Abstract:
Changes in biodiversity due to human impact of domestic grazers are
occurring in many parts of the world, and the net effect of this
change could have detrimental effects on ecosystem functioning. The
selective removal of palatable grass species results in localized
species loss from areas subject to heaving grazing, which may have
consequences for carbon and nitrogen cycling. Moreover, in areas
... where
shrub encroachment is not occurring, the changes due to human impact
within functional groups may be very important. We explored the
relative importance of dominant grass species in a water-limited
ecosystem in the Patagonian steppe of temperate South
America. Dominant grass species from the Patagonian steppe in southern
Argentina were collected and used in a manipulative decomposition
experiment to examine the role of these species, which vary in
palatability, in affecting decomposition and nutrient turnover. All
litter types were decomposed singly and in all possible mixtures (7)
over a three-year period and effects of litter quality as well as
location next to the three grass species were evaluated. These data
were collected as part of the project CRN 012 examining the effects of
biodiversity on ecosystem functioning, led by Dr. Osvaldo Sala. 
