Establishment of Native Semidesert Grasses into Existing Stands of Eragrostis lehmanniana in Southeastern Arizona

Abstract

The semidesert grassland in southern Arizona has changed from a native grassland to a scattered Prosopis juliflora var. velutina (mesquite) woodland with an understory of African Eragrostis lehmanniana (Lehmann lovegrass) on many sites. To determine native grass restoration potential, seven species were direct seeded into E. lehmanniana stands that were left alive, burned, sprayed with an herbicide and then either left standing, or mowed. Initial native grass establishment was limited in the live standing treatment but was successful for all other treatments when either June or August sowing was followed by consistent summer precipitation and soil water availability. Four species, Bothriochloa barbinodis (cane beardgrass), Bouteloua curtipendula (sideoats grama), Digitaria californica (Arizona cottontop), and Leptochloa dubia (green spangletop) initially established most successfully, while only Muhlenbergia porteri (bush muhly) had consistently limited or no establishment. E. lehmanniana establishment from the seed bank was increased by canopy removal associated with burning. Densities of native grasses one year after successful initial establishment were much lower than that of E. lehmanniana. A possible revegetation strategy would be to spray emergent E. lehmanniana seedlings and surviving plants with an herbicide during the summer rainy season after spring burning. Native grasses could then be established by sowing in early August of that year or June and August of subsequent years until consistent precipitation produces a native grass stand.

Absence of a Grass/Fire Cycle in a Semiarid Grassland: Response to Prescribed Fire and Grazing

“…Although two studies have demonstrated increased postfire abundance of Lehmann lovegrass (Cable 1965;Martin 1983), our research is consistent with many more studies that find a lack of evidence to support a grass/fire cycle, postulates 3 and 4 (Humphrey and Everson 1951;Pase 1971;Cox et al 1988;Bock and Bock 1992;Biedenbender and Roundy 1996;McGlone and Huenneke 2004;Geiger 2006). In addition, the low diversity found in invaded plots can occur without the effects of fire.…”

Surface soil water loss after summer rainfall in a semidesert grassland

“…For slow drying conditions, 1-2, 3-4, and 5-7 rainy days followed by over 6, 7, and over 8 rainless days, respectively, would result in seedling desiccation. These estimates generally agree with data of and Biedenbender and Roundy (1996), in which seedings failed in revegetation studies under fast to moderate drying conditions when initial rain or available water periods of 1-3 days were followed by over 4 days of drought. Consistent rainfall apparently is necessary for these warm-season grasses to establish.…”

Effects of Initial Site Treatments on Early Growth and Three‐Year Survival of Idaho Fescue

“…Strategies for reintroducing native grasses into communities dominated by non‐natives include no‐till planting, burning, grazing, applying herbicides, inoculating with mycorrhizae, and impoverishing the soil (Patton et al 1988; Nelson & Allen 1993; Biedenbender & Roundy 1996; Huntsinger et al 1996; Masters et al 1996; Masters & Nissen 1998). In abandoned agricultural fields in California, Stromberg and Kephart (1996) summarized successful restoration methods as ensuring good site preparation (native seedlings worked best in a competition‐free environment), seeding with fresh seed with a high germination rate, and mowing annuals before their seeds mature.…”