Haigh Kennadie, Parra Guido J, Möller Luciana, Steiner Aude, Bossley Mike
Cetacean Ecology, Behaviour and Evolution Lab, College of Science and Engineering Flinders University Adelaide South Australia Australia.
Bressaucourt Switzerland.
Ecol Evol. 2025 Jan 6;15(1):e70834. doi: 10.1002/ece3.70834. eCollection 2025 Jan.
Understanding population demography of threatened species and how they vary in relation to natural and anthropogenic stressors is essential for effective conservation. We used a long-term photographic capture-recapture dataset (1993-2020) of Indo-Pacific bottlenose dolphins () in the highly urbanised Adelaide Dolphin Sanctuary (ADS), South Australia, to estimate key demographic parameters and their variability over time. These parameters were analysed in relation to environmental variables used as indicators of local and large-scale climatic events. Our findings indicate that apparent survival was high (0.98-0.99) and did not vary seasonally. Estimates of abundance were not directly related to environmental variables but were linked to seasonal temporary emigration. Abundance peaked in summer with an average of 85.37 dolphins (SD = 30.23) and was lowest in winter, with 68.57 (SD = 24.70) individuals. Site fidelity at the population level was low, but lagged identification rates revealed a population of approximately 28 individuals at any one time. Trend analysis suggests an increase in dolphin abundance from 1993 and persistence of the population over decades despite significant urbanisation, although numbers have declined in more recent years. Further research is needed to understand the cumulative impacts leading to this population decline and to assess its future viability under different management scenarios. Conservation strategies aimed at increasing reproductive rates and promoting connectivity to adjacent waters are likely to be more effective in reversing population declines.
了解濒危物种的种群统计学特征以及它们如何随自然和人为压力源而变化，对于有效的保护工作至关重要。我们利用了南澳大利亚高度城市化的阿德莱德海豚保护区（ADS）中印度-太平洋宽吻海豚（）的长期照片捕捉-重捕数据集（1993 - 2020年），来估计关键的人口统计学参数及其随时间的变化。这些参数与用作当地和大规模气候事件指标的环境变量相关进行了分析。我们的研究结果表明，明显生存率很高（0.98 - 0.99）且没有季节性变化。丰度估计与环境变量没有直接关系，但与季节性临时迁徙有关。丰度在夏季达到峰值，平均有85.37只海豚（标准差 = 30.23），在冬季最低，有68.57只（标准差 = 24.70）个体。种群水平的地点忠诚度较低，但滞后识别率显示在任何时候都有大约28只个体的种群。趋势分析表明，尽管城市化程度很高，但自1993年以来海豚丰度有所增加，并且该种群在几十年间持续存在，尽管近年来数量有所下降。需要进一步研究以了解导致该种群数量下降的累积影响，并评估其在不同管理情景下的未来生存能力。旨在提高繁殖率和促进与相邻水域连通性的保护策略可能在扭转种群数量下降方面更有效。
