Indicators of movement and space use for two co-occurring invasive crayfish species

• Published in: Ecological indicators Vol. 53; no. C; pp. 171 - 181
• Main Authors: Anastácio, P.M., Banha, F., Capinha, C., Bernardo, J.M., Costa, A.M., Teixeira, A., Bruxelas, S.
• Format: Journal Article
• Language: English
• Published: Netherlands Elsevier Ltd 01-06-2015; Elsevier
• Subjects: Biological invasions; Brackish; Cambaridae; Consistency; Crayfish; Crustacea; Dispersal; Ecology; Habitats; Iberian Peninsula; Indicators; Movement; Pacifastacus leniusculus; Pools; Procambarus clarkii; Radio-tracking; River; Vegetation; Crustacea; Biological invasions; Iberian Peninsula; River; Radio-tracking; Dispersal
• ISSN: 1470-160X; 1872-7034
• DOI: 10.1016/j.ecolind.2015.01.019

•Through radio-tracking we studied how the two coexisting crayfish species move and use space.•Movement and space use by Procambarus clarkii and Pacifastacus leniusculus differed.•Two new indices of movement consistency revealed a large interindividual variation.•P. clarkii showed a preference for pool areas with riparian vegetation cover.•P. leniusculus preferred riffle and pool areas with riparian vegetation cover.
Red swamp crayfish (Procambarus clarkii) and signal crayfish (Pacifastacus leniusculus) are two invasive freshwater species with a worldwide distribution. The objective of this work was to investigate how the two species move and use space in an area of recent coexistence. Simultaneously, we test the use of new tools and indices to describe their movement patterns. To accomplish this we performed a radio-tracking program within a river-type habitat during two different periods (September/October 2010 and June/July 2013). We used spatial analysis tools to map crayfish radio-location data with and without accounting for the curvature of the river. To assess the consistency of the direction of movement and of the distances traveled by crayfish, two indices were developed. To assess the habitat preferences of each species we applied Ivlev's Electivity Index and the Standardized Forage Ratio. Movement of P. clarkii and P. leniusculus differed. The average detected movement was 8.8mday−1 for P. clarkii and 17.5mday−1 for P. leniusculus. However, crayfish behavior ranged from almost complete immobility – sometimes during several days – to large movements, in half a day, up to a maximum of 255m for P. clarkii and 461m for P. leniusculus. The proportion of upstream or downstream movements was independent of the species and both species displayed no preference for either direction. The indices of consistency of movement showed a large interindividual variation. Species and period (2010 or 2013) affected the mean daily distance traveled, maximum observed distance from location of release and percentage of observations under vegetation cover. The Ivlev's Electivity Index and the Standardized Forage Ratio presented similar results. P. clarkii showed a preference for pool areas with riparian vegetation cover while P. leniusculus preferred riffle and pool areas with riparian vegetation cover. Our work provided new and valuable data for modeling the active dispersal of these two problematic invaders in a context of coexistence.