Prevention of natural grassland invasion by Eragrostis plana Nees using ecological management practices

Abstract

-The objective of this research was to evaluate the effects of different types of disturbance on the ability of the natural grassland to avoid the invasion of Eragrostis plana Nees (South African lovegrass). The experiment was carried out in Dom Pedrito, Rio Grande do Sul, Brazil, in an area free of South African lovegrass, from Feb. 2004 to Apr. 2007. The treatments were: 1) grassland management regimes: exclusion; low grazing intensity (rotational grazing), ±10 cm; and high grazing intensity (continuous grazing), ±5 cm; 2) initial levels of soil disturbance: high grassland, ±10 cm; low grassland, ±5 cm height; and low grassland with scarified soil; 3) fertilization regimes: without fertilization; phosphorus; and nitrogen. The experimental design was a split-split-plot type in complete blocks, with three replicates. Three winter cultivated species -Trefoil repens L., Lotus corniculatus L., Lolium multiflorum Lam. and South African lovegrass -were sown in 54 split-splitplots (split-plots: low grassland, and low grassland with scarified soil). The other 27 split-split-plots (split-plots: high grassland) were sown only with South African lovegrass. The grassland height, plant number of South African lovegrass, grassland dry mass and photosynthetic active radiation intercepted (FARint) at the soil level were recorded. The fertilization regimes did not influence the South African lovegrass plant number. The initial levels of soil disturbance and grassland management regimes influenced the invasion of South African lovegrass. The invasion was favored by the lower grassland height and lower forage mass, higher intensity of the soil disturbance, and higher FARint due to the continuous grazing. On the contrary, higher grassland height, higher forage mass, lower soil disturbance and lower FARint, associated with rotational grazing or exclusion, showed higher potential to control the invasion of South African lovegrass in the natural grassland.

Grazing management for more resilient mixed livestock farming systems on native grasslands of southern South America

“…While this experimental result suggests the good resilience of Uruguay's grasslands, we caution that this condition might change under conditions of long‐term overgrazing (under LHA). Conditions that might affect resilience include the appearance of areas of bare soil, induced soil erosion (Roesch Wurdig et al, ) and invasion of non‐productive non‐native species (such as Eragrostis plana Nees) (Bresciano, Rodrigues, Lezama, & Altesor, ; Focht & Borges de Medeiros, ). These were not, however, observed during our experiment.…”

The growth form of dominant grasses regulates the invasibility of Uruguayan grasslands

“…Our study suggests that architectural variation of the plant canopy constitutes an important factor that should be considered when trying to understand the mechanisms underlying biotic resistance of C 4 grasses. Grazing management, through its ability to regulate canopy architecture, is a potentially important tool in controlling invasion (Focht and Medeiros 2012).…”

Landscape structure and climate affect plant invasion in subtropical grasslands

“…It has been shown before that areas invaded by E. plana are often associated with previous high levels of disturbance, e.g. along roadsides (Medeiros & Ferreira ), but also past agricultural use and overgrazing (Focht & Medeiros ). Spread of U. europaeus has been associated with the structure of road networks, suggesting that local and paved roadsides close to urban or agricultural areas and adjacent natural vegetation had the highest probability of invasion (Cordero et al.…”