Mathematical Model Analysis for the Stability Change of Ecosystem by Elimination of Interspecific Relationship

消除种间关系引起生态系统稳定性变化的数学模型分析

基本信息

批准号：
14540120
负责人：
SENO Hiromi
金额：
$ 1.98万
依托单位：
HIROSHIMA UNIVERSITY
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (C)
财政年份：
2002
资助国家：
日本
起止时间：
2002 至 2003
项目状态：
已结题

项目摘要

1. As for Lotka-Volterra competing two species system with temporally intermittent competitive relationship, the temporally intermittent competition could realize the coexistence or emphasize the competition as a result. We introduce in addition the spatial distribution of those two species, making a mathematical model with reaction-diffusion system, and discuss the expansion or the shrinking of spatial distribution as a travelling wave problem. Until now we find that the temporally intermittent competition could cause the coexistence of two species at the same site, with their spatially overlapping distributions. Mathematically the conditions for such co-location coexistence would be closely related to the condition for coexistence in case of population dynamics without taking account of spatial distribution. Moreover, in case of spatial co-location coexistence, each spatial distribution invades into the habitat of another species. Numerical calculations indicate that the front of suc … More h spatial invasion can be treated as a stationary travelling wave with a constant speed2. As for Lotka-Volterra predator-prey system, we investigate the possibility of coexistence of preys with competition which mediates the apparent competition by a common predator. We can show that, even when a prey tends to go extinct due to predation by a predator that feeds another preys, the prey could survive if it has an appropriate competitive relationship with another prey(s), with or without predators extinction. This implies that, with an elimination of competitive relationship between preys within a food web, some preys could go extinct due to such indirect effect. Consequently it is indicated that the competitive relationship could promote the coexistence between those competing species. Therefore, the competitive relationship within a stable ecosystem may stabilize the system. On the other hand, the invasion of new species may considerably destabilize the system, depending on the possible predation for the invading species Less

1.对于具有时间间歇性竞争关系的Lotka-Volterra竞争两个物种系统，时间间歇性竞争可以实现共存或强调竞争，我们另外引入了这两个物种的空间分布，并建立了数学模型。反应扩散系统，并将空间分布的扩张或收缩作为行波问题进行讨论。到目前为止，我们发现时间间歇性竞争可能导致两个物种在同一地点共存。从数学上讲，这种共存共存的条件将与人口动态情况下的共存条件密切相关，而无需考虑空间分布。此外，在空间共存共存的情况下，每个空间分布都会侵入。数值计算表明，这种入侵的前部空间可以被视为具有恒定速度的静止行波2。在这个系统中，我们研究了猎物与竞争共存的可能性，这种竞争调解了共同捕食者的明显竞争。我们可以证明，即使当一个猎物由于捕食另一个猎物的捕食而趋于灭绝时，猎物也可以生存。如果它与其他猎物有适当的竞争关系，无论捕食者是否灭绝，这意味着，随着食物网内猎物之间竞争关系的消除，一些猎物可能会由于这种间接影响而灭绝。表明的竞争关系可以促进这些竞争物种之间的共存，因此，稳定的生态系统内的竞争关系可以稳定系统，另一方面，新物种的入侵可能会大大破坏系统的稳定，这取决于对生态系统可能的捕食。入侵物种较少