Dissecting the effects of simulated cattle activity on floristic composition and functional traits in Mediterranean grasslands

PLoS One. 2013 Nov 20;8(11):e79822. doi: 10.1371/journal.pone.0079822. eCollection 2013.

Abstract

Livestock exerts direct and indirect effects on plant communities, changing colonization and extinction rates of species and the surrounding environmental conditions. There is scarce knowledge on how and to what extent these effects control the floristic and functional composition of plant communities in grasslands. We performed an experiment that included several treatments simulating trampling, defoliation, faeces addition and their combinations in a Mediterranean scrub community grazing-abandoned for at least 50 years. We monitored the plots for four years, and collected data on species composition, photosynthetically active radiation (PAR) and red∶far-red ratio (R∶FR), soil moisture and compaction. We estimated community weighted means (CWM) for height, habit, life cycle, seed mass and SLA. Neither compaction nor soil moisture were modified by the treatments, while PAR and R∶FR increased in all treatments in comparison to the Control and Faeces treatments. The floristic composition of all treatments, except for Faeces, converged over time, but deviated from that of the Control. The functional traits displayed the trends expected in the presence of grazing: loss of erect species and increased cover of short species with light seeds, with rosettes and prostrate habit. However, contrary to the results in literature, SLA was lower in all the treatments than Control plots. Like the results for floristic composition, all treatments except for Faeces converged towards a similar functional composition at the end of the four year period. The results of this study show the initial evolution of a Mediterranean plant community in the presence of grazing, driven primarily by the destructive action of livestock. These actions seem to directly affect the rates of extinction/colonization, and indirectly affect the light environment but not the soil conditions. However, their effects on floristic and trait composition do not seem to differ, at least at the small spatio-temporal scale.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Cattle
  • Livestock
  • Mediterranean Region
  • Poaceae*

Grants and funding

Financial support was provided by the Spanish Ministry of Education and Science (CGL2007-63382, CGL2011-24871, FPI scholarship BES-2004-4396 for Iker Dobarro and FPI scholarship BES- 2008-009821 for C.P. Carmona), the Programa de Actividades de I+D de la Comunidad de Madrid (Consejería de Educación, Comunidad Autónoma de Madrid, Spain) REMEDINAL-CM (S-0505/AMB/000335, S-2009/AMB/1783) and the REMEDINAL2 Programme (S- 2009/AMB/1783), supported by the Comunidad de Madrid and the European Social Fund. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.