シオマネキの分布に対するヨシの影響

Abstract

The influence of reed marshes on the distribution of the fiddler crab Uca arcuata was examined by means of field experiments in the salt marsh of the estuary of the Katsuura River, Tokushima Prefecture, western Japan. When pots with reeds and pots without reeds were set out with 6 replicates on a tidal flat during the recruitment season, the number of recruits in the pots did not differ between the two treatments. When aboveground reeds were removed from some areas of the marsh, the number of recruits was greater there than in the intact area, while abundance of adult crabs showed no difference. When juveniles were introduced into a box with mud only and into a box with mud and reeds, all of which were set out on the tidal flat, more of the juveniles survived in a box without reeds than in the box with reeds. These results suggest that reed marshes have a negative effect on the distribution of juveniles, while no effect on the distribution of adult crabs in their habitat.