Modelling connectivity at a regional scale during seasonal movements of the greater horseshoe bat

Connectivity modelling is a powerful tool for strengthening the link
between landscape and species conservation. This approach often relies on
expert knowledge of connectivity indicators or limited, small numbers and
small-scale monitoring data, for example during animal foraging
activities. However, integrating larger-scale movement data, including
dispersal or seasonal movements, is crucial to making conservation
relevant by covering the entire life cycle of species. Using Resource
Selection Function, the movement patterns of greater horseshoe bats (GHB)
studied on a local scale were transposed to a regional scale to model the
connectivity in western France. GHB is highly sensitive to loss of
connectivity and makes seasonal regional migrations. How the local
landscape heterogeneity influenced the conductance parameters estimation
for modelling was examined using gap-crossing method at four different
sites with variable landscape composition. The inferred parameters were
used to create a regional connectivity map based on circuit theory. To
validate this map, acoustic monitoring was conducted during the autumn
migration to assess its effectiveness in identifying connectivity
gradients. Finally, the resulting connectivity map was superimposed on the
Natura 2000 network. Firstly, it can be assumed that connectivity
parameters are identical whatever the landscape context. Secondly, the
regional connectivity model identified the main potential corridors
connecting all the major sites in the region. Finally, based on acoustic
sampling, the number of GHB in transit was significantly higher in areas
of higher connectivity. In terms of overlap with conservation, the
functional connectivity of the GHB have been variously addressed in the
current Natura 2000 network, with an overall lack of representativeness.
Studying pathways during high mobility periods is one of the main missing
elements for effective conservation, particularly for small species such
as bats. An acoustic, stratified sampling at both local and large scale
provided sufficient spatial and temporal accuracy to model connectivity
throughout the life cycle of bats. This framework can easily be applied to
other bat species to improve our understanding of connectivity, in order
to explicitly integrate this crucial aspect for highly mobile species into
the protection network.