Potential movement corridors and areas of high predicted road mortality are in different locations for wild cats in Brazil
Written By Rafaela Cobucci Cerqueira, Jochen A.G. Jaeger, Lucas Gonçalves da Silva, Clara Bentes Grilo, Anthony AP Clevenger and Paul B Leonard
23rd August 2021
A jaguarundi (Herpailurus yagouaroundi) killed by road traffic. Photo by Lucas Gonçalves da Silva
A common practice when prioritizing locations for mitigating the negative effects of roads on wildlife is to consider road segments where the potential for wildlife movement and road mortality are high. However, it is not clear to what degree these types of road segments overlap. If the locations where animals following corridors move across roads coincides with locations where they are often killed by vehicles, mitigation is clearly needed there. However, if corridors and road mortality rarely occur in the same locations, decision-makers and road agencies must decide which of these road segments should be prioritized. Because this question is still a controversial issue in road ecology, we compared movement-corridor and road-mortality models as means of prioritizing road segments for mitigation.
We compared connectivity and mortality models for wild cats
We focused our study on five species of Brazilian wild cats (felids), namely, two species of tiger cats (modelled together), ocelot, jaguarundi, and puma (Figure 1). To identify locations of potential movement corridors of these species across roads, we applied connectivity models that employ circuit theory and used habitat-suitability models based on opportunistic occurrence data. To predict road segments of high mortality probability, we used maximum-entropy models based on road-kill records. These are methods commonly used to predict animal movement and mortality risk, respectively.
Figure 1. a) Northern tiger cat (Leopardus tigrinus); b) Southern tiger cat (L. guttulus); c) Ocelot (L. pardalis), d) Jaguarundi (H. yagouaroundi) and e) Puma (Puma concolor). Photos by Lucas Gonçalves da Silva
We then assessed if corridor locations overlapped with locations of high road-mortality likelihood using a statistical technique that measures the amount of agreement between the two methods.
Locations of high connectivity were not the same as locations of high mortality likelihood
For all species together, ~81,700 km of roads (~5% of the Brazilian road network) were identified as high priority for mitigation by at least one of the two methods, but the road length for which the two methods agreed represented only ~5,300 km, i.e., a small fraction of 6.5%. This means the levels of spatial agreement between the two methods were low for all species (Figure 2).
Figure 2. Road segments that are crossed by potential movement corridors (blue) and segments of high road-mortality risk (orange).
Implications for road mitigation
Our findings indicate that potential movement corridors in well-connected stretches of the landscape that are crossed by roads do not necessarily promote higher road mortality. This means that landscape connectivity and road mortality may be independent. This finding supports the use of both methods in parallel to identify priority areas for mitigation. Usually, road mortality is associated with periods of high movement of the animals, such as the phases of breeding and dispersal, and it is likely that most road-mortality models capture these behaviours, while movement-corridor models may include a wider range of reasons for movement, such as daily movements and dispersal. Thus, when movement corridors and vehicle-collisions for a species do not overlap, this means that they may represent different mechanisms of interactions between animals and roads and therefore each method identifies areas that are used by individuals in different periods of their life cycle. Thus, in the case of a lack of coincidence, the complementary use of both approaches should be considered in decision-making rather than just one.
Author information:
Rafaela Cobucci Cerqueira. Universidade Federal de Lavras, Brazil.
rafaelacobucicerqueira@gmail.com
Jochen A.G. Jaeger. Concordia University Montreal, Canada.
Lucas Gonçalves da Silva. Universidade de Brasília, Brazil.
Source:
Cerqueira RC, Leonard PB, da Silva LG, Bager A, Clevenger AP, Jaeger JAG, Grilo C (2021) Potential Movement Corridors and High Road-Kill Likelihood do not Spatially Coincide for Felids in Brazil: Implications for Road Mitigation. Environmental Management 67, 412-423. http://doi.org/10.1007/s00267-020-01411-4.
Editor:
Fernanda Teixera
Cite this summary:
Cerqueira, R., Jaeger, J. & Gonçalves da Silva, L. (2021). Potential movement corridors and areas of high predicted road mortality are in different locations for wild cats in Brazil. Edited by Teixera, F. TransportEcology.info, Accessed at: https://transportecology.info/research/potential-corridors-wild-cats-brazil [Date accessed].
