Testing the effects of anthropogenic pressures on a diverse African herbivore community
Testing the effects of anthropogenic pressures on a diverse African herbivore community
复制标题
测试人为压力对非洲多样化食草动物群落的影响
作者：
Milan A. Vinks;S. Creel;P. Schuette;E. Rosenblatt;W. Matandiko;C. Sanguinetti;Kambwiri Banda;Ben Goodheart;M. Becker;Clive Chifunte;Chuma Simukonda
近几十年来，世界各地的大型食草动物群落急剧减少。尽管过度采集森林猎物被认为是许多生态系统中食草动物数量减少的主要原因，但在大多数正在经历数量减少的系统中，人为压力对大型食草动物种群的直接影响仍然鲜有描述。为了测试被认为正在经历人为衰退的保护区 (PA) 中大型食草动物受到生态和人为因素影响的程度，我们将距离抽样模型与卡富埃国家公园 (KNP) 系统性地面调查的七年数据进行拟合，以估计 10 种大型食草动物的种群密度和分布，并测试影响这些参数的因素。 KNP 中 10 种最丰富的大型食草动物的种群密度远低于生态相似且偷猎压力较小的 PA 的种群密度。尽管物种和大小类别之间存在重要的生态差异，但不同物种和地区的低密度是一致的。相对于体型较小的物种，体型较大的食草动物的密度大大降低。这种模式对大量食肉动物种群有直接和间接的影响，对生态旅游和战利品狩猎业具有广泛的影响。存在统计和方法上严格的方法来测试人为和环境变量对密度和分布的影响，但很少应用于大型食草动物。为了量化草食动物种群的趋势并评估保护行动的有效性，我们的结果表明，采用分层地面监测进行距离采样是一种高效且有效的方法。在大卡富埃生态系统（GKE）中，需要持续加强资源保护，以促进具有经济和生态重要性的大型食草动物协会的恢复。更广泛地说，我们的结果证实，即使在非常大的保护区，人为对所有物种（特别是行会中较大成员）的大型食草动物分布和丰度的影响也很大。
Large herbivore communities around the world have declined steeply in recent decades. Although excessive bushmeat harvesting is thought to be the primary cause of herbivore declines in many ecosystems, the direct effects of anthropogenic pressures on large herbivore populations remain poorly described in most of the systems experiencing decline. To test the extent to which large herbivores are impacted by ecological and anthropogenic factors in a protected area (PA) thought to be experiencing human-caused decline, we fit distance sampling models to seven years of data from systematic ground-based surveys in Kafue National Park (KNP) to estimate the population densities and distributions of 10 species of large herbivores, and to test what factors affect these parameters. Population densities of the ten most abundant large herbivores in KNP were substantially lower than those reported for an ecologically similar PA with less poaching pressure. Low densities were consistent across species and areas, though there was ecologically important variation among species and size classes. Densities of larger-bodied herbivores were greatly depressed relative to smaller species. This pattern has direct and indirect effects on large carnivore populations, with broad implications for the ecotourism and trophy hunting industries. Statistically and methodologically rigorous methods to test the effects of anthropogenic and environmental variables on density and distribution exist, but are rarely applied to large herbivores. To quantify trends in herbivore populations and evaluate the effectiveness of conservation actions, our results show that distance sampling with stratified ground-based monitoring is an efficient and effective method. In the Greater Kafue Ecosystem (GKE), continued increases in resource protection are needed to facilitate the recovery of an economically and ecologically important large herbivore guild. More broadly, our results confirm that anthropogenic effects on large herbivore distribution and abundance can be strong over wide areas for all species (particularly the larger members of the guild), even in very large PAs.