Temporal variability in lotic macroinvertebrate communities associated with invasive signal crayfish (Pacifastacus leniusculus) activity levels and substrate character

Kate L Mathers,Stephen P Rice,Paul J Wood

doi:10.1007/s10530-017-1557-3

Kate L Mathers, Stephen P Rice + Show 1 more

Open Access

https://doi.org/10.1007/s10530-017-1557-3

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Journal: Biological Invasions	Publication Date: Sep 7, 2017
Citations: 9	License type: open-access

Affiliation: Loughborough University

Abstract

Invasive signal crayfish (Pacifastacus leniusculus) are considered to be the most prevalent non-native crayfish species in Europe. Where large populations become established they have significant and long-term effects on benthic macroinvertebrate communities. However, much less is known about how community effects associated with crayfish invasion change in the short-term as a function of varying activity levels during the summer months. We examined the macroinvertebrate community composition of two lowland UK rivers, one which supported a well-established non-native crayfish population (invaded) and one in which crayfish had not been recorded (control). Colonisation cylinders were deployed which recorded community composition over a 126-day time period. Results indicate that once the activity period commences, invasive crayfish consistently altered macroinvertebrate community structure regardless of substrate character. Invaded communities displayed reduced beta-diversity compared to control sites. However, effects on the macroinvertebrate assemblage varied over the period when crayfish were active probably reflecting the behavioural activity of crayfish (which intensifies with increasing water temperature and during the spawning season) and life histories of other macroinvertebrates. The results indicate that crayfish invasions modify macroinvertebrate community composition, but over shorter timescales, the effects vary associated with their activity levels.

Highlights

Across the globe invasive species are spreading rapidly and represent one of the most significant threats to biodiversity, economic development and human health (Simberloff et al 2013; Early et al 2016)
The results indicate that crayfish invasions modify macroinvertebrate community composition, but over shorter timescales, the effects vary associated with their activity levels
A total of 69 taxa were recorded from the 169 colonisation cylinders; of these 57 were recorded in the invaded river and 54 in the control river

Summary

Introduction

Across the globe invasive species are spreading rapidly and represent one of the most significant threats to biodiversity, economic development and human health (Simberloff et al 2013; Early et al 2016). Crayfish are widely acknowledged to be keystone species and often dominate benthic biomass where they occur (Crandall and Buhay 2008). Their polytrophic feeding habits ensure that if they reach high population densities within invaded ecosystems, their effects are extensive and often resonate throughout the food web (Momot et al 1978; Guan and Wiles 1998). Only a few studies have considered the long term effect of signal crayfish on freshwater macroinvertebrate communities (see Wilson et al 2004; McCarthy et al 2006; Ruokonen et al 2016; Mathers et al 2016) and none have considered intra-annual temporal dynamics at shorter time scales (i.e. multiple months) once an invasive population has become established (i.e. associated with key life history characteristics and crayfish activity levels). Understanding and quantifying the extent of invader effects will continue to be constrained until studies are conducted that span the appropriate spatial and temporal scales (McCarthy et al 2006)

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