Linking intrinsic scales of ecological processes to characteristic scales of biodiversity and functioning patterns

Ecology is a science of scale, which guides our description of both ecological processes and patterns, but we lack a systematic understanding of how process scale and pattern scale are connected. Recent calls for a synthesis between population ecology, community ecology, and ecosystem ecology motivate the integration of phenomena at multiple levels of organization. Furthermore, many studies leave out the scaling of a critical process: species interactions, which may be non-local through mobility or vectors (resources or species) and must be distinguished from dispersal scales. Here, we use simulations to explore the consequences of different process scales (i.e. species interactions, dispersal, and the environment) on emergent patterns of biodiversity, ecosystem functioning, and their relationship, in a spatially-explicit landscape. A major result of our study is that the spatial scales of dispersal and species interactions have opposite effects: a larger dispersal scale homogenizes spatial biomass patterns, while a larger interaction scale amplifies their heterogeneity. We find that an interesting interplay between process scales occurs when the spatial distribution of species is heterogeneous at large scales, i.e., when the environment is not too uniform and dispersal not very strong. Interestingly, the specific scale at which scales of dispersal and interactions begin to influence landscape patterns depends on the environmental heterogeneity of the landscape -- in other words, the scale of one process allows important scales to emerge in other processes. Finally, contrary to our expectations, we observe that the spatial scale of ecological processes is more clearly reflected in landscape patterns (i.e. distribution of local outcomes) than in global patterns such as Species-Area Relationships or large-scale biodiversity-functioning relationships.