Low genetic variability in the recovering urban banded leaf monkey population of Singapore

Abstract

The banded leaf monkey (Presbytis femoralis femoralis) is critically endangered in Singapore and affected by widespread deforestation in southern Peninsular Malaysia. The Singapore population has recovered from a low of 15-20 to more than 40 individuals, but prior to our study it was unclear how severely the past bottleneck had depleted the genetic diversity of the population. Here, we provide the first analysis of the genetic variability based on seven samples (ca. 20% of population) collected over two years of fieldwork. We find only two haplotypes that differ only in one variable site for the hypervariable region I (HV-I) of the mitochondrial d-loop. Compared to available population-level data for other colobines (proboscis monkey, Yunnan snub-nosed monkey, Sichuan snub-nosed monkey, Angolan black and white colobus), the banded leaf monkey population in Singapore has the lowest number and the most similar haplotypes. This low genetic variability is the next challenge for the conservation of the population. Protected habitats in prospering urban environment may become important sanctuaries for endangered species, but reintroductions may have to be considered in order to restore genetic variability that was lost during past bottlenecks.