Arizona exhibits great diversity in riparian communities and the dominant plant species. Elevation and latitude and the resulting climate drive much of this variation. At low elevations, riparian communities tend to be characterized by cottonwoods and willows. Ascending in elevation, ash, sycamores, and walnut trees become more common. At elevations above 6,500 feet, willows, chokecherry, boxelder, and maples dominate. Montane streams host alder and aspen species. All of these communities share their dependence on perennial water.

Left: Image courtesy of In Stream Corridor Restoration: Principles, Processes, and Practices (10/98). Interagency Stream Restoration Working Group (15 federal agencies).

Wetlands, marshes, and swamps are perennially wet areas that may or may not be connected to a stream. These areas can be supported by a spring or seep. Cienega is another name for this type of wet community, restricted mainly to lower elevation areas (below 6,000 feet). Cattails, rushes, grasses, and sedges are common in cienegas.

Dry washes, though not characterized by perennial surface water flow, are also typically distinguishable from the surrounding landscape. The intermittent presence of water is enough to support a different community of plants than the drier upland landscape. Frequently, dry washes will be thick with palo verde, ironwood, and willow trees. These ribbons of forest in desert, grassland, and scrubland communities provide habitat for 90% of Arizona’s bird species (Dimmitt 2000) and are important wildlife corridors.

Much more can be learned about Arizona's riparian areas in the "Arizona Riparian Areas" web module.

Left: Dry washes can clearly be identified in this photograph as ribbons of green vegetation.