A Multiscale Translation of Tilman R and Its Empirical Application in the Cerrado

Abstract

Translating Tilman resource-ratio model (R) to the metacommunity scale bridges local plant competition and landscape dynamics, moving ecological niche theory beyond controlled experiments. By incorporating scale dependence, stochasticity, dispersal limitation, and the stress-disturbance dichotomy, this framework also accounts for the drivers of both alpha and beta diversity. To achieve this integration, this work presents the Metacommunity Resource-Ratio Model (MetcommR) and its graphical tool, the Patchwork Biplot. This approach adapts the traditional continuous plane with a granular patch space, where each patch represents a discrete community with its area and internal variability, tracking net vectors of resource consumption and release relative to species-limiting isoclines. MetcommR articulates two fundamental regimes. In disturbance-governed metacommunities, biomass loss releases resources, interrupting depletion and preventing competitive exclusion, which promotes coexistence via the competition-colonization trade-off and maintains alpha and beta diversity. Conversely, in stress-governed systems, biomass accumulation and severe resource scarcity push communities toward isoclines, favoring the monodominance of tolerant species through competitive exclusion under the tolerance-fecundity trade-off. We demonstrate the model's empirical utility through a Cerrado case study in the Paraopeba Reserve. Analyzing canopy openness (light) and soil nitrogen reveals that long-term fire suppression induces light stress, elevating competitive exclusion risks for shade-intolerant species. Consequently, the Patchwork Biplot serves as a tool for evaluating ecological dynamics and vulnerabilities to guide management and conservation strategies.