Roadkilled mammals in the northern Amazon region and comparisons with roadways in other regions of Brazil

Abstract

Roadways and road traffic modify landscapes, posing a threat to the conservation of species in different biomes. The aim of the present study was to analyze roadkill records of wild mammals and to compare the results to findings from 37 other studies conducted in Brazil, to evaluate the richness and diversity of threatened species in different eco-regions of the country. This study was conducted between June 2007 and June 2008, along 60 km of the inter-state highway BR-364, which connects the municipalities of Ouro Preto d’Oeste and Presidente Médici in the state of Rondônia (northern Brazil). Two hundred twenty roadkills were recorded involving 13 species of mammals. Cingualata, Pilosa and Carnivora were the most represented orders. The most represented were the generalist species Dasypus novemcinctus (56.7%), Tamandua tetradactyla (10.5%), and Cerdocyon thous (8.2%), reflecting the adaptability of these species to habitat changes and presence of humans. The number of roadkilled individuals and species indicated no significant differences between the dry and rainy seasons. The findings indicate a high index of roadkills (3.38 individuals/km/year) and moderate number of run over species (0.20 species/km/year) in the region in comparison to records from other roadways in Brazil, with 46% species having an endangered status. Roadways in the eco-regions of the Cerrado (Brazilian savanna) accounted a significantly larger proportion of endangered species (mean: 52%) in comparison to the Pampa (lowlands of southern Brazil; 24%), but the differences in comparison to roadways in Amazonia (37%) and the Atlantic Forest (31%) were non-significant. The present findings underscore the need for emergency measures to minimize the impact of roadkills on mammals. Moreover, priority should be given to more impacted roadways and more threaten eco-regions.

Mammalian Roadkill in a Semi-Arid Region of Brazil: Species, Landscape Patterns, Seasonality, and Hotspots

“…The seasonal effect observed here contrasts with the findings of studies of mammals in other biomes [27,31,88,110,111]. In the present study, the seasonal effect may be related to the predominance of generalist species that have an enormous capacity to adapt to shifts in the environment, thus exploiting different types of resource over the course of the year [24]. The vulnerability of E. sexcinctus and P. cancrivorus to roadkill in the rainy season may be associated with the greater activity of individuals in this period, driven by the increased availability of food resources, the search for breeding partners, or even the less extreme climatic conditions [23,24].…”

“…Mammals are exposed to traffic when traveling on highways that traverse their home ranges or when they are attracted to patches of resources [15], which may concentrate roadkill rates in certain specific stretches of a highway [22]. Species with large home ranges, such as top predators, tend to cross more roads and, thus, encounter more traffic, which intensifies the negative impacts on these species [23,24]. These impacts also disproportionately affect species that are better adapted to anthropogenic habitats [25].…”

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.…”

The ecological corridor as a strategy for connectivity between Atlantic Forest fragments in Northeast Brazil

“…As the proposed ecological corridor includes areas with a federal highway and urban buildings, which are a negative factor since they are barriers to the displacement of species due to the ow of vehicles, accidents and people, it is necessary to propose measures and strategies that reduce environmental impacts (Louzada et al 2012;Caires et al 2019). In this case, the passage of aerial fauna is recommended, which is effective for mitigation of accidents (ALHO et al, 2019), installation of signs, speed cameras and speed bumps in areas that are more critical and that have an intense ow of vehicles and people.…”