PARTITIONING OF RESOURCES AND OUTCOME OF INTERSPECIFIC COMPETITION - MODEL AND SOME GENERAL CONSIDERATIONS
PARTITIONING OF RESOURCES AND OUTCOME OF INTERSPECIFIC COMPETITION - MODEL AND SOME GENERAL CONSIDERATIONS
复制标题
DOI：
10.1086/282825
复制
发表时间：
1973-01-01
影响因子：
2.9
通讯作者：
LEVIN, BR
中科院分区：
文献类型：
--
作者：
STEWART, FM;LEVIN, BR
在传统的物种间竞争模型中，资源和竞争之间的关系是不明确的；然而，从这些模型得出的理论的生物学解释通常是从资源的角度来表达的。在这里，我们开发了精确定义资源和竞争之间关系的模型。我们考虑了两种资源开发模式：(1)持续供应资源，同时不断清除生物体和废物的均衡模式；(2)季节性模式，资源作为离散实体呈现给种群，被入侵和耗尽，当一小部分幸存人口入侵新资源时，循环重复。对于这两个系统来说，资源和竞争之间的关系是相同的。考察了这些模型的一般性质，特别强调了允许两个种群共存的稳定平衡的资源划分条件。1.在资源开发的均衡模式下，两个物种只有在至少拥有两个资源的情况下才能共存。在这两个物种可以分割两种资源的所有三种定性不同的方式下都可以出现稳定的共存状态：(1)每个物种的独占资源，(2)一个物种的独占资源，和(3)两个物种的共享资源。2.在季节性资源开发模式下，在上述三种定性不同的资源划分方式下，两个物种有可能获得稳定的共存状态。此外，最有趣的是，在这种资源开发模式下，有可能获得两个物种竞争单一资源的稳定共存状态。当一个物种在高浓度下生长得更快，而另一个物种在限制资源的低浓度下生长得更快时，可能会发生后一种情况。3.在考虑单个种群和混合种群平衡点的相对位置时，我们发现了稳定的平衡点，在Volterra-Gose竞争模型中只能出现不稳定的平衡点，在Volterra-Gose模型预测稳定的区域中发现了不稳定的平衡点。4.对该模型的局限性以及这些发现对竞争理论的影响进行了一些考虑。
In traditional models of interspecific competition, the relationship between resources and competition is unspecified; yet the biological interpretation of the theory derived from these models is most often expressed in terms of resources. Here we develop models in which the relationship between resources and competition is precisely defined. We consider two modes of resource exploitation: (1) an equable mode in which resources are continuously supplied while organisms and wastes are continuously removed and (2) a seasonal mode in which resources are presented to the populations as discrete entities which are invaded and exhausted and the cycle is repeated when a small fraction of the surviving population invades a new resource. The relationship between resources and competition is identical for both systems. The general properties of these models are examined, with particular emphasis given to the conditions of resource partitioning which allow for stable equilibria with two species coexisting. 1. under the equable mode of resource exploitation, two species can coexist only if they have at least two resources. Stable states of coexistence can occur under all three qualitatively distinct ways in which the two species can partition two resources: (1) exclusive resources for each species, (2) an exclusive resource for one species, and (3) shared resources for both species. 2. Under the seasonal mode of resource exploitation, it is possible to obtain stable states of coexistence for two species under all three of the above qualitatively distinct ways of partitioning the resources Furthermore, and most interestingly, under this mode of resource exploitation it is possible to obtain stable states of coexistence for two species competing for a single resource. The latter can occur when one species grows faster at high concentrations while the other grows faster at low concentrations of the limiting resource. 3. In considering the relative positions of the equilibria for single species and for mixed populations, we found stable equilibria where only unstable equilibria can occur in the Volterra-Gause competition models and unstable equilibria in regions where the Volterra-Gause model predicts stability. 4. Some consideration was given to the limitations of the model and to the implications of these findings for competition theory.