Gorilla gorilla

Assessment Information: Justification: Gorilla gorillahas a large geographic range, covering over 700,000 km². The size of the population is currently being evaluated, but thought to be in the order of a few hundred thousand (Strindberg et al. in prep). Only a very small number of Western Gorillas are the G. g. diehli subspecies, therefore this rationale focuses on the G. g. gorilla subspecies. The country of Gabon lost over half its Gorilla population between 1983 and 2000 (Walsh et al. 2003). More recent population declines have been estimated using a predictive model that incorporated survey data collected between 2003 and 2013 across the entire range of Western Lowland Gorillas. The results reveal an 18.75% decline between 2005 and 2013, corresponding to an annual loss of ~2.56% (Strindberg et al. in prep). These population decreases were driven by poaching and disease (Ebolavirus) outbreaks.Despite their abundance and wide geographic range, Western Gorillas qualify as Critically Endangered under criterion A: a population reduction of more than 80% over three generations (one generation is ~22 years). This listing is based on ongoing population losses due to illegal hunting, disease and habitat loss: poaching is intensifying with the expansion of access routes into forests and Zaire Ebolavirus remains a highly significant threat. At a conservative rate of reduction (2.56% per year rather than 4%, calculated from Walsh et al. 2003), the reduction in the Western Gorilla population is predicted to exceed 80% over three generations (i.e., 66 years, 2005-2071). Illegal hunting has not ceased despite intense anti-poaching efforts, and the threat of Ebolavirus has not been removed. In addition, the scale of habitat conversion to industrial agriculture will increase, and the effects of climate change will become more evident.Gorilla gorillathus qualifies as Critically Endangered (A4bcde)

Regional Action Plan for the Conservation of the Cross River Gorilla (Gorilla gorilla diehli)

From Executive Summary: This document represents the consensus of experts who met at a workshop in April 2006 in Calabar, Cross River State, Nigeria, to formulate a set of priority actions that would increase the survival prospects for the Cross River gorilla (Gorilla gorilla diehli). The Cross River gorilla is recognized by IUCN as Critically Endangered, and is the most threatened taxon of ape in Africa. It is the most westerly and northerly form of gorilla, and occurs only in a limited area around the mountainous headwaters of the Cross River, straddling the border between Cameroon and Nigeria. Participants at the 2006 workshop, which built upon the outcomes of previous meetings in Calabar in 2001 and Limbe, Cameroon, in 2003, included representatives of forestry and wildlife conservation agencies from the two range countries, of local and international nongovernmental conservation and development organizations, and of university-based researchers

Revised Regional Action Plan for the Conservation of the Cross River Gorilla (Gorilla gorilla diehli) 2014–2019

This plan outlines measures that should ensure that Cross River gorilla numbers are able to increase at key core sites, allowing them to extend into areas where they have been absent for many years

The complex Y-chromosomal history of gorillas

Studies of the evolutionary relationships among gorilla populations using autosomal and mitochondrial sequences suggest that male-mediated gene flow may have been important in the past, but data on the Y-chromosomal relationships among the gorilla subspecies are limited. Here, we genotyped blood and noninvasively collected fecal samples from 12 captives and 257 wild male gorillas of known origin representing all four subspecies (Gorilla gorilla gorilla, G. g. diehli, G. beringei beringei, and G. b. graueri) at 10 Y-linked microsatellite loci resulting in 102 unique Y-haplotypes for 224 individuals. We found that western lowland gorilla (G. g. gorilla) haplotypes were consistently more diverse than any other subspecies for all measures of diversity and comprised several genetically distinct groups. However, these did not correspond to geographical proximity and some closely related haplotypes were found several hundred kilometers apart. Similarly, our broad sampling of eastern gorillas revealed that mountain (G. b. beringei) and Grauer's (G. b. graueri) gorilla Y-chromosomal haplotypes did not form distinct clusters. These observations suggest structure in the ancestral population with subsequent mixing of differentiated haplotypes by male dispersal for western lowland gorillas, and postisolation migration or incomplete lineage sorting due to short divergence times for eastern gorillas

Historical sampling reveals dramatic demographic changes in western gorilla populations

Background: Today many large mammals live in small, fragmented populations, but it is often unclear whether this subdivision is the result of long-term or recent events. Demographic modeling using genetic data can estimate changes in long-term population sizes while temporal sampling provides a way to compare genetic variation present today with that sampled in the past. In order to better understand the dynamics associated with the divergences of great ape populations, these analytical approaches were applied to western gorillas (Gorilla gorilla) and in particular to the isolated and Critically Endangered Cross River gorilla subspecies (G. g. diehli).Results: We used microsatellite genotypes from museum specimens and contemporary samples of Cross River gorillas to infer both the long-term and recent population history. We find that Cross River gorillas diverged from the ancestral western gorilla population ~17,800 years ago (95% HDI: 760, 63,245 years). However, gene flow ceased only ~420 years ago (95% HDI: 200, 16,256 years), followed by a bottleneck beginning ~320 years ago (95% HDI: 200, 2,825 years) that caused a 60-fold decrease in the effective population size of Cross River gorillas. Direct comparison of heterozygosity estimates from museum and contemporary samples suggests a loss of genetic variation over the last 100 years.Conclusions: The composite history of western gorillas could plausibly be explained by climatic oscillations inducing environmental changes in western equatorial Africa that would have allowed gorilla populations to expand over time but ultimately isolate the Cross River gorillas, which thereafter exhibited a dramatic population size reduction. The recent decrease in the Cross River population is accordingly most likely attributable to increasing anthropogenic pressure over the last several hundred years. Isolation of diverging populations with prolonged concomitant gene flow, but not secondary admixture, appears to be a typical characteristic of the population histories of African great apes, including gorillas, chimpanzees and bonobos

