Manipulative experiments networks on response and adaptation of terrestrial ecosystems to environmental changes:...

The feedback relationship between organisms or ecosystems and environment has been a key issue in ecological research. Manipulative experiments with changing biological or environmental factors and large-scale field experiment networks were regarded as effective approaches to understand and accurately quantify the process and mechanisms underlying ecosystem response and adaptation to environmental changes. In recent years, a few networks have been developed, including large-scale networks of field physics simulation experiment (i.e., ECOTRON), ecosystem analysis and experiment platform (AnaEE), international Drought Network, Nutrient Network, and experiment networks based on regional ecological observation stations (i.e., USA-ILTER) at global scale. The development of continent-scale experiment network platform is attracting more attention from the academic community, and will play a more important role in understanding the process and mechanism underlying ecosystem responses to environmental change. We reviewed the development of method and experiment system of ecosystem manipulative experiments, and clearly pointed out that different experiments should form a joint collaborative system to answer fundamental scientific questions about the response and adaptation of ecosystem to global environment change. Manipulative experiments could be classified into four types: 1) Physiological and ecological experiments in closed laboratory equipment; 2) semi-open experiments with changing environmental factors in the field; 3) near-natural field experiments; 4) experiment networks based on field ecological station. Furthermore, we discussed the trends in network design of manipulative experiments focusing on ecosystem response and adaptation to environmental changes and the advantages of large-scale experiments based on natural environmental gradients. We put forward a proposal of integrating the technical advantages of different types of experiments and developing a new generation of field experiment network system. The study discussed the research system based on field experiment network, demonstrated the possibility to understand the patterns and mechanisms of the ecosystem short-term response and long-term adaptation to environmental changes, and proposed some equations to quantify the environmental response of ecosystems. The application of the design plan of the manipulative experiments network proposed here will greatly promote the scientific research level of ecosystems and environmental changes in China and even over the whole world, which has important scientific significance for the national response to climate change and ecological environmental construction.