Global change human modification

Human Modification of the Earth System Global Change... 

In most of the world s watercourses, dramatic modifications have occurred as a consequence of their intensive use by human societies [1]. Pollution, water abstraction, riparian simplification, bank alteration, straightening of watercourses, dam construction, and species introduction are widespread perturbations in river ecosystems. These human-driven alterations are part of global changes. The simplification of the channel network and the alteration of water fluxes reduce the capacity of fluvial systems to recover from namral disturbances. Hydrologic alterations affect the functional organisation of streams and rivers, and lead to a simplification and impoverishment of the biota within these ecosystems. 

---