昆明滇蛙和昭觉林蛙食物比较及益害评价

:对1998年5月—2003年11月采自昆明白龙寺、花红洞及西街口的1105只滇蛙(Rana pleuraden)及428只昭觉林蛙(Rana chaochiaoensis),采用剖胃法作食性分析,分别计算它们的食物数量和频次百分比、α多样性指数、百分率相似性指数、营养生态位宽度、营养生态位重叠值和有益系数等。分析和计算结果显示,不同采集地的滇蛙以及滇蛙与昭觉林蛙之间的主要食物组成基本相同;但两种蛙之间,甚至同一物种的雌雄之间的食物多样性及营养生态位均存在分化。滇蛙和昭觉林蛙周年的有益系数都为正值,说明它们对人类的益处大于害处,其中又以滇蛙的有益程度较昭觉林蛙的高。研究结果表明,同一物种采自不同地域的种群和(或)同一种群采自不同的季节或年份,其有益系数均具可变性,即有益系数不具可比性。此系数仅表示蛙在一定时期对人类的益害程度。

Comparison of Food Components Between Rana pleuraden and Rana chaochiaoensis from Kunming and Evaluation of Their Benefit and Harm

Food components of 1 105 individuals of Ranapleuraden and 428 Rana chaochiaoensis collected from Bailongsi, Huahongdong and Xijiekou of Kunming from May 1998 to November 2003 were analyzed by dissecting their stomachs. It was calculated that percentage of number and frequency, a diversity index, index of percent similarity, width of trophic ecological niche, overlap of trophic ecological niche and beneficial coefficient of the two frog species. According to results, major food components of different populations of R. pleuraden collected from different localities as well between R. pleuraden and R. chaochiaoensis were basically identical. However, there were differentiation in food diversity and trophic ecological niche between R. pleuraden and R. chaochiaoensis as well between their males and females. The annual beneficial coefficients of both R. pleuraden and R. chaochiaoensis were positive, which implied that their benefit for mankind was larger than harm. The beneficial level of R. pleuraden was higher than one of R. chaochiaoensis. The study results showed that beneficial coefficient could be changed among populations of a species collected from different regions and/or the same population collected from different seasons or years, which meant that the beneficial coefficient could not be compared. This coefficient only expressed the level of benefit and harm for mankind in the certain period.