A model for niche differentiation in Lower Mississippian crinoid communities
A model for niche differentiation in Lower Mississippian crinoid communities
复制标题
密西西比河下游海百合群落的生态位分化模型
DOI：
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发表时间：
1980
期刊：
影响因子：
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通讯作者：
W. Ausich
中科院分区：
文献类型：
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作者：
W. Ausich
在密西西比河下游的表层动物悬浮摄食群落中研究了海百合生态位的分化。这些群落分为三个级别：低（距基质上方 0 至 15-20 厘米）、中（1520 至 50）和高（50 至 100）。这种分层效应是一阶利基差异化。二阶生态位分化是通过每个级别内的食物大小选择来完成的。古生代有柄海百合被解释为低能流变体，现代有柄海百合也是如此。这两个群体的进食行为被认为是相似的。对密西西比河下游海百合的生物特征分析表明，海百合臂能够充分利用其臂作为过滤器的物理和流体动力学特性。根据该分析，提出了海百合生态位分化谱。尽管存在一些重叠，但海百合的不同主要类群在此谱上占据不同的位置。在分类学上不同的同时代群落中，整个生态位谱都被占据。生态位谱上的类群浓度和群落的主要分类组成由食物大小的可用性控制。有证据表明，生态位是通过分散的种间竞争建立和维持的。羽化被认为是对特定食物范围的适应。
Crinoid niche differentiation is examined within Lower Mississippian epifaunal suspension-feeding communities. Three levels-low (0 to 15-20 cm above the substrate), intermediate (1520 to 50), and high (50 to 100)-are recognized in these communities. This tiering effect is a firstorder niche differentiation. Second-order niche differentiation is accomplished by food-size selection within each level. Paleozoic stalked crinoids are interpreted as low-energy rheophiles, as are modern stalked crinoids. Feeding behavior is considered analogous between these two groups. A biometric analysis of Lower Mississippian crinoids demonstrates that crinoid arms were adapted to take the best advantage of the physical and hydrodynamic properties oi their arms as filters. From this analysis a crinoid niche differentiation spectrum is proposed. Although there is some overlap, different major groups of crinoids occupy different positions on this spectrum. In taxonomically distinct contemporaneous communities, the entire niche spectrum is occupied. Concentrations of taxa on the niche spectrum and the major taxonomic composition of the community is controlled by food-size availability. Evidence is provided to suggest that niches were established and maintained by diffuse interspecific competition. Pinnulation is considered to be an adaptation for a specific range of food.