by the animals.Resource selection function was constructed as a log-linear mode：logit（P）=8.027＋2.792×grass cover ＋0.325×slope aspect.From this model,we can estimate the habitat selection probability as P=elogit（P）/（1＋elogit（P））,which could be used to predict spatial distribution of the animal during the summer in the reserve.