Reproductive phenology of Leptolobium dasycarpum and L. elegans across the Brazilian savanna based on herbarium records

Abstract

Changes in phenological events have a prominent position in current global change research. Phenological studies for the Brazilian savannah plants are geographically restricted and long-term variation is still unclear. Thus the use of herbarium data can provide long-term phenological evaluation and it is important to understand the phenology-climate dynamics on broader scales. We used climatic data and 252 herbarium specimens collected between 1961 and 2012 to examine the phenological trends in Leptolobium dasycarpum and L. elegans (Leguminosae, Papilionoideae). We tested the effect of average temperature and rainfall of each specimen’s month of flowering and/or fruiting and the three months prior using generalized least squares models. The species presented similar flowering and fruiting seasons, peaking in the wet season. Across this hotspot of biodiversity characterized by extraordinary environmental variations between the wet and dry seasons, L. dasycarpum and L. elegans tend to delay their phenophases with increasing temperature and precipitation. However, we did not find a significant alteration of the phenophase dates over the 52 years. In addition, although the temperature in Cerrado has increased during the period investigated, these two species were not affected by the climatic changes, indicating that additional factors or even the interaction of multiple drivers may have determined their flowering/fruiting control.