DISTRIBUTION AND OCCURRENCE
SPECIES: Ambrosia deltoidea | Triangle Bursage 



GENERAL DISTRIBUTION : 
Triangle bursage occurs throughout much of the Sonoran Desert.  It
extends southward from southwestern Arizona into Sonora and Baja
California, Mexico [2,3,16,24,27].


ECOSYSTEMS : 
   FRES30  Desert shrub
   FRES40  Desert grasslands


STATES : 
     AZ  MEXICO


ADMINISTRATIVE UNITS : 
     ORPI  SAGU


BLM PHYSIOGRAPHIC REGIONS : 
    7  Lower Basin and Range
   12  Colorado Plateau


KUCHLER PLANT ASSOCIATIONS : 
   K042  Creosotebush - bursage
   K043  Paloverde - cactus shrub


SAF COVER TYPES : 
   242 Mesquite


SRM (RANGELAND) COVER TYPES : 
NO-ENTRY


HABITAT TYPES AND PLANT COMMUNITIES : 
Triangle bursage is a dominant or codominant member of the Arizona
Upland Subdivision of the Sonoran Desert [5,8,16].  Although it mostly
occurs in the ecotone between upper and lower bajadas, it also grows on
upper bajadas, in lowland communities dominated by creosotebush (Larrea
tridentata), and in desert grassland communities [3,4,10,16,33].

In the ecotone between upper and lower bajadas, characterized by steep,
gravelly slopes, triangle bursage occurs in a paloverde (Cercidium
spp.)-cacti-mixed scrub series and the desert scrub community type.
Associated species include yellow paloverde (C. microphyllum), saguaro
(Carnegiea gigantea), condalia (Condalia lycioides), ocotillo
(Fouquieria splendens), jatropha (Jatropha cardiophylla), and prickly
pear (Opuntia spp.) [3,8,16].

On upper bajadas, triangle bursage is codominant with jojoba (Simmondsia
chinensis), yellow paloverde, mesquite (Prosopis juliflora), and
ironwood (Olneya tesota) [4].

In desert grassland communities that have been overgrazed, triangle
bursage can be found among other invading perennial shrubs including
corvillea (Corvillea tridentata), yellow paloverde, jojoba, ocotillo,
wolfberry (Lycium spp.), acacia (Acacia spp.), canotia (Canotia
holacantha), velvet mesquite (Prosopis juliflora var. velutina), and
saguaro [33].

Publications listing triangle bursage as a dominant or codominant
species include:

The Natural Vegetation of Arizona [19]
Sonoran Desertscrub [32]
Vegetation of the Santa Catalina Mountains: community types and
  dynamics [20]

Other species associated with triangle bursage but not previously
mentioned are brittle bush (Encelia farinosa), false-mesquite
(Calliandra eriophylla), Berlandier wolfberry (Lycium berlandieri),
hedgehog cactus (Echinocereus engelmanii), ferocactus (Ferocactus
acanthodes), and white ratany (Krameria grayi).

  

Related categories for Species: Ambrosia deltoidea | Triangle Bursage