Environmental niche differentiation and paleodistribution of the rare montane woodrats of the genus Nelsonia (Rodentia: Cricetidae)

Abstract

Nelsonia is an extant genus of North American woodrats, in which most of the biological information remains unknown. Only N. neotomodon and N. goldmani are recognized inhabiting in similar temperate environments. Recently, a biogeographic hypothesis for the genus pointed out that Nelsonia after diverging from Repomys or Protorepomys in the Californian-Rocky Mountains in USA, the Mexican highlands in Mexico played a significant role in how the two species of Nelsonia became established in two different mountain ranges: N. neotomodon in the Sierra Madre Occidental and N. goldmani in the Transmexican Volcanic Belt. However, no other evidence exists about the biogeographic history of both species that improve the explanation about how past climate events affected their distribution, as well as whether the current environmental space occupied by both species are similar such as previous studies have argued. Therefore, this study aimed to characterize the environmental niche of both species, to test environmental differences, overlap, equivalence, and niche similarity, and lastly, to build their current niche model and paleodistribution for three past scenarios: Pliocene, Last Interglacial, and Last Glacial Maximum. The results revealed significant differences in niche centroid, low niche overlap, and no niche equivalence or similarity, suggesting niche divergence. The current niche suitability showed that the two species have small and restricted potential habitats highlighting the need to reevaluate the current international conservation category of N. neotomodon. The paleodistribution suggested that both species of Nelsonia have contractions and expansions of niche suitability in the past.