The Role of Patch Size in Driving Meta-Ecosystem Biodiversity and Function

The flow of resources between ecosystems is crucial for how these systems function and support biodiversity, but we still do not fully understand how landscape features like ecosystem size and species dispersal affect these processes. Ecosystem size influences properties that can potentially influence the quantity, quality, and heterogeneity of resources being exchanged, as well as how susceptible ecosystems are to these resource flows. Additionally, dispersal could allow the establishment of species in ecosystems where resource flow increases function, creating a stronger effect of resource flows on function if the established species is highly productive. To study the interaction between resource flows and ecosystem size, as well as between resource flows and dispersal, without the confounding factors found in field studies, I conducted a series of protist microcosm experiments in controlled laboratory conditions. My research shows that ecosystem size significantly affects the effects of resource flows on biodiversity and function, with a mediating effect of both the size of the target and connected ecosystems, the spatial scale examined, the trophic type of the ecosystem, and the magnitude of disturbances that trigger resource flows. I also developed a new experimental system to study how resource flows and dispersal interact to influence ecosystem function and biodiversity; however, the extinction of a key species prevented me from drawing conclusions on this interaction. This thesis provides novel findings and experimental approaches that advance our conceptual understanding of the effects of resource flows. As a next step, the findings of my research can be combined with field studies and mathematical models to also make this research applicable to natural ecosystems.