Individual-based modelling is an increasingly popular framework for modelling biological systems. Many of these models represent space as a lattice, thus imposing unrealistic limitations on the movement of the modelled individuals. We adapt an existing model of three competing species by using a lattice-free approach, thereby improving the realism of the spatial dynamics. We retrieve the same qualitative dynamics as the lattice-based approach. However, by facilitating a higher spatial heterogeneity and allowing for small spatial refuges to form and persist, the maintenance of coexistence is promoted, in correspondence with experimental results. We also implement a directed movement mechanism allowing individuals of different species to pursue or flee from each other. Simulations show that the effects on coexistence depend on the level of aggregation in the community: a high level of aggregation is advantageous for maintaining coexistence, whereas a low level of aggregation is disadvantageous. This agrees with experimental results, where pursuing and escaping behaviour has been observed to be advantageous only in certain circumstances.

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基于格形与无格的基于个人的模型：对竞争社区中共存的影响

基于个人的建模是一种越来越流行的用于对生物系统进行建模的框架。这些模型中的许多模型将空间表示为晶格，因此对建模个体的移动施加了不切实际的限制。我们使用无格方法调整了三个竞争物种的现有模型，从而改善了空间动力学的真实性。我们检索与基于格的方法相同的定性动力学。但是，通过促进更高的空间异质性并允许小型空间庇护所形成并持续存在，与实验结果相对应，促进了共存的维持。我们还实施定向运动机制，允许不同物种的个体相互追击或逃离。模拟表明，对共存的影响取决于社区中聚合的级别：较高的聚合级别有利于维持共存，而较低的聚合级别则不利。这与实验结果相吻合，在实验结果中，只有在某些情况下才观察到逃避行为是有利的。