| Summary: | The regularities of our planet’s climate determine a large part of the form and function of Earth’s ecosystems. The frequently nonlinear operation of the atmosphere gives rise to a rich complexity of variability superimposed on the fundamental regularities. A traditional definition of climate is “the long-term state of the atmosphere encompassing the aggregate effect of weather phenomena—the extremes as well as the mean values” (Barry and Chorley 1987). Ecosystems share some of the same properties as the climate system. At one level their operation is fairly straightforward. Ecologists, to a certain extent, understand the flows of energy and matter through these systems. A good deal of ecosystem operation over time is characterized by some degree of homeostasis. On the other hand, nonlinear change and multiple variables have placed uncertainty and surprise at the forefront of much ecological research. In both the climate and the ecosystem the only certainty often appears to be change. The task of this book is to focus on some of this change at the interface between the climate and the ecosystem and by doing so gain insights into the operation of both systems. Millennial-scale (1000-year) climate variability has driven large changes of vegetation and fauna at almost all of the Long-Term Ecological Research (LTER) sites. Decadal climate variability at some sites has seen dramatic changes in fish catches and has altered tree species composition. During the first two decades of study, LTER sites have been affected by two super El Niño events and several more “normal” El Niños and La Niñas. Major droughts have affected species diversity and killed some trees. Severe storms and floods have damaged stream restoration structures. Coastal sites have measured a rise in sea level. Antarctic sites have documented the decrease of some penguin populations and a rise in other populations as a result of climatic warming over 50 or more years. Climate variability has constantly been on investigators’ minds. It is little wonder ...
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