Juvenile Resilience and Adult Longevity Explain Residual Populations of the Andean Wax Palm Ceroxylon quindiuense after Deforestation

Wax palms are an important element of the cloud forests in the tropical Andes. Despite heavy deforestation, the density of adults seems to be similar in deforested pastures as in forests. We aimed to infer the mechanisms responsible for this apparent resilience in pastures and we tested two hypotheses to explain it: 1) adult palms survived in pastures because they were spared from logging, and 2) adults occurred in pastures through the resilience of large juvenile rosettes, which survived through subterranean meristems and later developed into adults. For this purpose, we characterized the demographic structure of C. quindiuense in a total of 122 plots of 400 m(2) in forests and pastures at two sites with contrasted land use histories in Colombia and Peru. Additionally, we implemented growth models that allowed us to estimate the age of individuals at four sites. These data were combined with information collected from local land managers in order to complete our knowledge on the land use history at each site. At two sites, the presence of old individuals up to 169 years and a wide age range evidenced that, at least, a portion of current adults in pastures were spared from logging at the time of deforestation. However, at the two other sites, the absence of older adults in pastures and the narrow age range of the populations indicated that individuals came exclusively from rosette resilience. These interpretations were consistent with the land use history of sites. In consequence, the combination of the two hypotheses (spared individuals and rosette resilience) explained patterns of C. quindiuense in pastures on a regional scale. Regeneration through subterranean meristems in palms is an important, yet overlooked mechanism of resilience, which occurs in a number of palm species and deserves being integrated in the conceptual framework of disturbance ecology.