Wildlife roadkill survey & impact mitigation in National Forest Area
中華民國 101 年 11 月 27 日
本計畫為二年度計畫，總目標包含從地景和破碎化等因子進行較大尺度的敏感程度評估，分析區域性林道上道路致死課題，建立先期評估模式，並針對林務局所轄國有林範圍內的野生動物道路及周邊排水設施致死課題進行調查分析，根據調查結果找出野生動物道路致死敏感區段，並提出改善減輕的相關對策。第一年已完成初步的國有林班地內的林道道路致死敏感程度評估，並參考道路管制情形、林道通行狀況、既有景點設施等因子，挑選已知有道路致死課題的桶后林道、大雪山林道、宜專一線與翠峰林道等4條林道進行調查，記錄種類、數量、分布里程、周圍環境因子並分析熱點分布情形。第一年調查共記錄了2519筆的哺乳類、兩棲類、鳥類與爬蟲類道路致死紀錄，以兩棲類(1825筆)與爬蟲類(590筆)佔較多數，而保育類物種則記錄到18種81隻，以蛇類為主(11種54隻)。利用地理資訊系統(ArcGIS 10.0)與熱點顯著性檢定工具(Hot Spot Analysis, Getis-Ord Gi*)分析顯示，道路致死最為顯著的類群以溪流蛙類(梭德氏赤蛙)最高，在時間與空間分布上均有顯著高峰，地點主要位於桶后林道與大雪山林道。此外，本計畫第一年度亦蒐集了國內外關於道路致死生態課題的野生動物受影響案例、可能影響因子、調查系統建置、改善措施評估或指南等相關文獻，並參考相關內容，擬定第二年度建議辦理方向與其他建議項目，提供主辦單位作為本課題的對策參考。
The first year of the two-year project of roadkill survey of the forest roads was focused on evaluating and identifying the main issues that may impact the wildlife. We started from a landscape-level approach concerning all forests in the mountainous area and built a spatial analysis that predicted areas of high ecological sensitivity (i.e. high risk of animal mortality) according to species diversity and habitat quality. Four roads of high ecological sensitivity, including Tunghou, Tahsueshan, Yi-Zhuan First and Cui-Feng Forest Roads, were then chosen and a year-round roadkill survey were conducted to investigate the spatial distribution and potential factors of roadkills along each road. The location, species, maturity and number of animal mortality were recorded by GPS digital camera. The topography and land use beside the road was processed using ArcGIS 10.0 as environmental factors. The major road structure elements (including different types of fences, walls, and ditches) were recorded from field survey as road factors. We used both kernel density estimation and the Getis-Ord Gi* spatial clustering statistic to assess roadkill hot spots. The year-round survey on four roads recorded a total of 2519 roadkills (87 species), including 51 mammals (2.0%, 13species), 53 birds (2.1%, 17 species), 590 reptiles (23.4%, 46 species) and 1825 amphibians (72.4% 11 species), among them 81 were protective species (18 species) and 51 were snakes (11 species). Roadkill of river-breeding frogs had the highest number and was highly clustered seasonally and spatially on both Tahsueshan and Tunghou Forest Roads. Sections of the highest mortality and species diversity were listed as candidate sites for mitigation measures. The road and environmental factors were processed and stored in the form of geo-database for further analysis on the second year.
KEY WORDS: roadkill analysis, Getis-Ord statistic, Forest Road, road engineering, road ecology