Microhabitat use by the white‐clawed crayfish in a Tuscan stream

Abstract

Habitat modification, pollution, overfishing, poaching, competition from non‐indigenous species, and diseases have led to the extinction in Europe of many populations of indigenous crayfish. Under the rationale that any programme of reintroduction should be preceded by a thorough understanding of habitat requirements of the species of concern, we studied the microhabitat use of an Austropotamobius pallipes population in Tuscany, central Italy. Microhabitat use was assessed for water depth, current velocity, substrate, percentages of boulders, underwater tree roots, and in‐stream vegetation cover. Results show that A. pallipes' habitat use is size‐partitioned. Smaller individuals mostly occupy stream edges in shallow waters with submerged roots, whereas larger individuals use deeper waters, often associated with boulders. Crayfish spatial distribution is restricted mostly to the microhabitats characterised by extensive cover and slow current velocity. The study highlights the importance of habitat heterogeneity and cover elements for the protection of this indigenous species.

Keywords:

• Austropotamobius pallipes
• biodiversity conservation
• crayfish
• freshwater streams
• microhabitat use

Acknowledgements

The study was conducted as part of a Socrates/Erasmus research exchange project. Thanks are due to Silvia Barbaresi and Ilaria Cipriani for their help in the field work, and to Sebastiano Salvidio for constructive comments on earlier versions of this manuscript. Sadie K. Reed Stimmell, Francisco B.G. Moore, Brenton Knott, and two anonymous reviewers greatly improved an early draft of the manuscript with their language revision and useful suggestions.