TY - JOUR

T1 - Dietary niche constriction when invaders meet natives

T2 - evidence from freshwater decapods

AU - Jackson, Michelle C.

AU - Grey, Jonathan

AU - Miller, Katie

AU - Britton, J. Robert

AU - Donohue, Ian

N1 - This is the peer reviewed version of the following article: Jackson, M. C., Grey, J., Miller, K., Britton, J. R. and Donohue, I. (2016), Dietary niche constriction when invaders meet natives: evidence from freshwater decapods. J Anim Ecol, 85: 1098–1107. doi:10.1111/1365-2656.12533 which has been published in final form at http://onlinelibrary.wiley.com/doi/10.1111/1365-2656.12533/abstract This article may be used for non-commercial purposes in accordance With Wiley Terms and Conditions for self-archiving.

PY - 2016/6

Y1 - 2016/6

N2 - SummaryInvasive species are a key driver of global environmental change, with frequently strong negative consequences for native biodiversity and ecosystem processes. Understanding competitive interactions between invaders and functionally similar native species provides an important benchmark for predicting the consequences of invasion. However, even though having a broad dietary niche is widely considered a key factor determining invasion success, little is known about the effects of competition with functionally similar native competitors on the dietary niche breadths of invasive species.We used a combination of field experiments and field surveys to examine the impacts of competition with a functionally similar native crab species on the population densities, growth rates and diet of the globally widespread invasive red swamp crayfish in an African river ecosystem.The presence of native crabs triggered significant dietary niche constriction within the invasive crayfish population. Further, growth rates of both species were reduced significantly, and by a similar extent, in the presence of one another. In spite of this, crayfish maintained positive growth rates in the presence of crabs, whereas crabs lost mass in the presence of crayfish. Consequently, over the 3-year duration of the study, crab abundance declined at those sites invaded by the crayfish, becoming locally extinct at one.The invasive crayfish had a dramatic effect on ecosystem structure and functioning, halving benthic invertebrate densities and increasing decomposition rates fourfold compared to the crabs. This indicates that replacement of native crabs by invasive crayfish likely alters the structure and functioning of African river ecosystems significantly.This study provides a novel example of the constriction of the dietary niche of a successful invasive population in the presence of competition from a functionally similar native species. This finding highlights the importance of considering both environmental and ecological contexts in order to predict and manage the impacts of invasive species on ecosystems.

AB - SummaryInvasive species are a key driver of global environmental change, with frequently strong negative consequences for native biodiversity and ecosystem processes. Understanding competitive interactions between invaders and functionally similar native species provides an important benchmark for predicting the consequences of invasion. However, even though having a broad dietary niche is widely considered a key factor determining invasion success, little is known about the effects of competition with functionally similar native competitors on the dietary niche breadths of invasive species.We used a combination of field experiments and field surveys to examine the impacts of competition with a functionally similar native crab species on the population densities, growth rates and diet of the globally widespread invasive red swamp crayfish in an African river ecosystem.The presence of native crabs triggered significant dietary niche constriction within the invasive crayfish population. Further, growth rates of both species were reduced significantly, and by a similar extent, in the presence of one another. In spite of this, crayfish maintained positive growth rates in the presence of crabs, whereas crabs lost mass in the presence of crayfish. Consequently, over the 3-year duration of the study, crab abundance declined at those sites invaded by the crayfish, becoming locally extinct at one.The invasive crayfish had a dramatic effect on ecosystem structure and functioning, halving benthic invertebrate densities and increasing decomposition rates fourfold compared to the crabs. This indicates that replacement of native crabs by invasive crayfish likely alters the structure and functioning of African river ecosystems significantly.This study provides a novel example of the constriction of the dietary niche of a successful invasive population in the presence of competition from a functionally similar native species. This finding highlights the importance of considering both environmental and ecological contexts in order to predict and manage the impacts of invasive species on ecosystems.

KW - community structure

KW - diet breadth

KW - ecosystem functioning

KW - field experiment

KW - interspecific competition

KW - invasive species

KW - Procambarus clarkii

KW - stable isotopes

U2 - 10.1111/1365-2656.12533

DO - 10.1111/1365-2656.12533

M3 - Journal article

VL - 85

SP - 1098

EP - 1107

JO - Journal of Animal Ecology

JF - Journal of Animal Ecology

SN - 0021-8790

IS - 4

ER -