The effect of roadkills on the persistence of xenarthran populations: the case of the Brazilian Cerrado

Abstract

The Brazilian Cerrado possesses a great diversity of xenarthrans with 12 species: eight armadillos, three anteaters, and one sloth. Even though several of these species are threatened, roadkill is considered a major threat only to Bradypus variegatus and a justification for listing Myrmecophaga tridactyla as Vulnerable. Here we present evidence that roadkill is a risk factor for xenarthran persistence, even to non-threatened species. To assess roadkill impact, we compiled articles related to mammal roadkill in the Brazilian Cerrado. One or more species of Xenarthra were among the top five most common roadkilled species in over 90% of the studies. The group represented over 50% of the recorded mammals in 33.3% of the papers and more than 40% in 66.6% of them. In 33.3% of the papers Pilosa contributed over 25% of the records and Cingulata presented the same proportion in 44.4% of them. This study reinforces the idea that roadkill must be considered a major threat to xenarthran populations in conservation status assessments. Therefore, we suggest that mitigation measures be implemented, and that the IUCN take into account that roadkill is one of the greatest threats to populations of xenarthrans.

Does Moonlight Increase Predation Risk for Elusive Mammals in Costa Rica?

“…); and (3) the retinal tapetum (RT) is found in fruit bats and opossums (Schwab et al., 2002). Some mammals have no tapetum (NT), such as monotremes (primitive mammals), most primates (including humans), most rodents (e.g., squirrels, agouti, porcupines), lagomorphs such as rabbits, suids such as pigs and peccaries, and xenarthrans such as armadillos (Alina et al., 2008; Huck et al., 2017; Ribeiro et al., 2017; Schwab et al., 2002; Table 2).…”

“… a Schwab et al. 2002, p. 72. b Huck et al., 2017; Prugh & Golden, 2014; Schwab et al., 2002; Ollivier et al., 2004; Michalski & Norris, 2011; McDonough & Loughry, 1995; Ribeiro et al., 2017; De Oliveira, 1998; De Farias Rocha et al., 2009. c Rank is the level of nocturnal visual acuity of taxa from best (1) to worst (4).…”

“… b Huck et al., 2017; Prugh & Golden, 2014; Schwab et al., 2002; Ollivier et al., 2004; Michalski & Norris, 2011; McDonough & Loughry, 1995; Ribeiro et al., 2017; De Oliveira, 1998; De Farias Rocha et al., 2009.…”

“…Based on the information presented above, we drew the following conclusions (Table 2): (1) the CTC (choroidal tapetum fibrosum) of carnivorans has greater light reflectance than the CTF (choroidal tapetum fibrosum) of herbivore ungulates, (2) the CTC of felids is more efficient than that of canids or mustelids, (3) opossums, paca, procyonids (e.g., raccoon, coati), and tapir (related to the horse) have good night vision, whereas (4) armadillos, skunks, and tamandua rely heavily on olfaction and have poor eyesight, and (5) lagomorphs and pigs (including peccary) lack a tapetum lucidum and thus have poor night vision. To test the predictions of the predation risk and visual acuity hypotheses, we computed the number of independent records in each quarter of the moon for each species by dividing the moon phase cycle from 0 to 2p into 4 equal quadrants centered on Huck et al, 2017;Prugh & Golden, 2014;Schwab et al, 2002;Ollivier et al, 2004;Michalski & Norris, 2011;McDonough & Loughry, 1995;Ribeiro et al, 2017;De Oliveira, 1998;De Farias Rocha et al, 2009. c Rank is the level of nocturnal visual acuity of taxa from best (1) to worst (4).…”

Can Human Demographic or Biological Factors Influence Mammal Roadkill? A Case Study in the Go-060 Highway

“…Even though we recorded only one occurrence of this species, the roadkill of C. brachyurus is a concern because it naturally occurs in low densities (Paula et al 2013). Thus, even though roadkill is not directly connected to its extinction rate, it is relevant and should be considered in future studies that investigate the causes of local and global extinction of this species (Ribeiro et al 2017).…”