railways. We thus decided to examine the role of railway verges as a habitat for two
groups: common bats and Tettigoniidae (Orthoptera) (Vandevelde et al. 2014;
Penone et al. 2013).
Bats Along Railway Verges in an Intensive Agricultural Landscape
Studies have shown that bat activity and species richness decrease when
approaching a motorway (Berthinussen and Altringham 2012). Some studies
stressed particular negative effects, such as road casualties (Lesinski et al. 2011).
Others found that roads formed strong barriers to the movements of bats within the
landscape (Bach et al. 2004; Kerth and Melber 2009; Abbott et al. 2012).
Yet, very few studies have focused on the potential positive effects of linear
infrastructures such as railway verges on bats. Some bat species fly along such
features when commuting from roosts to foraging areas because these linear elements could constitute commuting paths away from predators and wind (Limpens
and Kapteyn 1991). In addition, some species forage regularly along linear elements (Verboom and Huitema 1997). Indeed, foraging activity is facilitated close to
these features because of greater abundance of some preys (Verboom and Spoelstra
1999). These contrasting behaviours among species may be linked to their specific
foraging ecology (Kerth and Melber 2009).
We hypothesized that railway verges impacted negatively some species, particularly gleaner species generally linked with forest habitat (such as species from
the Myotis genus). These species could perceive railway verges as an inadequate
habitat and in addition could be impacted by the fragmentation effect of these
verges. Conversely, aerial hawking species that generally forage in more open
habitats, such as species of the genus Pipistrellus, Nyctalus or Eptesicus, could
benefit from the edge effect of railway verges, using them as a foraging/commuting
habitat (Vandevelde et al. 2014).
To test this hypothesis, we examined the potential use by bats of railway verges
crossing woodland patches within an agricultural matrix as foraging/commuting
habitats. We tested whether (i) at a large scale (national level), railways lines were
globally a preferred foraging/commuting habitat for these different common bats
species, and (ii) at a local scale (landscape level), woodland-railway verges had an
effect on bat activity compared to other habitat types like woodland-field verges,
woodland habitats and field habitats. At local scale, we also tested the influence of
landscape composition on bat activity over habitat types (Vandevelde et al. 2014).
We identified ten similar sites via aerial photographs and field visits: each site
consisted of a railway portion of 600 m to 2 km long fragmenting a woodland patch
within a farmland matrix. We used two distinct sets of data for bat calls.
‘Local-scale’ data from railway sites were sampled in the summer of 2010 following a similar protocol to the one designed for the French Bat Monitoring
Programme (named Vigie-Chiro), from which we used ‘large-scale’ (national) data
collected from 2006 to 2011. For both local- and large-scale data sets, bat calls were
detected. Each point was monitored twice: once in the period between June 15 and
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J.-C. Vandevelde and C. Penone
groups: common bats and Tettigoniidae (Orthoptera) (Vandevelde et al. 2014;
Penone et al. 2013).
Bats Along Railway Verges in an Intensive Agricultural Landscape
Studies have shown that bat activity and species richness decrease when
approaching a motorway (Berthinussen and Altringham 2012). Some studies
stressed particular negative effects, such as road casualties (Lesinski et al. 2011).
Others found that roads formed strong barriers to the movements of bats within the
landscape (Bach et al. 2004; Kerth and Melber 2009; Abbott et al. 2012).
Yet, very few studies have focused on the potential positive effects of linear
infrastructures such as railway verges on bats. Some bat species fly along such
features when commuting from roosts to foraging areas because these linear elements could constitute commuting paths away from predators and wind (Limpens
and Kapteyn 1991). In addition, some species forage regularly along linear elements (Verboom and Huitema 1997). Indeed, foraging activity is facilitated close to
these features because of greater abundance of some preys (Verboom and Spoelstra
1999). These contrasting behaviours among species may be linked to their specific
foraging ecology (Kerth and Melber 2009).
We hypothesized that railway verges impacted negatively some species, particularly gleaner species generally linked with forest habitat (such as species from
the Myotis genus). These species could perceive railway verges as an inadequate
habitat and in addition could be impacted by the fragmentation effect of these
verges. Conversely, aerial hawking species that generally forage in more open
habitats, such as species of the genus Pipistrellus, Nyctalus or Eptesicus, could
benefit from the edge effect of railway verges, using them as a foraging/commuting
habitat (Vandevelde et al. 2014).
To test this hypothesis, we examined the potential use by bats of railway verges
crossing woodland patches within an agricultural matrix as foraging/commuting
habitats. We tested whether (i) at a large scale (national level), railways lines were
globally a preferred foraging/commuting habitat for these different common bats
species, and (ii) at a local scale (landscape level), woodland-railway verges had an
effect on bat activity compared to other habitat types like woodland-field verges,
woodland habitats and field habitats. At local scale, we also tested the influence of
landscape composition on bat activity over habitat types (Vandevelde et al. 2014).
We identified ten similar sites via aerial photographs and field visits: each site
consisted of a railway portion of 600 m to 2 km long fragmenting a woodland patch
within a farmland matrix. We used two distinct sets of data for bat calls.
‘Local-scale’ data from railway sites were sampled in the summer of 2010 following a similar protocol to the one designed for the French Bat Monitoring
Programme (named Vigie-Chiro), from which we used ‘large-scale’ (national) data
collected from 2006 to 2011. For both local- and large-scale data sets, bat calls were
detected. Each point was monitored twice: once in the period between June 15 and
264
J.-C. Vandevelde and C. Penone