Author(s): Kei Nukazawa; So Kazama; Akihiko Takase; Kozo Watanabe
Linked Author(s): So Kazama
Keywords: Distributed runoff model; Functional feeding group; HSI; Habitat value; Landscape genetics; Life types; Trichopter
Abstract: A vast number of researches in landscape genetics of river have been focused on how habitat fragmentation or exogenous invasion ascribed to dam or stocking degrades native genetic diversity. However, there still is an unsolved question in this arena; how are physical habitat characteristics related to genetic diversity. As the habitat nature arguably contributes to not only faunal structure but intra-specific trait through gene flow, drift and selection, this association needs to be revealed for future river management plan with a conservation perspective. In this study, we evaluated the linkage between genetic diversity and habitat suitability index (HSI) of aquatic animals including freshwater fishes, amphibians and macroinvertebrates in the Natori River basin located at the middle of Miyagi prefecture. The HSI has been structured by hydraulic and thermal variables calculated from a distributed hydro-thermal model and GIS based geographical variables. We found a strong positive correlation between genetic diversity and HSI in one caddisfly (Hydropsychidae), indicating that a prospective habitat (i.e., locality which has high HSI) might contribute to increase in genetic diversity. The genetic diversity of one caddisfly (Hydropsychidae) had significant positive correlations with the HSIs of predatory fishes and aquatic insects. This result suggests that exposures to predation pressure can enhance genetic diversity. We derived negative correlations between genetic diversity and the HSIs within niche competitors, suggesting inter-species selective pressure constrains intra-species genetic diversity.