Relationship between reservoir size and genetic differentiation of the stream caddisfly Stenopsyche marmorata

Kozo Watanabe, Tatsuo Omura

Research output: Contribution to journalArticlepeer-review

13 Citations (Scopus)


Reservoirs have the potential to block the gene flow of stream macroinvertebrates along a channel, which takes place via larval drift and adult flight, resulting in genetic differentiation above and below the reservoirs. Gene flow across the reservoirs may be strongly obstructed if the area of standing water is larger. Using random amplified polymorphic DNA markers, we investigated the genetic structure of Stenopsyche marmorata (Stenopsychidae: Trichoptera) populations found above and below the reservoirs, and the reference stream of six reservoirs with small to large water surface area ranging from 0.12 km2 to 6.00 km2. As a result, the two largest reservoirs with a standing water area larger than 3.27 km2 showed significant differences in pairwise θ between fragmented and reference streams, whereas the other four reservoirs with a standing water area smaller than 1.64 km2 showed insignificant differences. The genetic differentiations in the two largest reservoirs did not result in the reduction of genetic diversities in the fragments. Based on the significant correlation between relative population size and mean expected heterozygosity, we concluded that local genetic diversities were constrained in smaller populations due to the effect of genetic drift.

Original languageEnglish
Pages (from-to)203-211
Number of pages9
JournalBiological Conservation
Issue number2
Publication statusPublished - 2007 Apr
Externally publishedYes


  • Gene flow
  • Genetic diversity
  • Habitat fragmentation
  • Population size
  • RAPD

ASJC Scopus subject areas

  • Ecology, Evolution, Behavior and Systematics
  • Nature and Landscape Conservation


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