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Effects of habitat fragmentation by damming on salmonid fishes: lessons from white‐spotted charr in Japan
Author(s) -
Morita Kentaro,
Morita Shoko H.,
Yamamoto Shoichiro
Publication year - 2009
Publication title -
ecological research
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.628
H-Index - 68
eISSN - 1440-1703
pISSN - 0912-3814
DOI - 10.1007/s11284-008-0579-9
Subject(s) - habitat , fish migration , habitat fragmentation , ecology , fragmentation (computing) , population , fishery , habitat destruction , biology , ecosystem , geography , demography , sociology
Dam construction has serious consequences, and one of the most serious concerns is the fragmentation of riverine ecosystems. We reviewed the influence of habitat fragmentation on white‐spotted charr Salvelinus leucomaenis populations. First, habitat fragmentation by damming has serious consequences in terms of alternative life‐history strategies. Most fish in dammed‐off areas do not migrate to the sea and instead become resident forms. This loss of the anadromous form negatively affects populations through decreased spawning biomass. In addition, the smaller population sizes in dammed‐off habitats can negatively affect population dynamics through demographic, environmental, and genetic stochasticity. Therefore, the population viability is reduced in small, dammed‐off habitats. White‐spotted charr populations also likely experience different selection pressures after damming. Many of these effects of habitat fragmentation due to damming are not immediate but rather occur gradually over several generations. Because most Japanese dams were constructed after 1970, some effects of damming may not yet be obvious.