Abstract

A time-continuous, spatially discrete motile predator–immobile prey model has been developed to describe the interactions between harpacticoid copepods and benthic microalgae in the intertidal zone. Harpacticoids perform periodic and nondirectional migrations; the local intensity of these migrations is trophic-dependent, related to the ratio of real to maximum food consumption rates. The zero-dimensional (non-spatial) analog of the model has three nontrivial equilibrium states, two of which are stable: one corresponds to overgrazing (permanently low abundance of prey controlled by hungry predator); the second is “welfare” (well-fed predator and resource-limited prey). Simulations show that in the spatially distributed model with close-to-real parameter values, two regimes can be realized: either total overgrazing or a persistent heterogeneous dynamic regime with short-lived patches of both populations, similar to that observed in nature. The predator’s ability to migrate narrows the “welfare” domain in parametric space, but increases the trophic efficiency of the system: in this domain, both average prey abundance and average consumption rate for the predator are higher than without migrations. The migrating gain is larger in an environment that is spatially heterogeneous for prey. Assumption of local awareness of the predator (preferred migrations toward a high abundance of prey) has no significant effect on the state of the system.

中文翻译：

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具有周期性迁移的捕食者的空间分布捕食者－食饵系统建模（以白海潮间类类动物和底栖微藻为例）

摘要

建立了一个时间连续的，空间上不连续的运动性捕食者-不动产猎物模型，以描述潮间带类拟ha足类和底栖微藻之间的相互作用。立足类动物进行周期性和非定向的迁徙。这些迁移的局部强度与营养有关，与实际食物消耗率与最大食物消耗率之比有关。该模型的零维（非空间）类似物具有三个非平凡的平衡状态，其中两个是稳定的：一个对应于过度放牧（由饥饿的捕食者控制的永久性低度的猎物）；第二个是“福利”（饱食的捕食者和资源有限的猎物）。仿真表明，在具有接近真实参数值的空间分布模型中，可以实现两种状态：总体上是过度放牧，或者是两个种群都有短暂生命斑块的持久异质动态机制，这与自然界观察到的相似。捕食者的迁移能力缩小了参数空间中的“福利”域，但提高了系统的营养效率：在此域中，捕食者的平均猎物丰度和平均消耗率均高于没有迁移的情况。在对于猎物而言空间异质的环境中，迁移增益更大。假定当地对捕食者的了解（优先向大量猎物迁移）对系统状态没有重大影响。但是却提高了系统的营养效率：在这个域中，捕食者的平均猎物丰度和平均消耗率都比没有迁徙时要高。在对于猎物而言空间异质的环境中，迁移增益更大。假定当地对捕食者的了解（优先向大量猎物迁移）对系统状态没有重大影响。但是却提高了系统的营养效率：在这个域中，捕食者的平均猎物丰度和平均消耗率都比没有迁徙时要高。在对于猎物而言空间异质的环境中，迁移增益更大。假定当地对捕食者的了解（优先向大量猎物迁移）对系统状态没有重大影响。