Ecological Archives E095-244-A5

Erica A. Newman, Mary Ellen Harte, Natalie Lowell, Mark Wilber, John Harte. 2014. Empirical tests of within- and across-species energetics in a diverse plant community. Ecology 95:2815–2825. http://dx.doi.org/10.1890/13-1955.1

Appendix E. Additional analysis of SEDs.

FigE1

Fig. E1. Slopes of predicted vs. observed data for all SEDs of species with n ≥ 5, organized by average photosynthetic area (equivalent to average metabolic rate) of an individual within a species. Each point represents one species, and species are in rank order from largest to smallest average photosynthetic area (equivalent to ranking by metabolic rate) of the individuals of that species. An exponential trendline is shown on the graph. A good fit of the predicted vs. observed data points would be a slope of 1, however, we see variable, increasing slope here.


 

FigE2

Fig. E2. R² values for predicted SED distributions vs. observed data. Species are in rank order from largest to smallest average photosynthetic area (metabolic rate). Outlier points with low R² values are Lupinus argentus (rank 6 by average size) and Thlaspi montanum, (rank 20 by average metabolic rate), both of which have one very large outlying individual. High R² values naturally result from ranked data that falls along a straight line on a log-log graph of an exponential distribution.


 

One way to interpret these results is to say that the exponential model is a good model, however, the slopes are incorrect. We note that the intercepts are also incorrect for this model, which may indicate that one or more important constraints are missing from the model.


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