LAMBERTUCCI Sergio Agustin
congresos y reuniones científicas
Catastrophic Events as Pulsed Resources Scenarios for Scavengers: Andean Condors Dealing with Volcanic Eruption-Induced Mass Deaths
ALARCON PAE; LAMBERTUCCI, S. A.; DONÁZAR, J. A.; HIRALDO, F.; SANCHEZ-ZAPATA, J.A.; BLANCO G.; MORALES J. M
Congreso; I Worldwide Raptor Conference; 2013
Catastrophic events are large spatially extended, infrequent and unpredictable phenomena promoting sudden and unexpected changes in ecological systems. Given their characteristics, these phenomena often produce a sharp increase of mortality rates in ecosystems, which could translate into food pulses for scavenger animals. Our aim was to evaluate the effect of mass deaths of medium-to-large herbivores (mainly livestock) caused by the Puyehue-Cordón Caulle eruption in 2011 on foraging patterns of a top scavenger, the Andean Condor (Vultur gryphus). Our hypothesis was that the volcanic ash fall after the eruption produced a food pulse for condors which would have led them to modify their foraging patterns. For this, we used a map of ash-deposits thickness as a proxy of the ?disturbance level? throughout the study area. To describe the foraging patterns of condors, we tagged 10 individuals with GPS telemetry units and monitored them before and after the eruption. Under a use-availability design, we generated control points and assessed changes in foraging habitat preferences through time by fitting binomial regression models with ash thickness and time as predictors. We found that the probability of using different foraging areas depended on time. During the two months immediately after the eruption, when the highest mortality of fauna was recorded, the areas more affected by ashes were more likely to be used, indicating the eruption-induced food pulse translated into a short-duration switch in the foraging habitat preference of condors. This increase in food probably benefited condors in the short term, although a posterior period of strong food declining may have resulted in a disadvantage with demographic implications, typical of pulse events. Our study provides an empirical evidence of animal behavioral responses when faced with rapidly changing conditions such as those prevailing during catastrophes.