Xero-riparian is somewhat of a southwest regional vegetation community that many have never heard about. It is, however, extremely important for wildlife. There are very few perinnial streams in our region, but there are innumerable dry washes, which can carry a lot of runoff during our intense monsoon storms. All of this extra water, although it exists for brief periods, along with better associated bottomland soil, are enough to create this community.
Species diversity of flora and fauna increase substantially in xero-riparian areas, but more importantly the stature of trees and shrubs changes drastically. Some vegetation along desert washes even in extremely dry western Sonora can be impenetrable jungles of thorny plants and trees, providing more of everything species and the 'web of life' needs to thrive. Indeed many species would certainly not exist in our region at all if it were not for this community.
The most dominate and maybe most important species of xero-riparian is the velvet mesquite (Prosopis velutina). It dominates xero-riparian in most of our region in both Sonoran Desert as well as thorn-scrub. Only in extreme western Sonora and Arizona does it get out-competed by two other common xero-riparian trees, ironwood (Olneya tesota) and to a lesser extent blue paloverde (Parkinsonia florida). Another sometimes dominant, and generally restricted to xero-riparian areas in central and eastern Sonora is the chino (Havardia mexicana), which can grow double the height of mesquite in the same drainage.