China is the world's most populous country and a major emitter of greenhouse gases. Consequently, much research has focused on China's influence on climate change but somewhat less has been written about the impact of climate change on China. China experienced explosive economic growth in recent decades, but with only 7% of the world's arable land available to feed 22% of the world's population, China's economy may be vulnerable to climate change itself. We find, however, that notwithstanding the clear warming that has occurred in China in recent decades, current understanding does not allow a clear assessment of the impact of anthropogenic climate change on China's water resources and agriculture and therefore China's ability to feed its people. To reach a more definitive conclusion, future work must improve regional climate simulations-especially of precipitation-and develop a better understanding of the managed and unmanaged responses of crops to changes in climate, diseases, pests and atmospheric constituents.

High biodiversity of forests is not predicted by traditional models, and evidence for trade‐offs those models require is limited. High‐dimensional regulation (e.g., N factors to regulate N species) has long been recognized as a possible alternative explanation, but it has not be been seriously pursued, because only a few limiting resources are evident for trees, and analysis of multiple interactions is challenging. We develop a hierarchical model that allows us to synthesize data from long‐term, experimental, data sets with processes that control growth, maturation, fecundity, and survival. We allow for uncertainty at all stages and variation among 26 000 individuals and over time, including 268 000 tree years, for dozens of tree species. We estimate population‐level parameters that apply at the species level and the interactions among latent states, i.e., the demographic rates for each individual, every year. The former show that the traditional trade‐offs used to explain diversity are not present. Demographic rates overlap among species, and they do not show trends consistent with maintenance of diversity by simple mechanisms (negative correlations and limiting similarity). However, estimates of latent states at the level of individuals and years demonstrate that species partition environmental variation. Correlations between responses to variation in time are high for individuals of the same species, but not for individuals of different species. We demonstrate that these relationships are pervasive, providing strong evidence that high‐dimensional regulation is critical for biodiversity regulation.

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The Three Gorges Dam in China is the largest dam ever built. Its impacts on the biodiversity and ecological processes in the region are causing concern to ecologists worldwide. The dam and associated environmental alterations may result in a number of regional changes in terrestrial and aquatic biodiversity, as well as in ecosystem structure and functioning. The dam may also provide a rare opportunity for a grand‐scale experiment in habitat fragmentation, allowing ecologists to develop and test a series of hypotheses concerning the dynamics of biodiversity and biotic communities and their responses to disturbances. Such research can help improve conservation practices, stimulate international collaborations, and promote public education on the environment.

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