Maintenance of Functional Diversity by Self-Organized Pattern Formation

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We recently described a novel mechanism for supporting functional diversity in metacommunities that builds on self-organized pattern formation. This process leads to the emergence of spatially heterogeneous distributions of species and their resources, caused only by the interplay of the feeding interactions of the species and their movement in space. Self-organized formation of spatial patterns is known from a variety of different ecosystems, but so far, little is known about how these patterns affect the diversity of communities. Using a model of a generic meta-foodweb with a diverse community of autotrophs (plants or algae), we have shown that the emerging patterns in the abundances of the species and their resources create locally different selection pressures on a functional trait of the autotrophs. This leads to biomass-trait feedbacks that increase the functional diversity of the autotrophs (as measured by the width of the distribution of the functional trait) tenfold compared to situations without self-organized pattern formation. This increase in diversity is significant, because it allows the autotroph communities to continually adapt to potential changes in environmental conditions. However, in order to facilitate a detailed understanding of this mechanism for supporting diversity, central model settings like the spatial arrangement of the habitat patches or the biodiversity throughout the food chain have been deliberately kept very simple. The main objective of this proposal is therefore to establish the generality and ecological significance of the described basic mechanism by developing the model further along three important axes of complexity. First, it is planned to determine conditions under which self-organized pattern formation can support functional diversity in realistic (i.e., large and complex) networks of habitat patches and to assess how these are affected by anthropogenic interference (e.g. habitat loss). We will then go on to explore the interaction between ubiquitous environmental heterogeneity, which by itself already creates different selection pressures on the functional trait, and the maintenance of functional diversity by self-organized pattern formation. Last, we will investigate the potential of the basic mechanism to support multi-trophic functional diversity by extending the model to include co-adaptation of diverse prey and predator communities. The anticipated results of the project will thus provide a comprehensive picture on the importance of self-organized pattern formation as a generic mechanism for supporting functional diversity in metacommunities, and they will shed light on how sensitive this mechanism is to human interference.