Temporal dynamics in plant communities under fire and biological invasion

Abstract

Over time fire acted as a selective force shaping biodiversity in savannas. Changing fire regimes can modify characteristic phytophysiognomies, which consequently has effects on biodiversity patterns. Management has been using fire as a way to control biological invasions in savannas. In the Brazilian tropical savanna, Cerrado, the invasive species with the greatest negative impacts are African grasses of the genus Urochloa and Melinis minutiflora. Spatial and temporal beta diversity analyses are essential to understand what effects the interaction of fire and biological invasions have in the composition of communities. This variation can mostly happen by two components: nestedness and turnover. In this study, we will focus on the use of time series data from a savanna to understand the effects of invasive grasses and different fire regimes on community temporal dynamics. We will use data sampled in a protected area in southeastern Brazil to compare invaded areas with the exclusion of fire to those with different fire regimes, and with different exotic species. We expect that the invasive species and the fire regime used will have an effect on the variation in composition and nestedness to be larger in burnt communities, with their intensity varying according to the frequency of fires. (AU)