The MESI database

Scientists who wish to study ecosystem responses to climate- and other environmental changes have multiple tools to their disposal. One such tool are experiments, performed outside in the field, in a growth chamber, greenhouse or alike, in which environmental variables are manipulated, such as the temperature, atmospheric CO₂-concentration, precipitation or soil fertility. Depending on the research topic, effects of these single or combined factors are measured on a variety of possible responses, such as plant biomass or yields, exchange of CO₂ between ecosystem and atmosphere, or concentrations of nutrients present in the vegetation.

Example of a ‘global change’ experiment: extreme drought simulation in a grassland in the Stubai Valley, Austria at the initiative of Prof. Michael Bahn, University of Innsbruck (Photo: Kevin Van Sundert, 2017).

Such individual experiments have often lead to interesting and novel findings. To name a few examples: estimating of the CO2-fertilization effect on crop yields, impacts of simulated extreme drought on the carbon balance of a tropical rain forest, or observations of decreased plant nitrogen concentrations under elevated CO2, associated with impoverished nutritional value and a limitation to CO₂-fertilization. Findings such as these are reported in scientific journals.

Different ecosystems may respond differently to global change. In order to draw conclusions at large and even global scales, scientists therefore need data from a large number of spatially distinct experiments. Such data are typically extracted from original publications per experiment, and once a dataset with data from many such publications is complete, syntheses are performed with a statistical method called meta-analysis.

Collecting anew data from literature each time costs valuable time. Precious time of which researchers will now waste less, thanks to the international ‘MESI’ initiative, led by Kevin Van Sundert and Sara Vicca (Global Change Ecology Centre, research group Plants and Ecosystems). In this initiative, data from thousands of experiments were collected, curated and presented in a dynamic database, openly available to everyone. Fellow scientists can from now on not only use the database as a starting point for answering their favorite questions, but also suggest improvements and expansions to the database, or contribute themselves, with as reward for substantial contributions co-authorship on future versions. The aim of this initiative is to substantially facilitate synthesis work, including comparisons against mathematical models that project the future of land ecosystems. Ultimately, this work will improve our understanding and the predictability of ecosystem functioning in a rapidly changing world.

Link to the study: doi.org/10.1111/gcb.16585

Spatial distribution of experiments in the MESI database. Multifactorial experiments combine two or more of the environmental variables temperature, CO₂, precipitation or soil fertility.