TY - JOUR
KW - climate change
KW - conservation
KW - Lepidoptera
KW - modelling
KW - range changes
AU - Bell Fiona
AU - Botham Marc
AU - Brereton Tom M.
AU - Fenton Andy
AU - Hodgson Jenny
AB - Abstract Aim Climate change has been predicted to facilitate poleward expansion of many early-successional specialist invertebrates. The Grizzled Skipper, Pyrgus malvae, is a threatened butterfly in long-term decline that has not met expectations of northern expansion in Britain, possibly indicating that climate change has not improved northern habitat suitability or that another driver (e.g. land use change) is masking its effects. Here, we explore the effect of climate on population size trends over four decades, and whether any regions show an improving population trend that may be a precursor to northern expansion. Examining detailed spatio-temporal abundance data can reveal unexpected limitations to population growth that would not be detectable in widely used climate envelope models. Location Central and southern England. Methods Mixed models were used to investigate P. malvae population size in relation to time and monthly climate measures across its UK range since 1976, based on repeated transect walks. Results We found that P. malvae population size declined more over time in the north and west of its UK range than in the south and east, and was negatively related to high December temperature and summer rainfall. However, the effect sizes of temperature and rainfall were minimal. Main Conclusions The last 40 years of climate change have not ameliorated climate suitability for P. malvae at its range edge, contrary to expectations from spatial-only climate envelope models. The clear long-term downward trends in population size are independent of climate change and we propose probably due to habitat deterioration. Our findings highlight potential hazards in predicting species range expansions from spatial models alone. Although some climate variables may be associated with a species? distribution, other factors may be more dominant drivers of trends and therefore more useful predictors of range changes.
BT - Diversity and Distributions
DA - 2021/06/01
DO - https://doi.org/10.1111/ddi.13245
IS - 6
M3 - https://doi.org/10.1111/ddi.13245
N1 - https://doi.org/10.1111/ddi.13245
N2 - Abstract Aim Climate change has been predicted to facilitate poleward expansion of many early-successional specialist invertebrates. The Grizzled Skipper, Pyrgus malvae, is a threatened butterfly in long-term decline that has not met expectations of northern expansion in Britain, possibly indicating that climate change has not improved northern habitat suitability or that another driver (e.g. land use change) is masking its effects. Here, we explore the effect of climate on population size trends over four decades, and whether any regions show an improving population trend that may be a precursor to northern expansion. Examining detailed spatio-temporal abundance data can reveal unexpected limitations to population growth that would not be detectable in widely used climate envelope models. Location Central and southern England. Methods Mixed models were used to investigate P. malvae population size in relation to time and monthly climate measures across its UK range since 1976, based on repeated transect walks. Results We found that P. malvae population size declined more over time in the north and west of its UK range than in the south and east, and was negatively related to high December temperature and summer rainfall. However, the effect sizes of temperature and rainfall were minimal. Main Conclusions The last 40 years of climate change have not ameliorated climate suitability for P. malvae at its range edge, contrary to expectations from spatial-only climate envelope models. The clear long-term downward trends in population size are independent of climate change and we propose probably due to habitat deterioration. Our findings highlight potential hazards in predicting species range expansions from spatial models alone. Although some climate variables may be associated with a species? distribution, other factors may be more dominant drivers of trends and therefore more useful predictors of range changes.
PB - John Wiley & Sons, Ltd
PY - 2021
SN - 1366-9516
SP - 962
EP - 972
EP - 
T2 - Diversity and Distributions
TI - Grizzled Skippers stuck in the south: Population-level responses of an early-successional specialist butterfly to climate across its UK range over 40 years
UR - https://doi.org/10.1111/ddi.13245
VL - 27
Y2 - 2022/05/06
ER -