Extreme Conservation Leads to Recovery of the Virunga Mountain Gorillas

Abstract

As wildlife populations are declining, conservationists are under increasing pressure to measure the effectiveness of different management strategies. Conventional conservation measures such as law enforcement and community development projects are typically designed to minimize negative human influences upon a species and its ecosystem. In contrast, we define “extreme” conservation as efforts targeted to deliberately increase positive human influences, including veterinary care and close monitoring of individual animals. Here we compare the impact of both conservation approaches upon the population growth rate of the critically endangered Virunga mountain gorillas (Gorilla beringei beringei), which increased by 50% since their nadir in 1981, from approximately 250 to nearly 400 gorillas. Using demographic data from 1967–2008, we show an annual decline of 0.7%±0.059% for unhabituated gorillas that received intensive levels of conventional conservation approaches, versus an increase 4.1%±0.088% for habituated gorillas that also received extreme conservation measures. Each group of habituated gorillas is now continuously guarded by a separate team of field staff during daylight hours and receives veterinary treatment for snares, respiratory disease, and other life-threatening conditions. These results suggest that conventional conservation efforts prevented a severe decline of the overall population, but additional extreme measures were needed to achieve positive growth. Demographic stochasticity and socioecological factors had minimal impact on variability in the growth rates. Veterinary interventions could account for up to 40% of the difference in growth rates between habituated versus unhabituated gorillas, with the remaining difference likely arising from greater protection against poachers. Thus, by increasing protection and facilitating veterinary treatment, the daily monitoring of each habituated group contributed to most of the difference in growth rates. Our results argue for wider consideration of extreme measures and offer a startling view of the enormous resources that may be needed to conserve some endangered species.

Alternative biological assumptions strongly influence models of climate change effects on mountain gorillas

“…Combined with 'extreme conservation' (Robbins et al 2011b) of continuous monitoring and health care, the existing gorilla parks may continue to provide stable or increasing populations of mountain gorilla. Although the methodological uncertainty in biological response models is problematic, the results presented here provide useful information for mountain gorilla research and conservation.…”

“…1). Mountain gorilla research and conservation has been very influential in conservation biology, including early and continued ecology and behavior research (Schaller 1963, Watts 1984, development of the flagship species approach (Fossey 1983), development of ecotourism to produce financial incentives and constituency building for conservation (Webber and Vedder 2001), development of multi-generational behavior studies (Robbins et al 2001), and most recently, 'extreme conservation' through the development of wildlife veterinary intervention and monitoring (Robbins et al 2011b).…”

“…The extent of the habitat available to gorillas has declined in the second half of the 20th century, but the mountain gorilla population size has increased in recent decades because of improved management, including stronger anti-poaching measures and veterinary interventions, stimulated by the financial benefits from tourism (Robbins et al 2011b). Nevertheless, the mountain gorilla population size is very low, which exposes them to additional risks including inbreeding depression (Garner and Ryder 1996).…”

Abrupt Decline in a Protected Population of Siamangs (Symphalangus syndactylus) in Southern Sumatra

“…Health-monitoring programmes and interventions directed specifically at great ape populations have shown substantial promise for reducing extinction risk [Robbins et al, 2011]. However, such programmes have not yet been developed for most other wild primates, including gibbons.…”

Lignes directrices pour de meilleures pratiques en matière de suivi de la santé et de contrôle des maladies des populations de grands singes

“…pour le tourisme). Pour les gorilles de montagne, une politique proactive d'intervention s'est avérée être un facteur majeur du rétablissement de la population des Virunga (Robbins et al 2011). Pour certains responsables d'AP+, la décision d'une intervention clinique en cas de blessure ou de maladie d'un grand singe repose sur l'obligation plus ou moins ressentie d'intervenir : certains soutiennent que si une blessure ou une maladie chez un grand singe est provoquée par l'homme (par ex.…”