Emergent Global Patterns of Ecosystem Structure and Function from a Mechanistic General Ecosystem Model

Publication Date: 22 April, 2014

This report details how Microsoft's Computational Science Lab andUnited Nations Environment Programme World Conservation Monitoring Centre (UNEP-WCMC), based in Cambridge UK, have developed the first computer model able to simulate how all organisms interact on a global scale. The model creates a simulation of life on Earth, following a set of basic ecological tools found in the real world.

Abstract:

Anthropogenic activities are causing widespread degradation of ecosystems worldwide, threatening the ecosystem servicesupon which all human life depends. Improved understanding of this degradation is urgently needed to improve avoidanceand mitigation measures. One tool to assist these efforts is predictive models of ecosystem structure and function that aremechanistic: based on fundamental ecological principles. Here we present the first mechanistic General Ecosystem Model(GEM) of ecosystem structure and function that is both global and applies in all terrestrial and marine environments.Functional forms and parameter values were derived from the theoretical and empirical literature where possible.Simulations of the fate of all organisms with body masses between 10 mg and 150,000 kg (a range of 14 orders of magnitude) across the globe led to emergent properties at individual (e.g., growth rate), community (e.g., biomass turnoverrates), ecosystem (e.g., trophic pyramids), and macroecological scales (e.g., global patterns of trophic structure) that are ingeneral agreement with current data and theory. These properties emerged from our encoding of the biology of, and interactions among, individual organisms without any direct constraints on the properties themselves. Our results indicate that ecologists have gathered sufficient information to begin to build realistic, global, and mechanistic models of ecosystems, capable of predicting a diverse range of ecosystem properties and their response to human pressures.