Do roads act as a barrier to gene flow of subterranean small mammals? A case study with Ctenomys minutus

  • Isadora Beraldi EsperandioEmail author
  • Fernando Ascensão
  • Andreas Kindel
  • Ligia Tchaicka
  • Thales Renato Ochotorena de Freitas
Research Article


Road-barrier effects can lead to population isolation, with consequent negative outcomes for individuals and populations. Small mammals have been identified as particularly vulnerable to barrier effects, yet few studies have focused on subterranean species. Given the burrowing habit of these species, we hypothesized that roads block their movement and therefore the gene flow between roadside populations. The tiny tuco-tuco (Ctenomys minutus), a small subterranean rodent that inhabits the coastal plains of southern Brazil, was used as a model species to test this hypothesis. We used 14 microsatellites to genotype 80 individuals from four colonies (n = 20 per colony). We compared the population differentiation (FST, GST and DEST) and population structuring (STRUCTURE and GENELAND, and discriminant analysis of principal components) of two colony pairs, one pair divided by a road, and the other with no road or other potential barrier between the colonies (control). The results indicated higher genetic differentiation and structuring between the roadside colonies than in the control sites, although less evident than initially predicted. We concluded that the road reduced but did not halt the gene flow of C. minutus. Nevertheless, in view of the rapid economic development of the region, measures to ensure long-term gene flow, i.e., installation or retrofitting of crossing structures, should be considered. This study complements previous analyses of road-barrier effects on small mammals, suggesting that subterranean species such as C. minutus can cope with these barriers, at least in conditions similar to our study area.


Road avoidance Microsatellite Habitat fragmentation Genetic differentiation Brazil Road ecology 



We thank the Laboratory of Cytogenetics and Evolution of the Department of Genetics/UFRGS for making the samples available, and all colleagues who collaborated in the laboratory work. We thank C.B. Grilo, G.L. Gonçalves, D.L. Guadagnin and the anonymous reviewers for comments on a previous version of this manuscript. I.B.E. would like to thank CAPES for her scholarship. FA was funded by a FCT postdoctoral grant (Fundação para a Ciência e Tecnologia, SFRH/BPD/115968/2016) and LT was funded by FAPEMA (Fundação de Amparo à Pesquisa e ao Desenvolvimento Científico, Tecnológico do Maranhão, CBIOMA 3812/15). We also thank CNPq (Conselho Nacional de Desenvolvimento Científico e Tecnológico) and FAPERGS (Fundação de Amparo à Pesquisa do Estado do Rio Grande do Sul).

Supplementary material

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Supplementary material 1 (DOCX 160 KB)


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© Springer Nature B.V. 2019

Authors and Affiliations

  1. 1.Programa de Pós-Graduação em EcologiaUniversidade Federal do Rio Grande do SulPorto AlegreBrazil
  2. 2.Programa de Pós-Graduação em Recursos Aquáticos e Pesca, Centro de Educação, Ciências Exatas e NaturaisUniversidade Estadual do MaranhãoSão LuísBrazil
  3. 3.CIBIO/InBio, Centro de Investigação em Biodiversidade e Recursos GenéticosUniversidade do PortoVairãoPortugal
  4. 4.CEABN/InBio, Centro de Ecologia Aplicada “Professor Baeta Neves”, Instituto Superior de AgronomiaUniversidade de LisboaLisbonPortugal
  5. 5.Departamento de GenéticaUniversidade Federal do Rio Grande do SulPorto AlegreBrazil

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