Crustaceans in changing climate: Global warming and invasion of tropical land hermit crabs (Crustacea: Decapoda: Anomura: Coenobitidae) into temperate area in Japan

Abstract

There is currently a strong scientific consensus that recent global change of climate, including the global warming, seriously damage ecosystems of both lands and oceans. Here, I review recent drastic northern expansion of distribution of tropical land hermit crabs (Coenobita) into temperate Japan. Seto Marine Biological Laboratory of Kyoto University has a long history (97 years) and has been conducting various programs of long-term monitoring survey on coastal biota. A part of the results is also introduced here. Seventeen species of land hermit crabs are known from tropical regions worldwide, and seven species are known in Japan, which are mainly distributed in tropical region of Japan. Recent intensive studies on coastal areas of Japan have shown that many juveniles and small individuals of land hermit crabs are found during warm season in temperate regions. The finding of the species that were identified by DNA analysis as Coenobita rugosus and C. purpureus might be an indication for the global warming effect. Further, I here introduce the model of northern limit of distribution proposed by Gorodkov (1986) which explains change of detailed structure of population toward the limit of distribution. Moreover, I here propose the model of stages of adaptation of tropical species to temperate zone through ecological and evolutional times. These two models are useful and helpful to understand the things happen in populations in the limit of distribution and, therefore, useful for conservation of species and biological communities.