Vegetation Response to Removal of Plant Groups and Grass Seeding in a Microphyllous Desert Shrubland: A 4-Year Field Experiment

Abstract

Grazing is one of the most important land management activities worldwide, and cases of overgrazing increase erosion, land degradation, and plant invasion. The objective of this study was to assess the effect on individual species and species composition in response to groups of plants removals or grass seeding after four years of vegetation transformation in a microphyllous desert shrubland excluded from cattle grazing. Nine treatments involved (1) clearing of vegetation and seeding of Bouteloua curtipendula (BOCU), a native grass, (2) clearing and seeding of Chloris gayana (CHGA), an introduce grass from Africa, (3) clearing except for grasses (GRA), (4) clearing except for grasses and fodder shrubs (GRA-SHR), (5) free grazing by cattle (GRAZ), (6) clearing except fodder shrubs (SHR), (7) no modification (CON), (8) clearing of all plants (BARE), and (9) clearing except plants not eaten by cattle (UND). Treatments were replicated five times each in 10 m × 10 m experimental plots. Plots were surveyed for density, cover of all plants, and standing forage. Total plant cover was higher in CON and UND than the other treatments. Except for BOCU, where forage production was the highest, forage production ha−1 was low among all other treatments. Plant density was highest in SHR and lowest in CON. Results after four years of transformation indicate that seeded Chloris gayana failed to become established, but seeding of Bouteloua curtipendula was able to persist, and had the greatest influence on the vegetation restoration, which is what we consider the most appropriate restoration treatment.

Keywords

• rehabilitation
• semi-arid
• shrub
• grasses
• grazing