Does High Impact Grazing Change Plant Species Composition or Diversity of Northern Argentinean Grasslands?
- Publication Type
- Contribution to conference
- Authors
- Windisch, S., Kurtz, D., Asch, F.
- Year of publication
- 2015
- Published in
- Management of land use systems for enhanced food security: conflicts, controversies and resolutions
- Pubisher
- Cuvillier Verlag , Göttingen
- Page (from - to)
- 231
- Conference name
- Tropentag 2015
- Conference location
- Berlin
Rangelands of northern Argentina are core areas for livestock production but theseasonality of net primary productivity with a high accumulation of standing deadbiomass is limiting the stocking rates of cattle. High impact grazing has been shownto be a promising management tool to reduce standing dead biomass as an alternativeto the burning practice, however, effects on plant species composition and grasslanddiversity were not analysed so far.A grazing experiment was established on the experimental station (INTA-Corrientes)on a 24ha large grassland area, split into three paddocks with 12 plots and a con-trol area without high impact grazing.Heavy impact grazing with 150 cattle ha−1day−1stocking rate was conducted in spatially confined paddocks and within differentseasons of the year. To investigate the changes in botanical composition, we assessedspecies abundance and plant cover during the main growing season in February.The analysis of biodiversity parameters showed no significant variation of speciesrichness. The Shannon-Wiener diversity index (H) and Shannon’s equitability (EH)were at the same level in the heavy impact grazing plots and the control, also theplant species composition did not change. Analysing the plant functional groups, wefound a shift in the green biomass proportions towards C3 species. The proportionof mono- and dicotyledonous species did not change after a heavy impact grazing.Seasonal impact timing had no effects on plant species composition. The repeatedbunch trampling by grazing cattle enhanced the growth of new patterns with morefavoured C3 fodder plants (Poaceae species:Leersia hexandra,Paspalum notatum).We conclude that intensive trampling andgrazing disturbance does not change thecomposition of the existingflora of the grassland of Corrientes. A slight shift towardsC3 plants might contribute to the cold season rangeland productivity. However, moredetailed studies are needed to cover long term effects of high impact grazing distur-bance and to analyse the species composition during the winter. High impact grazingseems to be a promising alternative to the extensively used burning practice and couldtherefore contribute to a sustainable management of northern Argentinean rangelands.