基于野外观测检验动物廊道选址模型的准确性——以白头叶猴为例

Testing accuracy of the animal corridor site selection models based on field observations:A case study of white-headed langur(Trachypithecus leucocephalus)

廊道构建是减少栖息地破碎化负面影响的重要策略之一。目前,已经有许多模型用于动物廊道的选址,而"选址模型是否能准确预测动物迁移的实际发生位置"一直是保护生物学最为关注的问题。最小成本路径模型(LCP)和条件最小成本廊道模型(CMTC)是两种较为常用的廊道选址模型。以白头叶猴(Trachypithecus leucocephalus)为目标物种,分别运用LCP和CMTC模拟生成白头叶猴迁移廊道,将模拟结果与野外观测廊道进行对比,检验两种方法的准确性。结果表明:与野外观测实际廊道相比,LCP模型模拟结果的完全准确率为46.7%,部分准确率为20%,完全不准确率为33.3%;CMTC模型模拟结果的完全准确率为26.7%,其余73.3%为部分准确,无完全不准确的结果;总体上看,CMTC廊道的准确率较LCP高,因而CMTC模型模拟白头叶猴实际迁移廊道位置的准确性优于LCP模型。输入"源"要素类型、阻力面栅格尺度设定、栖息地土地利用类型变化以及动物迁移行为复杂性4个因素是影响该模拟结果准确性的主要原因。

Habitat fragmentation is a hot issue of global biodiversity conservation,and corridor construction is one of the important strategies to reduce the negative impact of habitat fragmentation.To date,many models have been used for the prediction location of animal corridors,one key concern from conservation biologist is whether these models can accurately predict actual dispersal paths of target species.In this work,the white-headed langur(Trachypithecus leucocephalus),an unique endangered primate to Guangxi,China,was chosen as target species,it inhabits karstic rocky mountain areas,where is facing severe fragmentation problems due to increased human disturbance.During the last century,this species experienced a severe population declines,with an estimated 80% contraction in its distribution and a 60% reduction in its total population.They are now only distributed in small isolated habitat patches with limited opportunities to exchange gene among populations.The corridors can help this species disperse from one patch to another,and the connectivity of isolated patches is enhanced consequently.Least Cost Path(LCP)model and Conditional Minimum Transit Cost(CMTC)model are two commonly used corridor site selection models,whereas their outputs have never been validated using the actual observations data.For this purpose,LCP model and CMTC model were used to simulate the dispersal corridors of T.leucocephalus,respectively,and the simulation results from two models were further compared with field observated data for the accuracy test of these two models.The results revealed that:The fully accuracy rate for predictions of LCP model was 46.7%,partial accuracy was 20%,the complete inaccuracy rate was 33.3%.The full accuracy rate for predictions of CMTC model was 26.7%,the remnant 73.3% were all partially accurate and there was no completely inaccurate outputs from CMTC model.In general,the accuracy rate for predictions of CMTC model was higher than the outcome of LCP model,and thus the CMTC model had better performance on prediction for corridor location of T.leucocephalus than LCP model.The type of input source feature,grid size configuration of cost surface,changes in habitat land use types and complexity of animal movement behavior were four main factors affecting the accuracy of model prediction results.