DISTRIBUTION AND OCCURRENCE
SPECIES: Prosopis pubescens | Screwbean Mesquite 



GENERAL DISTRIBUTION : 
Screwbean mesquite is largely confined to valley bottomlands and its
distribution often follows major water courses.  In New Mexico and
Texas, screwbean mesquite occurs along the Rio Grande from the Big Bend
area northward to the town of Bernardo in central New Mexico [8,25].
Farther west it occurs in northern Baja California, throughout much of
southeastern California, southern Nevada, eastern Arizona, and extreme
southwestern Utah [25].  Its distribution is continuous along the
Colorado River from about 50 miles (80 km) south of the Mexican-U.S.
border northward to the Virgin River near Overton, Nevada [19,25].
Along the Virgin River, screwbean mesquite occurs northward to the
Arizona-Utah border.  Along the Gila River, screwbean mesquite has a
continuous distribution eastward to midway between Florence and Kelvin,
Arizona [19].  Along the Salt River, it occurs from the Salt River-Gila
River confluence eastward to the Salt River Indian Reservation.

A disjunct population occurs in the San Joaquin Valley of California.
These plants became established between 1870 and 1890, probably from
livestock-transported seed left along railways [20].


ECOSYSTEMS : 
   FRES30  Desert shrub
   FRES33  Southwestern shrubsteppe
   FRES40  Desert grasslands


STATES : 
     AZ  CA  NV  NM  TX  UT  MEXICO


ADMINISTRATIVE UNITS : 
     BIBE  DEVA  GRCA  GUMO  JOTR  LAME
     ORPI


BLM PHYSIOGRAPHIC REGIONS : 
    7  Lower Basin and Range
   13  Rocky Mountain Piedmont


KUCHLER PLANT ASSOCIATIONS : 
   K027  Mesquite bosque
   K041  Creosote bush
   K042  Creosote bush - bursage
   K043  Palo verde - cactus shrub
   K044  Creosote bush - tarbush
   K045  Ceniza shrub


SAF COVER TYPES : 
   235  Cottonwood - willow
   242  Mesquite


SRM (RANGELAND) COVER TYPES : 
NO-ENTRY


HABITAT TYPES AND PLANT COMMUNITIES : 
In general, screwbean mesquite only becomes a dominant or codominant in
woodlands or scrublands along riparian zones.

Associated trees and shrubs include saltcedar (Tamarix ramosissima),
western honey mesquite (Prosopis glandulosa var. torreyana), velvet
mesquite (P. velutina), seepwillow (Baccharis glutinosa), arroweed
(Tessaria sericea), quailbush (Atriplex lentiformis), seepweed (Suaeda
torreyana), skunkbrush sumac (Rhus trilobata), and wolfberry (Lycium
andersonii) [8,31].  Along the Rio Grande, saltgrass (Distichlis
spicata) and alkali sacaton (Sporobolus airoides) are common understory
grasses [8].

Related categories for Species: Prosopis pubescens | Screwbean Mesquite