Kentish plover capture histories

Global biodiversity loss is a major environmental concern. The wildlife on islands are particularly vulnerable to threats posed by alien predators, habitat loss and overexploitation. Effective conservation management of vulnerable species requires reliable information on vital population rates for all life stages and an understanding of key environmental drivers. However, demographic data are often not available for island populations before they decline or are extirpated. Here, we use Cormack-Jolly-Seber (CJS) models and 15 years of data for 1370 juveniles and 687 adults to estimate apparent survival for a genetically distinct resident population of Kentish plovers (Charadrius alexandrinus) on the island of Maio, Cabo Verde. We report two main findings. First, environmental conditions have a large effect on demographic performance since chicks that hatch during dry years experience a tenfold reduction in first-year survival compared to chicks that hatch during wet years. Second, female and male plovers in Maio are expected to live for 7.41 ± 0.69 (mean ± SE) years and 6.75 ± 0.64 years, respectively, due to relatively high annual survival among comparable-sized shorebirds. High adult survival thus could buffer the population against low reproductive success that this population has experienced over the last decade. Cabo Verde is typical of tropical islands with increased development that can impact native breeders and/or will accelerate habitat loss. Thus, more frequent droughts associated with climate change may exacerbate the prospects of native wildlife on many islands.全球生物多样性丧失是当前重大的环境议题。岛屿野生动物尤其容易受到外来捕食者、栖息地丧失与过度开发带来的威胁。对脆弱物种开展有效的保护管理，需要获取各生命阶段关键种群参数的可靠数据，并厘清核心环境驱动因素。然而，岛屿种群在数量下降或局部灭绝之前，往往难以获取其种群统计数据。本研究采用科马克-乔利-西贝尔（Cormack-Jolly-Seber, CJS）模型，结合佛得角马约岛上1370只幼鸟与687只成鸟的15年监测数据，对该岛遗传分化明显的居留种群环颈鸻（Charadrius alexandrinus）的表观存活率进行估算。本研究得到两项核心结论：其一，环境条件对种群统计表现影响显著：干旱年份孵化的幼鸟首年存活率较湿润年份孵化的幼鸟降低至原来的1/10；其二，相较于同类体型的滨鸟，马约岛环颈鸻的年均存活率较高，雌鸟与雄鸟的预期寿命分别为7.41±0.69（平均值±标准误）年与6.75±0.64年。因此，较高的成鸟存活率可缓冲该种群近十年面临的低繁殖成功率压力。佛得角群岛是热带岛屿的典型代表，当地开发强度不断提升，既会对本土繁殖鸟类造成影响，也可能加速栖息地丧失。因此，气候变化引发的干旱频次增加，可能会加剧全球众多岛屿本土野生动物的生存困境。