Talk Spatial patterns of road mortality in medium to largesized mammals of the Cerrado and Pantanal

Brazil has one of the richest biodiversity and one of the most extensive road networks in the world. Several negative impacts emerge from this interaction, including wildlife-vehicle collisions (WVC).

We analyzed the spatial patterns of WVC from medium-large sized mammals (>1 kg) collected along three transects (920 km), fortnightly over one year. We aimed to
i) evaluate the relative influence of land cover patterns on the distribution of WVC;
ii) assess if WVCs are clustered forming hotspots of mortality, and if so
iii) evaluate the benefits of mitigating only hotspot sections.

We studied the seven most represented species: lowland tapir (Tapirus terrestris), capybara (Hydrochoerus hydrochaeris), giant anteater (Myrmecophaga tridactyla), southern tamandua (Tamandua tetradactyla), crab-eating fox (Cerdocyon thous), six-banded armadillo (Euphractus sexcinctus) and nine-banded armadillo (Dasypus novemcinctus) (n=924, 92% of records).

We found a strong association between WVC probability and road sections with high overall mortality for all focal species. Distance to riparian areas, tree cover, terrain ruggedness and distance to urban areas were also important predictors. We detected several hotspots of mortality, though they overlapped little.

Our results suggest that road mitigation solely focused on hotspots may fail to significantly reduce overall roadkill. The results support focusing more on habitat quality and landscape connectivity for a better assessment of road mortality. At the local scale, a larger number and improved road passages with exclusionary fencing of appropriate mesh in riparian areas may provide safe crossings for many species and constitute a promising mitigation measure.

wildlife-vehicle collisions; spatial clustering; hotspots; Brazil; road mitigation; road management