Here we report on the ninth iteration of the biennial listing of a consensus of the 25 primate species considered to be among the most endangered worldwide and the most in need of conservation measures. The 2016–2018 list of the world’s 25 most endangered primates has five species from Africa, six from Madagascar, nine from Asia, and five from the Neotropics.

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Primates in Peril: The World's 25 Most Endangered Primates 2008–2010

To determine who fathers the offspring in wild mountain gorilla groups containing more than one adult male silverback, we genotyped nearly one-fourth (n = 92) of the mountain gorillas (Gorilla beringei beringei) living in the Virunga Volcanoes region of Africa. Paternity analysis of 48 offspring born into four groups between 1985 and 1999 revealed that, although all infants were sired by within-group males, the socially dominant silverback did not always monopolize reproduction within his group. Instead, the second-ranking male sired an average of 15% of group offspring. This result, in combination with previous findings that second-ranking males fare best by not leaving the group but by staying and waiting to assume dominance even if no reproduction is possible while waiting, is not consistent with expectations from a reproductive skew model in which the silverback concedes controllable reproduction to the second-ranking male. Instead, the data suggest a "tug-of-war" scenario in which neither the dominant nor the second-ranking male has full control over his relative reproductive share. The two top-ranked males were typically unrelated and this, in combination with the mixed paternity of group offspring, means that multimale gorilla groups do not approximate family groups. Instead, as long-term assemblages of related and unrelated individuals, gorilla groups are similar to chimpanzee groups and so offer interesting possibilities for kin-biased interactions among individuals.

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Mountain gorilla tug-of-war: Silverbacks have limited control over reproduction in multimale groups

The design of the 2010 State of the Forest report does not differ fundamentally from that of the 2008 report and relies on indicators decided on collectively by about sixty contributors Data collection was organized from 2009 to 2010 using national groups consisting of four to ten members, depending on the countries, all of whom worked for public administrations dealing with forest issues Data collected, covering for the most part 2008 and 2009, was validated during national workshops for public administration officials, environmental NGO representatives, the private sector and development projects The data served to support the inputs provided by contributors of chapters for the current report, under the supervision of internationally recognized scientific committees Furthermore, a State of the Forest 2010 sub-regional validation workshop was organized from 29 to 30 March 2011 for about 100 participants working in forest management, comprising representatives from the ten COMIFAC member countries, and several of its partners

The Forests of the Congo Basin: State of the Forest 2010

Life-history traits and ecological conditions have an important influence on primate social systems. Most of what we know about the life-history patterns and social structure of gorillas comes from studies of eastern gorillas (Gorilla beringei sp.), which live under dramatically different ecological conditions compared to western gorillas (Gorilla gorilla sp.). In this paper we present new data on western gorilla social structure and life histories from four study sites, and make comparisons with eastern gorilla populations. Data were obtained from two study sites with gorilla groups undergoing the habituation process (Lossi, Democratic Republic of Congo and Bai Hokou, Central African Republic) and two "bai" studies (Maya Nord and Mbeli Bai, Republic of Congo). The size and structure of these groups were similar to those seen in eastern gorillas. However, differences in the occurrence of various group transitions (group formations, changes between one-male and multimale composition, and group disintegrations) exist, and western gorillas notably exhibit much higher rates of male emigration and correspondingly fewer multimale groups compared to mountain gorillas. Certain phenomena have been observed only rarely, including predation by leopards. The preliminary data show no significant differences in birth rates between western gorillas and mountain gorillas. The ecological variability across gorilla habitats likely explains the flexibility in the social system of gorillas, but we need more information on the social relationships and ecology of western gorillas to elucidate the causes for the similarities and differences between western and eastern gorillas on the levels of individuals, social groups, and population dynamics.

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Social structure and life-history patterns in western gorillas (Gorilla gorilla gorilla).

The combination of threats currently facing the remaining great apes requires immediate conservation action at all scales  from site-level initiatives, through national and regional strategies, to international conventions and action plans. This document outlines current approaches to great ape surveys and monitoring for field biologists, protected area managers, government wildlife departments and the conservation community at large. It contains detailed, additional information on survey design, field methods, analytical approaches, and practical considerations such as logistics, finance, and standardized reporting.

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Best practice guidelines for surveys and monitoring of great ape populations

Small populations are particularly susceptible to disturbance. Routine censusing to monitor changes is important for understanding both population dynamics and the effectiveness of conservation strategies. Mountain gorillas Gorilla beringei beringei in the Virunga Volcanoes region of Rwanda, Uganda and the Democratic Republic of Congo have been censused five times since 1970. However, due to war and political unrest in the region since 1990, no census had been conducted since 1989, when the population was thought to number 324 gorillas. In 2000 we estimated population size using repeated observations of 17 habituated groups and information on 15 unhabituated groups obtained during patrols. The minimum population was 359 gorillas, and a best-case scenario correcting for groups that might not have been counted was 395. Using the minimum population and best-case scenario respectively, this represents a 0.9% or 1.8% annual growth rate over the last decade and 1.0% or 1.3% annual growth rate since 1972. This is lower than growth estimates made in several population viability analyses, but approximately 5% of the 1989 population is known to have died due to military activity over the last decade. Different subsets of the population exhibited different responses to disturbance caused by war. We discuss conservation strategies that are likely to have contributed to an increase in the gorilla population during this time of turmoil. While the population has grown, the results should be viewed with caution, not only because all known growth during the last decade can be attributed to one subset of the population, but also because the region is still plagued by political unrest.

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José Kalpers

Papers

Gorillas in the crossfire: population dynamics of the Virunga mountain gorillas over the past three decades