Riparian zones are a key mediator of terrestrial-aquatic connectivity. Land use and climate change impacts can alter the function of riparian zones influencing streams. Grasslands globally are experiencing woody riparian expansion, moving them toward forest dominance. Our research on grassland and cropland riparian zones suggests that those bordering first order streams are the most influential on downstream water quality; 1st order riparian cover is more strongly correlated with water quality at 4th order stations than riparian cover at those stations. Woody expansion shifts streams from green to brown food webs by decreasing in-channel primary production and increasing seasonal allochthonous inputs seasonally, shifting algal communities and moving invertebrate communities from grazers toward shredders. Cattle alter riparian zone function, leading to lower water quality as evidenced in whole-watershed exclusion/ inclusion experiments. Cattle have particularly strong influences when there are riparian trees where cattle “loaf” during hot days. Woody expansion can also decrease downstream water yield, but this influence is context dependent. A decade long whole-watershed woody removal experiment in a grassland-dominated watershed experiencing riparian woody expansion elicited strong but transient responses in nutrient and sediment transport, long-term decreases in allochthonous inputs to the stream, and inconclusive effects on watershed hydrology. With current anthropogenically induced shifts, woody expansion appears inexorable without severe control methods in regions where C4 grasses were competitive dominants in the riparian zone. In our region, even annual burning does not control woody riparian expansion as the native woody species re-sprout and fire does not carry as well in forested areas as in grass dominated areas. Given increases in carbon dioxide concentrations that lower competitive advantages of C4 photosynthesis and elevated atmospheric N deposition, the riparian ecosystems in the Central Plains of the United States have been pushed into a new trajectory making them more like nearby wetter deciduous forests.