IFEVA   02662
INSTITUTO DE INVESTIGACIONES FISIOLOGICAS Y ECOLOGICAS VINCULADAS A LA AGRICULTURA
Unidad Ejecutora - UE
artículos
Título:
Tree species identity alters forest litter decomposition through long-term plant and soil interactions in Patagonia, Argentina
Autor/es:
VIVANCO, LUCIA; AMY T. AUSTIN
Revista:
JOURNAL OF ECOLOGY (PRINT)
Referencias:
Año: 2008 vol. 96 p. 727 - 736
ISSN:
0022-0477
Resumen:
A major challenge in predicting biodiversity
effects on ecosystem functioning is to understand the linkages between
above-ground and below-ground components in natural communities.
However, incongruities in spatial and temporal scale between plant and
soil processes, and confounding ecological factors, have impeded our
understanding of biodiversity effects on below-ground processes,
particularly in natural ecosystems with long-lived species such as
forests.
We
designed an approach to isolate plant species composition effects from
other ecosystem factors, in order to evaluate the effects of individual
tree species and tree species mixtures on litter decomposition in a
mixed old-growth forest in temperate South America. We identified 'tree
triangles' where the intersection of plant canopies directly controlled
micro-environmental and biogeochemical conditions on the forest floor.
The monospecific treatment included triangles composed of three trees
of a single species of Nothofagus dombeyi, N. obliqua or N. nervosa, while the mixed-species triangles consisted in the intersections of the three different Nothofagus species.
We placed litterbags with N. dombeyi, N. obliqua or N. nervosa litter and mixed litter of the three species within all these triangles and estimated the decomposition constant (k)
after 1 year of incubation. We also used a standard litter type in all
triangles to independently evaluate the tree triangle effects on
decomposition.
We
found that plant species affected decomposition through both direct and
indirect effects. Direct effects were mediated through leaf litter
quality, while indirect effects were related to unique conditions that
the plant species created in the surrounding environment. Despite
litter decomposition variation among triangles, standard soil
biogeochemical conditions such as soil C : N ratios, microbial biomass
and pH were similar among microsites.
Most
interestingly, we explicitly demonstrated that long-term effects of
plant species created specific conditions that enhanced decomposition
of their own litter, establishing affinity effects between
single-species litter and their own microenvironment.6.
Synthesis.
Our results highlight that plant species identity and long-term
plantsoil feedbacks are important in affecting litter decomposition in
this temperate Patagonian forest. Thus, changes or losses in temperate
forest above-ground biodiversity can directly impact litter
decomposition both through changes in litter quality inputs and,
additionally, through the loss of specific plantsoil interactions that
affect below-ground processes.