Table_2_Long-term trends in elephant mortality and their causes in Kenya.docx

High mortality poses a serious threat to sustainable conservation of the African elephant (Loxodonta africana). Using detected carcass data collected by the Kenya Wildlife Service (KWS) during 1992-2017, we analyze temporal and spatial variation in elephant mortality in Kenya. We investigate the major mortality causes and means used to kill elephants, carcass category, tusk recovery status, variation in mortality with elephant age and sex classes, differences between inside and outside protected areas (PAs), the Proportion of Illegally Killed Elephants (PIKE) and the overall mortality rate (MR — the number of dead/number of live elephants in a given year). In total 9,182 elephant deaths were recorded during the 26 years. Elephant mortality increased over time and was attributed primarily to natural (33.1%) and human-related causes, particularly ivory poaching (31.5%) and human-elephant conflicts (19.9%). Elephant mortality varied across Kenya’s 47 counties in correspondence with variation in elephant population size and was the highest in the leading elephant range counties of Taita Taveta, Laikipia, Samburu and Meru. Mortality was higher for males and adults and outside the protected areas. Most elephant carcasses had tusks (75.1%) but a few did not (12.5%). Yearly PIKE values peaked in 2012, the year with the highest poaching levels in Kenya during 1992-2017. MR increased throughout 1992-2017. Temporal variation in elephant mortality probability was significantly influenced by human and livestock population densities, average annual maximum temperature and total annual rainfall and the strength of these influences varied across the seven leading elephant range counties of Kenya. Natural processes are increasingly contributing to elephant mortality likely due to climate change and the associated food and water stress, exacerbated by contracting range. Enhancing anti-poaching and strategies for mitigating climate change impacts and human-elephant conflict and reducing range contraction while sustaining habitat connectivity can help reduce mortality and promote elephant conservation. Strengthening enforcement of international wildlife laws can further reduce illegal trade in tusks and killing of elephants.

高死亡率对非洲象（Loxodonta africana）的可持续保护构成严重威胁。本研究基于肯尼亚野生动物服务局（Kenya Wildlife Service, KWS）1992年至2017年间收集的已发现象尸数据，分析了肯尼亚境内象死亡率的时空变化特征。研究探讨了象死亡的主要诱因与猎杀手段、象尸类别、象牙留存状态、不同年龄与性别类群象的死亡率差异、保护区（Protected Areas, PAs）内外的死亡率差异、非法猎杀象比例（Proportion of Illegally Killed Elephants, PIKE）以及总死亡率（MR——即某一年内死亡象数量与存活象数量的比值）。26年间共计记录到9182头象的死亡案例。象死亡率随时间呈上升趋势，主要归因于自然因素（33.1%）与人为相关因素，其中尤以象牙偷猎（31.5%）和人象冲突（19.9%）为主。肯尼亚47个郡的象死亡率随象种群规模变化而存在差异，其中泰塔塔维塔、莱基皮亚、桑布卢和梅鲁这几个主要象栖息地郡的死亡率最高。雄性象与成年象的死亡率更高，且保护区外的死亡率高于保护区内。多数象尸留存有象牙（75.1%），仅少数未留存象牙（12.5%）。年度非法猎杀象比例在2012年达到峰值，该年份也是1992年至2017年间肯尼亚偷猎活动最猖獗的一年。总死亡率在1992年至2017年间持续上升。象死亡概率的时间变化显著受人类与家畜种群密度、年平均最高气温以及年总降雨量的影响，且这些影响的强度在肯尼亚7个主要象栖息地郡间存在差异。自然因素导致的象死亡占比不断上升，这可能源于气候变化及相关的食物与水源短缺，而栖息地缩减进一步加剧了这一状况。强化反偷猎工作、制定减缓气候变化影响与人象冲突的策略、减少栖息地缩减同时维持栖息地连通性，有助于降低象死亡率并推动象保护工作。加强国际野生动物保护法律的执法力度，可进一步减少象牙非法贸易与象类猎杀行为。