Orthoptera Along Railway Verges in an Urban Landscape
Railway verges could potentially provide a habitat for Orthoptera in an urban
landscape because the majority of these insects in Europe are grassland species and
some occur at roadsides (Theuerkauf and Rouys 2006). We thus studied
Tettigonidae along railway verges in urban landscapes using an original method.
Because Orthoptera produce mating calls that are species-specific, it is possible to
collect large standardised datasets using sound recording devices. To sample a large
number of landscapes, we thus recorded Orthoptera sounds from running trains
along five long-established railway lines in the Paris region (Penone et al. 2013).
We did not sample the entire community of singing Orthoptera but rather focused
on insects that produced powerful stridulations, which were not masked by the
noise produced by trains.
We detected 2003 individuals of 10 species of bush-crickets from the
Tettigoniidae family along 209 km of railway verges (Penone et al. 2013). This
represented 59% of Tettigoniidae species known to exist in the region (Voisin
2003) and included specialist species (e.g. Conocephalus fuscus). These results
suggest that railway verges play a habitat role for these arthropods even for specialist species that are more heavily affected by anthropogenic changes. This was
further strengthened by the fact that Orthoptera abundance was significantly lower
when the trains crossed areas with paved (non vegetated) railway verges (Penone
et al. 2013). We also detected a significant negative effect of urbanisation on species
richness, abundance and community specialization, over a broad set of spatial
scales (Penone et al. 2013). This effect was partly mitigated when railway verges
were vegetated, suggesting that these zones are not only habitats but could even act
as refugia for Orthoptera in an urban landscape. Therefore, if extensively managed
(Marini et al. 2008), railway verges could play a role in the conservation of biodiversity in urban areas. More generally, we believe that acoustic surveys are a
simple and cost-effective method, allowing long-term and large-scale surveys that
can help advance railway ecology studies.
Railways as Corridors in an Urban Landscape (Longitudinal
Connectivity)
Habitat fragmentation is a major perturbation that affects biodiversity at local,
regional and global scales (Fahrig 2003; Krauss et al. 2010). Fragmentation has
effects not only at the population level but also on taxonomic and functional
composition of communities and on species interactions (Fahrig 2003; Fischer and
Lindenmayer 2007; Krauss et al. 2010). Fragmented landscapes, including urban
ones, are characterised by small habitat patches isolated by a matrix that filters
species according to their mobility and dispersal abilities (Ewers and Didham 2006;
Ricketts 2001). In this context, functional connectivity is crucial to maintain
266
J.-C. Vandevelde and C. Penone
Railway verges could potentially provide a habitat for Orthoptera in an urban
landscape because the majority of these insects in Europe are grassland species and
some occur at roadsides (Theuerkauf and Rouys 2006). We thus studied
Tettigonidae along railway verges in urban landscapes using an original method.
Because Orthoptera produce mating calls that are species-specific, it is possible to
collect large standardised datasets using sound recording devices. To sample a large
number of landscapes, we thus recorded Orthoptera sounds from running trains
along five long-established railway lines in the Paris region (Penone et al. 2013).
We did not sample the entire community of singing Orthoptera but rather focused
on insects that produced powerful stridulations, which were not masked by the
noise produced by trains.
We detected 2003 individuals of 10 species of bush-crickets from the
Tettigoniidae family along 209 km of railway verges (Penone et al. 2013). This
represented 59% of Tettigoniidae species known to exist in the region (Voisin
2003) and included specialist species (e.g. Conocephalus fuscus). These results
suggest that railway verges play a habitat role for these arthropods even for specialist species that are more heavily affected by anthropogenic changes. This was
further strengthened by the fact that Orthoptera abundance was significantly lower
when the trains crossed areas with paved (non vegetated) railway verges (Penone
et al. 2013). We also detected a significant negative effect of urbanisation on species
richness, abundance and community specialization, over a broad set of spatial
scales (Penone et al. 2013). This effect was partly mitigated when railway verges
were vegetated, suggesting that these zones are not only habitats but could even act
as refugia for Orthoptera in an urban landscape. Therefore, if extensively managed
(Marini et al. 2008), railway verges could play a role in the conservation of biodiversity in urban areas. More generally, we believe that acoustic surveys are a
simple and cost-effective method, allowing long-term and large-scale surveys that
can help advance railway ecology studies.
Railways as Corridors in an Urban Landscape (Longitudinal
Connectivity)
Habitat fragmentation is a major perturbation that affects biodiversity at local,
regional and global scales (Fahrig 2003; Krauss et al. 2010). Fragmentation has
effects not only at the population level but also on taxonomic and functional
composition of communities and on species interactions (Fahrig 2003; Fischer and
Lindenmayer 2007; Krauss et al. 2010). Fragmented landscapes, including urban
ones, are characterised by small habitat patches isolated by a matrix that filters
species according to their mobility and dispersal abilities (Ewers and Didham 2006;
Ricketts 2001). In this context, functional connectivity is crucial to maintain
266
J.-C. Vandevelde and C. Penone