DISTRIBUTION AND OCCURRENCE
SPECIES: Ambrosia psilostachya | Western Ragweed 



GENERAL DISTRIBUTION : 
Western ragweed's range extends from southern British Columbia east to
Nova Scotia [51,81,107] and southward through the United States from the
Appalachians to the West Coast and into central Mexico
[38,74,90,104,108].  Western ragweed was introduced from North America
into Europe and southwestern Russia [115].


ECOSYSTEMS : 
   FRES15  Oak - hickory
   FRES21  Ponderosa pine
   FRES31  Shinnery
   FRES32  Texas savanna
   FRES33  Southwestern shrubsteppe
   FRES34  Chaparral - mountain shrub
   FRES38  Plains grasslands
   FRES39  Prairie
   FRES42  Annual grasslands


STATES : 
     AZ  CA  CO  CT  ID  IL  IA  KS  LA  ME
     MA  MI  MO  MN  MT  NE  NH  NC  ND  OH
     OK  OR  SC  SD  TX  UT  VT  WA  WI  WY
     AB  BC  MB  NS  ON  PE  PQ  SK  MEXICO


ADMINISTRATIVE UNITS : 
     AGFO  AMIS  BITH  CACA  CHIR  COLM
     CODA  GLAC  GRCA  GUMO  JELA  LAME
     LAMR  MOCA  PAIS  PIPE  ROMO  SAMO
     SCBL  SLBE  THRO  WACA  WICA  WUPA
     ZION


BLM PHYSIOGRAPHIC REGIONS : 
    3  Southern Pacific Border
    5  Columbia Plateau
    7  Lower Basin and Range
   10  Wyoming Basin
   12  Colorado Plateau
   13  Rocky Mountain Piedmont
   14  Great Plains
   16  Upper Missouri Basin and Broken Lands


KUCHLER PLANT ASSOCIATIONS : 
   K033  Chaparral
   K035  Coastal sagebrush
   K053  Grama - galleta steppe
   K054  Grama - tobosa prairie
   K057  Galleta - three-awn shrubsteppe
   K058  Grama - tobosa shrubsteppe
   K060  Mesquite savanna
   K061  Mesquite - acacia savanna
   K062  Mesquite - live oak savanna
   K063  Foothills prairie
   K064  Grama - needlegrass - wheatgrass
   K065  Grama - buffalograss
   K067  Wheatgrass - bluestem - needlegrass
   K068  Wheatgrass - grama - buffalograss
   K069  Bluestem - grama prairie
   K070  Sandsage - bluestem prairie
   K071  Shinnery
   K074  Bluestem prairie
   K075  Nebraska Sandhills prairie
   K076  Blackland prairie
   K078  Southern cordgrass prairie
   K081  Oak savanna
   K084  Cross Timbers
   K085  Mesquite - buffalograss
   K086  Juniper - oak savanna
   K087  Mesquite - oak savanna
   K100  Oak - hickory forest


SAF COVER TYPES : 
    40  Post oak - blackjack oak
    42  Bur oak
    66  Ashe juniper - redberry (Pinchot) juniper
    68  Mesquite
    72  Southern scrub oak
    73  Southern redcedar
    89  Live oak
   220  Rocky Mountain juniper
   235  Cottonwood - willow
   238  Western juniper
   242  Mesquite
   244  Pacific ponderosa pine - Douglas-fir
   255  California coast live oak


SRM (RANGELAND) COVER TYPES : 
NO-ENTRY


HABITAT TYPES AND PLANT COMMUNITIES : 
Western ragweed is a principal or dominant forb in many grasslands, such
as little bluestem (Schizachyrium scoparium) and shortgrass communities
[6].  It is of secondary importance in big bluestem (Andropogon gerardii
var. garardii) communities, but it is still the dominant forb [6,113].
It is a dominant forb in the Cross Timbers range, sand plains, and
prairies of Texas [44,86].  Western ragweed is dominant in sand
tallgrass prairies and sand hills of the Midwest [105,120].  It is the
principal forb in the shortgrass-ponderosa pine (Pinus ponderosa)
woodlands of north-central Arizona [18,28,60].  Western ragweed is
present in the Gambel oak (Quercus gambeli) grasslands of the west
[29,39].  Western ragweed is codominant in saltgrass (Distichlis
spicata) communities and in grasslands found above salt marshes [22,26,
34,42].

In riparian habitat types of Wyoming, western ragweed is listed as
codominant with western wheatgrass (Pascopyrum smithii) in the
Grass/Sedge Meadow subtype [90].  Western ragweed is a important forb,
but not an indicator, in steppe habitat types of North Dakota and South
Dakota:  (1) needle-and-thread grass (Stipa comata)/threadleaf sedge
(Carex filifolia), (2) green ash (Fraxinum pennsylvanica)/common
chokecherry (Prunus virginiana), and in Montana:  (1) needle-and-thread
grass/sun sedge (Carex heliophila), (2) Idaho fescue (Festuca
idahoensis)/sun sedge, (3) bluebunch wheatgrass (Psuedoroegnaria
spicata)/sideoats grama (Bouteloua curtipendula), (4) bluebunch
wheatgrass/threadleaf sedge, (5) fragrant sumac (Rhus aromatica)/
bluebunch wheatgrass, and (6) fragrant sumac/Idaho fescue [64].

Publications that list western ragweed as dominant are:

(1)  The vegetation of the Grand River/Cedar River, Sioux, and Ashland
     Districts of the Custer National Forest: a habitat type
     classification [64]. 
(2)  A physical and biological characterization of riparian habitat and its
     importance to wildlife in Wyoming [90].

Related categories for Species: Ambrosia psilostachya | Western Ragweed