IFEVA   02662
INSTITUTO DE INVESTIGACIONES FISIOLOGICAS Y ECOLOGICAS VINCULADAS A LA AGRICULTURA
Unidad Ejecutora - UE
artículos
Título:
Grazing-induced losses of biodiversity affect the transpiration of an arid ecosystem.
Autor/es:
VERÓN S.R, PARUELO J.M. Y OESTERHELD M
Revista:
OECOLOGIA
Editorial:
SPRINGER
Referencias:
Año: 2010 p. 1 - 10
ISSN:
0029-8549
Resumen:
Degradation
processes often lead to species loss.
Such losses
would impact on ecosystem functioning
depending
on the extinction order and the functional and
structural
aspects of species. For the Patagonian arid steppe,
we used a
simulation model to study the effects of species
loss on the
rate and variability (i.e. stability) of transpiration
as a key
attribute of ecosystemfunctioning.We addressed (1)
the
differences between the overgrazing extinction order and
other potential
orders, and (2) the role of biomass abundance,
biomass
distribution, and functional diversity on the effect of
species
loss due to overgrazing.We considered a community
composed of
ten species which were assigned an order of
extinction
due to overgrazing based on their preference by
livestock.
We performed four model simulations to test for
overgrazing
effects through different combinations of
species
loss, and reductions of biomass and functional
diversity.
In general, transpiration rate and variability were
positively
associated to species richness and remained fairly
constant
until half the species were lost by overgrazing. The
extinction
order by overgrazingwas themost conservative of
all
possible orders. The amount of biomass was more
important
than functional diversity in accounting for the
impacts of
species richness on transpiration. Our results
suggest
that, to prevent Patagonian steppes from shifting to
stable,
low-production systems (by overgrazing), maintain-
ing
community biomass is more important than preserving
species
richness or species functional diversity.