How do landscape context and fences influence roadkill locations of small and medium-sized mammals?

Plante, Judith; Jaeger, Jochen A.G.; Desrochers, André

doi:10.1016/j.jenvman.2018.10.093

Cited by 35 publications

(31 citation statements)

References 39 publications

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“…2016; Plante et al. 2019). To lessen the risk of a fence‐end effect, a promising, but untested, approach is to extend the fences to the next wildlife crossing structure or drainage culvert that could be used by wildlife (Brunen et al 2020).…”

Section: Discussionmentioning

confidence: 99%

An adaptive plan for prioritizing road sections for fencing to reduce animal mortality

Spanowicz

Teixeira

Jaeger

2020

Conservation Biology

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Mortality of animals on roads is a critical threat to many wildlife populations and is poised to increase strongly because of ongoing and planned road construction. If these new roads cannot be avoided, effective mitigation measures will be necessary to stop biodiversity decline. Fencing along roads effectively reduces roadkill and is often used in combination with wildlife passages. Because fencing the entire road is not always possible due to financial constraints, high-frequency roadkill areas are often identified to inform the placement of fencing. We devised an adaptive fence-implementation plan to prioritize road sections for fencing. In this framework, areas along roads of high, moderate, and low levels of animal mortality (respectively, roadkill hotspots, warmspots, and coldspots) are identified at multiple scales (i.e., in circles of different diameters [200-2000 m] in which mortality frequency is measured). Fence deployment is based on the relationship between the amount of fencing being added to the road, starting with the strongest roadkill hotspots, and potential reduction in road mortality (displayed in mortality-reduction graphs). We applied our approach to empirical and simulated spatial patterns of wildlife-vehicle collisions. The scale used for analysis affected the number and spatial extent of roadkill hot-, warm-, and coldspots. At fine scales (e.g., 200 m), more hotspots were identified than at coarse scales (e.g., 2000 m), but combined the fine-scale hotspots covered less road and less fencing was needed to reduce road mortality. However, many short fences may be less effective in practice due to a fence-end effect (i.e., animals moving around the fence more easily), resulting in a trade-off between few long and many short fences, which we call the FLOMS (few-long-or-many-short) fences trade-off. Thresholds in the mortality-reduction graphs occurred for some roadkill patterns, but not for others. Thresholds may be useful to consider when determining road-mitigation targets. The existence of thresholds at multiple scales and the FLOMS trade-off have important implications for biodiversity conservation.

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Section: Discussionmentioning

confidence: 99%

An adaptive plan for prioritizing road sections for fencing to reduce animal mortality

Spanowicz

Teixeira

Jaeger

2020

Conservation Biology

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“…The consequences of road-induced fragmentation for the integrity of natural environments are well-researched [ 76 , 77 ]. Several different, yet not mutually exclusive, mechanisms restrict animal dispersal across roads—lethal road collisions, the avoidance of the road or roadside habitat and the inability to traverse the road or nearby area, such as due to a central median or parallel drainage ditch [ 78 ]. Road mortality is likely to act as a filter to movement for many species, rather than an absolute barrier, as animals may be able to make successful journeys across the road, even across large roads and bridges [ 79 ].…”

Section: The Role Of Road Mortality In Fragmentation Effectsmentioning

confidence: 99%

“…It is possible that physical barriers such as roadside fencing and road avoidance behaviour cause fragmentation via more stringent restrictions to movement. Both barriers and road avoidance behaviour are particularly common on roads with higher traffic volumes and speeds [ 78 ]. Dowding et al [ 58 ] reported avoidance of foraging near roads, but not of crossing quieter roads, by E. europaeus .…”

Section: The Role Of Road Mortality In Fragmentation Effectsmentioning

confidence: 99%

“…Several authors recommend removing or reducing shrubbery in central medians to reduce road mortality [ 116 , 117 ] (but see [ 118 ]). The use of central medians by fauna has not been well-studied and, if they are in fact beneficial to animal movement across a road, their removal may exacerbate barrier effects [ 78 ]. Modifying hedgerows, which act as conduits of hedgehog movements, near roads is also likely to be an important action.…”

Section: Potential Road Mitigation Measures For Hedgehog Populatiomentioning

confidence: 99%

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Impacts and Potential Mitigation of Road Mortality for Hedgehogs in Europe

