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Updated: Aug 31, 2025

A Low-Cost Method of Measuring the In Situ Primary Productivity of Periphyton Communities of Lentic Waters
Published on: December 16, 2022
An equation of state unifies diversity, productivity, abundance and biomass
John Harte1,2,3, Micah Brush4,5, Erica A Newman6
1The Energy and Resources Group, University of California, Berkeley, CA, 94720, USA. jharte@berkeley.edu.
Abstract:
To advance understanding of biodiversity and ecosystem function, ecologists seek widely applicable relationships among species diversity and other ecosystem characteristics such as species productivity, biomass, and abundance. These metrics vary widely across ecosystems and no relationship among any combination of them that is valid across habitats, taxa, and spatial scales, has heretofore been found. Here we derive such a relationship, an equation of state, among species richness, energy flow, biomass, and abundance by combining results from the Maximum Entropy Theory of Ecology and the Metabolic Theory of Ecology. It accurately captures the relationship among these state variables in 42 data sets, including vegetation and arthropod communities, that span a wide variety of spatial scales and habitats. The success of our ecological equation of state opens opportunities for estimating difficult-to-measure state variables from measurements of others, adds support for two current theories in ecology, and is a step toward unification in ecology.
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