Trophic structure patterns of Brazilian reef fishes: a latitudinal comparison
Trophic structure patterns of Brazilian reef fishes: a latitudinal comparison
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DOI：
10.1111/j.1365-2699.2004.01044.x
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发表时间：
2004-07-01
影响因子：
3.9
通讯作者：
Joyeux, JC
中科院分区：
文献类型：
--
作者：
Ferreira, CEL;Floeter, SR;Joyeux, JC
目的研究珊瑚鱼的营养结构如何响应纬度变化，使用一个简单的模型：广阔的巴西海岸。选取纬度0 ~ 27度之间的6个巴西热带和亚热带珊瑚和岩石海岸珊瑚礁，以及海洋岛屿Atol das Rocas。方法利用作者收集的水下视觉普查数据（5个地点）和文献资料（2个地点），估计了33个珊瑚礁相关科123种鱼类的相对丰度。隐种被排除在分析之外。鱼类被分为8个营养类别：流动食草动物、领土食草动物、流动无脊椎捕食动物、无固定无脊椎捕食动物、杂食动物、浮游动物、鱼食动物和食肉动物。在基于系统发育、生理约束和人为影响的一系列详细预测之后，分析了沿纬度梯度以及沿海、中岸和海洋站点的群落营养结构。结果巴西珊瑚鱼群落的营养结构随纬度变化明显。在低纬度地区，流浪草食动物（如scarids和acanthurids）的数量比例更高。食草动物棘足虫则遵循相反的纬度分布模式。Sparisoma鹦嘴鱼属的食性比Scarus类更具可塑性，分布范围更广。地域食草动物的相对丰度没有随着纬度的升高而降低。在所有沿海地区，移动无脊椎动物是最重要的（低纬度地区）或第二重要的营养行会（高纬度地区）。无根无脊椎取食动物没有显示出任何明显的纬度趋势，尽管预计在低纬度地区丰度会增加。杂食动物以高纬度珊瑚礁（南纬27度）为主，浮游动物以海洋岛屿Atol das Rocas为主。鱼类和食肉动物在高纬度地区的比例更高。主要结论：纬度格局似乎受到系统发育、生理限制（主要与温度有关）以及人为影响的影响。食草藻和棘藻主要局限于热带珊瑚礁，并在南纬23度以上急剧下降。这并不能反映藻类的数量，但可能是温度依赖的生理限制。其他食草动物似乎通过共生微生物消化过程来克服这一问题（棘足类），操纵藻皮的结构或增加来自领土内的动物蛋白质（pomacentrids）。杂食动物主要分布在南部的Arraial do Cabo和Arvoredo，它们更适应与季节和/或随机变化相关的环境约束。大型食肉动物（包括鱼食动物）向高纬度栖息地扩展得更远，显然不受限制食草动物的热阈值的限制。过度捕捞和/或观赏性捕捞确实改变了当地鱼类群落，但在本研究中发现的大规模模式中无法适当地发现。提出的数据首次证明了珊瑚鱼的营养结构如何在广阔的西南大西洋纬度梯度中表现出来。
Aim To investigate how reef fish trophic structure responds to latitudinal changes, using a simple model: the extensive Brazilian coast.Location Six Brazilian tropical and subtropical coral and rocky coastal reefs, and the oceanic island of Atol das Rocas, between latitudes 0degrees and 27degrees S.Methods Underwater visual census data collected by the authors (five locations) or obtained from the literature (two locations) were used to estimate the relative abundance of 123 fish species belonging to 33 reef-associated families. Cryptic species were excluded from the analysis. Fishes were grouped in eight trophic categories: roving herbivores, territorial herbivores, mobile invertebrate feeders, sessile invertebrate feeders, omnivores, planktivores, piscivores and carnivores. After a series of detailed predictions based on phylogeny, physiological constraints and anthropogenic impacts was established, the community trophic structure was analysed along a latitudinal gradient and among coastal, mid-shore and oceanic sites.Results The trophic structure of Brazilian reef fish assemblages clearly changed with latitude. Roving herbivores such as scarids and acanthurids were proportionally more abundant at low latitudes. The browsing herbivores kyphosids followed an opposite latitudinal pattern. The parrotfish genus Sparisoma, more plastic in its feeding habits than Scarus, presented wider distribution. The relative abundance of territorial herbivores did not decrease towards higher latitudes. Mobile invertebrate feeders were the most important (in low latitudes) or the second most important trophic guild (in high latitudes) at all coastal sites. Sessile invertebrate feeders did not show any clear latitudinal trend, despite an expected increase in abundance towards low latitudes. Omnivores dominated high latitude reefs (27degrees S) and planktivores the oceanic island Atol das Rocas. Piscivores and carnivores were proportionally better represented in high latitudes.Main conclusions Latitudinal patterns seem to be influenced by phylogeny, physiological constraints (mainly related to temperature), and also by anthropogenic impacts. Grazing scarids and acanthurids are largely restricted to tropical reefs and show an abrupt decline beyond 23degrees S. This does not reflect the amount of algae present, but probably temperature-dependent physiological constraints. Other herbivores seem to overcome this through symbiotic microbial digestive processes (kyphosids), manipulating the structure of algal turfs or increasing animal protein from within the territory (pomacentrids). Omnivores dominate the southern sites Arraial do Cabo and Arvoredo, being more adapted to environment constraints related to seasonal and/or stochastic shifts. Large carnivores (including piscivores) extend farther into high-latitude habitats, apparently not constrained by thermal thresholds that limit the herbivores. Overfishing and/or ornamental harvesting certainly has been modifying local fish communities, but could not be detected properly at the large-scale patterns found in this study. The data presented put in evidence for the first time how reef fish trophic structure behave in the extensive south-western Atlantic latitudinal gradient.