Reciprocal facilitation and non-linearity maintain habitat engineering on coral reefs
Reciprocal facilitation and non-linearity maintain habitat engineering on coral reefs
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DOI：
10.1111/j.1600-0706.2012.20576.x
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发表时间：
2013-03-01
期刊：
影响因子：
3.4
通讯作者：
Mumby, Peter J.
中科院分区：
文献类型：
--
作者：
Bozec, Yves-Marie;Yakob, Laith;Mumby, Peter J.
创造栖息地的生态系统工程师促进了许多相互作用的物种的共存。这种对栖息地工程的生物反应可能会导致非直观的级联相互作用，可能包括对工程师的反馈。这种反馈机制，无论是积极的还是消极的，对于维持生物生境及其在整个社区的促进作用可能特别重要。在这里，我们描述了复杂的相互作用和反馈，链接海洋栖息地形成工程师，造礁珊瑚，和一组食草动物，鹦鹉鱼;后者防止过度生长的大型藻类，珊瑚的主要竞争对手。使用密度数据的八种鹦嘴鱼在加勒比海的珊瑚礁，我们首先描述的形式的响应鹦嘴鱼丰度增加的地形复杂性所产生的珊瑚生长。地形的复杂性提高了鹦嘴鱼的丰富，促进栖息地的适宜性，但形状（线性与渐近）和强度不同的物种和大小，这种反应。鹦嘴鱼放牧强度，估计从丰富的数据和物种，大小和生命阶段的具体放牧率也增加了地形的复杂性，尽管增加的表面积，鹦嘴鱼吃草。根据鱼类的种类，这种功能反应被认为是线性或渐近的。使用一个简单的分析模型，然后，我们探讨了地形复杂性和捕捞压力对珊瑚藻竞争的影响，特别强调放牧强度的非线性的影响。模拟表明，捕鱼和栖息地退化损害的性能放牧，但渐近响应的放牧强度地形复杂性增加了珊瑚礁的生态恢复力。鹦嘴鱼和珊瑚是互惠互利的创造一个循环的积极，间接的反馈，保持自己的结构和功能：珊瑚生长促进栖息地适合鹦嘴鱼，一致地提高放牧强度，这反过来又有利于珊瑚生长，减少竞争排斥大型藻类。我们的结论是，生物栖息地的弹性增强工程的非线性生物反应，并出现互惠便利连接栖息地工程和响应生物。
Ecosystem engineers that create habitats facilitate the coexistence of many interacting species. This biotic response to habitat engineering may result in non-intuitive cascading interactions, potentially including feedbacks to the engineer. Such feedback mechanisms, either positive or negative, may be especially important for the maintenance of biogenic habitats and their community-wide facilitation. Here, we describe the complex interactions and feedbacks that link marine habitat-forming engineers, the reef-building corals, and a group of herbivores, the parrotfishes; the latter preventing the overgrowth of macroalgae, a major competitor of corals. Using density data of eight parrotfish species on a Caribbean reef, we first describe the form of the response of parrotfish abundance to increasing topographic complexity generated by coral growth. Topographic complexity enhanced parrotfish abundance by promoting habitat suitability, but the shape (linear vs asymptotic) and strength of this response varied across species and size. Parrotfish grazing intensity, estimated from data on abundance and species-, size- and life phase-specific grazing rates also increased with topographic complexity despite an increase in the surface area over which parrotfish graze. Depending on fish species, this functional response was found to be linear or asymptotic. Using a simple analytical model we then explored the effects of topographic complexity and fishing pressure on coral-algal competition, with particular emphasis on the implications of non-linearities in the intensity of grazing. Simulations demonstrate that fishing and habitat degradation impair the performance of grazing, but that an asymptotic response of grazing intensity to topographic complexity increases the ecological resilience of coral reefs. Parrotfish and corals are mutually beneficial by creating a loop of positive, indirect feedbacks that maintain their own structure and function: coral growth promotes habitat suitability for parrotfish, concordantly enhancing grazing intensity, which in turn facilitates coral growth by reducing competitive exclusion by macroalgae. We conclude that the resilience of biogenic habitats is enhanced by non-linear biotic responses to engineering and by the emergence of reciprocal facilitation linking habitat engineering and response organisms.