Holbrook S J, Forrester G E, Schmitt R J
Department of Ecology, Evolution and Marine Biology, and Coastal Research Center, Marine Science Institute, University of California, Santa Barbara, CA 93106, USA, , , , , , US.
Department of Biological Sciences, University of Rhode Island, Kingston, RI 02881, USA, , , , , , US.
Oecologia. 2000 Jan;122(1):109-120. doi: 10.1007/PL00008826.
For species with metapopulation structures, variation in abundance among patches can arise from variation in the input rate of colonists. For reef fishes, variability in larval supply frequently is invoked as a major determinant of spatial patterns. We examined the extent to which spatial variation in the amount of suitable habitat predicted variation in the abundance of the damselfish Dascyllus aruanus, an abundant planktivore that occupies live, branched coral throughout the Indo-Pacific. Reef surveys established that size, branching structure and location (proximity to sand) of the coral colonies together determined the "suitability" of microhabitats for different ontogenetic stages of D. aruanus. Once these criteria were known, patterns of habitat use were quantified within lagoons of five Pacific islands. Availability of suitable habitat generally was an excellent predictor of density, and patterns were qualitatively consistent at several spatial scales, including among different lagoons on the same island, among different islands and between the central (French Polynesia and Rarotonga) and western (Great Barrier Reef, Australia) South Pacific. A field experiment that varied the amount of suitable coral among local plots indicated that habitat for settlers accounted for almost all of the spatial variation in the number of D. aruanus that settled at that location, suggesting that spatial patterns of abundance can be established at settlement without spatial variation in larval supply. Surveys of four other species of reef-associated fish revealed that a substantial fraction of their spatial variation in density also was explained by availability of suitable reef habitat, suggesting that habitat may be a prevalent determinant of spatial patterns. The results underscore the critical need to identify accurately the resource requirements of different species and life stages when evaluating causes of spatial variation in abundance of reef fishes.
对于具有集合种群结构的物种而言，斑块间丰度的差异可能源于殖民者迁入率的变化。对于珊瑚礁鱼类，幼体供应的变异性常被认为是空间格局的主要决定因素。我们研究了适宜栖息地数量的空间变化在多大程度上能够预测雀鲷（Dascyllus aruanus）丰度的变化，雀鲷是一种数量众多的浮游生物食性鱼类，在整个印度 - 太平洋地区栖息于活的、分支状的珊瑚中。珊瑚礁调查表明，珊瑚群体的大小、分支结构和位置（与沙地的距离）共同决定了不同发育阶段的阿鲁安雀鲷微生境的“适宜性”。一旦明确了这些标准，就在五个太平洋岛屿的泻湖内对栖息地利用模式进行了量化。适宜栖息地的可利用性通常是密度的良好预测指标，并且在几个空间尺度上模式在定性上是一致的，包括同一岛屿上不同泻湖之间、不同岛屿之间以及南太平洋中部（法属波利尼西亚和拉罗汤加）和西部（澳大利亚大堡礁）之间。一项在局部区域改变适宜珊瑚数量的野外实验表明，定居者的栖息地几乎解释了在该位置定居的阿鲁安雀鲷数量的所有空间变化，这表明在定居时丰度的空间格局可以在没有幼体供应空间变化的情况下形成。对其他四种与珊瑚礁相关鱼类的调查显示，它们密度的很大一部分空间变化也可以由适宜珊瑚礁栖息地的可利用性来解释，这表明栖息地可能是空间格局的普遍决定因素。这些结果强调了在评估珊瑚礁鱼类丰度空间变化原因时，准确识别不同物种和生命阶段资源需求的迫切必要性。
