Collision and Electrocution in Overhead Wires
Flying animals may collide or be electrocuted in the overhead wires that provide
electrical energy to trains—the catenary (SCV 1996). Thus, specific mitigation
measures should be taken whenever high levels of mortality are expected or
identified. These measures are similar to those used to prevent collision and electrocution in powerlines (Bevanger 1994; Barrientos et al. 2011). Additionally, the
tubular poles often used to support the overhead wires can cause death if uncapped,
especially among cavity nesting birds (Malo et al. 2016). The compulsory use of
capped poles can easily avoid this problem, since it prevents birds from falling
inside the poles.
Evaluating the Effectiveness of Mortality Mitigation
Measures
Along with adequate planning for railway corridors, which accounts for the
expected impacts on wildlife, another fundamental and final step to reduce the
negative effects of railways is a thorough evaluation of the effectiveness of the
mitigation measures (Grilo et al. 2010; Glista et al. 2009; van der Grift et al. 2013).
Poor mitigation measures, which do little to reduce wildlife mortality, represent a
waste of valuable resources. Moreover, some structures may reduce animal
movement, disrupt landscape connectivity, or have negative implications for erosion and grazing.
Guidelines for evaluating the effectiveness of road mitigation measures have
been proposed for roads (van der Grift et al. 2013; Rytwinski et al. 2015; van der
Grift and van der Ree 2015), but since no similar research has been done specifically for railways, one can consider the guidelines for roads as a starting point.
Step 1 Identify the species requiring mitigation measures and determine the
specific goals for them.
Step 2 Select the species (from the targeted species list) that will be used for
evaluation.
Step 3 Select the best measures of interest, i.e., those that are most closely related
to the aim of the mitigation (e.g., casualty rate, number of crossings,
population trend).
Step 4 Select the adequate study design, including a spatial and temporal
sampling strategy. Whenever possible, the best study design is a replicated
BACI at mitigation sites (where measures were taken) and control sites
(with similar characteristics but where no mitigation measures were
applied).
Step 5 Determine the best sampling scheme, including the number of sites, the
frequency of visits, the monitoring methods, and the number of replicates.
3 Methods to Monitor and Mitigate Wildlife Mortality in Railways
37
Flying animals may collide or be electrocuted in the overhead wires that provide
electrical energy to trains—the catenary (SCV 1996). Thus, specific mitigation
measures should be taken whenever high levels of mortality are expected or
identified. These measures are similar to those used to prevent collision and electrocution in powerlines (Bevanger 1994; Barrientos et al. 2011). Additionally, the
tubular poles often used to support the overhead wires can cause death if uncapped,
especially among cavity nesting birds (Malo et al. 2016). The compulsory use of
capped poles can easily avoid this problem, since it prevents birds from falling
inside the poles.
Evaluating the Effectiveness of Mortality Mitigation
Measures
Along with adequate planning for railway corridors, which accounts for the
expected impacts on wildlife, another fundamental and final step to reduce the
negative effects of railways is a thorough evaluation of the effectiveness of the
mitigation measures (Grilo et al. 2010; Glista et al. 2009; van der Grift et al. 2013).
Poor mitigation measures, which do little to reduce wildlife mortality, represent a
waste of valuable resources. Moreover, some structures may reduce animal
movement, disrupt landscape connectivity, or have negative implications for erosion and grazing.
Guidelines for evaluating the effectiveness of road mitigation measures have
been proposed for roads (van der Grift et al. 2013; Rytwinski et al. 2015; van der
Grift and van der Ree 2015), but since no similar research has been done specifically for railways, one can consider the guidelines for roads as a starting point.
Step 1 Identify the species requiring mitigation measures and determine the
specific goals for them.
Step 2 Select the species (from the targeted species list) that will be used for
evaluation.
Step 3 Select the best measures of interest, i.e., those that are most closely related
to the aim of the mitigation (e.g., casualty rate, number of crossings,
population trend).
Step 4 Select the adequate study design, including a spatial and temporal
sampling strategy. Whenever possible, the best study design is a replicated
BACI at mitigation sites (where measures were taken) and control sites
(with similar characteristics but where no mitigation measures were
applied).
Step 5 Determine the best sampling scheme, including the number of sites, the
frequency of visits, the monitoring methods, and the number of replicates.
3 Methods to Monitor and Mitigate Wildlife Mortality in Railways
37