Climate and habitat configuration limit range expansion and patterns of
dispersal in a non-native lizard
Abstract
ABSTRACT Aim Invasive species are one of the main causes of biodiversity
loss world-wide. As introduced populations increase in abundance and
geographical range, so does the potential for negative impacts on native
communities. As such, there is a need to better understand the processes
driving range expansion as species become established in recipient
landscapes. We investigated the potential for population growth and
range expansion of introduced populations of a non-native lizard
(Podarcis muralis), considering multi-scale factors
influencing growth and spatial spread. Location England, UK Methods We
collated records of P. muralis presence through field surveys and
a citizen science campaign. We used presence-only models to predict
climate suitability at a national scale (5km resolution), and fine-scale
habitat suitability at the local scale (2m resolution). We then
integrated local models into an individual-based modelling platform to
simulate population dynamics and forecast range expansion for 10
populations in heterogeneous landscapes. Results National-scale models
indicated climate suitability restricted to the southern parts of the
UK, limited by a latitudinal cline in overwintering conditions. Patterns
of population growth and range expansion were related to differences in
local landscape configuration and heterogeneity. Growth curves suggest
populations could be in the early stages of exponential growth. However,
annual rates of range expansion are predicted to be low (5-16 m).
Conclusions We conclude that extensive nationwide range expansion
through secondary introduction is likely to be restricted by currently
unsuitable climate beyond southern regions of the UK. However,
exponential growth of local populations in habitats providing transport
pathways is likely to increase opportunities for regional expansion. The
broad habitat niche of P. muralis, coupled with configuration of
habitat patches in the landscape, allows populations to increase locally
with minimal dispersal.