IPEEC - CENPAT   25619
INSTITUTO PATAGONICO PARA EL ESTUDIO DE LOS ECOSISTEMAS CONTINENTALES
Unidad Ejecutora - UE
artículos
Título:
Land degradation affects shrub growth responses to precipitation in a semiarid rangeland of north-eastern Patagonia (Argentina)
Autor/es:
ROSTAGNO, CÉSAR MARIO; CAMPANELLA, MARÍA VICTORIA; BISIGATO, ALEJANDRO JORGE; VIDELA, LINA SONIA
Revista:
AUSTRAL ECOLOGY
Editorial:
WILEY-BLACKWELL PUBLISHING, INC
Referencias:
Lugar: Londres; Año: 2018 vol. 43 p. 280 - 287
ISSN:
1442-9985
Resumen:
Arid land degradation diminishes the proportion of precipitation conducted to infiltration andincreases the proportion lost to run-off and evaporation. Consequently, we expect that the effects of annual pre-cipitation on shrub growth vary with land degradation as a result of changes in soil available water. Chuquiragaavellanedae is the dominant shrub and the main indicator of land degradation in semiarid rangelands of north-eastern Patagonia. We chose two communities with a different degree of land degradation: an herbaceous steppewith shrubs (HSS) and a degraded shrub steppe (SS). Vegetative growth of C. avellanedae was determined non-destructively using a double-sampling approach. Soil water content was estimated for the two communities usinga soil water balance model. Linear regressions were used to evaluate the relationships between shrub growth and(i) annual precipitation and (ii) mean available water during the period of high vegetative growth in the soil layerthat each plant community concentrates their roots. In SS, with elevated clay content, there were more roots ofC. avellanedae in the upper layers of soil while in HSS, with coarse-textured soil, C. avellanedae had more rootsin deeper layers. Vegetative growth of C. avellanedae, both in HSS and SS communities, was positively related toannual precipitation but, for a given precipitation, C. avellanedae presented higher vegetative growth in HSS thanin SS. We also found a positive relationship between vegetative growth and soil available water, and this relation-ship did not differ between communities. SS presented lower water availability because of lower infiltration rates.Our results showed that, irrespective of the degree of land degradation, plants respond directly to water contentof the soil layers where most roots are present at a specific window of time