基于野外痕迹点和GIS技术定量评估步道对大熊猫活动的影响

道路建设不仅直接导致野生动物死亡,还能对栖息地形成阻碍效应,导致小种群出现或隔离,增加物种灭绝的风险。生态学家在道路对野生动物影响研究中的一个重要进展是道路影响域(road-effectzone)的提出,但影响域既不能反映道路影响的变化性,也难以满足栖息地评估对数据的要求。为此,我们以大熊猫(Ailuropoda melanoleuca)为例来探讨道路影响的定量评估方法。在佛坪和长青保护区内选择了3条步道,获取了步道周边1,042个大熊猫的痕迹点数据,通过GIS计算各痕迹点到步道的距离,统计距离步道每20m内的痕迹点数量,以此作为其活动频率。在距步道每100m处设置检测点,通过非参数检验比较检测点前后活动频率分布的变化,寻找道路对大熊猫活动影响的突变点,确定影响变化的阈值距离和评价标准。研究发现在距离步道1,000m内,随距离的增加,大熊猫活动频率逐渐增大,大熊猫有明显的回避效应;在距步道500m、1,000m处发现活动频率发生了显著变化,为影响的阈值距离。本研究基于痕迹点和阈值距离的评估方法可以反映道路影响连续、渐变的特点,使定量、准确评估其影响成为可能。

The quantitative assessing of trail impacts on giant panda activity based on field track points and GIS

Trails have been shown to have impacts on wildlife, which may include injury, death, habitat hindrance, and then cause small population or population isolation and increase species extinction risk. Road effect zone was widely used to examine the wildlife responses to roads and trails, but had shortages in quantifying the changes of causative factors, and meeting the data requirements for habitat evaluation. In this research, we evaluated the impacts of trails on giant panda activity based on giant panda tracking data. The study sites were centered in Foping and Changqing natural reserves, and 1,042 giant panda tracking points were collected in association with three major trails. By aids of GIS, the distance of every track point to the trails was obtained, and then the amount and frequencies of track points every 20 m from trail were calculated. To identify the impact threshold of trails on giant panda activity, we established the testing points every 100 m from the trail for analysis of the activity frequency pattern. The results showed that within 1,000 m from the trails, the giant panda activity frequencies increased with the distance. The tracking point frequency showed significant changes at 500 meters and 1,000 meters from the trails, which represent impact threshold of trails on giant panda activity. The method based on track points and impact threshold can provide a more feasible and a quantitative evaluation for disturbances of trails and other infrastructure on wildlife activity.