Competitive exclusion can be classified as deterministic or as historically contingent. While competitive exclusion is common in nature, it has remained unclear when multispecies communities formed by more than two species should be dominated by deterministic or contingent exclusion. Here, we take a fully parameterised model of an empirical competitive system between invasive annual and native perennial plant species to explain both the emergence and sources of competitive exclusion in multispecies communities. Using a structural approach to understand the range of parameters promoting deterministic and contingent exclusions, we then find heuristic theoretical support for the following three general conclusions. First, we find that the life-history of perennial species increases the probability of observing contingent exclusion by increasing their effective intrinsic growth rates. Second, we find that the probability of observing contingent exclusion increases with weaker intraspecific competition, and not with the level of hierarchical competition. Third, we find a shift from contingent exclusion to deterministic exclusion with increasing numbers of competing species. Our work provides a heuristic framework to increase our understanding about the predictability of species persistence within multispecies communities.

中文翻译：

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了解多物种社区中偶然性和确定性排斥的出现

竞争排斥可分为确定性或历史偶然性。虽然竞争性排斥在自然界中很常见，但仍不清楚由两个以上物种形成的多物种群落何时应该由确定性或偶然性排斥来主导。在这里，我们采用了入侵性一年生植物和本地多年生植物物种之间经验竞争系统的完全参数化模型来解释多物种群落中竞争排斥的出现和来源。使用结构方法来理解促进确定性和或然排除的参数范围，然后我们为以下三个一般结论找到启发式理论支持。第一的，我们发现，多年生物种的生活史通过增加其有效的内在增长率来增加观察偶然排斥的可能性。其次，我们发现观察到偶然排斥的概率随着种内竞争的减弱而增加，而不是随着等级竞争的水平而增加。第三，随着竞争物种数量的增加，我们发现从偶然排除到确定性排除的转变。我们的工作提供了一个启发式框架，以增加我们对多物种群落中物种持久性的可预测性的理解。随着竞争物种数量的增加，我们发现从偶然排除到确定性排除的转变。我们的工作提供了一个启发式框架，以增加我们对多物种群落中物种持久性的可预测性的理解。随着竞争物种数量的增加，我们发现从偶然排除到确定性排除的转变。我们的工作提供了一个启发式框架，以增加我们对多物种群落中物种持久性的可预测性的理解。