Spatial self-organisation enables species coexistence in a model for savanna ecosystems
| Autor: | Jonathan A. Sherratt, Lukas Eigentler |
|---|---|
| Jazyk: | angličtina |
| Rok vydání: | 2019 |
| Předmět: |
0301 basic medicine
Statistics and Probability Biome Plant Development Poaceae General Biochemistry Genetics and Molecular Biology Ecosystem engineer Trees 03 medical and health sciences 0302 clinical medicine Competitive exclusion principle Ecosystem Quantitative Biology - Populations and Evolution General Immunology and Microbiology Ecology Applied Mathematics Niche differentiation Populations and Evolution (q-bio.PE) General Medicine Vegetation Grassland Colonisation 030104 developmental biology Modeling and Simulation FOS: Biological sciences Environmental science Tiger bush General Agricultural and Biological Sciences 030217 neurology & neurosurgery |
| Popis: | The savanna biome is characterised by a continuous vegetation cover, comprised of herbaceous and woody plants. The coexistence of species in arid savannas, where water availability is the main limiting resource for plant growth, provides an apparent contradiction to the classical principle of competitive exclusion. Previous theoretical work using nonspatial models has focussed on the development of an understanding of coexistence mechanisms through the consideration of resource niche separation and ecosystem disturbances. In this paper, we propose that a spatial self-organisation principle, caused by a positive feedback between local vegetation growth and water redistribution, is sufficient for species coexistence in savanna ecosystems. We propose a spatiotemporal ecohydrological model of partial differential equations, based on the Klausmeier reaction-advection-diffusion model for vegetation patterns, to investigate the effects of spatial interactions on species coexistence on sloped terrain. Our results suggest that species coexistence is a possible model outcome, if a balance is kept between the species’ average fitness (a measure of a species’ competitive abilities in a spatially uniform setting) and their colonisation abilities. Spatial heterogeneities in resource availability are utilised by the superior coloniser (grasses), before it is outcompeted by the species of higher average fitness (trees). A stability analysis of the spatially nonuniform coexistence solutions further suggests that grasses act as ecosystem engineers and facilitate the formation of a continuous tree cover for precipitation levels unable to support a uniform tree density in the absence of a grass species. |
| Databáze: | OpenAIRE |
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