Spatial patterns in abundance of a damselfish reflect availability of suitable habitat
Spatial patterns in abundance of a damselfish reflect availability of suitable habitat
复制标题
DOI：
10.1007/pl00008826
复制
发表时间：
2000-01-01
期刊：
影响因子：
2.7
通讯作者：
Schmitt, RJ
中科院分区：
文献类型：
--
作者：
Holbrook, SJ;Forrester, GE;Schmitt, RJ
对于具有超种群结构的物种，斑块间丰度的变化可能是由殖民者输入率的变化引起的。对于礁鱼来说，幼虫供应的变异性经常被认为是空间格局的主要决定因素。我们研究了适合栖息地数量的空间变化在多大程度上预测了小雀鲷（Dascyllus aruanus）丰度的变化，小雀鲷是一种丰富的浮游生物，占据了整个印度太平洋地区的活枝珊瑚。珊瑚礁调查表明，珊瑚群落的大小、分支结构和位置（靠近沙子）共同决定了微栖息地对不同个体发育阶段的“适宜性”。一旦知道了这些标准，在五个太平洋岛屿的泻湖内对生境利用模式进行了量化。适宜生境的可获得性通常是密度的一个很好的预测指标，并且在几个空间尺度上，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岛）和西部（澳大利亚大堡礁）之间的模式在质量上是一致的。一项改变当地样地适宜珊瑚数量的野外试验表明，定居生境几乎占了定居在该地点的黄颡鱼数量的所有空间变化，这表明在没有幼虫供应空间变化的情况下，可以在定居地建立丰度的空间格局。对其他四种与珊瑚礁有关的鱼类的调查显示，它们的密度空间变化的很大一部分也可以用合适的珊瑚礁栖息地的可用性来解释，这表明栖息地可能是空间格局的一个普遍决定因素。这些结果强调了在评估珊瑚礁鱼类丰度空间变化的原因时，准确识别不同物种和生命阶段的资源需求至关重要。
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.