Desert heterogeneity and tree-ring growth dynamics: disentangling the influence of landform variability upon the relation between stem growth, precipitation, and disturbance of Prosopis flexuosa DC

ROIG-JUÑENT, FIDEL ALEJANDRO; PIRAINO, SERGIO; ABRAHAM, ELENA MARIA

Mendoza

Conferencia; AmeriDendro 2016 - Third American Dendrochronology Conference; 2016; 2016

Arid ecosystems are characterized by a high degree of environmental heterogeneity, expressed for example by the spatial patch organization of plant communities. In the Central Monte Desert, P. flexuosa grows in territories characterized by diverse environmental conditions, mainly resulting of landform variability. We assessed the influence of landform heterogeneity upon radial growth, its relation with precipitation, and postdisturbance stem growth of several P. flexuosa woodlands distributed along a landform gradient, represented by river, paleo-river, inter-dune and lowland units. High- and lowfrequency tree-ring development reflected landform differences. At a regional scale, precipitation influenced radial growth at the beginning and the end of the growing season, while the different dendroclimatological signals emerged at the local scale are probably landform-dependent. Disturbance, represented by selective tree-removal, modified the forest growth dynamics, as suggested by the presence of release pulses in stem growth during the  post-disturbance periods. Nevertheless, anthropogenic influence shaped in an uneven way the selected landform units. In this sense, disturbance play a more important role in most mesic environments, namely river and paleo-river, while at the remaining landforms both biotic and abiotic drivers regulated the occurrence of stem growth pulses. Through this analysis, we highlighted the influence of spatial heterogeneity typical of drylands upon the forest growth dynamics of a desert tree species.