visit the railways to maintain the rails, electric components, or fences (Huijser et al.
2012), thus occasionally recording casualties but without a fixed periodicity
(Gundersen et al. 1998; Kušta et al. 2014; SCV 1996). Recently, to minimize bias
and identify hotspots properly, some studies have used reports of train drivers
obtained systematically, with information on both the species and location of the
accident (Dorsey 2011; Kušta et al. 2011, 2015). However, these studies are limited
to large species, those that impede train operations and are easily observed (e.g.,
Singh et al. 2001). Some studies have depended on inquiries to railway staff about
mortality data (Huijser et al. 2012), while others use anecdotal data from inhabitants, forest workers, naturalists, hunters, etc. (Singh et al. 2001).
• Surveys by sidewalks along the railways
Sidewalk surveys were mainly used in systematic studies by experienced technicians to detect mortality hotspots (Heske 2015; Peña and Llama 1997; Wells et al.
1999). Usually, these surveys aim to monitor and quantify all taxonomic groups
(from small to large animals) independently of the mortality source (train collisions,
entrapment in the track lines or electrocution) (Peña and Llama 1997; Wells et al.
1999).
• Surveys by video vigilance
In Alaska (USA), Rea et al. (2010) used movies from the YouTube video-sharing
website, made mainly by employees of train companies and some anonymous
people, to record the behavior of moose and other ungulates in the presence of
trains. The use of video vigilance devices attached to trains, or cameras set on
specific railway stretches, allowed continuous and clear recording of the animals’
behavior toward trains (Kinley et al. 2003; Babińska-Werka et al. 2015). Video
vigilance is particularly valuable in the winter in regions where snow cover and/or
steep embankments impede the use of other methods (Rea et al. 2010). However,
this method is expensive and thus has a limited observational range, and it cannot
capture the entire vertebrate community in the railway vicinity.
Standardization of Monitoring
Studies should have standardized survey methods across different geographic areas,
and combine several methods in order to reduce bias and contribute to better
estimates of mortality on railways (Iuell et al. 2003; van der Grift et al. 2013). For
instance, railway mortality should be presented as an index, reflecting the number
of casualties/km/year, and these results should include information on sampling
effort and periodicity (Peña and Llama 1997; SCV 1996). In order to achieve
consistency in the use of similar methods over temporal and spatial scales so that
comparisons can be made, cooperation is required, and specialized personnel
should be trained (Roedenbeck et al. 2007; Rytwinski et al. 2015).
28
F. Carvalho et al.
2012), thus occasionally recording casualties but without a fixed periodicity
(Gundersen et al. 1998; Kušta et al. 2014; SCV 1996). Recently, to minimize bias
and identify hotspots properly, some studies have used reports of train drivers
obtained systematically, with information on both the species and location of the
accident (Dorsey 2011; Kušta et al. 2011, 2015). However, these studies are limited
to large species, those that impede train operations and are easily observed (e.g.,
Singh et al. 2001). Some studies have depended on inquiries to railway staff about
mortality data (Huijser et al. 2012), while others use anecdotal data from inhabitants, forest workers, naturalists, hunters, etc. (Singh et al. 2001).
• Surveys by sidewalks along the railways
Sidewalk surveys were mainly used in systematic studies by experienced technicians to detect mortality hotspots (Heske 2015; Peña and Llama 1997; Wells et al.
1999). Usually, these surveys aim to monitor and quantify all taxonomic groups
(from small to large animals) independently of the mortality source (train collisions,
entrapment in the track lines or electrocution) (Peña and Llama 1997; Wells et al.
1999).
• Surveys by video vigilance
In Alaska (USA), Rea et al. (2010) used movies from the YouTube video-sharing
website, made mainly by employees of train companies and some anonymous
people, to record the behavior of moose and other ungulates in the presence of
trains. The use of video vigilance devices attached to trains, or cameras set on
specific railway stretches, allowed continuous and clear recording of the animals’
behavior toward trains (Kinley et al. 2003; Babińska-Werka et al. 2015). Video
vigilance is particularly valuable in the winter in regions where snow cover and/or
steep embankments impede the use of other methods (Rea et al. 2010). However,
this method is expensive and thus has a limited observational range, and it cannot
capture the entire vertebrate community in the railway vicinity.
Standardization of Monitoring
Studies should have standardized survey methods across different geographic areas,
and combine several methods in order to reduce bias and contribute to better
estimates of mortality on railways (Iuell et al. 2003; van der Grift et al. 2013). For
instance, railway mortality should be presented as an index, reflecting the number
of casualties/km/year, and these results should include information on sampling
effort and periodicity (Peña and Llama 1997; SCV 1996). In order to achieve
consistency in the use of similar methods over temporal and spatial scales so that
comparisons can be made, cooperation is required, and specialized personnel
should be trained (Roedenbeck et al. 2007; Rytwinski et al. 2015).
28
F. Carvalho et al.