Conservation biology


extinction, habitat loss, fragmentation, local population, genetic diversity, invasive species, urbanization, umbrella species, keystone species, charismatic species

Study species

(native species) Dolly Varden, white-spotted charr, Sakhalin taimen, sticklebacks, Ural owl, Blakiston’s fish owl, Red-crowned crane, Eurasian red squirrel, Japanese crayfish, (invasive species) rainbow trout, brook trout, raccoon, signal crayfish

Japan is designated as a biodiversity hotspot where various wildlife are living together with over 120,000,000 people (see also here: link to About our lab). Therefore, we need to continuously assess human impacts on wildlife and search for the best ways to preserve native ecosystems. We are studying various topics, such as extinction risk assessment, effects of urbanization and introduced species, genetic diversity and inbreeding, management units, and so on. Actually, most of our study projects are somehow related to conservation.

スクリーンショット(2013-12-11 6.57.24)スクリーンショット(2013-12-11 6.57.44)

  • Ishiyama N, Koizumi I, Yuta T and Nakamura F. (in press) Differential effects of spatial network structure and scale on population size and genetic diversity of the ninespine stickleback in a remnant wetland system. Freshwater Biology
  • Higa M, Yamaura Y, Koizumi I, Yabuhara Y, Senzaki M and Ono S. (2015) Mapping large-scale bird distributions using occupancy models and citizen data with spatially biased sampling effort. Diversity and Distributions, 21, 46-54
  • Negishi JN, Soga M, Ishiyama N, Suzuki N, Yuta T, Sueyoshi M., Yamazaki C, Koizumi I., Mizugaki S, Hayashida K, Nunokawa M. and Yoshimura N. (2014) Geomorphic legacy controls macrophyte distribution within and across disconnected floodplain lakes. Freshwater Biology, 59, 942-954
  • Kobayashi F, Toyama M. & Koizumi I. (2014) Potential resource competition between an invasive mammal and native birds: overlap in tree cavity preferences of feral raccoons and Ural owls. Biological Invasions, 16, 1453-1464.
  • Kitano S., Ohdachi S., Koizumi I. and Hasegawa K. (2014) Hybridization between native white-spotted charr and nonnative brook trout in the upper Sorachi River, Hokkaido, Japan. Ichthyological Research, 61, 1-8
  • Soga M., Ishiyama N., Sueyoshi M., Yamaura Y., Hayashida K., Koizumi I., Negishi J.N. (2014) Interaction between patch area and shape: ponds with different formation processes have contrasting area and shape effects on macrophyte diversity. Landscape & Ecological Engineering, 10, 55-64
  • Koizumi I., Usio N., Kawai T., Azuma N. and Masuda R. (2012) Loss of genetic diversity means loss of geological information: the endangered Japanese crayfish possessed remarkable historical footprints. PLoS ONE, 7, e33986
  • Koizumi I. (2011) Integration of ecology, demography and genetics to reveal population structure and persistence: a mini review and case study of stream-dwelling Dolly Varden. Ecology of Freshwater Fish, 20, 352-363
  • Azuma N., Usio N., Korenaga T., Koizumi I., and Takamura N. (2011) Genetic population structure of the invasive signal crayfish Pacifastacus leniusculus in Japan inferred from newly developed microsatellite markers. Plankton & Benthos Research, 6, 179-186
  • Griffiths A.M., Koizumi I., Bright D. & Stevens J. (2009) A case of isolation by distance and short-term temporal stability of population structure in brown trout (Salmo trutta) within the River Dart, southwest England. Evolutionary Applications, 2, 537-554
  • Raeymaekers J.A.M., Raeymaekers D., Koizumi I., Geldof S. & Volckaert F.A.M. (2009) Guidelines for restoring connectivity around water mills: a population genetic approach to the management of riverine fish. Journal of Applied Ecology, 46, 562-571
  • Dunham J.B., Baxter C., Fausch K.D., Fredenberg W., Kitano S., Koizumi I., Morita K., Nakamura T., Rieman B.E., Savviatova A., Stanford J., Taylor E.B. & Yamamoto S. (2008) Ecology and conservation of Dolly Varden, white-spotted char and bull trout. Fisheries, 33, 537-550
  • Yamamoto, S., Maekawa, K., Tamate, T., Koizumi, I., Hasegawa, K. & Kubota, H. (2006) Genetic evaluation of translocation in artificially isolated populations of white-spotted charr (Salvelinus leucomaenis). Fisheries Research, 78, 352-358.
  • Koizumi I., Kobayashi H., Maekawa K., Azuma N. & Nagase T. (2005) Hybridization between endemic Miyabe charr (Salvelinus malma miyabei) and introduced masu salmon (Oncorhynchus masou) in Shikaribetsu Lake. Ichthyological Research, 52, 83-85.
  • Yamamoto S., Morita K., Koizumi I. & Maekawa K. (2004) Genetic differentiation of white-spotted charr (Salvelinus leucomaenis) populations after habitat fragmentation: spatio-temporal changes of gene frequencies. Conservation Genetics, 5, 529-538.