Empirical tests of within‐ and across‐species energetics in a diverse plant community

Abstract

19Many fundamental properties of ecological systems and interactions are tied to body size, and a 20 related metric, the metabolic rate distribution, both within and across species. A previously 21proposed Maximum Entropy Theory of Ecology (METE) predicts numerous interrelated 22 macroecological patterns, including spatial distributions of individuals within species, abundance 23 distributions across species, species area relationships, and distributions of metabolic rates of all 24 individuals within a community. Extensive tests of METE's macroecological predictions 25 generally support the theory, but two related predictions have not been evaluated against full 26 community census data: the distribution of metabolic rates of individuals within species as a 27 function of the abundance of the species, and the distribution of average individual metabolic 28 rates across species. We test the metabolic predictions of METE for herbaceous plants in a 29 subalpine meadow and show that while this theory realistically predicts the distribution of 30 individual metabolic rates across the entire community, the within and across species predictions 31 generally fail. We also test the energy-equivalence type prediction that arises as a consequence 32 of the prediction for the distribution of average individual metabolic rates across species. We 33 suggest several possible explanations for the empirical deviations from theory, and distinguish 34 between the expected deviations caused by ecological disturbance and those deviations that 35 might be corrected within the theory. 36 37 Key words 38 metabolism, macroecology, scaling laws, Maximum Entropy Theory of Ecology, METE, 39 information entropy, energy equivalence 40 41 Erica A. Newman et al., 3 Introduction 42

An extensive comparison of species-abundance distribution models

“…Regardless of the underlying reason that the models performed similarly, our results indicate that the SAD usually does not contain sufficient information to distinguish among the possible statistical processes—let alone biological processes—with any degree of certainty (Volkov et al, 2005), though it is possible that this result differs in marine systems (see Connolly et al, 2014). A more promising way to draw inferences about ecological processes is to evaluate each model’s ability to simultaneously explain multiple macroecological patterns, rather than relying on a single pattern like the SAD (McGill, 2003; McGill, Maurer & Weiser, 2006; Newman et al, 2014; Xiao, McGlinn & White, 2015). It has also been suggested that examining second-order effects, such as the scale-dependence of macroecological patterns (Blonder et al, 2014) or how the parameters of the distribution change across gradients (Mac Nally et al, 2014), can provide better inference about process from these kinds of pattern.…”

meteR: an r package for testing the maximum entropy theory of ecology

“…Because the deviation between the patterns predicted by theory and empirical data from disturbed systems appears to itself follow a systematic pattern (Newman et al . ; Rominger et al ., in prep. ), clues exist for how to extend the static theory to the dynamic realm.…”

“…; Harte, Smith & Storch ; Harte ; White, Thibault & Xiao ; Newman et al . ); however, a great deal of further testing is needed to establish METE's generality, strengths and weaknesses. Existing tests have focused on SADs or SARs while tests of metabolic rate distributions are rare (but see Harte ; Newman et al .…”

“…Existing tests have focused on SADs or SARs while tests of metabolic rate distributions are rare (but see Harte ; Newman et al . ; Xiao, McGlinn & White ). However, the most illuminating cases are perhaps those where METE fails (Harte ), as these will demonstrate what attributes of a community drive it away from the simple steady state into alternate, more complex or transient states.…”

Reinterpreting maximum entropy in ecology: a null hypothesis constrained by ecological mechanism

“…This is particularly relevant given that METE does not universally succeed in predicting macroecological patterns (Newman et al . ; Xiao et al . ), potentially due to system‐specific biological constraints being ignored, and the issue was raised in earlier METE papers (Harte et al .…”