Genetic assessment of the Atlantic Forest bristle porcupine, Chaetomys subspinosus (Rodentia: Erethizontidae), an endemic species threatened with extinction

Abstract

ABSTRACT. The bristle-spined porcupine, Chaetomys subspinosus, an endemic rodent from Atlantic Forest, was considered to be abundant in the recent past, but population reductions due to habitat loss and expansion of human activities caused this species to be included in the "vulnerable" category of the World Conservation Union Red List. We performed the first genetic assessment in natural populations of this focal species along its geographical distribution. Thirty-five noninvasive samples (hair) were collected from three natural populations in the Brazilian States of Sergipe, Bahia and Espírito Santo. Genetic similarity obtained by Jaccard's index, based on dominant RAPD and ISSR markers, varied between 25 and 100%. Four clusters, mainly coincident with the geographical distribution of the populations, were observed. Analysis of molecular variance based on 47 polymorphic loci showed that there was 15.99% genetic variability among populations and 84.01% within populations. The estimated genetic structure among populations (f ST ) was 0.16. The populations may have formed a continuum along the past distribution of the Atlantic rainforest but historical events of human occupation resulted in recent divergence among sampled populations.

Combining species distribution modeling and field surveys to reappraise the geographic distribution and conservation status of the threatened thin-spined porcupine (Chaetomys subspinosus)

“…We walked inside forest remnants and visually inspected the intermediary and superior strata, mainly tangles of vines, forks, bromeliads, palms, and tree holes, which are structures commonly used by species as diurnal resting sites [ 16 , 21 , 33 ]. Once located, we captured, immobilized and photographed each animal and collected quills for genetic analysis [ 28 , 34 ]. Despite the effort directed, most of the records compiled in our database (75%) were results of opportunistic sightings, while 29 records were acquired through active search.…”

“…The first one in the triangle immediately to the north of the municipality of Salvador (38 o 31'W 13 o 01'S), in the Bahia state, and the second and larger one in north-western parts of Espirito Santo (near to 40 o 13'W 18 o 24'S). This last hiatus finds further support, as populations from northern and southern are relatively divergent and genetically structured [ 28 ]. In addition, Chaetomys subspinosus occurs in sympatry and syntopy with the Bahia hairy dwarf porcupine, Coendou insidiosus (here named Bahia porcupine), which is considered more common, widely distributed and non-threatened [ 16 ].…”

Do we underestimate the impact of roads on arboreal animals? Roadkill as an important threat to Chaetomys subspinosus (Mammalia: Rodentia)

“…The Thin-spined Porcupine may have been continuously distributed throughout its original range, but Atlantic Forest has since been several subdivided by anthropic forest fragmentation, thereby causing genetic divergence between remaining isolated populations, and drastic reduction in the gene pool of the species (Oliveira et al 2011). Thus, additional mortality associated with highways will cause further reduction of the remaining populations and reduce gene flow (and genetic variability) both on a local scale and throughout its current, fragmented, distribution.…”

“…It is endemic to the Atlantic Forest where its historical range extends from northern Rio de Janeiro to southern Sergipe (Oliver & Santos 1991). Recent porcupine sighting records are restricted to a narrow strip along the coast from southern Espírito Santo to Sergipe (Oliveira et al 2011). Remaining populations of C. subspinosus are declining (Faria et.al.…”

Home range and multiscale habitat selection of threatened thin-spined porcupine in the Brazilian Atlantic Forest

“…These results further support the idea that not only habitat loss through deforestation (Chiarello et al 2008;Faria et al 2011;IUCN 2014), but also conversion to shade plantations are important drivers of population decline. In fact, the avoidance of such matrix habitats may be one cause of the critical genetic erosion in this region (Oliveira et al 2011a).…”