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.

探究本土物种对引入类群的负面影响，或可通过强化这类效应，为入侵物种的防控提供全新思路。此前已有研究报道，在澳大利亚，入侵性海蟾蜍（Rhinella marina）的蝌蚪会因与本土无尾类幼虫的竞争受到抑制，但该现象并未在北美被观测到。本研究于日本南部的石垣岛开展室内试验，评估日本本土蛙类幼虫（饰纹姬蛙Microhyla ornata、石垣泽蛙Fejervarya sakishimensis、吴氏树蛙Rhacophorus owstoni）对海蟾蜍蝌蚪存活率、生长及发育速率的影响。试验结果显示，本土蛙类并未对海蟾蜍蝌蚪的存活率产生显著影响，但与叉舌蛙科（Dicroglossidae）及树蛙科（Rhacophoridae）类群的竞争（而非姬蛙科Microhylidae类群）显著降低了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（SVL）与体重外，还会降低其身体状况指数。因此，在日本已遭海蟾蜍入侵的区域增殖本土蛙类种群，或可助力降低入侵性海蟾蜍的种群数量。