Moore

Petrovan

Baker

et al. 2020

Animals

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Transport infrastructure is a pervasive element in modern landscapes and continues to expand to meet the demands of a growing human population and its associated resource consumption. Road-induced mortality is often thought to be a major contributor to the marked declines of European hedgehog populations. This review synthesizes available evidence on the population-level impacts of road mortality and the threat to population viability for the five hedgehog species in Europe. Local and national studies suggest that road mortality can cause significant depletions in population sizes, predominantly removing adult males. Traffic collisions are a probable cause of fragmentation effects, subsequently undermining ecological processes such as dispersal, as well as the genetic variance and fitness of isolated populations. Further studies are necessary to improve population estimates and explicitly examine the consequences of sex- and age-specific mortality rates. Hedgehogs have been reported to use crossing structures, such as road tunnels, yet evaluations of mitigation measures for population survival probability are largely absent. This highlights the need for robust studies that consider population dynamics and genetics in response to mitigation. In light of ongoing declines of hedgehog populations, it is paramount that applied research is prioritised and integrated into a holistic spatial planning process.

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“…Use of WCS by certain species may be altered by their size, design and location, presence of vegetation and various natural structures (logs, branches and tree stumps) and protective fences along motorways. Also, barriers like rainwater tanks, ditches and other constructions at entrances and the risk of flooding of underpasses, as well as activity of people, play an important role (Ascensão and Mira 2007;Mata et al 2008;Craveiro et al 2019;Plante et al 2019). There is also evidence that use of WCS can be affected by awareness of mammals on such constructions as well as their experiences in passing through (Ascensão et al 2014).…”

Section: Introductionmentioning

confidence: 99%

Mammal use of wildlife crossing structures along a new motorway in an area recently recolonized by wolves

Mysłajek

Olkowska²,

Wronka-Tomulewicz³

et al. 2020

Eur J Wildl Res

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Wildlife crossing structures (WCSs) enhance connectivity between habitats of wild animals fragmented by fenced motorways, but factors affecting their use by targeted species remain understudied, particularly in areas recently recolonized by large carnivores. We investigated the use of WCS—6 overpasses (width 30-45m), 5 large underpasses (width 33–114 m) and 4 small underpasses (width 15–19 m)—located along the A4 motorway in the Lower Silesian Forest (western Poland), a large forest tract recently recolonised by wolves (Canis lupus). Identifying and counting tracks of mammals left on sand-beds as well as individuals recorded by camera traps were used to determine species diversity, number and activity patterns of mammals on WCS, and to reveal seasonal and temporal changes of WCS use over 3 years of study (2010–2013). WCSs were mostly used by wild species (51.5%), followed by humans (34.8%), livestock and pets (13.7%). Among wild species, ungulates were the most common (77.4% of crossings), while lagomorphs and carnivores were recorded less often (15% and 7.6% of crossings, respectively). The number of species and crossings of wild mammals, especially wild ungulates and wolves, was substantially higher on overpasses (mean effective number of species (Hill numbers): 0D = 7.8, 1D = 4.1 and 2D = 3.3) than on underpasses (0D = 6.3, 1D = 2.9 and 2D = 2.3) and was not affected by distance between WCS and human settlements or WCS width. There was a higher diversity of wild species and more crossings under large extended bridges than on smaller underpasses. The number of species and number of crossings of wild mammals, domestic animals and people increased from 2010 to 2013. There was a significant difference in activity patterns, with almost all wild species being nocturnal, in contrast to people and dogs. There was no relationship between crossing time and rates of wild carnivores and potential prey. We conclude that overpasses, even with steep entrance slopes (25–26.5%) or integrated with moderately used gravel roads, maintain movement of wild terrestrial mammals much better than underpasses, and the presence of wolves does not hamper the movement of other wild species. As there are significant temporal changes in use of WCS by mammals, we recommend monitoring WCS in all seasons for at least 3 years as a minimum standard for the post-investment assessment of WCS utilization by animals.

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How do landscape context and fences influence roadkill locations of small and medium-sized mammals?

Cited by 35 publications

References 39 publications

An adaptive plan for prioritizing road sections for fencing to reduce animal mortality

An adaptive plan for prioritizing road sections for fencing to reduce animal mortality

Impacts and Potential Mitigation of Road Mortality for Hedgehogs in Europe

Mammal use of wildlife crossing structures along a new motorway in an area recently recolonized by wolves

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