Long-term monitoring provides insight into estuarine top predator (Carcharhinus leucas) resilience following an extreme weather event
Long-term monitoring provides insight into estuarine top predator (Carcharhinus leucas) resilience following an extreme weather event
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DOI：
10.3354/meps13269
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发表时间：
2020-04-02
影响因子：
2.5
通讯作者：
Heithaus, Michael R.
中科院分区：
文献类型：
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作者：
Matich, Philip;Strickland, Bradley A.;Heithaus, Michael R.
慢性环境变化威胁着生物多样性，但急性干扰事件带来的威胁更为迅速和直接。2010年，一股寒流席卷了南佛罗里达，产生了广泛的影响，包括对休闲渔业、农业和生态社区的负面影响。在这里，我们使用声学遥测和历史的延绳钓监测，以评估这一事件的长期影响，少年牛鲨在佛罗里达大沼泽地leucas。尽管几乎所有的人都失去了（约。90%）的鲨鱼河口在寒流期间，0岁的鲨鱼的单位努力渔获量（CPUE）的延绳钓恢复通过招聘在6-8个月的事件。声学遥测显示，0-2岁鲨鱼的栖息地利用模式在4-6年达到平衡。相比之下，CPUE和栖息地使用的年龄3鲨鱼需要5-7年，类似于前寒流模式。环境条件和捕食风险恢复到以前的水平内1年的寒流，但一些猎物物种的丰度仍然低迷了几年。减少猎物的可用性可能已经改变了一些微栖息地的盈利能力后，寒流，导致更快的个体发育转移到海洋沃茨鲨鱼数年。加速个体发育的转变，再加上个体间的行为变异的牛鲨可能会导致一个缓慢的恢复率比预测的基础上，整体鲨鱼CPUE。虽然在动态生态系统中由随机性驱动的内在变化可能会增加物种对慢性和急性干扰的抵抗力，但如果超过抵抗能力，它也可能会增加恢复时间，以填补干扰前占据的生态位多样性。
Chronic environmental change threatens biodiversity, but acute disturbance events present more rapid and immediate threats. In 2010, a cold snap across south Florida had wide-ranging impacts, including negative effects on recreational fisheries, agriculture, and ecological communities. Here, we use acoustic telemetry and historical longline monitoring to assess the long-term implications of this event on juvenile bull sharks Carcharhinus leucas in the Florida Everglades. Despite the loss of virtually all individuals (ca. 90%) within the Shark River Estuary during the cold snap, the catch per unit effort (CPUE) of age 0 sharks on longlines recovered through recruitment within 6-8 mo of the event. Acoustic telemetry revealed that habitat use patterns of age 0-2 sharks reached an equilibrium in 4-6 yr. In contrast, the CPUE and habitat use of age 3 sharks required 5-7 yr to resemble pre-cold snap patterns. Environmental conditions and predation risk returned to previous levels within 1 yr of the cold snap, but abundances of some prey species remained depressed for several years. Reduced prey availability may have altered the profitability of some microhabitats after the cold snap, leading to more rapid ontogenetic shifts to marine waters among sharks for several years. Accelerated ontogenetic shifts coupled with inter-individual behavioral variability of bull sharks likely led to a slower recovery rate than predicted based on overall shark CPUE. While intrinsic variation driven by stochasticity in dynamic ecosystems may increase the resistance of species to chronic and acute disturbance, it may also increase recovery time in filling the diversity of niches occupied prior to disturbance if resistive capacity is exceeded.