Genetic analysis reveals population structure and recent migration within the highly fragmented range of the Cross River gorilla (Gorilla gorilla diehli).

Anthropology Department, City University of New York Graduate Center, 365 Fifth Avenue, New York, NY 10016, USA.
Molecular Ecology (Impact Factor: 6.28). 03/2007; 16(3):501-16. DOI: 10.1111/j.1365-294X.2006.03159.x
Source: PubMed

ABSTRACT Recently developed methods of individual-based analysis of genetic data allow an unprecedented opportunity to understand the relationships among fragmented populations. By defining population structure and identifying migrant individuals, such analyses can provide a framework to aid in evaluating the threats posed by inbreeding and reduced genetic variability as a consequence of limited gene flow among fragments. Here we investigate population structure in the critically endangered Cross River gorilla (Gorilla gorilla diehli) by applying a suite of individual-based analyses to data obtained from between one-quarter and one-third of the estimated total population through the use of noninvasively collected DNA samples. The population structure inferred using data from 11 autosomal microsatellite loci was broadly consistent with geography and habitat fragmentation, but showed no simple isolation-by-distance effects. In contrast to previous field surveys, which suggested that all gorilla localities were isolated from one another, we infer low levels of gene flow and identify migrants between habitat fragments as well as individuals of admixed ancestry, suggesting persistent recent reproductive contact between many of the localities. These results are encouraging for the conservation of the Cross River gorilla population. Conservation efforts should strive to maintain connectivity between subpopulations that are still in migratory contact and attempt to restore connectivity where it has been lost.

  • [Show abstract] [Hide abstract]
    ABSTRACT: Freshwater Sawfish (Pristis microdon) movements and population demographics in the Fitzroy River, Western Australia and genetic analysis of P. microdon and Pristis zijsron. This report is divided into two sections. Section I reports on the habitat use, movements, morphology, population demographics and distribution of the critically endangered Freshwater Sawfish (Pristis microdon) and Northern River Sharks (Glyphis garricki) in the Fitzroy River and King Sound, Western Australia in 2008 and 2009. Section II provides the preliminary results of an analysis of spatial patterns of microsatellite variation in P. microdon, and of mitochondrial DNA variation in Pristis zijsron, in Australian waters. This research is part of an on-going investigation into the genetic diversity and population structure of Pristis sawfishes in these waters. The results for P. microdon are based upon the analysis of variation at three tetranucleotide microsatellite loci in 22 or more individuals from the Fitzroy River region and 38 or more from the Gulf of Carpentaria region, with at least 60 individuals genotyped for each locus. The results for P. zijsron are based upon variation in the nucleotide sequence of a 352-bp portion of the control region in the mitochondrial genome in a total of 42 individuals from three geographic regions, namely the west coast (N = 22), the Gulf of Carpentaria (N = 9), and the east coast (N = 11).
  • [Show abstract] [Hide abstract]
    ABSTRACT: Connectivity among subpopulations is vital for the persistence of small and fragmented populations. For management interventions to be effective conservation planners have to make the critical distinction between structural connectivity (based on landscape structure) and functional connectivity (which considers both landscape structure and organism-specific behavioral attributes) which can differ considerably within a given context. We assessed spatial and temporal changes in structural and functional connectivity of the Cross River gorilla Gorilla gorilla diehli (CRG) population in a 12,000 km2 landscape in the Nigeria-Cameroon border region over a 23-year period, comparing two periods: 1987–2000 and 2000–2010. Despite substantial forest connections between occupied areas, genetic evidence shows that only limited dispersal occurs among CRG subpopulations. We used remotely sensed land-cover data and simulated human pressure (using a spatially explicit agent-based model) to assess human impact on connectivity of the CRG population. We calculated cost-weighted distances between areas occupied by gorillas as measures of connectivity (structural based on land-cover only, functional based on both land-cover and simulated human pressure). Whereas structural connectivity decreased by 5% over the 23-year period, functional connectivity decreased by 11%, with both decreasing more during the latter compared to the earlier period. Our results highlight the increasing threat of isolation of CRG subpopulations due to human disturbance, and provide insight into how increasing human influence may lead to functional isolation of wildlife populations despite habitat continuity, a pressing and common issue in tropical Africa often not accounted for when deciding management interventions. In addition to quantifying threats to connectivity, our study provides crucial evidence for management authorities to identify actions that are more likely to be effective for conservation of species in human-dominated landscapes. Our approach can be easily applied to other species, regions, and scales. Am. J. Primatol. © 2014 Wiley Periodicals, Inc.
    American Journal of Primatology 04/2014; · 2.46 Impact Factor
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: Abstract The Guinean Forests are renowned for their primate diversity, with nearly 30 distinct species. These forests have been identified as some of Africa's most critical primate conservation areas. However, intensive poaching pressure and habitat degradation cause severe threats to these species. The remaining primate populations have low population densities, have secretive habitats, and are wary of humans. This can make field studies and direct observation difficult. To develop a reliable, sensitive and simple molecular identification method using Polymerase Chain Reaction (PCR), we sequenced the mitochondrial D-loop Hypervariable 1 region (HVR1) of Diana monkey (Cercopithecus diana) and Campbell monkey (Cercopithecus campbelli). From these sequences and their orthologs within Eastern black-and-white colobus (Colobus guereza) obtained from GenBank, we designed species-specific primers to amplify fragments of the mitochondrial D-loop HVR1 gene from faecal samples. These primers allow us to differentiate between Diana monkey (C. diana), Campbell monkey (C. campbelli), lesser spot-nosed monkey (Cercopithecus petaurista), Red colobus (Piliocolobus badius), Olive colobus (Procolobus verus), King colobus (C. polykomos), and Geoffroy’s black-and-white colobus (C. vellerosus), demonstrating their potential for the identification of West African threatened primates.
    Tropical Conservation Science 09/2014; 7(3):548-560. · 1.09 Impact Factor


Available from