台灣中部蛙類與蟾蜍在時間分布、空間偏好

Altitudinal Differences in Temporal Distribution, Spatial Preference and Timing of Breeding Climax of Frogs and Toads in the Central Taiwan

This study compared temporal niche breadth, temporal niche overlap, spatial preference, and timing of breeding climax of frogs and toads in Wushikeng at 1,000m in elevation and in Chichi at 240m in the central Taiwan. The results showed that a species that had a wider temporal niche tended to have a wider niche overlap with other species. Also, the temporal niche breadths of the frogs and toads were significantly correlated with their temporal niche overlaps, while both niche breadths and overlaps were wider at the high elevation than at the low elevation. Most of the species expressed a spatial preference to either land or stream, but some showed no preference. An exception was Rana latouchii, which preferred land at the high elevation but stream at the low elevation. This was perhaps due to difference in water availability (precipitation) between the two elevations. The timing of breeding climax of most of the species at the high elevation was about two months later than that at the low elevation, except for Buergeria robustus the timing was the same at both elevations. 本研究選擇台灣中部地區海拔1,000m之烏石坑與海拔240m之集集，比較兩地蛙類與蟾蜍的時間生態區位寬度、時間生態區位重疊度、空間偏好及生殖高峰期的海拔差異。結果顯示：一物種若有較寬之時間生態區位，該物種與其共棲物種間也將擁有較大的生態區位重疊度。此外，時間生態區位寬度與時間生態區位重疊度呈現顯著性相關，且隨著烏石坑到集集海拔高度的降低，其寬度與重疊度亦下降。大部分物種在群聚中會表現出物種對空間偏好的特殊性，其選擇可以是陸域、溪流或沒有偏好。在此兩海拔物種空間偏好方面，唯一例外的是拉都希氏赤蛙，該蛙在烏石坑偏好出現在陸域，而在集集則偏好在溪流。其原因可能由於兩地海拔差異導致雨水的可利用性（降雨量）不同所致。在烏石坑大部分蛙類的生殖高峰比集集約晚2個月，只有褐樹蛙例外，該蛙在兩地擁有相同的生殖高峰。