Species Packing and Niche Complementarity in Three Sunfishes
Species Packing and Niche Complementarity in Three Sunfishes
复制标题
三种太阳鱼的物种包装和生态位互补性
作者：
E. Werner
本研究提出了一种将觅食理论与物种聚集理论联系起来的方法。对三种形态上有系统差异的太阳鱼（Centrarchidae）进行了成本曲线的定量测定，该成本曲线是根据它们对捕食者的成本效益比对猎物进行排序的。成本曲线用于估计鱼类在给定其大小和形态（物种）的情况下，其饮食中食物大小范围的极值。可用资源的分布被发现是对数正态分布，并且在上述饮食范围内，允许计算个体鱼的生态位宽度和食物大小轴上的位置。这些物种的大小分布种群的生态位宽度和位置的极端值，然后通过组合和权衡每个大小类别的贡献来确定。结果表明，大翅蝗种群和小翅蝗种群的食物大小坐标重叠与目前物种包装理论预测的非常接近。预测这些物种在食物大小轴上具有相似的生境和分离，而形态上处于中间的第三种（L. cyanellus）应被排除在这些生境之外，并在生态位维度上具有互补性。来自自然群落的这些物种的栖息地利用数据证实了这些预测。讨论了物种在食物大小坐标上的分布与物种种群大小分布的关系。
This study develops a method to relate foraging theory to species-packing theory. Cost curves, which rank prey by their cost-benefit ratio to the predator, are quantitatively determined for three species of sunfishes (Centrarchidae) that differ systematically in their morphology. The cost curves are used to estimate extremes in the range of food sizes in the diet of a fish given its size and morphology (species). The distribution of available resources is found to be lognormal and, with the above diet ranges, permits the calculation of the niche width and location on the food size axis for individual fish. The extremes in niche width and location for size-distributed populations of these species are then determined by combining and weighing the contribution of each size class. Overlap on the food size coordinate for populations of Lepomis macrochirus and Micropterus salmoides is shown to be very close to that predicted by current species-packing theory. It is predicted that these species occupy similar habitats and segregate on the food size axis while the third species, which is intermediate in morphology (L. cyanellus), should be excluded from these habitats and show complementarity on niche dimensions. Data on habitat utilization of these species from natural communities confirm these predictions. Species packing on the food size coordinate is discussed in relation to species populations which are size distributed.