Data from: Biotic resistance to an alien amphibian: larval competition between Japanese frogs and invasive cane toads

Understanding negative effects of native species on introduced taxa may suggest novel ways to control the invasive species by enhancing such effects. Previous studies have reported that the larvae of invasive cane toads (Rhinella marina) are suppressed by competition with the larvae of native anurans in Australia, but not in North America. We conducted laboratory trials to measure the effect of exposure to the larvae of Japanese frogs (Microhyla ornata, Fejervarya sakishimensis, Rhacophorus owstoni) on rates of survival, growth and development of cane toad tadpoles in Ishigaki Island, in southern Japan. Survival rates were not affected by native species, but competition with Dicroglossids and Rhacophorids (but not Microhylids) strongly reduced rates of growth and development in the tadpoles of cane toads. Dicroglossid tadpoles also reduced the body condition to toad tadpoles in addition to effects on SVL and mass. Encouraging populations of native frogs in toad-invaded areas of Japan thus may help to reduce the numbers of invasive cane toads.

探明本土物种对引入类群的负面效应，或可通过强化该类效应为入侵物种的防控提供全新思路。既往研究显示，在澳大利亚，入侵性海蟾蜍（Rhinella marina）的蝌蚪会因与本土无尾类蝌蚪的竞争而受到抑制，但该现象并未在北美被观测到。本研究于日本南部石垣岛开展室内受控试验，旨在量化海蟾蜍蝌蚪暴露于日本本土蛙类蝌蚪（饰纹姬蛙Microhyla ornata、冲绳陆蛙Fejervarya sakishimensis、奥氏树蛙Rhacophorus owstoni）环境中时，其存活率、生长速率与发育进程所受的影响。试验结果表明，本土蛙类对海蟾蜍蝌蚪的存活率无显著影响，但与叉舌蛙科（Dicroglossidae）和树蛙科（Rhacophoridae）物种（而非姬蛙科（Microhylidae）物种）的竞争，会显著抑制海蟾蜍蝌蚪的生长与发育速率。此外，叉舌蛙科蝌蚪除了会影响海蟾蜍蝌蚪的吻肛长（Snout-Vent Length，SVL）与体重外，还会降低其身体状况评分。因此，在日本已遭海蟾蜍入侵的区域，通过扶持本土蛙类种群，或可助力降低入侵性海蟾蜍的种群数量。