Short and Narrow Roads Cause Substantial Impacts on Wildlife

Abstract

Short and narrow roads are generally overlooked when assessing road impacts on biodiversity. However, these roads bisect natural environments and may cause significant impacts on wildlife in local scale. Thus, we monitored roadkills along a short two-lane road (CPM road) in Southeastern Brazil and propose mitigation strategies to reduce wildlife mortality. We monitored roadkilled vertebrates along 5 km of CPM road from 2010 to 2016 and we also compiled data from previous studies along the same road. We conducted a hotspot analysis to identify CPM road areas with significant roadkill aggregation. We recorded 77 roadkilled vertebrates from 14 taxonomic groups along the CPM road. Mammals were the most frequently recorded group (91% of roadkills), which represented 56% of all medium-and large-sized mammal species known to occur in the study area. We identified three roadkill hotspots along the CPM road. Two of them were located at two stream crossings, where the road cut across the associated riparian forests, and the other was at a road section with water drainage from a pond, also connected to a riparian forest. These riparian forests are part of the remaining natural habitat that provides connectivity between the forest remnants in the landscape, and therefore, for wildlife. Our results showed that even short and narrow roads can have considerable roadkill, which may have severe effects for wildlife on a local scale. The results stress the need to carefully look at these types of roads and propose measures to reduce impacts. We propose the creation of safe crossing opportunities in the hotspot zones combined with wildlife fencing to keep the animals off the road and guide them towards the safe crossing opportunities.

Use of highway culverts by the water opossum (Chironectes minimus) in southeastern Brazil

“…The absence of roadkill records of C. minimus is congruent with previous studies (Prada 2004, Coelho et al 2008, Caires et al 2019, Magioli et al 2019, even though the recorded individuals frequently used areas adjacent to the studied highway. Vehicle collision rate seems to be low for C. minimus even when compared with other semi-aquatic mammals such as the capybara (Hydrochoerus hydrochaeris) and the Neotropical otter (Lontra longicaudis) (Coelho et al 2008, Huijser et al 2013, Magioli et al 2019. A plausible explanation for the rarity of roadkills is that C. minimus seems to never leave watercourses during its daily movements (Leite et al 2016).…”

Does the shape of the road influences wildlife roadkills? Evidence from a highway in Central Andes of Colombia

“…We conducted a cluster analysis of roadkilled animals to identify roadkill hotspots (Magioli et al, 2019), using the 'Siriema' software (Coelho et al, 2014). First, we used the 2-D Ripley's K statistic, which identifies non-random spatial distribution of roadkilled animals through multiple scales (Coelho et al, 2008) and which takes the sinuosity of the road into account (Magioli et al, 2019).…”

“…We conducted a cluster analysis of roadkilled animals to identify roadkill hotspots (Magioli et al, 2019), using the 'Siriema' software (Coelho et al, 2014). First, we used the 2-D Ripley's K statistic, which identifies non-random spatial distribution of roadkilled animals through multiple scales (Coelho et al, 2008) and which takes the sinuosity of the road into account (Magioli et al, 2019). Afterwards, a 2-D Hotspots analysis was carried out using the following parameters: radius = 70 m, number of simulations = 1,000, confidence interval = 95%, for a random distribution of the roadkill locations (Magioli et al, 2019).…”

“…To identify if roadkill hotspots were associated to forest corridors or watercourses, since these are common wildlife crossings (Bueno et al, 2013;de Freitas et al, 2015;Magioli et al, 2019), we manually performed a classification of the landscape surrounding the highway, using ArcGIS 10.0 software (ESRI 2012), with aerial images from Google Earth and the land cover of the department of Antioquia (Free download at https://sigot.igac.gov.co/), also comparing with observations in the field (de Freitas et al, 2015). We classified four characteristics of the landscape: agriculture (with grasslands), forest, herbaceous vegetation and urban areas (urban, rural and material exploitation areas); we also measured the distance to the nearest watercourse (river/stream; Bueno et al, 2013), taking into account covers surrounding the roadkill hotspots up to 300 m. Note: As we only found three vertical curves with a shorter sight distance than the crestal length, these were (1) K1+800 (6°26'51.9" N, 75°44'27.3" W);…”

Mammal-vehicle collisions on toll roads in São Paulo State: implications for wildlife, human safety and costs for society

“…The roadkill monitoring program is extensive and has a relatively consistent and frequent search and reporting effort; the entire length of the toll roads is checked at least once every three hours. -JORGE et al, 2008;GALETTI et al, 2016;MAGIOLI et al, 2016MAGIOLI et al, , 2018AZEVEDO et al, 2018;BOVO et al, 2018).…”