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. 深入了解物种的功能生态位，是开展生态群落与生态过程研究的核心前提。若要解析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性的相关研究尤为关键。
2. 珊瑚礁是受威胁最为严重的海洋生态系统之一，人类活动正持续改变珊瑚礁的功能组成。其中植食性鱼类的消亡尤其令人担忧——藻类的移除对于珊瑚的生长与存活至关重要，但目前学界对各类植食性鱼类的觅食模式仍知之甚少。
3. 本研究基于多维分析框架，针对植食性珊瑚礁鱼类群落开展了全新的物种实际功能生态位个体水平分析。研究以21个物种觅食过程中的微生境利用模式为依据，计算其生态位体积并测算功能重叠度，以此量化功能冗余或功能互补性。其中功能互补性为功能冗余的反向指标，定义为生态位体积重叠度低于50%。
4. 分析结果显示群落整体存在显著的功能互补性，平均功能重叠度仅为15.2%。此外，研究将植食性珊瑚礁鱼类划分为两大类群：第一类群以刺尾鱼和鹦嘴鱼为主，其觅食对象为裸露表面以及开阔的珊瑚礁基质或沙质底质，生态位体积较小且功能互补性较强。与之相对的第二类群以蓝子鱼为主，其觅食覆盖的微生境范围更广，可穿透珊瑚礁基质以利用各类底质的隐蔽表面；该类群个体间的生态位差异显著，因此生态位体积更大、功能重叠度更高，功能互补性则相对较弱。
5. 本研究结果对于我们理解珊瑚礁上的植食性过程具有重要意义——藻类移除效果与植食动物的物种特异性微生境利用模式密切相关。此外，研究证实了基于个体的分析方法即使在珊瑚礁这类高多样性生态系统中，也能有效揭示物种功能生态位的差异，证明该方法具备应用于其他高多样性生态系统的潜力。