In many parts of East Africa, wildlife populations have declined over the past decades. Given these trends, site-based studies are needed to assess how protected areas with differing management strategies enable the effective conservation of wildlife populations. In Tanzania, game reserves are managed for tourist hunting, while national parks are managed for non-consumptive wildlife-based tourism. To assess the relative performance of these management strategies, we here focus on two areas: Rukwa Game Reserve (RGR) and Katavi National Park (KNP). Based on systematically designed line distance surveys in 2004 and 2021, we compared densities and group sizes of large mammal populations (African elephant, giraffe, buffalo, zebra, topi, and hartebeest) over time. Contrary to published ecosystem-wide declines observed in numerous species which considered earlier baselines, we did not detect significant population declines between 2004 and 2021. While these new results showing apparent stable populations do not invalidate earlier studies on wildlife declines, they could indicate a stabilisation phase after declines. This highlights the importance of considering appropriate temporal baselines and historical contexts when assessing conservation effectiveness.

中文翻译：

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评估坦桑尼亚西部保护区的有效性：重复样线调查的见解

在东非许多地区，野生动物数量在过去几十年里有所下降。鉴于这些趋势，需要进行实地研究来评估采用不同管理策略的保护区如何能够有效保护野生动物种群。在坦桑尼亚，野生动物保护区的管理目的是为了旅游狩猎，而国家公园的管理目的是为了非消费性野生动物旅游业。为了评估这些管理策略的相对绩效，我们重点关注两个区域：鲁夸野生动物保护区 (RGR) 和卡塔维国家公园 (KNP)。根据 2004 年和 2021 年系统设计的线距调查，我们比较了大型哺乳动物种群（非洲象、长颈鹿、水牛、斑马、托皮和狷羚）随时间变化的密度和群体规模。与已发表的在考虑早期基线的许多物种中观察到的生态系统范围内的下降相反，我们没有发现 2004 年至 2021 年间种群数量出现显着下降。虽然这些显示种群数量明显稳定的新结果并没有使早期关于野生动物下降的研究无效，但它们可能表明稳定状态下降后的阶段。这凸显了在评估保护有效性时考虑适当的时间基线和历史背景的重要性。