Variações nos atributos funcionais de espécies lenhosas em savanas sul-americanas: influências de fatores ambientais e distúrbios

Abstract

Savannas cover about 20% of the terrestrial surface and exhibit a rich diversity of species. Despite of their importance, the factors regulating their occurrences have been little studied. This study analyzed the functional traits of woody plant species, such as relative height, bark thickness, and presence of thorns to understand adaptations to environmental pressures, including water stress, herbivory, and fire. Common woody species in South American savannas were listed, and their functional traits were compiled. We used Kruskal-Wallis test to test for differences in quantitative traits and Fisher’s Exact test for differences in qualitative traits. We did not find significant differences among savannas in traits such as relative height, bark thickness, and wood density, although the Chaco savannas stood out by presenting the highest proportion of species with thorns. This phenomenon suggests adaptations to herbivory pressures, likely due to the region's historical megafauna, now extinct. Despite variations in rainfall regimes, traits like wood density and bark thickness did not differentite the savannas, indicating similar ecological pressures on these traits. The research also suggests that considering intraspecific variation in functional traits might be important, as it can influence ecological interactions and community dynamics.