Kiffner Christian, Kioko John, Baylis Jack, Beckwith Camille, Brunner Craig, Burns Christine, Chavez-Molina Vasco, Cotton Sara, Glazik Laura, Loftis Ellen, Moran Megan, O'Neill Caitlin, Theisinger Ole, Kissui Bernard
Center for Wildlife Management Studies The School For Field Studies Karatu Tanzania.
Department of Environmental Studies and Sciences Santa Clara University Santa Clara CA USA.
Ecol Evol. 2020 Aug 7;10(18):10000-10016. doi: 10.1002/ece3.6658. eCollection 2020 Sep.
Facilitating coexistence between people and wildlife is a major conservation challenge in East Africa. Some conservation models aim to balance the needs of people and wildlife, but the effectiveness of these models is rarely assessed. Using a case-study approach, we assessed the ecological performance of a pastoral area in northern Tanzania (Manyara Ranch) and established a long-term wildlife population monitoring program (carried out intermittently from 2003 to 2008 and regularly from 2011 to 2019) embedded in a distance sampling framework. By comparing density estimates of the road transect-based long-term monitoring to estimates derived from systematically distributed transects, we found that the bias associated with nonrandom placement of transects was nonsignificant. Overall, cattle and sheep and goat reached the greatest densities and several wildlife species occurred at densities similar (zebra, wildebeest, waterbuck, Kirk's dik-dik) or possibly even greater (giraffe, eland, lesser kudu, Grant's gazelle, Thomson's gazelle) than in adjacent national parks in the same ecosystem. Generalized linear mixed models suggested that most wildlife species (8 out of 14) reached greatest densities during the dry season, that wildlife population densities either remained constant or increased over the 17-year period, and that herbivorous livestock species remained constant, while domestic dog population decreased over time. Cross-species correlations did not provide evidence for interference competition between grazing or mixed livestock species and wildlife species but indicate possible negative relationships between domestic dog and warthog populations. Overall, wildlife and livestock populations in Manyara Ranch appear to coexist over the 17-year span. Most likely, this is facilitated by existing connectivity to adjacent protected areas, effective anti-poaching efforts, spatio-temporal grazing restrictions, favorable environmental conditions of the ranch, and spatial heterogeneity of surface water and habitats. This long-term case study illustrates the potential of rangelands to simultaneously support wildlife conservation and human livelihood goals if livestock grazing is restricted in space, time, and numbers.
促进人类与野生动物的共存是东非面临的一项重大保护挑战。一些保护模式旨在平衡人类和野生动物的需求，但这些模式的有效性很少得到评估。我们采用案例研究方法，评估了坦桑尼亚北部一个牧区（曼亚拉牧场）的生态表现，并建立了一个长期野生动物种群监测项目（2003年至2008年期间间歇性开展，2011年至2019年期间定期开展），该项目嵌入了距离抽样框架。通过将基于道路样带的长期监测的密度估计值与系统分布样带得出的估计值进行比较，我们发现与样带非随机放置相关的偏差不显著。总体而言，牛、绵羊和山羊的密度最高，几种野生动物的密度与同一生态系统中相邻国家公园的密度相似（斑马、角马、水羚、柯氏犬羚），甚至可能更高（长颈鹿、大羚羊、东非紫羚、格兰特瞪羚、汤氏瞪羚）。广义线性混合模型表明，大多数野生动物物种（14种中的8种）在旱季密度最高，野生动物种群密度在17年期间要么保持不变，要么有所增加，食草家畜物种数量保持不变，而家犬数量随时间减少。跨物种相关性没有提供放牧或混合家畜物种与野生动物物种之间存在干扰竞争的证据，但表明家犬和疣猪种群之间可能存在负相关关系。总体而言，曼亚拉牧场的野生动物和家畜种群在17年期间似乎共存。这很可能得益于与相邻保护区现有的连通性、有效的反偷猎措施、时空放牧限制、牧场有利的环境条件以及地表水和栖息地的空间异质性。这项长期案例研究表明，如果在空间、时间和数量上限制牲畜放牧，牧场有潜力同时支持野生动物保护和人类生计目标。
