Coordinated Approaches for Studying Long-Term Ecosystem Responses to Global Change

The rapidly-growing world population, over-exploitation of natural resources, climate change and land-use changes stimulate ecological research at all scales. Within this complex reality, ecological research should aim to project future ecosystem states and processes over time scales of decades and centuries, and spatially from the plot size to the global scale. However, do we know what are the best strategies and requirements for achieving this goal? It is increasingly recognized that there are three key components to planning global change research: First, a long-term research approach is needed to identify ecological and physiological adjustments, feedbacks and community-level changes that are relatively slow in pace. Too often, global change experiments are conducted across a wide range of managed and natural ecosystems, effectively characterizing short-term, rapid and small-scale processes (Fraser et al. 2013). Second, research within the global change framework should combine monitoring, observational research, experimental manipulations and modeling. In particular, ‘monitoring', such as of background climatic conditions, should be distinguished from long-term ‘experiments' that permit the formulation of theory on ecophysiological and population-to-community-scale processes, and testing of that theory. In other words, we must conceive and conduct experiments at large enough spatial and temporal scales, and with sufficient complexity to effectively define ecosystem-level feedbacks (Osmond et al. 2004; Baldocchi et al. 2001). In more recent years, we have had access to process-based models that provide a useful means of generating hypotheses that can be tested by observations and experiential work. This permitted us to conduct experiments in silico: searching for optimal fits between theory and observations using models and maximum likelihood statistics. The models used for long-term assessments are usually built upon knowledge of ecosystem processes, and are often parameterized by short-term observations and experimental manipulation data. While this is still necessary, we can now go beyond this and use observations in ways other than for parameterization. Observations can now be used to test the adequacy for theory to represent processes, and provide validation through the assimilation of observations into the models with robust statistical tests of how well the theory permits the model to match the data (e.g., Zobitz et al. 2011; Leuzinger et al. 2011). The third component of global change ecological studies refers to the large-scale context of the study and its environmental representation. This may require large facilities, extensive instrumentation, and a large spatial scale of observation (e.g., remote sensing; Sellers 1993), networks of research sites (e.g., Baldocchi et al. 2001), or large-scale experimental systems (Gonzalez-Meler et al. 2014). While these requirements are often recognized individually, they are rarely discussed in an integrative manner within national or international research frameworks conducting global change research (Osmond et al. 2004). For many of the environmental issues we are facing, it is no longer possible for a single investigator, or even a team of investigators, to address large-scale ecological questions at the local or regional level (Luo et al. 2011). Coordinated distributed ecological experiments based on international collaboration are needed to address problems at regional and global scales in order to understand ecological patterns and processes, and to develop solutions for environmental management based on sound scientific data (Fraser et al. 2013). The lack of integrative national-scale frameworks in Israel, and many other countries, led to the convening of a special “Batsheva de Rothschild seminar on coordinated approaches for studying long-term ecosystem responses to global change”, in the fall of 2013, at the Ramat Hanadiv Nature Park in Israel (http://www.ramat-hanadiv.org.il/en). The seminar, supported by the Batsheva de Rothschild Fund of the Israel Academy of Sciences and Humanities, gathered international experts to discuss, and ultimately propose, a coordinated approach for a ‘National Platform for Long-Term Global Change Research' in Israel. An Israeli program, in turn, can serve as a model for national-scale platforms, by virtue of Israel's location in a complex ecological junction spanning a relatively small spatial scale (Safriel 2010; Sternberg et al. 2014). This seminar generated a cluster of papers by seminar participants, their colleagues and researchers who could not attend, but are conducting research of a similar nature, which comprise the Special Section of the current issue of Oecologia.