Cytomegalovirus distribution and evolution in hominines

Herpesviruses are thought to have evolved in very close association with their hosts. This is notably the case for cytomegaloviruses (CMVs; genus Cytomegalovirus) infecting primates, which exhibit a strong signal of co-divergence with their hosts. Some herpesviruses are however known to have crossed species barriers. Based on a limited sampling of CMV diversity in the hominine (African great ape and human) lineage, we hypothesized that chimpanzees and gorillas might have mutually exchanged CMVs in the past. Here, we performed a comprehensive molecular screening of all 9 African great ape species/subspecies, using 675 fecal samples collected from wild animals. We identified CMVs in eight species/subspecies, notably generating the first CMV sequences from bonobos. We used this extended dataset to test competing hypotheses with various degrees of co-divergence/number of host switches while simultaneously estimating the dates of these events in a Bayesian framework. The model best supported by the data involved the transmission of a gorilla CMV to the panine (chimpanzee and bonobo) lineage and the transmission of a panine CMV to the gorilla lineage prior to the divergence of chimpanzees and bonobos, more than 800,000 years ago. Panine CMVs then co-diverged with their hosts. These results add to a growing body of evidence suggesting that viruses with a double-stranded DNA genome (including other herpesviruses, adenoviruses, and papillomaviruses) often jumped between hominine lineages over the last few million years.Peer Reviewe

Regional Action Plan for the Conservation of the Nigeria–Cameroon Chimpanzee (Pan troglodytes ellioti)

First paragraph: This document represents the consensus of views from forestry and wildlife conservation agencies in Nigeria and Cameroon, local and international nongovernmental conservation organizations, and university-based researchers who met at a series of workshops in Cameroon and Nigeria to formulate a set of actions that, if implemented, will increase the longterm survival prospects of the Nigeria-Cameroon chimpanzee, Pan troglodytes ellioti. The Nigeria-Cameroon chimpanzee is the most endangered of all currently recognized chimpanzee subspecies, with a total remaining population of between 3,500 and 9,000 living in forested habitat to the north of the Sanaga River in Cameroon, the eastern edge of Nigeria, and in forest fragments in the Niger Delta and southwestern Nigeri

Predicting range shifts of African apes under global change scenarios

Aim: Modelling African great ape distribution has until now focused on current or past conditions, while future scenarios remain scarcely explored. Using an ensemble forecasting approach, we predicted changes in taxon-specific distribution under future scenarios of climate, land use and human populations for (1) areas outside protected areas (PAs) only (assuming complete management effectiveness of PAs), (2) the entire study region and (3) interspecies range overlap. Location: Tropical Africa. Methods: We compiled occurrence data (n = 5,203) on African apes from the IUCN A.P.E.S. database and extracted relevant climate-, habitat- and human-related predictors representing current and future (2050) conditions to predict taxon-specific range change under a best- and a worst-case scenario, using ensemble forecasting. Results: The predictive performance of the models varied across taxa. Synergistic interactions between predictors are shaping African ape distribution, particularly human-related variables. On average across taxa, a range decline of 50% is expected outside PAs under the best scenario if no dispersal occurs (61% in worst scenario). Otherwise, an 85% range reduction is predicted to occur across study regions (94% worst). However, range gains are predicted outside PAs if dispersal occurs (52% best, 21% worst), with a slight increase in gains expected across study regions (66% best, 24% worst). Moreover, more than half of range losses and gains are predicted to occur outside PAs where interspecific ranges overlap. Main Conclusions: Massive range decline is expected by 2050, but range gain is uncertain as African apes will not be able to occupy these new areas immediately due to their limited dispersal capacity, migration lag and ecological constraints. Given that most future range changes are predicted outside PAs, Africa\u27s current PA network is likely to be insufficient for preserving suitable habitats and maintaining connected ape populations. Thus, conservation planners urgently need to integrate land use planning and climate change mitigation measures at all decision-making levels both in range countries and abroad

The time scale of recombination rate evolution in great apes

We present three linkage-disequilibrium (LD)-based recombination maps generated using whole-genome sequence data from 10 Nigerian chimpanzees, 13 bonobos, and 15 western gorillas, collected as part of the Great Ape Genome Project (Prado-Martinez J, et al. 2013. Great ape genetic diversity and population history. Nature 499:471-475). We also identified species-specific recombination hotspots in each group using a modified LDhot framework, which greatly improves statistical power to detect hotspots at varying strengths. We show that fewer hotspots are shared among chimpanzee subspecies than within human populations, further narrowing the time scale of complete hotspot turnover. Further, using species-specific PRDM9 sequences to predict potential binding sites (PBS), we show higher predicted PRDM9 binding in recombination hotspots as compared to matched cold spot regions in multiple great ape species, including at least one chimpanzee subspecies. We found that correlations between broad-scale recombination rates decline more rapidly than nucleotide divergence between species. We also compared the skew of recombination rates at centromeres and telomeres between species and show a skew from chromosome means extending as far as 10-15Mb from chromosome ends. Further, we examined broad-scale recombination rate changes near a translocation in gorillas and found minimal differences as compared to other great ape species perhaps because the coordinates relative to the chromosome ends were unaffected. Finally, on the basis of multiple linear regression analysis, we found that various correlates of recombination rate persist throughout the African great apes including repeats, diversity, and divergence. Our study is the first to analyze within- And between-species genome-wide recombination rate variation in several close relatives