Department of Primatology, Max Planck Institute for Evolutionary Anthropology, Leipzig, Germany.
PLoS One. 2011;6(6):e19788. doi: 10.1371/journal.pone.0019788. Epub 2011 Jun 8.
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.
随着野生动物数量的减少，保护主义者面临越来越大的压力，需要衡量不同管理策略的有效性。传统的保护措施，如执法和社区发展项目，通常旨在最大限度地减少人类对物种及其生态系统的负面影响。相比之下，我们将“极端”保护定义为旨在有意增加人类积极影响的努力，包括兽医护理和对个别动物的密切监测。在这里，我们比较了这两种保护方法对极度濒危的维龙加山地大猩猩（Gorilla beringei beringei）种群增长率的影响，自 1981 年种群数量达到最低点以来，大猩猩的数量增加了 50%，从大约 250 只增加到近 400 只。利用 1967 年至 2008 年的人口数据，我们发现，接受高强度传统保护措施的未驯化大猩猩的年增长率为 0.7%±0.059%，而接受极端保护措施的驯化大猩猩的增长率为 4.1%±0.088%。现在，每一组驯化的大猩猩在白天都由一组单独的野外工作人员持续看守，并接受陷阱、呼吸道疾病和其他危及生命的疾病的兽医治疗。这些结果表明，传统的保护措施防止了总体人口的严重下降，但需要额外的极端措施才能实现正增长。人口统计学随机性和社会生态因素对增长率的变化影响很小。兽医干预措施可能占到驯化大猩猩和未驯化大猩猩增长率差异的 40%，其余差异可能来自对偷猎者的更大保护。因此，通过增加保护和促进兽医治疗，对每个驯化群体的日常监测有助于解释增长率差异的大部分原因。我们的研究结果表明，需要更广泛地考虑极端措施，并提供了一个惊人的视角，即可能需要巨大的资源来保护一些濒危物种。
