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H umans have long been fascinated by the dynamism of free-flowing waters. Yet we have expended great effort to tame i rivers for transportation, water supply , flood control, agriculture, and ; f power generation. It is now recognized that harnessing of streams and rivers comes at great cost: Many. rivers no longer support socially valued native species or(More)
SUMMARY 1. The flow regime is a primary determinant of the structure and function of aquatic and riparian ecosystems for streams and rivers. Hydrologic alteration has impaired riverine ecosystems on a global scale, and the pace and intensity of human development greatly exceeds the ability of scientists to assess the effects on a river-by-river basis.(More)
SUMMARY 1. In an effort to develop quantitative relationships between various kinds of flow alteration and ecological responses, we reviewed 165 papers published over the last four decades, with a focus on more recent papers. Our aim was to determine if general relationships could be drawn from disparate case studies in the literature that might inform(More)
Understanding the mechanisms by which nonnative species successfully invade new regions and the consequences for native fauna is a pressing ecological issue, and one for which niche theory can play an important role. In this paper, we quantify a comprehensive suite of morphological, behavioral, physiological, trophic, and life-history traits for the entire(More)
C onflicts based on the perceived needs of ecosystems versus humans for fresh water are increasingly seen in the news. In the US, a fiery debate has erupted in the Klamath basin of Oregon and California, where farmers have protested the loss of irrigation water to protect endangered fish, and where over 30 000 chinook salmon and other fish recently died,(More)
The origin of Galactic cosmic rays (with energies up to 10 15 eV) remains unclear, though it is widely believed that they originate in the shock waves of expanding supernova remnants [1][2]. Currently the best way to investigate their acceleration and propagation is by observing the γ-rays produced when cosmic rays interact with interstellar gas [3]. Here(More)
A significant fraction of the energy density of the interstellar medium is in the form of high-energy charged particles (cosmic rays). The origin of these particles remains uncertain. Although it is generally accepted that the only sources capable of supplying the energy required to accelerate the bulk of Galactic cosmic rays are supernova explosions, and(More)
Community convergence across biogeographically distinct regions suggests the existence of key, repeated, evolutionary mechanisms relating community characteristics to the environment. However, convergence studies at the community level often involve only qualitative comparisons of the environment and may fail to identify which environmental variables drive(More)
Animal movements are influenced by the structure and arrangement of patches in a landscape. Most movement studies occur in terrestrial landscapes, though aquatic landscapes are equally heterogeneous and feature patches that differ in resistance to animal movements. Furthermore, the variable and highly directional flow of water over streambed landscapes is a(More)