A spatio-temporal contrast of the predatory impact of an invasive freshwater crustacean

Josephine C. Iacarella*, Jaimie T. A. Dick, Anthony Ricciardi

*Corresponding author for this work

Research output: Contribution to journalArticle

18 Citations (Scopus)

Abstract

Aim: Impacts of invasive species may vary across invasion gradients, owing to trait-based sorting of individuals through dispersal: those aggregating at invasion fronts may be more aggressive and voracious. We examine, in the field and laboratory, variation in the predatory impacts of an invasive Ponto-Caspian crustacean Hemimysis anomala G.O. Sars, 1907 at two sites along a spatio-temporal gradient of invasion.

Location: Republic of Ireland.

Methods: We used reciprocal transplant field-deployed mesocosms to compare predation rates of invasion front and well-established H. anomala on natural zooplankton assemblages. In the laboratory, we measured the functional response (relationship between predation rate and prey supply) of H. anomala from both sites, for a per capita mechanistic comparison of predation efficiency. We also assessed prey selectivity of H. anomala in the mesocosm experiments to further compare feeding behaviour. Finally, we used a correlative approach to assess the community impact of H. anomala across sites, including a nearby uninvaded site, by comparing zooplankton diversities and densities.

Results: Invasion front H. anomala had higher predation rates than well-established H. anomala at high in situ zooplankton densities. Invasion front H. anomala also had higher functional responses - in particular showing higher 'attack rates' - indicating a heightened ability to locate and capture prey. Prey selectivity was consistent across the spatio-temporal contrast, with positive selection for cladocerans. Zooplankton diversity and density declined with time since H. anomala invasion, both being maximal at the uninvaded site.

Main conclusions: Our study, for the first time, (1) reveals differences in predatory per capita effects and associated behavioural traits between two sites along a spatio-temporal invasion gradient and (2) shows a negative community-level impact of the invasive H. anomala in natural water bodies. Further spatio-temporal comparisons of predatory per capita effects of invaders are needed to assess the generality of these results.

Original languageEnglish
Pages (from-to)803-812
Number of pages10
JournalDiversity and Distributions
Volume21
Issue number7
Early online date16 Feb 2015
DOIs
Publication statusPublished - Jul 2015

Keywords

  • Functional response
  • impact
  • invasion front
  • invasive species
  • per capita effect
  • zooplankton
  • PONTO-CASPIAN INVADER
  • FUNCTIONAL-RESPONSES
  • HEMIMYSIS-ANOMALA
  • ECOLOGICAL IMPACTS
  • RANGE EXPANSION
  • NEOGOBIUS-MELANOSTOMUS
  • BEHAVIORAL FLEXIBILITY
  • PERSONALITY-TRAITS
  • ROUND GOBY
  • CANE TOADS

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