评估不同尺度下农牧地对滇金丝猴景观连接度的影响

基于图论法原理,综合最小费用距离和猴群的最小家域,建立了滇金丝猴栖息地的潜在扩散廊道及廊道缓冲区。在此区域内,根据遗传距离与栖息地连接最小费用距离的相关性,确定了5个不同管理单元间猴群可能扩散的阈值,并根据此阈值计算获得可能连通性指数(PC)去评估不同尺度下农牧地对滇金丝猴栖息地景观连接度的影响。结果表明:在距离为2.15km的廊道缓冲区范围内,5个不同管理单元间猴群可能扩散的最小费用距离阈值为1600,在两个斑块之间的费用距离小于或等于1600时,两个斑块能够连接,猴群可能在这两个斑块进行扩散,超过费用距离1600时,两个斑块不再连接,即猴群在这两个斑块间不会扩散。景观尺度下,PC指数逐渐增加,意味着未来4种不同的农牧地改善情景(C1,C2,C3,C4)都将促进景观连接度的增加;在斑块尺度下,通过确定出的最佳距离阈值,将整个研究区域分成不同的组分,小于或等于阈值的相邻斑块被划分在同一个组分中,大于阈值则不在一个组分中,研究区域中的5个不同管理单元间的猴群被划分在3个不同的组分中,情景C1,C2中组分数量没有变化,意味着连接度没有发生改变,但在情景C3,C4中,组分数量减少,并与相邻的组分融为一个组分,意味着连接度发生改变,滇金丝猴的活动范围扩大,更有利于猴群的基因交流。研究结果将为滇金丝猴栖息地的保护、未来廊道的恢复建设提供科学依据,同时也能为类似的研究提供方法上的参考。

Impact evaluation on the Yunnan snub-nosed monkey's habitat in terms of landscape connectivity by agricultural land with consideration at different scale scenarios

In this paper, we identified potential corridors and buffers for connecting all the existing sub-populations of the Yunnan snub-nosed monkey (Rhinopithecus bieti) based on graph theory approach and the principle of the least cost distance and the least home range model for the monkey species. According to the correlation between genetic distance and habitat connectivity of the least cost distance, the threshold for potential dispersal was identified for the sub-populations in each of the five management units. Potential connectivity (PC) index could be then evaluated with the threshold, and the PC index could be used to estimate the impact on the monkey''s habitat by agricultural land in terms of landscape connectivity at different scale scenarios. In this study, we found:(1)the threshold for the most optimum least cost distance of dispersal was estimated about 1600 between the monkey sub-populations in each of the management units in a 2.15 km buffer.(2)The improvement of four types the agricultural land situation could promote increasing landscape connectivity.(3)the 15 existing Yunnan snub-nosed monkey sub-populations were divided into 3 different quantities and structural in the patch scale, in scenario C1 and C2,the landscape connectivity was not changed, while in scenario C3 and scenario C4 the landscape connectivity was decreased and adjacent components would merge into one. Thus, the home range of the monkey snub-population would expend, which in turn would be conducive for gene flow. This finding might be significant for conserving the monkey species range-widely.