Spatial structures of 7 types of aquatic habitat at the reach scale were delineated using a high precision Global Position System (GPS) in 3 dam-impacted and 6 reference riverrine reaches in Miyagi Prefecture, Japan. Taxonomic and functional compositions of quantitative benthic invertebrate samples were also investigated. Out of the three dams, two indicated decreased levels of habitat diversity indexes (S, H', a, and E) at the outlet reaches due to reduced sediment supply and reduced hydraulic variation through dam-operation; but one dam connected to meandering outlet reach did not. Percentage of total area of lentic habitats (i. e., backwater and isolated pool) at the dam-impacted reaches (mean= 1.5%) was significantly lower than reference reaches (mean=5.5%). The taxon richness, abundance of swimmers, predators, attachers and crawlers increased with the percentage of lentic habitat area (P<0.05, n=9), which suggests that lentic habitats contribute to maintain species diversity and the functional groups at the reach scale. Our data indicated a high application potential of the GPS-based evaluation of habitat structure for biodiversity conservation in rivers.
- Benthic invertebrates
- Global positioning system (gps)
- Habitat heterogeneity
- Lentic habitat
ASJC Scopus subject areas
- Civil and Structural Engineering