INVESTIGADORES
MARQUEZ Javier Andres
artículos
Título:
Pine afforestation changes more strongly community structure than ecosystem functioning in grassland mountain streams
Autor/es:
PRINCIPE, R.E.; MÁRQUEZ, J. A.; CIBILS MARTINA, LUCIANA; JOBBÁGY, ESTEBAN G.; ALBARIÑO, RICARDO J.
Revista:
ECOLOGICAL INDICATORS
Editorial:
ELSEVIER SCIENCE BV
Referencias:
Lugar: Amsterdam; Año: 2015 vol. 57 p. 366 - 375
ISSN:
1470-160X
Resumen:
In the past decades, afforestation of grassland landscapes has gained importance both as an economic
activity and a mechanism to mitigate anthropogenic carbon emissions. This study evaluates the effect
of pine afforestation on grassland streams analyzing changes in two integrative ecological indicators:
leaf litter breakdown and primary production. We compare those results with changes in structural
attributes of benthic biota (primary producers and invertebrates). Six contiguous first-order streams
were selected in the upper basin of the Ctalamochita river (Córdoba, Argentina): three reference streams
draining grasslands and three streams draining Pinus elliottii afforestations. Two in situ experiments were
performed to compare leaf litter breakdown and primary production between grassland and afforested
streams. Additionally, invertebrate assemblages in leaf litter and riffles, and periphyton standing stock
were sampled and assessed. Nine out of 26 structural indicators showed differences between stream
types but indicators measuring changes at the basal level of the food web (i.e. detritus and primary
producers) were less sensitive than those recording changes in consumers. Our attempt to measure
direction and magnitude of changes on stream functioning following afforestation was halted by our
simple implemented methodology (i.e. leaf pack method for leaf litter decay and biofilm accrual on
natural stone substrates for primary production assessments); only 1 out of 4 indicators differed. We
argue that the lack of strong differences in elemental measurements of primary production and needle
decay between afforested and grassland streams resulted from compensating opposing forces controlling
such processes, i.e. higher grazing vs. higher sunlight in grassland streams and higher shredding vs. lower
microbial decomposition mediated by lower temperature in afforested streams. Attributes related to the
invertebrate compartment showed the highest sensitivity to afforestation, emphasizing their value as
biological indicators of stream ecological integrity.