Assessing the relationship between illegal hunting of ungulates, wild prey occurrence and livestock depredation rate by large carnivores

1. Illegal hunting of ungulates can reduce the prey base of carnivores, which can increase human-carnivore conflict (HCC) through livestock depredation. However, the relationship between ungulate poaching, wild prey abundance and livestock depredation has rarely been empirically studied.
2. We surveyed 18 sites across the Hyrcanian forest in northern Iran; a global biodiversity hotspot under pressure of illegal hunting of ungulates, prey depletion, livestock grazing and HCC. We conducted three field surveys across 1204 km in 93 4×4 km cells to count signs of ungulate poaching as well as encounters with livestock and prey species of the Persian leopard Panthera pardus saxicolor and the grey wolf Canis lupus. We documented sheep/goat and cattle depredation from interviews with 201 herders and analysed the effects of illegal hunting of ungulates, forest cover, IUCN categories of reserves, elevation, distance to villages, and wild prey and livestock encounter rates on carnivore depredation rates using generalized linear models.
3. Illegal hunting of ungulates was the most influential depredation predictor. An increase in the illegal hunting of ungulates by one sign/km significantly increased depredation by up to four times. We also found significantly lower levels of ungulate poaching in national parks (IUCN category II) compared to protected areas (V), wildlife refuges (IV) and no-hunting areas, though poaching signs were frequently found in most cells (58%). Encounters with livestock was inversely linked to wild prey species, but positively coupled with signs of ungulate poaching.
4. Synthesis and applications. Our study reveals that: (i) an increase in the intensity of illegal hunting of ungulates can intensify livestock depredation by carnivores; (ii) future efforts in reducing human-carnivore conflict (HCC) to acceptable levels require a combination of law enforcement, prey recovery approaches and mitigation measures; (iii) there is an urgent need to better understand the root causes of poaching of ungulates to help minimize HCC.

1. 非法捕猎有蹄类动物（ungulates）会缩减食肉动物（carnivores）的猎物基础，进而通过家畜被捕食加剧人兽冲突（human-carnivore conflict, HCC）。然而，目前鲜有实证研究探讨有蹄类盗猎、野生猎物丰度与家畜被捕食之间的关联。
2. 我们在伊朗北部的希尔卡尼亚森林（Hyrcanian forest）内对18个调查样点开展了实地调研。该区域作为全球生物多样性热点地区，正面临有蹄类非法捕猎、猎物资源枯竭、家畜放牧以及人兽冲突的多重生存压力。我们在93个4×4平方千米的网格单元内完成了3次野外调查，总行程达1204千米，以此统计有蹄类盗猎痕迹，并记录家畜以及波斯豹（Panthera pardus saxicolor）、灰狼（Canis lupus）的猎物物种的偶遇情况。我们通过对201名牧民的访谈记录了绵羊/山羊和牛的被捕食事件，并采用广义线性模型（generalized linear models）分析了有蹄类非法捕猎强度、森林覆盖率、国际自然保护联盟（IUCN）保护区等级、海拔、距村庄的距离以及野生猎物和家畜的偶遇频次对食肉动物家畜被捕食率的影响。
3. 有蹄类非法捕猎是影响家畜被捕食率最具影响力的预测因子。每千米样线内有蹄类盗猎痕迹每增加1处，家畜被捕食率将显著提升至多4倍。我们还发现，与保护区（V类）、野生动物庇护所（IV类）及禁猎区相比，国家公园（II类 IUCN 保护区等级）内的有蹄类盗猎痕迹显著更少，尽管58%的网格单元中均频繁发现盗猎痕迹。家畜偶遇频次与野生猎物物种呈负相关关系，却与有蹄类盗猎痕迹呈正相关关系。
4. 研究总结与应用启示。本研究结果表明：其一，有蹄类非法捕猎强度的提升会加剧食肉动物对家畜的捕食行为；其二，未来若要将人兽冲突控制在可接受水平，需综合采取执法监管、猎物种群恢复措施以及冲突缓解手段；其三，亟需深入解析有蹄类盗猎的根本成因，以助力最大限度降低人兽冲突（HCC）。