rspb20192221_si_001.pdf (1.77 MB)

Electronic supplementary figures and tables from A regional-scale assessment of using the metabolic scaling theory to predict ecosystem properties

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journal contribution
posted on 04.11.2019, 10:58 by James K. McCarthy, John M. Dwyer, Karel Mokany
The metabolic scaling theory (MST) is one of ecology's most high-profile general models and can be used to link size distributions and productivity in forest systems. Much of MST's foundation is based on size distributions following a power law function with a scaling exponent of −2, a property assumed to be consistent in steady-state ecosystems. We tested the theory's generality by comparing actual size distributions with those predicted using MST parameters assumed to be general. We then used environmental variables and functional traits to explain deviation from theoretical expectations. Finally, we compared values of relative productivity predicted using the MST with a remote-sensed measure of productivity. We found that fire-prone heath communities deviated from MST-predicted size distributions, whereas fire-sensitive rainforests largely agreed with the theory. Scaling exponents ranged from −1.4 to −5.3. Deviation from the power law assumption was best explained by the specific leaf area which varies along fire frequency and moisture gradients. While the MST may hold in low-disturbance systems, we show that it cannot be applied under many environmental contexts. The theory should remain general, but understanding the factors driving deviation from the MST and subsequent refinements are required if it is to be applied robustly across larger scales.