Competition among plant species that interactwith their environment at different spatial scales

摘要

Clonal plants that are physiologically integrated might perceive and interact with their environment at acoarser resolution than smaller, non-clonal competitors. We develop models to explore the implications ofsuch scale asymmetries when species compete for multiple depletable resources that are heterogeneouslydistributed in space across two patches. Species are either 'non-integrators', whose growth in each patchdepends on resource levels in that patch alone, or 'integrators', whose growth is equal between patches anddepends on average resource levels across patches. Integration carried both benefits and costs. It tended tobe advantageous in poorer patches, where the integrators drew resources down further than the non-integrators (more easily excluding competitors) and might persist by using resources from richer adjacentpatches. Integration tended to be disadvantageous in richer patches, where integrators did not drawresources down as far (creating an opportunity for competitors) and could be excluded due to the cost ofsupporting growth in poorer adjacent patches. Complementarity between patches (each rich in a separateresource) favoured integrators. Integration created new opportunities for local coexistence, and for delayedsusceptibility of patches to invasion, but eliminated some opportunities for regional coexistence.Implications for the interpretations of species' zero net growth isoclines and R*s are also discussed.