As a result of human activities, forests and rangelands across the globe have undergone dramatic changes that have fundamentally altered ecosystem processes. Examples of these kinds of transformational changes include increasingly hot and extensive forest fires, die-off over vast areas of forest from insect infestations, large-scale encroachment of rangelands by woody plants and non-native invasive plants, and desertification. These changes have accelerated in pace, scale and magnitude in recent decades and have the potential to alter water, energy, and biogeochemical cycles in important but not fully understood ways. The related disciplines of ecohydrology and watershed management are being shaped and transformed by the need to understand the ecohydrological consequences of transformative landscape change as well as the need to mitigate and manage for these changes. Copyright © 2010 John Wiley & Sons, Ltd.