基于调查的推断,非洲大陆大象的数量下降
Charles T T Edwards1, Kathleen S Gobush2, Fiona Maisels3,4
1CEscape Consultancy Services, Knysna 6570, South Africa.
概括
非洲大象的数量显著下降,森林大象减少了90%以上,大草原大象减少了70%以上. 这项综合性研究强调了大象人口趋势的区域差异.
科学领域:
- 生态与保护生物学 生态与保护生物学
- 野生动物人口动力学
- 在生态学中的统计建模.
背景情况:
- 量化长期物种趋势对于保护地位的分配和管理干预至关重要.
- 由于方法的变化,监测数据的异质性给准确的趋势解释带来了挑战.
- 了解人口动态对于有效保护非洲大象物种至关重要.
研究的目的:
- 开发一个强大的统计模型,用不同的调查数据来估计非洲大象的地点密度趋势.
- 量化非洲森林象 (Loxodonta cyclotis) 和大草原象 (Loxodonta africana) 的长期人口趋势.
- 评估不同地区和物种的种群状况和趋势的变化.
主要方法:
- 开发一个分层的,随机效应的贝叶斯模型来分析地理分散的调查数据.
- 估计站点级密度趋势,将每个站点的趋势视为随机效应.
- 单独和组合地为森林和草原大象实施该模型,并按地区划分,使用来自37个国家的475个地点的数据 (1964-2016).
主要成果:
- 推断表明,在研究期间,非洲森林和大草原大象的平均地点水平下降.
- 森林大象的平均减少率估计超过90%,草原大象的平均减少率超过70%.
- 观察到所有地点的综合平均下降率为77%,趋势具有显著的异质性,特别稳定在南部非洲的增长趋势.
结论:
- 这项研究提供了迄今为止对非洲大象人口趋势的最全面的评估.
- 显著的人口下降需要紧急保护注意,对物种和地区的影响各不相同.
- 开发的贝叶斯建模方法有效地处理异质数据,为保护计划提供可靠的趋势估计.
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