Community and Ecosystem Effects of Buffelgrass (Pennisetum ciliare) and Nitrogen Deposition in the Sonoran Desert

Abstract

Buffelgrass is a non-indigenous, invasive, C4 grass that was introduced throughout much of southern Texas, the Southwestern United States, and northern and central Mexico to improve degraded rangelands. The successful introduction and spread of buffelgrass follows a trajectory similar to that of other invasive C4 grasses in arid and semiarid ecosystems. In the Plains of Sonora of the Sonoran Desert (Mexico) buffelgrass is favored by widespread removal of native vegetation and seeding, but, why, following initial introduction, the species persists remains unclear. In this study, we addressed two concerns associated with buffelgrass invasion in the Plains of Sonora. We hypothesized that under arid rangeland conditions, buffelgrass outcompetes native herbaceous species (1) through rapid acquisition of limiting nutrients (here assumed to be nitrogen) and (2) under conditions with high nitrogen input. In summer 2002, a 2 by 2 factorial experiment was established with buffelgrass removal and nitrogen addition in both intact desert and converted buffelgrass grassland habitats. In winter 2003, we found that, regardless of habitat type, buffelgrass removal had a positive effect on abundance, biomass, and richness of native herbaceous species while addition of nitrogen, as urea (at 50 kg N ha−1yr−1 or 9.18 lbs N ac−1yr−1), and disturbance resulted in reduction in abundance and biomass. Nitrogen addition did not negatively alter buffelgrass cover. Nitrogen addition had the expected result of increasing initial, peak and total NO3 and NH4 mineralization with the exception of NO3 measures in intact desert. Removal of buffelgrass did not result in significant increases in soil NO3 or NH4 with the exception of peak NH4 in intact desert. Results of this study support observations that native herbaceous species are displaced by buffelgrass invasion and that nitrogen pollution will likely favor buffelgrass over the native herbaceous species in this ecosystem.

Pyriculins A and B, two monosubstituted hex‐4‐ene‐2,3‐diols and other phytotoxic metabolites produced by Pyricularia grisea isolated from buffelgrass (Cenchrus ciliaris)

“…Unfortunately, buffelgrass started to spread into undisturbed natural areas and since the 1980s it has become one of the most serious invaders in some parts of its introduced range . Particularly dramatic is the situation in the Sonoran Desert of southern Arizona, where it has infested thousands of acres of public and private lands, including Saguaro National Park and the Coronado and Tonto National Forests. Buffelgrass invasion has negatively influenced native vegetation through competition for water, nutrients, and space, and it has also caused an increase in fire frequency .…”

Non‐native grasses reduce scaled quail habitat

“…Non-native grasses may affect scaled quail on an even broader geographic scale in the future. These grasses are widely established and continue to be sown following brush clearing, particularly in Texas and Mexico (Arriaga et al 2004, Lyons et al 2013. The geographic range of buffelgrass is limited because the grass lacks cold tolerance (Burson et al 2015), but its range may expand in the future with predicted changes in climate (Archer and Predick 2008).…”

“…are invasive and readily spread from established stands into native plant communities (Gabbard and Fowler , Marshall et al ). Invasion by these grasses results in altered ecosystem function and the replacement of native grasslands with non‐native grasses that often form nearly monotypic stands with decreases in plant diversity (Gabbard and Fowler , Marshall et al , Ruffner et al , Lyons et al ). The likelihood of these invasive non‐native grasses affecting wildlife populations increases as they become abundant and dominant on the landscape (Fulbright et al ).…”

Quality of Top, Middle and Bottom Buffelgrass Seeds From Different Collecting Sites

“…Buffelgrass (Cenchrus ciliares L.), a forage perennial grass belonging to the Poaceae family, is native to Africa and is widely grown across warm climates worldwide owing to its easy establishment, high nutritional value, and tolerance for drought, contributing to the reduction of nutritional deficiencies in livestock. Furthermore, its root system greatly deepens into the soil, being able to withstand heavy grazing and responds quickly to soil moisture (Miller, Friedel, Adam, & Chewings, 2010;Voltolini, Moraes, Araújo, & Pereira, 2011;Marshall, Lewis, & Ostendorf, 2012;Lyons, Maldonado-Leal, & Owen, 2013;Burson, Renganayaki, Dowling, Hinze, & Jessup, 2015). Buffelgrass is generally used as a pastoral species and more recently for mine site rehabilitation and erosion control (Tefera et al, 2010;Guevara et al, 2009;Bhattarai, Fox, & Gyasi-Agyei, 2008;Praveen et al, 2005;Harwood et al, 1999;Walker & Weston, 1990).…”