Increasing the resilience of long-term ecological research

Background information. Environmental processes require research across an extensive range of space-time scales to understand them and assist in decision-making. For objective social, economic, and institutional reasons, long-term ecological research (LTER) is subject to more stress factors. The work's goal is to identify possibilities for increasing LTER resilience. The objectives are to map LTER's knowledge production from a global to a national scale, produce a model of institutional development of successful LTERs, and propose strategies to increase LTER resilience. Approaches and methods. We adopted an evolutionary approach to LTER, from systems ecology founders to active researchers. The methods included searches in the Web of Science for the scientific production of key investigators, LTER keywords in the articles' topics, and further geographical and scientific domain analyses directly in the Web of Science or using Citespace, followed by secondary data processing methods. A model LTER site was investigated through social immersion to understand the phases of its successful development. Contributions from the work. The number of LTER articles and the number of authors from a country citing these articles can be predicted by the number of LTER sites, the GDP, and the percentage allocated to research and development (42 countries, R² = 0.57-0.73). The slope of the linear equation relating the number of articles and the number of LTER sites is much larger for the American states than for European ones. American production mainly focused on life and earth sciences, while European and Chinese production was richer in keywords related to theory and decision making. Chinese authors prefer to cite HT Odum, and American authors prefer EP Odum. The production development over time at the regional and site scales has a lag, growth, stationary, and a decrease phase. The relatively lower interest in the USA compared to Europe and China for the theoretical approaches, decision making, and transdisciplinary approaches in LTER sites is confirmed by analyzing the presence of keywords over time at the country, site, and principal investigators (PIs) level. The selected very productive site (Hubbard Brook) had an organic development with five phases, from less complex projects to socio-ecological ones. Take-home messages. A strategy to improve resilience includes increasing GDP and the RD percentage in GDP, optimizing the number of LTER sites, having diverse LTER sites, diversifying the objectives of mature LTERs to increase their lifetime, starting the new LTERs with strong PIs, and gradually increasing the research complexity.