impacts of new projected linear infrastructures must always be assessed. Thus,
measures should be taken before construction starts, and then during the construction phases to mitigate those impacts on wild species present: this includes
paying attention to fences (adequate mesh size, buried, and without holes), fauna
passes, and, mainly because of amphibians, the preservation of existing ponds (Iuell
et al. 2003). Usually, a monitoring plan must follow four important steps: (1) the
choice of the target species; (2) the selection of the spatio-temporal scale of the
study; (3) the selection of methods to estimate mortality; and (4) the standardization
of the variables influencing wildlife mortality, so that they are easily replicable and
comparable (Roedenbeck et al. 2007; van der Grift et al. 2013). To achieve these
goals, the co-operation between railway company workers, stakeholders and
wildlife researchers at all stages of the monitoring plan (Iuell et al. 2003;
Roedenbeck et al. 2007).
Selecting the Target Species
The selection of the species to be monitored depends on their traits (e.g., vagility,
conservation status, or sensitivity to fragmentation), on features of the landscape
crossed by the railway, and on the characteristics of the railway. For instance, if the
railway has overhead electric lines and pylons special care should be taken with
birds and bat species (Peña and Llama 1997; Rose and Baillie 1989; SCV 1996); if
there is a risk of entrapment inside the rail lines, low vagile reptiles (e.g., turtles)
and amphibians (e.g., toads) must be prioritized (Kornilev et al. 2006; Pelletier et al.
2006).
Species that show strong responses toward linear infrastructures and traffic flow,
such as carnivores and ungulates, are often selected as target species. These animals
are good models for evaluating the factors influencing mortality, because they have
large individual territories and large daily and seasonal movements that increase the
probability of crossing and of being hit by a train (Iuell et al. 2003; van der grift
et al. 2013). Some habitat specialists, like forest-dwelling ones (e.g., the tawny owl
Strix aluco), should also be considered in this group as they often use specific
corridors that cross railways, thus increasing their risk of collision.
Relying on larger species (or species with high visibility) may increase the
detection probability because recording wildlife mortality on railways is often
harder than on roads, as railways have lower accessibility, narrower corridors, lack
of lateral dirt roads, and a highly variable topographic profile (Dorsey 2011; Wells
et al. 1999). In addition, choosing abundant species will likely increase sample
sizes, and thus the power of the analyses and some species might serve as a proxy
for rarer ones that allows obtaining crucial data that otherwise will be not possible
(e.g., Roedenbeck et al. 2007).
3 Methods to Monitor and Mitigate Wildlife Mortality in Railways
25
measures should be taken before construction starts, and then during the construction phases to mitigate those impacts on wild species present: this includes
paying attention to fences (adequate mesh size, buried, and without holes), fauna
passes, and, mainly because of amphibians, the preservation of existing ponds (Iuell
et al. 2003). Usually, a monitoring plan must follow four important steps: (1) the
choice of the target species; (2) the selection of the spatio-temporal scale of the
study; (3) the selection of methods to estimate mortality; and (4) the standardization
of the variables influencing wildlife mortality, so that they are easily replicable and
comparable (Roedenbeck et al. 2007; van der Grift et al. 2013). To achieve these
goals, the co-operation between railway company workers, stakeholders and
wildlife researchers at all stages of the monitoring plan (Iuell et al. 2003;
Roedenbeck et al. 2007).
Selecting the Target Species
The selection of the species to be monitored depends on their traits (e.g., vagility,
conservation status, or sensitivity to fragmentation), on features of the landscape
crossed by the railway, and on the characteristics of the railway. For instance, if the
railway has overhead electric lines and pylons special care should be taken with
birds and bat species (Peña and Llama 1997; Rose and Baillie 1989; SCV 1996); if
there is a risk of entrapment inside the rail lines, low vagile reptiles (e.g., turtles)
and amphibians (e.g., toads) must be prioritized (Kornilev et al. 2006; Pelletier et al.
2006).
Species that show strong responses toward linear infrastructures and traffic flow,
such as carnivores and ungulates, are often selected as target species. These animals
are good models for evaluating the factors influencing mortality, because they have
large individual territories and large daily and seasonal movements that increase the
probability of crossing and of being hit by a train (Iuell et al. 2003; van der grift
et al. 2013). Some habitat specialists, like forest-dwelling ones (e.g., the tawny owl
Strix aluco), should also be considered in this group as they often use specific
corridors that cross railways, thus increasing their risk of collision.
Relying on larger species (or species with high visibility) may increase the
detection probability because recording wildlife mortality on railways is often
harder than on roads, as railways have lower accessibility, narrower corridors, lack
of lateral dirt roads, and a highly variable topographic profile (Dorsey 2011; Wells
et al. 1999). In addition, choosing abundant species will likely increase sample
sizes, and thus the power of the analyses and some species might serve as a proxy
for rarer ones that allows obtaining crucial data that otherwise will be not possible
(e.g., Roedenbeck et al. 2007).
3 Methods to Monitor and Mitigate Wildlife Mortality in Railways
25