We found a match
Your institution may have access to this item. Find your institution then sign in to continue.
- Title
Relationship betweem productivity, and species and functional group diversity on grazed and non-grazed Pampas grassland.
- Authors
Oesterheld, M.
- Abstract
Most hypotheses addressing the effect of diversity on ecosystem function indicate the occurrence of higher process rates with increasing diversity, and only diverge in the shape of the function depending ontheir assumptions about the role of individual species and functional groups. Contrarily to these predictions, we show that grazing of the Flooding Pampas grasslands increased species richness, but drastically reduced above ground net primary production, even when communities with similar initial biomass were compared. Grazing increased species richness through the addition of a number of exotic forbs, withoutreducing the richness and cover of the native flora. Since these forbs were essentially cool-season species, and also because their introduction has led to the displacement of warm-season grasses from dominant to subordinate positions in the community, grazing not only decreased productivity, but also shifted its seasonality towards the cool season. These results suggest that species diversity and/or richness alone are poor predictors of above-ground primary production. Therefore, models that relate productivity to diversity should take into account the relative abundance and identity of species that are added ordeleted by the specific disturbances that modify diversity.
- Subjects
GRAZING; PLANT ecology
- Publication
Oikos, 1997, Vol 78, Issue 3, p519
- ISSN
0030-1299
- Publication type
Article