Mammalian fatalities on roads: how sampling errors affect road prioritization and dominant species influence spatiotemporal patterns

Franceschi, Ingridi Camboim; Gonçalves, Larissa Oliveira; Kindel, Andreas; Trigo, Tatiane Campos

doi:10.1007/s10344-021-01540-z

Cited by 4 publications

(3 citation statements)

References 58 publications

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“…Although we acknowledge that factors beyond the number of carcasses, road mileage and days of effort can influence the persistence of carcasses and the efficiency of observers, potentially leading to biased roadkill rates (Franceschi et al, 2021), comparing the observed roadkill rates of two different roads can be informative to understand the roadkill dynamic in these roads, becoming a starting point for future studies to delve into analyzes that cover other characteristics not yet studied.…”

Section: Discussionmentioning

confidence: 99%

Vertebrates’ roadkill in the southern region of the Atlantic Forest, Paraná coast – Brazil

et al. 2023

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Being a significant global biodiversity hotspot, the Atlantic Forest has been drastically reduced by human activities. Among the anthropic activities that most affect the biodiversity of this biome is the construction and operation of roads and highways. Between harmful effects of these infrastructures, wildlife roadkill is currently considered one of the biggest causes of mortality of wild vertebrates. This study evaluated patterns of vertebrates’ roadkill on two roads in the coastal region of the largest continuous remnant of the Brazilian Atlantic Forest. For twelve months, we carry out weekly samples with a motor vehicle at a constant speed of 40 km/h to search for carcasses along the roads. All carcasses found were georeferenced and identified to the lowest possible taxonomic level. Then, using Siriema v.2.0 software, we analyzed roadkill aggregation and the spatial distribution of hotspots of wildlife roadkill. In 43 sampling days, 209 road-killed animals were registered (average roadkill rate of 0.105 and 0.111 animals/kilometer/day for PR-407 e PR-508, respectively). Extrapolating the rates found, we estimate that about 1,773 animals can be roadkill every year on these roads. The most affected groups were birds (33.01%) and amphibians (30.62%), followed by reptiles (19.13%) and mammals (17.33%). Warmer months had the highest roadkill rates. We found two critical roadkill hotspots for the PR-407 (kilometer 11.7 to 12.5 and kilometer 14.7 to 16.7). For the PR-508, we found a critical point of 5.2 km (kilometer 5 to 10.2). As a short-term measure, we recommend installing speed reducers in the identified stretches and implementing environmental education campaigns with residents and tourists, especially during the summer months, aiming to mitigate the roadkill on both roads. However, due to the importance and environmental fragility of the area, we emphasize the need for running periodic road ecology and local wildlife population viability studies in the medium and long term.

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Section: Discussionmentioning

confidence: 99%

Vertebrates’ roadkill in the southern region of the Atlantic Forest, Paraná coast – Brazil

et al. 2023

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“…For animal fatality estimates, p is usually a combination of carcass detection and persistence probabilities, estimated from two experiments (e.g. Gonçalves et al 2018;Dornas et al 2019). The first is designed to measure the proportion of carcasses detected by the observers from a known set, and the second is to measure the proportion of carcasses that persist on the road over the days.…”

Section: Introductionmentioning

confidence: 99%

“…Carcass detection and persistence are usually estimated from experiments carried out a few times during the study period with a limited number of previously collected carcasses or from literature values (e.g. Gonçalves et al 2018;Silva et al 2020;Ascensão et al 2021;Franceschi et al 2021). Carcass detection and persistence are expected to vary either along the road(s) or at different times, because the road pavement, traffic volume, weather, scavenger abundance, and activity may vary along these dimensions (Guinard et al 2012;Korner-Nievergelt et al 2015).…”

Section: Introductionmentioning

confidence: 99%

Estimating roadkill rates while accounting for carcass detection and persistence using open-population capture–recapture models

Menger,

Kindel,

Brack

2023

Wildlife Res.

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Context Accurately estimating wildlife roadkill is necessary to compare different roads, periods, and species, and to plan and assess mitigation effectiveness. We must account for the two main sources of errors associated with carcass sampling – carcass detection and persistence. Open-population models are used to estimate abundance, survival probabilities, and recruitment in living animal populations, accounting for imperfect detection, and they can be used in the context of animal fatalities. Aims The aim of this study was to explore an open-population approach to estimate comparable roadkill rates from carcass capture–recapture data, accounting for carcass detection and persistence. Methods We surveyed carcasses of the white-eared opossum (Didelphis albiventris) and black-and-white tegu lizard (Salvator merianae) on four road stretches using two sampling designs with different number of visits and sampling sessions. Carcasses were marked to be recaptured over visits within the same sampling session, resulting in a capture history for each carcass. Encounter history data were modelled using the superpopulation formulation of the open-population capture–recapture model under Bayesian inference for different datasets. A daily roadkill rate per kilometre was derived from the model entry probability estimate. Key results We estimated a daily roadkill rate with 1501 captures from 447 opossum carcasses and 511 captures from 218 tegu carcasses. For full data, mean carcass detection over the sessions ranged from 0.49 to 0.85 for the opossum and from 0.27 to 0.80 for the tegu, and mean carcass persistence ranged from 0.60 to 0.94 for the opossum and from 0.64 to 0.91 for the tegu. Scenarios with more occasions and captures increased precision of roadkill rates. Conclusions We were able to explicitly estimate roadkill rates using an open-population capture–recapture model under a Bayesian framework. It provides accurate roadkill numbers for a known time frame and road extension, accounting for imperfect detection and its associated uncertainty. Under scenarios of few carcasses, users should consider a higher number of occasions. Implications Not addressing carcass sampling errors or simplistically addressing them (e.g. only once during the study period) could mislead mitigation efforts. The approach used here can be used to estimate fatalities in other locations, such as windfarms and powerlines, for which repeated observations of marked carcasses are an option.

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The spatial, climatic and temporal factors influencing roadkill change according to the taxonomic level

Firmino Carvalho-Roel,

Iannini-Custódio,

Marçal Júnior

et al. 2023

Journal of Environmental Management

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Mammalian fatalities on roads: how sampling errors affect road prioritization and dominant species influence spatiotemporal patterns

Cited by 4 publications

References 58 publications

Vertebrates’ roadkill in the southern region of the Atlantic Forest, Paraná coast – Brazil

Vertebrates’ roadkill in the southern region of the Atlantic Forest, Paraná coast – Brazil

Estimating roadkill rates while accounting for carcass detection and persistence using open-population capture–recapture models

The spatial, climatic and temporal factors influencing roadkill change according to the taxonomic level

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