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There is growing interest in identifying the impacts of extreme climate events on natural systems. Two principles of such detection are that it should be based on a scientific understanding of the processes by which climate affects the system of interest and that non-climate factors that also affect the system should be controlled for. Using a simple temperature-dependent predator-prey model, this paper illustrates the importance of these principles in the context of establishing a link between temperature and population extremes. The results suggest that a naive approach based only on the co-occurrence of temperature and population extremes may fail. In the second part of the paper, some reasons for focusing attention on the ecological impacts of extreme climate events are briefly reviewed. It is suggested that, while extreme ecological events may be important for society, this does not imply that an analysis aimed at connecting them to extreme climate events should necessarily be based on extreme events themselves. [ABSTRACT FROM AUTHOR]

Drylands occupy large portions of the Earth, and are a key terrestrial biome from the socio-ecological point of view. In spite of their extent and importance, the impacts of global environmental change on them remain poorly understood. In this introduction, we review some of the main expected impacts of global change in drylands, quantify research efforts on the topic, and highlight how the articles included in this theme issue contribute to fill current gaps in our knowledge. Our literature analyses identify key under-studied areas that need more research (e.g. countries such as Mauritania, Mali, Burkina Faso, Chad and Somalia, and deserts such as the Thar, Kavir and Taklamakan), and indicate that most global change research carried out to date in drylands has been done on a unidisciplinary basis. The contributions included here use a wide array of organisms (from micro-organisms to humans), spatial scales (from local to global) and topics (from plant demography to poverty alleviation) to examine key issues to the socio-ecological impacts of global change in drylands. These papers highlight the complexities and difficulties associated with the prediction of such impacts. They also identify the increased use of long-term experiments and multidisciplinary approaches as priority areas for future dryland research. Major advances in our ability to predict and understand global change impacts on drylands can be achieved by explicitly considering how the responses of individuals, populations and communities will in turn affect ecosystem services. Future research should explore linkages between these responses and their effects on water and climate, as well as the provisioning of services for human development and well-being. [ABSTRACT FROM AUTHOR]