Interacting Effects of Soil Degradation and Precipitation on Plant Productivity in NE Patagonia, Argentina.

CAMPANELLA, M.V.; ROSTAGNO, C.M.; VIDELA, L.S.; BISIGATO, A.

ARID LAND RESEARCH AND MANAGEMENT

TAYLOR & FRANCIS INC

Lugar: Londres; Año: 2015

1532-4982

Our objective was to examine the effects of inter-annual variation ofprecipitation on productivity of two dominant species (Chuquiragaavellanedae, an evergreen shrub, and Nassella tenuis, a perennialgrass) in two communities of contrasting soil degradation: aherbaceous steppe with shrubs (HSS) and a degraded shrub steppe(SS). Data were collected during two consecutive years with differentannual precipitation. Aboveground productivity was determinednondestructively using a double sampling approach. The number ofinflorescences per plant was recorded too. Perennial grass productivitywas lower in SS than in HSS in both years, while shrub productivitywas lower in SS only during the year of below average precipitation.With rising precipitation the perennial grass increased the number ofinflorescences while the evergreen shrub augmented vegetativebiomass. In summary, the effects of precipitation on plant productivityare community dependent; abiotic factors, such as superficial andsub-superficial soil characteristics, and biotic factors, such as leaf areaindex (LAI) or tussock sizes, may interact to influence the responses ofspecies to precipitation. Our results suggest that if precipitationincreased, this would favor the dominance of shrubs over grasses.