Habitat Relationships of Some Native Perennial Grasses in Southeastern Arizona

Successful management and restoration of any ecosystem requires knowledge of the habitat requirements of its component species, as manifested under natural or near - natural conditions. We measured abundances of common grasses in relation to environmental variables on an undisturbed grassland and oak savannah preserve in southeastern Arizona. Major environmental gradients separating species were 1) slope angle and associated soil differences, 2) distance above wash bottoms or floodplains, and 3) slope compass orientation and amount of oak canopy. Blue Grama (Bouteloua gracilis) was the most widespread and abundant species overall, but it reached highest densities on level lowlands, where it was dominant along with Sacaton (Sporobolus wrightii) and Vine Mesquite (Panicum obtusum). Sideoats Grama (B. curtipendula) was the most abundant species on steep slopes above floodplains and washes, regardless of tree canopy or slope compass orientation. Level to gently rolling uplands were dominated by Blue Grama, Plains Lovegrass (Eragrostis intermedia ), and Wolftail (Lycurus phleoides). Plains Lovegrass in particular seems to be increasing on the study area compared to adjacent grazed sites. Steep and rocky uplands were dominated by Threeawns (Aristida spp.), Curly Mesquite (Hilaria belangeri ), and Sprucetop Grama (B. chondrosioides). These species generally are characteristic of poor sites, and they were more common on grazed lands than on our study area.Desert Plants is published by The University of Arizona for the Boyce Thompson Southwestern Arboretum. For more information about this unique botanical journal, please email the College of Agriculture and Life Sciences Publications Office at pubs@cals.arizona.edu