Storm Zoe, Meekan Mark G, Eich Andreas, Speed Conrad W, Killen Shaun S, Lester Emily K
Australian Institute of Marine Science, Indian Ocean Marine Research Centre, University of Western Australia, Perth, Western Australia, Australia.
School of Biodiversity, One Health and Veterinary Medicine, University of Glasgow, Glasgow, UK.
J Anim Ecol. 2025 May;94(5):919-931. doi: 10.1111/1365-2656.70024. Epub 2025 Apr 7.
Natural experiments where populations of large predators have recovered following management initiatives offer insights into the potential for these animals to structure communities via consumptive and nonconsumptive effects on their prey. Ashmore Reef, a coral reef off the coast of Western Australia, provides such an opportunity. Here, reef shark populations have increased significantly since the enforcement of a no-take MPA in 2008. This change has been accompanied by an increase in the abundance of medium and large mesopredatory teleosts, but a decline in small mesopredatory teleosts. We explored whether these changes in abundance were accompanied by changes in anti-predator (nonconsumptive) behaviours of mesopredators due to an increase in both acute and chronic risks of predation. We analysed videos from Baited Remote Underwater Video Systems (BRUVS) collected prior to the enforcement of no-take status in 2004 and after enforcement and shark recovery in 2016 to quantify any changes in anti-predator behaviours of small (<50 cm TL), medium (50-100 cm TL) and large (>100 cm TL) size classes of teleost mesopredators. Comparisons of the effect of chronic and acute risk on the total time teleosts spent in the BRUVS videos, proportional time spent on activities associated with various risks, and foraging intensity were made both within years (acute risk: in videos where sharks were absent compared to present) and between years (chronic risk: 2004 and 2016). Our results indicate that both small- and medium-sized mesopredatory fishes exhibit behaviours indicative of risk-induced trait responses (anti-predator behaviours) in the presence of reef sharks and that these seem to occur as a joint response to the interaction of acute and chronic risks. Our study suggests that the decline of small mesopredatory fishes following the recovery of reef sharks could be due to both the consumptive and nonconsumptive impacts of sharks as predators in this system. These results show that both chronic and acute risks seem to play significant roles in shaping behaviours of mesopredators.
在管理措施实施后大型食肉动物种群数量得以恢复的自然实验，为这些动物通过对猎物的消费性和非消费性影响来构建群落的潜力提供了见解。西澳大利亚海岸外的珊瑚礁阿什莫尔礁就提供了这样一个机会。自2008年实施禁捕海洋保护区以来，这里的礁鲨种群数量显著增加。这一变化伴随着中型和大型中捕食性硬骨鱼数量的增加，但小型中捕食性硬骨鱼数量有所下降。我们探究了这些数量变化是否伴随着中捕食者因急性和慢性捕食风险增加而产生的反捕食（非消费性）行为变化。我们分析了2004年禁捕状态实施前以及2016年禁捕实施且鲨鱼数量恢复后从诱饵远程水下视频系统（BRUVS）收集的视频，以量化小型（全长<50厘米）、中型（全长50 - 100厘米）和大型（全长>100厘米）硬骨鱼中捕食者反捕食行为的任何变化。对慢性和急性风险对硬骨鱼在BRUVS视频中花费的总时间、与各种风险相关活动所花费的比例时间以及觅食强度的影响进行了年内比较（急性风险：在鲨鱼不存在与存在的视频中）和年间比较（慢性风险：2004年和2016年）。我们的结果表明，小型和中型中捕食性鱼类在礁鲨存在时均表现出表明风险诱导性状反应（反捕食行为）的行为，并且这些行为似乎是对急性和慢性风险相互作用的联合反应。我们的研究表明，礁鲨数量恢复后小型中捕食性鱼类数量的下降可能是由于该系统中鲨鱼作为捕食者的消费性和非消费性影响。这些结果表明，慢性和急性风险似乎在塑造中捕食者行为方面都发挥着重要作用。
