The three main factors controlling the behavior and responses of terrestrial ecosystems

Ecosystems provide multiple services. The quality of these services depends, however, on the characteristics of ecosystems and their functioning, which is determined both by natural conditions and factors such as climate, and by interaction with humans. A recent study, published in Nature, has identified three key functions that govern the behavior of ecosystems, and which are linked to their efficiency in the use of carbon and water. Observing these three key functions will allow us to monitor and study the behavior of terrestrial ecosystems and to understand their sensitivity to climate and environmental changes in progress, contributing to the optimization of their management.

Terrestrial ecosystems perform various functions of significant importance for natural dynamics and provide vital services for well-being and economic and social development, such as photosynthesis (absorption of CO2 and release of oxygen), production of biomass and food and regulation of the water cycle and climate. Climate and environmental changes and the impact of human action continually threaten these ecosystem functions. To understand how terrestrial ecosystems are responding and will respond in the future to these threats, it is essential to identify the main functions that regulate their complex behavior. A group of international researchers, led by Dr. Migliavacca of the Max Planck Institute for Biogeochemistry, Jena (Germany) and including scientists from the Institute for Atmospheric and Earth System Research (INAR) of University of Helsinki, has tried to answer this question, using ecological and environmental data obtained from global networks of measuring stations, combined with satellite observations, mechanistic and statistical models In particular, the researchers analyzed the exchange of carbon dioxide, water vapor and energy in 203 monitoring sites distributed globally (including ICOS-Finland Ecosystem Station FI-Hyy located in Hyytiälä). Three key factors were found that summarize the behavior of ecosystems: the maximum ability to assimilate CO2 from the atmosphere through photosynthesis, the efficiency of water use, and the efficiency of use of carbon for produce biomass. The analysis of the data and the models used have also determined that the three key functions identified are in turn linked to a series of characteristics such as the structure (height and biomass), the nutritional state (foliar nitrogen) and the greenness of the vegetation, which are properties that can be affected by disturbances and regulated by proper forest management. At the same time, the efficiency in the use of water and carbon also depends critically on the climate and above all on the length and frequency of drought periods. This once again highlights the relevance of ongoing climate change for the functioning of ecosystems in the years to come and the need to consider their adaptation. It is important to note that the study would not have been possible without the existence of global monitoring networks that in Europe have organized themselves in collaborative research infrastructures such as ICOS and eLTER. These networks collect valuable data that will also allow us to observe the control factors identified in the coming years.

Publication:

Migliavacca et al. The three major axes of terrestrial ecosystem function (2021) Nature, https://www.nature.com/articles/s41586-021-03939-9

Contact:

Ivan Mammarella, ivan.mammarella(a)helsinki.fi