NCEAS, Santa Barbara, USA.
UCI, San Diego, USA.
Sci Rep. 2024 Feb 15;14(1):3829. doi: 10.1038/s41598-024-52222-0.
Human impacts are dramatically changing ecological communities, motivating research on resilience. Tropical reefs are increasingly undergoing transitions to short algal turf, a successional community that mediates either recovery to coral by allowing recruitment or transitions to longer turf/macroalgae. Intense herbivory limits turf height; subsequently, overfishing erodes resilience of the desirable coral-dominated reef state. Increased sedimentation also erodes resilience through smothering and herbivory suppression. In spite of this critical role, most herbivory studies on tropical reefs focus on fishes, and the contribution of urchins remains under-studied. To test how different herbivory and sedimentation scenarios impact turf resilience, we experimentally simulated, in situ, four future overfishing scenarios derived from patterns of fish and urchin loss in other reef systems and two future sedimentation regimes. We found urchins were critical to short turf resilience, maintaining this state even with reduced fish herbivory and increased sediment. Further, urchins cleared sediment, facilitating fish herbivory. This study articulates the likelihood of increased reliance on urchins on impacted reefs in the Anthropocene.
人类活动正在显著改变生态群落，这促使人们对生态系统恢复力展开研究。热带珊瑚礁正逐渐向短藻草坪过渡，这是一种演替群落，它通过允许珊瑚礁的繁殖或向更长的草坪/大型藻类过渡来调节恢复过程。强烈的食草作用会限制草坪的高度；随后，过度捕捞会削弱理想的珊瑚礁主导状态的恢复力。沉积物的增加也会通过窒息和食草动物的抑制作用削弱恢复力。尽管具有如此重要的作用，但大多数关于热带珊瑚礁的食草动物研究都集中在鱼类上，而对海胆的贡献仍未得到充分研究。为了测试不同的食草动物和沉积物情景如何影响草坪的恢复力，我们在现场实验模拟了四种未来的过度捕捞情景，这些情景源自其他珊瑚系统中鱼类和海胆损失的模式，以及两种未来的沉积物情况。我们发现海胆对短草坪的恢复力至关重要，即使在鱼类食草动物减少和沉积物增加的情况下，也能维持这种状态。此外，海胆清除了沉积物，促进了鱼类的食草作用。这项研究阐明了在人类世，受影响的珊瑚礁可能更加依赖海胆。
