臺灣北部二種樹棲性蝸牛(多型高腰蝸牛和淡綠高腰蝸牛)的生態研究

Abstract

樹棲性蝸牛 (arboreal snails) 為一群生態特化的陸生蝸牛，主要棲息於熱帶至副熱帶地區的闊葉森林環境，在灌叢至樹冠層活動。本研究探討臺灣北部二種樹棲性蝸牛(多型高腰蝸牛 Satsuma polymorpha 和淡綠高腰蝸牛 S. viridibasis) 的生態特性。探討的項目包括:1) 在臺灣北部的空間分布情形； 2) 小尺度調查微棲地，以了解其對棲息植物的選擇和棲地類型的偏好；3) 大尺度進行生物分布模型，以了解其適存棲地和重要環境因子；4) 測試二種蝸牛的溫度偏好，並與空間分布特性做探討。 結果發現，二種樹棲性蝸牛的海拔和地理分布不同:多型高腰蝸牛分布在宜蘭至新竹深山地區而未分布至大屯山區，海拔範圍 254-1703 公尺，平均 698 公尺；淡綠高腰蝸牛分布在宜蘭至桃園淺山地區，涵蓋臺北盆地周圍，海拔範圍 41-831 公尺，平均 314 公尺。2) 二物種對棲息植物皆具有廣適性，主要利用喬木 (> 60 %) 和灌木 (20 %) 以及藤蔓 (10 %)，幾乎不會在地面活動 (< 2 %)。3) 對溫度的偏好實驗，多型高腰蝸牛在 15℃ 的攝食意願高於淡綠高腰蝸牛；淡綠高腰蝸牛在 25℃ 則高於多型高腰蝸牛。綜合以上結果，臺灣北部二種樹棲性蝸牛在地理分布、海拔和溫度偏好不同，但利用的森林微棲地類似，都是以喬木和灌木為主，並可廣泛利用各種闊葉植物。

Arboreal snail is a special eco-type in land snails, mainly live on shrubs and trees, in tropical and sub-tropical broadleaf forests. This research examined two arboreal snail species in Northern Taiwan, Satsuma polymorpha and S. viridibasis. Research institute including: 1) Species distribution in Northern Taiwan 2) Small scale for micro habitats preference, use line transect method to record the tree preferences and habitat types 3) Use species distribution models to recognize suitable habitats and important environment factors 4) Testing the activity of two snails in different temperature, and discuss with distribution pattern. The results revealed that two arboreal snails partitioning on: 1) Geographic distributions and elevation ranges: Satsuma polymorpha distributed from Yilan to Hsinchu’s higher mountain area without Mt. Datun, elevation ranges 250-1800 m, average on 650 m； S. viridibasis distributed from Ilan to Taoyuan include the hills around Taipei Basin, elevation ranges 411-831 m, average on 314 m. 2) Both were euryoecious on tree species, but prefered to similar micro habitats in the forest. Usually on trees (> 60 %), shrubs (20 %), and vines (10 %), rarely recorded on the ground (< 2 %). 3) In temperature-activity experience, S. polymorpha had significant higher proportion eating food in 15℃ than S. viridibasis； However, S. viridibasis performs better than S. polymorpha in 25℃. In conclusion, two arboreal snail species in Northern Taiwan have different distribution patterns in geography and elevation and different temperature preference. Both using the tree habitats in forest, euryoecious on tree species.