食物可获得性对白头叶猴(Trachypithecus leucocephalus)食物季节性组成的影响

Impact of food availability on seasonal diet composition of white-headed langur

研究喀斯特石山栖息地食物可获得性对食物多样性和种类季节相似性的影响是动物对环境适应研究的重要组成部分。采用瞬时扫描取样法(instantaneous scanning sampling)对广西扶绥白头叶猴(Trachypithecus leucocephalus)的食物多样性和季节性种类进行了研究;同时,采用固定样线法监测各月份白头叶猴家域内食物可获得性。结果表明,白头叶猴年平均食物多样性指数(FDI)为4.02,各月份间FDI没有显著变化(P=0.89),FDI与栖息地中主要食物的嫩叶的可利用性指数(FAI)有明显的负相关关系(P<0.05)。在全年取食的食物种类中,有8种食物在11个月份都被取食,其他种类则只在特定的月份被取食。各月份间食物种类的相似性在0.36(3—4月)和0.74(9—10月)之间变化,月份间FAI的相似度与月份间食物种类的相似度有明显的正相关关系(P<0.05)。白头叶猴对栖息地中食物种类的利用方式是:每个月用几种相同食物种类,并且主要食物可获得性高时,则集中采食,先满足基本的能量需求,再取食其他种类作为补充,使食物种类多样化,以满足不同的营养需求。

Study on the impact of food availability in limestone habitat on dietary diversity and monthly similarity is crucial to understand animal＇s adaptation to specific habitat. We collected data on food species,items and feeding time of white-headed langur（ Trachypithecus leucocephalus） via instantaneous scanning sampling method,and monitored food availability by fixed transect in their home range each month. The results showed that annual dietary diversity index was4.02. There was no significant monthly variation in dietary diversity（ P = 0.89）,and there was a significant negative correlation between dietary diversity and availability of young leaves of staple food（ P〈0.05）. Eight species were used by the langurs in all months,whereas others were consumed seasonally,despite of their higher availability. Food species overlap between months ranged from 0.36（ March and April） to 0.75（ September and October）. Moreover,we found a significant positive correlation between food availability similarity and dietary species similarity among months（ P〈0.05）. This study suggested that langurs inhabiting limestone hills diversified food species to meet nutrient demand by being selective in food species available in all months and consuming some seasonally available food species.