Cannibalism and Intraguild Predation Community Dynamics: Coexistence, Competitive Exclusion, and the Loss of Alternative Stable States
Cannibalism and Intraguild Predation Community Dynamics: Coexistence, Competitive Exclusion, and the Loss of Alternative Stable States
复制标题
同类相食和行会内掠夺群落动态：共存、竞争排斥和替代稳定状态的丧失
作者：
Benjamin J. Toscano;V. Hin;V. Rudolf
捕食者经常对猎物施加强有力的自上而下的监管，但在许多系统中，幼年捕食者必须与未来的猎物竞争共享资源。因此，在这种生活史群体内捕食（LHIGP）系统中，猎物也可以通过竞争来调节捕食者的招募和种群动态。理论预测，这种阶段结构的系统表现出广泛的动态，包括替代稳定状态。在这里，我们证明同类相食是自然 LHIGP 系统中极其常见的相互作用，它决定了可能的共存状态。使用模拟一系列沿着生产力梯度的个体发生饮食转变场景的建模方法，我们证明，只有当捕食者处于竞争优势时，同类相食才能通过允许猎物持续存在来促进共存。如果猎物在竞争中占主导地位，同类相食反而会导致捕食者的竞争排斥，并失去潜在的替代稳定状态。此外，相对于经验估计，捕食者排斥发生在食人偏好较低的情况下，并且在 LHIGP 系统中是一致的，其中捕食者在个体发育上经历了完全的饮食转变或饮食拓宽。鉴于猎物在自然系统中经常占据竞争主导地位，我们的研究结果表明，即使是微弱的同类相食也会抑制捕食者的持久性，从而促使人们探索使理论与自然界中常见的这种相互作用相一致的机制。
Predators often exert strong top-down regulation of prey, but in many systems, juvenile predators must compete with their future prey for a shared resource. In such life-history intraguild predation (LHIGP) systems, prey can therefore also regulate the recruitment and thus population dynamics of their predator via competition. Theory predicts that such stage-structured systems exhibit a wide range of dynamics, including alternative stable states. Here we show that cannibalism is an exceedingly common interaction within natural LHIGP systems that determines what coexistence states are possible. Using a modeling approach that simulates a range of ontogenetic diet shift scenarios along a productivity gradient, we demonstrate that only if the predator is competitively dominant can cannibalism promote coexistence by allowing prey to persist. If the prey is competitively dominant, cannibalism instead results in competitive exclusion of the predator and the loss of potential alternative stable states. Further, predator exclusion occurs at low cannibalistic preference relative to empirical estimates and is consistent across LHIGP systems in which the predator undergoes a complete diet shift or diet broadening over ontogeny. Given that prey is frequently competitively dominant in natural systems, our results demonstrate that even weak cannibalism can inhibit predator persistence, prompting exploration of mechanisms that reconcile theory with the common occurrence of such interactions in nature.
影响因子：
16.8
作者：
Arne Schröder;A. van Leeuwen;T. Cameron
通讯作者：
Arne Schröder;A. van Leeuwen;T. Cameron