European red squirrel population dynamics driven by squirrelpox at a gray squirrel invasion interface

Infectious disease introduced by non-native species is increasingly cited as a facilitator of native population declines, but direct evidence may be lacking due to inadequate population and disease prevalence data surrounding an outbreak. Previous indirect evidence and theoretical models support squ...

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Main Authors:	Chantrey, Julian, Dale, Timothy D, Read, Jonathan M, White, Steve, Whitfield, Fiona, Jones, David, McInnes, Colin J, Begon, Michael
Format:	Online
Language:	English
Published:	BlackWell Publishing Ltd 2014
Online Access:	https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4301051/

id	pubmed-4301051
recordtype	oai_dc
spelling	pubmed-43010512015-01-22 European red squirrel population dynamics driven by squirrelpox at a gray squirrel invasion interface Chantrey, Julian Dale, Timothy D Read, Jonathan M White, Steve Whitfield, Fiona Jones, David McInnes, Colin J Begon, Michael Original Research Infectious disease introduced by non-native species is increasingly cited as a facilitator of native population declines, but direct evidence may be lacking due to inadequate population and disease prevalence data surrounding an outbreak. Previous indirect evidence and theoretical models support squirrelpox virus (SQPV) as being potentially involved in the decline of red squirrels (Sciurus vulgaris) following the introduction of the non-native gray squirrel (Sciurus carolinensis) to the United Kingdom. The red squirrel is a major UK conservation concern and understanding its continuing decline is important for any attempt to mitigate the decline. The red squirrel–gray squirrel system is also exemplary of the interplay between infectious disease (apparent competition) and direct competition in driving the replacement of a native by an invasive species. Time series data from Merseyside are presented on squirrel abundance and squirrelpox disease (SQPx) incidence, to determine the effect of the pathogen and the non-native species on the native red squirrel populations. Analysis indicates that SQPx in red squirrels has a significant negative impact on squirrel densities and their population growth rate (PGR). There is little evidence for a direct gray squirrel impact; only gray squirrel presence (but not density) proved to influence red squirrel density, but not red squirrel PGR. The dynamics of red SQPx cases are largely determined by previous red SQPx cases, although previous infection of local gray squirrels also feature, and thus, SQPV-infected gray squirrels are identified as potentially initiating outbreaks of SQPx in red squirrels. Retrospective serology indicates that approximately 8% of red squirrels exposed to SQPV may survive infection during an epidemic. This study further highlights the UK red squirrel – gray squirrel system as a classic example of a native species population decline strongly facilitated by infectious disease introduced by a non-native species. It is therefore paramount that disease prevention and control measures are integral in attempts to conserve red squirrels in the United Kingdom. BlackWell Publishing Ltd 2014-10 2014-09-11 /pmc/articles/PMC4301051/ /pubmed/25614793 http://dx.doi.org/10.1002/ece3.1216 Text en © 2014 The Authors. Ecology and Evolution published by John Wiley & Sons Ltd. http://creativecommons.org/licenses/by/3.0/ This is an open access article under the terms of the Creative Commons Attribution License, which permits use, distribution and reproduction in any medium, provided the original work is properly cited.
repository_type	Open Access Journal
institution_category	Foreign Institution
institution	US National Center for Biotechnology Information
building	NCBI PubMed
collection	Online Access
language	English
format	Online
author	Chantrey, Julian Dale, Timothy D Read, Jonathan M White, Steve Whitfield, Fiona Jones, David McInnes, Colin J Begon, Michael
spellingShingle	Chantrey, Julian Dale, Timothy D Read, Jonathan M White, Steve Whitfield, Fiona Jones, David McInnes, Colin J Begon, Michael European red squirrel population dynamics driven by squirrelpox at a gray squirrel invasion interface
author_facet	Chantrey, Julian Dale, Timothy D Read, Jonathan M White, Steve Whitfield, Fiona Jones, David McInnes, Colin J Begon, Michael
author_sort	Chantrey, Julian
title	European red squirrel population dynamics driven by squirrelpox at a gray squirrel invasion interface
title_short	European red squirrel population dynamics driven by squirrelpox at a gray squirrel invasion interface
title_full	European red squirrel population dynamics driven by squirrelpox at a gray squirrel invasion interface
title_fullStr	European red squirrel population dynamics driven by squirrelpox at a gray squirrel invasion interface
title_full_unstemmed	European red squirrel population dynamics driven by squirrelpox at a gray squirrel invasion interface
title_sort	european red squirrel population dynamics driven by squirrelpox at a gray squirrel invasion interface
description	Infectious disease introduced by non-native species is increasingly cited as a facilitator of native population declines, but direct evidence may be lacking due to inadequate population and disease prevalence data surrounding an outbreak. Previous indirect evidence and theoretical models support squirrelpox virus (SQPV) as being potentially involved in the decline of red squirrels (Sciurus vulgaris) following the introduction of the non-native gray squirrel (Sciurus carolinensis) to the United Kingdom. The red squirrel is a major UK conservation concern and understanding its continuing decline is important for any attempt to mitigate the decline. The red squirrel–gray squirrel system is also exemplary of the interplay between infectious disease (apparent competition) and direct competition in driving the replacement of a native by an invasive species. Time series data from Merseyside are presented on squirrel abundance and squirrelpox disease (SQPx) incidence, to determine the effect of the pathogen and the non-native species on the native red squirrel populations. Analysis indicates that SQPx in red squirrels has a significant negative impact on squirrel densities and their population growth rate (PGR). There is little evidence for a direct gray squirrel impact; only gray squirrel presence (but not density) proved to influence red squirrel density, but not red squirrel PGR. The dynamics of red SQPx cases are largely determined by previous red SQPx cases, although previous infection of local gray squirrels also feature, and thus, SQPV-infected gray squirrels are identified as potentially initiating outbreaks of SQPx in red squirrels. Retrospective serology indicates that approximately 8% of red squirrels exposed to SQPV may survive infection during an epidemic. This study further highlights the UK red squirrel – gray squirrel system as a classic example of a native species population decline strongly facilitated by infectious disease introduced by a non-native species. It is therefore paramount that disease prevention and control measures are integral in attempts to conserve red squirrels in the United Kingdom.
publisher	BlackWell Publishing Ltd
publishDate	2014
url	https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4301051/
_version_	1613178853212028928

European red squirrel population dynamics driven by squirrelpox at a gray squirrel invasion interface

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