Changes in Individual Allometry Can Lead to Species Coexistence without Niche Separation
Changes in Individual Allometry Can Lead to Species Coexistence without Niche Separation
复制标题
个体异速生长的变化可以导致物种共存而无需生态位分离
作者：
E. Rastetter;G. I. gren
竞争排斥原理是生态学的一个基本原则。常用的竞争模型预测，在稳定状态下，每种有限资源最多只能有一个物种共存于同一环境中;因此，物种多样性的上限只取决于有限资源的数量，而不是资源供应的速度。我们证明，这种模型行为是生长和生物量周转函数与种群生物量成正比的结果。我们认为，至少生长函数应该是一个非线性的，向下凹的生物量的函数。生长函数的这种形式应该仅仅是由于种群中个体的异速生长的变化而出现的。随着模型结构的变化，我们证明了任何数量的物种可以共存于一个渐近稳定的稳态，即使只有一个有限的资源。此外，如果增长与生物量呈非线性增长，则稳态资源集中度和生物多样性的潜力会随着资源供应率的增加而增加。
AbstractThe principle of competitive exclusion is a fundamental tenet of ecology. Commonly used competition models predict that at most only one species per limiting resource can coexist in the same environment at steady state; hence, the upper limit to species diversity depends only on the number of limiting resources and not on the rates of resource supply. We demonstrate that such model behavior is the result of both the growth and biomass turnover functions being proportional to the population biomass. We argue that at least the growth function should be a nonlinear, concave downward function of biomass. This form for the growth function should arise simply because of changes in the allometry of individuals in the population. With this change in model structure, we show that any number of species can coexist at an asymptotically stable steady state, even where there is only one limiting resource. Furthermore, if growth increases nonlinearly with biomass, the steady-state resource concentration and hence the potential for biodiversity increases as the resource supply rate increases.