Impacto de los cambios climáticos y ambientales en el crecimiento y la respuesta fisiológica de "Prosopis caldenia" (BURKART)

Abstract

The driest part of the Argentinean pampas is occupied by semiarid woodlands dominates by (calden) Prosopis caldenia Burkart. Calden pods are a highly valuable fodder supplement for livestock but its production is highly variable. Our objective was to analyze and model the temporal pattern in inter-annual variability of calden pod production. Our key hypothesis was that weather conditions were the main determinant of the pod masting behaviour. The tree size and climatic variables were evaluated as explanatory covariates. Given the data structure, a Zero-Inflated Log-Normal mixture distribution was evaluated and fitted incorporating random components to carry out with the observed lack of independence. The proposed final model structure incorporated 25 parameters, including four variance components, two intercepts for both the logistic and the log-normal parts of the model and nineteen parameters associated with fixed effects. Climate has strong influence on the flowering-fruiting calden process and on the inter-annual variability of the final pod production at tree level. Temperatures during bud breaking, flowering and fruit shedding, together with the precipitation from the final month of fruit shedding and the total amount of the prior vegetative cycle, are the main weather covariates that affect the processes.

Shifting carbon pools along a plant cover gradient in woody encroached savannas of central Argentina

“…Woody plants <3.2 m in height were considered shrubs, and >3.2, trees. Species-, genus-or plant form-specific allometric equations were used to estimate above ground biomass per plant (Hierro et al, 2000;Belmonte Serrato and Lopez-Bermudez, 2003;Iglesias and Barchuk, 2010;Risio Allione, 2012;Conti et al, 2013). For P. caldenia, the most common species encountered, we produced a revised allometric equation, based on two existing models: (1) a species-specific model for small to medium sized trees (Risio Allione, 2012), and (2) a general equation for larger mesquite trees (Jenkins et al, 2003).…”