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Effects of local and landscape factors on the abundance of an endangered multivoltine butterfly at riverbanks

Zhang, Xin, Miyashita, Tadashi
Entomological science 2018 v.21 no.1 pp. 133-141
Plebejus, autumn, butterflies, ecosystems, forests, grasslands, habitat connectivity, habitat conservation, habitat fragmentation, host plants, invasive species, landscapes, multivoltine habit, nectar, riparian areas, rivers, shade, summer, Japan
Plebejus argyrognomon is one of the grassland‐dwelling butterflies undergoing rapid decline in recent decades. Grassland habitats for butterflies are generally threatened by fragmentation and invasive species, hence are among the most vulnerable ecosystems. We studied the seasonal abundance of P. argyrognomon at habitat patches along the banks of the Kinugawa River in eastern Japan, to identify environmental factors suitable for population persistence of this species, including habitat patch connectivity. Results showed that the patch's host plant cover had a positive effect on abundance in all three seasons, while the shading of the host plants by surrounding non‐host plants and nearby forested area showed negative effects. Additionally, habitat patch connectivity and nectar richness could be considered as positive factors in autumn and summer, respectively. Analysis of habitat connectivity also showed that the Kinugawa River did not appear to act as a dispersal barrier for P. argyrognomon. Our findings emphasize the importance of understanding environmental factors that may vary among seasons, and such understanding could contribute to habitat management of multivoltine butterflies in fragmented landscapes.