Genetic structure and diversity of the black and rufous sengi in Tanzanian coastal forests

The black and rufous sengi Rhynchocyon petersi is restricted to the Eastern Arc Mountains and coastal forests of East Africa and considered vulnerable because of habitat fragmentation and degradation. Coastal forests are believed to have been isolated from each other for thousands of years due to climatic changes. Since R. petersi is described as strongly dependent on its forest habitat, we hypothesized that R. petersi from different forests would show genetic divergence. We investigated the genetic structure and diversity of this species in four coastal forests in Tanzania using eight microsatellites and cytochrome b sequences. In total, 45 individuals were captured after strenuous sampling efforts. For comparative purposes we also sequenced the cytochrome b of 57 individuals from a sympatric rodent forest species, Beamys hindei. The results indicate extant R. petersi have descended from a single population of high effective size (Ne) with no forest-distinctive signal. In contrast, B. hindei is more genetically structured: Although the most common haplotype is found in the three closest forests, each forest harbours private haplotypes. Moreover, B. hindei Ne appeared 10 times smaller than R. petersi in Zaraninge forest. While B. hindei results are consistent with the scenario of long-term isolation of coastal forests, the R. petersi are not. We suggest R. petersi may less depend on forest habitat than previously suspected, consistent with anecdotal reports of sengis nesting in intervening agricultural habitat. From a conservation viewpoint, this sengi species therefore appears robust to the current spatial and temporal scale of habitat fragmentation.

Jaar van publicatie:2016