EFFECTS OF PLANT SPECIES TRAITS ON ECOSYSTEM FUNCTIONING IN THE PATAGONIAN STEPPE, ARGENTINA

P. FLOMBAUM; O. E. SALA

Pekín, China

Conferencia; ESSP Open Science Conference; 2006

Diversitas, IGBP

Previous experiments showed that increasing plant species richness results in increasing aboveground net primary production, but the mechanisms behind the observed relationship between biodiversity and ecosystem functioning needs further understanding. The objectives of this paper were to understand if different plant species affect differently ecosystem functioning, and if the diversity of plant species traits affect ecosystem functioning. We evaluated the effects of the 6 dominant-plant species in the Patagonian steppe on water, N, and C cycle. We selected 5 to 10 individuals per species and evaluated plant phenology, water absorption, and productivity, and soil N potential mineralization, respiration, and temperature. A multi variable analysis showed that life forms accounted for the largest part of variability which was mainly on the C and water cycles, and within life forms species differed on their effects on the N cycle. Furthermore, we explored the diversity of plant species traits that could affect productivity. We found that productivity increased with increased number of species traits, and that the diversity of traits was a better predictor than species richness for productivity. We concluded that the dominant species of the Patagonian steppe differed in their effects on ecosystem water, C, and N dynamics. Species grouped by dominant life forms, which are shrubs and grasses, accounted for a large proportion of the effects on water and C dynamics, and within life forms, species differed in their effects on N dynamic.