Pace Daniela Silvia, Di Marco Chiara, Giacomini Giancarlo, Ferri Sara, Silvestri Margherita, Papale Elena, Casoli Edoardo, Ventura Daniele, Mingione Marco, Alaimo Di Loro Pierfrancesco, Jona Lasinio Giovanna, Ardizzone Giandomenico
Department of Environmental Biology, Sapienza University of Rome, 00185 Rome, Italy.
CNR-IAS, Campobello di Mazara, 91021 Trapani, Italy.
Biology (Basel). 2021 Mar 28;10(4):275. doi: 10.3390/biology10040275.
Periodic assessments of population status and trends to detect natural influences and human effects on coastal dolphin are often limited by lack of baseline information. Here, we investigated for the first time the site-fidelity patterns and estimated the population size of bottlenose dolphins () at the Tiber River estuary (central Mediterranean, Tyrrhenian Sea, Rome, Italy) between 2017 and 2020. We used photo-identification data and site-fidelity metrics to study the tendency of dolphins to remain in, or return to, the study area, and capture-recapture models to estimate the population abundance. In all, 347 unique individuals were identified. The hierarchical cluster analysis highlighted 3 clusters, labeled resident (individuals encountered at least five times, in three different months, over three distinct years; = 42), part-time (individuals encountered at least on two occasions in a month, in at least two different years; = 73), and transient (individuals encountered on more than one occasion, in more than 1 month, none of them in more than 1 year; = 232), each characterized by site-fidelity metrics. Open POPAN modeling estimated a population size of 529 individuals (95% CI: 456-614), showing that the Capitoline (Roman) coastal area and nearby regions surrounding the Tiber River estuary represent an important, suitable habitat for bottlenose dolphins, despite their proximity to one of the major urban centers in the world (the city of Rome). Given the high number of individuals in the area and the presence of resident individuals with strong site fidelity, we suggest that conservation plans should not be focused only close to the Tiber River mouths but extended to cover a broader scale of area.
对种群状况和趋势进行定期评估以检测自然影响和人类对沿海海豚的作用，常常因缺乏基线信息而受到限制。在此，我们首次调查了2017年至2020年期间台伯河河口（意大利罗马，第勒尼安海，地中海中部）宽吻海豚的居留模式，并估计了其种群数量。我们使用照片识别数据和居留度指标来研究海豚留在或返回研究区域的趋势，并使用捕获-重捕模型来估计种群数量。总共识别出347个独特个体。层次聚类分析突出显示了3个聚类，分别标记为常住型（在三个不同年份的三个月中至少被遇到五次的个体；n = 42）、兼职型（在至少两个不同年份的一个月中至少被遇到两次的个体；n = 73）和暂居型（在超过1个月的时间内被遇到不止一次，且在超过1年的时间内均未被遇到超过1次的个体；n = 232），每个聚类都有其居留度指标特征。开放POPAN模型估计种群数量为529只（95%置信区间：456 - 614），这表明卡皮托利尼（罗马）沿海地区和台伯河河口周边附近区域是宽吻海豚的重要适宜栖息地，尽管它们靠近世界主要城市中心之一（罗马市）。鉴于该区域个体数量众多且存在具有强烈居留忠诚度的常住个体，我们建议保护计划不应仅聚焦于台伯河河口附近，而应扩大到更广泛的区域范围。
