Data from: Individual-based analyses reveal limited functional overlap in a coral reef fish community.

1.Detailed knowledge of a species’ functional niche is crucial for the study of ecological communities and processes. The extent of niche overlap, functional redundancy and functional complementarity are of particular importance if we are to understand ecosystem processes and their vulnerability to disturbances. 2.Coral reefs are among the most threatened marine systems, and anthropogenic activity is changing the functional composition of reefs. The loss of herbivorous fishes is particularly concerning as the removal of algae is crucial for the growth and survival of corals. Yet, the foraging patterns of the various herbivorous fish species are poorly understood. 3.Using a multidimensional framework, we present novel individual-based analyses of species’ realized functional niches, which we apply to a herbivorous coral reef fish community. In calculating niche volumes for 21 species, based on their microhabitat utilization patterns during foraging, and computing functional overlaps, we provide a measurement of functional redundancy or complementarity. Complementarity is the inverse of redundancy and is defined as less than 50% overlap in niche volumes. 4.The analyses reveal extensive complementarity with an average functional overlap of just 15.2%. Furthermore, the analyses divide herbivorous reef fishes into two broad groups. The first group (predominantly surgeonfishes and parrotfishes) comprises species feeding on exposed surfaces and predominantly open reef matrix or sandy substrata, resulting in small niche volumes and extensive complementarity. In contrast, the second group consists of species (predominantly rabbitfishes) that feed over a wider range of microhabitats, penetrating the reef matrix to exploit concealed surfaces of various substratum types. These species show high variation among individuals, leading to large niche volumes, more overlap and less complementarity. 5.These results may have crucial consequences for our understanding of herbivorous processes on coral reefs, as algal removal appears to depend strongly on species-specific microhabitat utilization patterns of herbivores. Furthermore, the results emphasize the capacity of the individual-based analyses to reveal variation in the functional niches of species, even in high diversity systems such as coral reefs, demonstrating its potential applicability to other high-diversity ecosystems.

1. 某物种功能生态位（functional niche）的详尽认知，对于生态群落与生态过程的研究至关重要。若要理解生态系统过程及其对干扰的脆弱性，生态位重叠程度、功能冗余与功能互补尤为关键。
2. 珊瑚礁（coral reef）是受威胁最严重的海洋生态系统之一，人类活动正改变着礁体的功能组成。其中植食性鱼类（herbivorous fishes）的流失尤其令人担忧，因为藻类的清除对于珊瑚的生长与存活至关重要。然而，各类植食性鱼类的觅食模式仍鲜为人知。
3. 本研究基于多维度框架，针对植食性珊瑚礁鱼类群落开展了全新的个体水平物种实际功能生态位（realized functional niche）分析。研究以21个物种的觅食微生境利用模式为依据，计算其生态位体积（niche volume）并测算功能重叠程度，以此量化功能冗余或功能互补；其中功能互补为功能冗余的对立面，定义为生态位体积重叠度低于50%。
4. 分析结果显示群落存在广泛的功能互补，平均功能重叠率仅为15.2%。此外，分析将植食性礁区鱼类划分为两大类群：第一类群（以刺尾鱼科鱼类和鹦嘴鱼科鱼类为主）的物种多栖息于裸露表面，主要取食开阔礁体基质或沙质底质，生态位体积较小且功能互补性强。与之相对，第二类群（以蓝子鱼科鱼类为主）的物种觅食微生境范围更广，会穿透礁体基质以利用各类底质的隐蔽表面；这类物种的个体间差异显著，导致生态位体积较大、重叠程度更高且功能互补性较弱。
5. 本研究结果对于我们理解珊瑚礁的植食作用过程具有重要意义，因为藻类清除效果似乎与植食动物的物种特异性微生境利用模式密切相关。此外，研究结果也凸显了个体水平分析在揭示物种功能生态位差异方面的能力——即便在珊瑚礁这类高多样性生态系统中亦是如此，这也证明了该方法在其他高多样性生态系统中的应用潜力。