Wildlife response to habitat fragmentation and other human influences in tropical montane evergreen forests, northern Thailand

Date

2018-01-08

Authors

Pattanavibool, Anak

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Abstract

Montane evergreen forests in northern Thailand have been severely fragmented and converted to agricultural lands and other forms of development that affect wildlife. The objectives of this study were to examine patterns and changes in montane evergreen forest patches, and document wildlife responses in terms of species diversity, abundance, and distribution. The study was conducted in Om Koi and Mae Tuen Wildlife Sanctuaries, Chiang Mai and Tak Provinces. LANDSAT TM imagery, aerial photographs, GIS, and the spatial pattern analysis program FRAGSTATS were employed to examine landscape patterns and changes. I found that Om Koi still maintained large patches (>400ha) with connectivity while Mae Tuen was comprised mainly of small isolated patches (<100 ha). Mae Tuen lost 2,640 ha of montane evergreen forest within 50 years compared to 888 ha in Om Koi. Road development and cabbage cultivation in Mae Tuen played a major role in accelerating forest loss. For the wildlife survey, I compared 4 forest patches in Mae Tuen, which are heavily fragmented and disturbed, with another 4 in Om Koi, where human influences are less. I used 1-km transects to survey animals in each patch. For mammals, 156 5 x 1m track recording stations were set up in each location for recording footprints. Over a 9-month period from September 1997 to June 1998 I found 9 species of mammals in Mae Tuen and 19 in Om Koi. I also found 89 species (1,238 detections) of birds in Mae Tuen and 119 (1,192) in Om Koi. Large patches (>400 ha) with connectivity still supported large mammals, primates, and a high diversity of birds. Bird diversities were significantly greater (P = 0.011) in large patches in Om Koi than in the small patches in Mae Tuen. Large frugivorous birds such as hornbills were found in Om Koi but there were none in Mae Tuen. Small patches (<100 ha) in Mae Tuen were still valuable for forest birds and virtually no penetration by clearing birds was found. Track counts gave 886 mammal tracks in Mae Tuen and 2,016 in Om Koi. Om Koi patches still support large mammals such as the Asian elephant (Elephas maximus), tiger (Panthera tigris), Asiatic black bear (Selenarctos thibetanus), and sambar (Cervus unicolor) but there were none in Mae Tuen. Three species of primates existed in Om Koi but they were virtually extinct from Mae Tuen. There were traces of a positive relationship between bird and mammal diversities and patch size. The distribution model for elephants suggests that villages in the middle of elephant seasonal migratory paths must be restricted from development and slash-and-burn cultivation to reduce the impact on elephant populations. The small population of bantengs (Bos javanicus) was confined to a small area as revealed by the distribution model. These animals need urgent and effective protection to avoid extirpation. Hunting, burning, and domestic cattle dispersing into the forest are other influences threatening wildlife in the areas.

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Keywords

Wildlife conservation, Forests and forestry, Deforestation, Thailand

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