Abstract
Many serious ecosystem consequences of climate change will take decades or even 50 centuries to emerge. Long-term ecological responses to global change are strongly regulated by 51 slow processes, such as changes in species composition, carbon dynamics in soil and by long-52 lived plants, and accumulation of nutrient capitals. Understanding and predicting these processes 53 requires experiments on decadal time scales. But decadal experiments by themselves may not be 54 adequate because many of the slow processes have characteristic time scales much longer than 55 experiments can be maintained. This article promotes a coordinated approach that combines 56 long-term, large-scale global change experiments with process studies and modeling. Long-term 57 global change manipulative experiments, especially in high-priority ecosystems such as tropical 58 forests and high-latitude regions, are essential to maximize information gain concerning future 59 states of the earth system. The long-term experiments should be conducted in tandem with 60 complementary process studies, such as those using model ecosystems, species replacements, 61 laboratory incubations, isotope tracers, and greenhouse facilities. Models are essential to 62 assimilate data from long-term experiments and process studies together with information from 63 long-term observations, surveys, and space-for-time studies along environmental and biological 64 gradients. Future research programs with coordinated long-term experiments, process studies, 65 and modeling have the potential to be the most effective strategy to gain the best information on 66 long-term ecosystem dynamics in response to global change. 67
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