台灣地區外來種亞洲錦蛙族群來源與生態研究

Abstract

亞洲錦蛙(Kaloula pulchra)在台灣是近期才發現的新紀錄種。為了解亞洲錦蛙基本的生物特性、在生態上可能的衝擊，以及族群遺傳結構的特性，我們在高雄縣鳳山水庫地區進行了21個月的野外調查。 利用剪趾標記法，估算族群動態並計算出其活動範圍。並利用趾骨鑑齡以了解其族群年齡結構。於野外調查過程中，紀錄所有樣區內各蛙種利用棲地類型，以了解牠們在棲地利用上資源競爭的情形。 在調查期間，估計族群數量為259隻，以生殖族群為主。大部分亞洲錦蛙個體活動範圍侷限在100 m2以內。族群活動與當日雨量有顯著正相關(R=0.7841, P<0.00004)，除了雨量外低溫也是影響亞洲錦蛙活動的因素。 在競爭方面，亞洲錦蛙在微棲地使用上很容易利用到其他原生蛙種的資源，微棲地利用寬度0.67±0.12，是在共域蛙種中最高，適應性很高。其他蛙種出現的月份亞洲錦蛙都會出現。牠與黑眶蟾蜍在食性上有很高的重疊指數0.98。尤其亞洲錦蛙與原生黑眶蟾蜍間食性重疊的現象。在生態衝擊上，亞洲錦蛙的出現可能會影響台灣地區原生蛙種組成。 利用PCR技術與定序，了解台灣地區亞洲錦蛙族群遺傳結構，並與香港地區標本進行比較。台灣地區亞洲錦蛙之46隻個體，只有1種基因型，香港地區7個標本有2種基因型。在族群遺傳結構結果顯示，台灣地區亞洲錦蛙為近期才進入台灣的物種，且來自單一地區族群，甚至是來自單一雌性個體所建立的後代。台灣與香港地區族群遺傳距離0.003，顯示其應不是來自於香港，至於物種來源方面之確認則還需要更多國外地區的樣本Asiatic painted frog, a medium size one is a newly recorded species in Taiwan. It belongs to family Microhylidae, genus Kaloula, Kaloula pulchra. Asiatic painted frog was suspected to be introduced with imported timbers in last couple years. In order to understand the ecological impacts from Kaloula pulchra on local frog fauna, we conducted a study in Fong Shan reservoir. We used Martof toe clipping method to mark each individual encountered in the wild. Population size in Fong Shan reservoir was estimated by using Jolly-Seber mark and recapture method. The population age structure was constructed by skeletochronology. Meanwhile, home ranges of several individuals were calculated. Niche breath of microhabitat resource and food items in the stomach were calculated by Hurlbert’s niche breath measurement. We also estimated niche overlap between Asiatic painted frog and other sympatric species. PCR and other molecular techniques were applied, and mtDNA were sequenced, we compared the genetic structure of individuals from Taiwan and Hong Kong. The estimated population size is about 259 individuals in Fong Shan reservoir, and captured individuals mainly are the breeding ones. The appearance of Kaloula during the night is significantly related to precipitation (R=0.7841, P<0.00004). Besides precipitation, the other factor affects the appearance of Kaloula is the low temperature in winter. In microhabitat resources, the niche breath of Kaloula is 0.67±0.12. The competition between Kaloula pulchra and Bufo melanostictus is prominent, Horn’s index is 0.98. We suspected that invaded Kaloula pulchra may cause species composition shift in a local frog fauna. Kaloula pulchra in Taiwan showed only one haplotype. While more than one haplotypes were discovered from Hong Kong frogs. This indicated that they invaded to Taiwan from a single source recently all descendants may come from a single female frog only. To find out the area where it came from, more specimens from other countries will be needed.