Food web effects of prey size refugia: Variable interactions and alternative stable equilibria
Food web effects of prey size refugia: Variable interactions and alternative stable equilibria
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DOI：
10.1086/303260
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发表时间：
1999-11-01
影响因子：
2.9
通讯作者：
Chase, JM
中科院分区：
文献类型：
--
作者：
Chase, JM
捕食者对食物网的丰度和组成有着高度可变的影响，顶级捕食者的影响从强到弱不等。典型的食物网模型假设个体猎物在其一生中对捕食者的敏感性是相同的，但许多猎物物种通过个体发育变得不那么容易受到捕食者的攻击。一组简单的模型进行了探讨，猎物必须通过一个脆弱的阶段之前，实现一个捕食者无懈可击的大小避难所。随着环境生产力的提高，捕食者的比例影响减少，因为更多的个体成为并保持在刀枪不入的成年阶段。增加一个竞争对手的猎物物种，不能实现大小避难所的结果形成对比。在低生产力下，小物种在竞争中获胜，系统受到强烈的消费者控制;在高生产力下，由于捕食者的存在，大物种获胜，系统变得不那么受消费者控制。在中等生产力下，小种群或大种群都可以获胜，这取决于初始条件，系统可以是强消费者控制的，也可以是弱消费者控制的。
Predators can have highly variable effects on the abundance and composition of food webs, ranging from strong to weak effects of top predators. Typical food web models assume that individual prey are identical in their susceptibility to predators throughout their lives, but many prey species become less vulnerable to predators through ontogeny. A simple set of models is explored where prey must pass through a vulnerable stage prior to achieving a predator-invulnerable size refuge. As productivity of the environment increases, the proportional impact of predators decreases because more individuals become and remain in the invulnerable adult stage. The addition of a competitor prey species that can not achieve size refuge results in contrasting outcomes. At low productivity the small species wins in competition, and the system is strongly consumer controlled At high productivity, the large species wins due to the presence of predators, and the system becomes less consumer controlled. At intermediate productivity either the small or the large species can win depending on initial conditions, and the system can be either strongly or weakly consumer controlled Such alternative stable equilibria derived from models with prey size refugia may help to explain many natural situations.