Spatial and seasonal variation in the species richness and abundance of ferns and lycophytes in gallery forests of Cerrado in Central Brazil

This study investigated the relationship between environmental factors and the spatial and seasonal variations in the species richness and abundance of ferns and lycophytes in four gallery forests in the Cerrado savanna biome of central Brazil. The species composition, diversity, and similarity of the assemblages were analyzed, along with the influence of environmental factors on the spatial-seasonal variation found in these parameters. A total of 72 species was recorded. Species richness was affected by the rockiness of the substrate in both the rainy and dry seasons. Abundance was affected by the presence of bamboos and Marantaceae in both seasons. Many species occurred in plots with reduced exposure to sunlight, and plots with the highest soil humidity had the highest species richness, including species found only in these plots. The seasonal variation in species richness and abundance was related primarily to the reduction in humidity during the dry season. Two highly similar groups were detected. For the first group, the factors that most influenced species richness (rockiness in the soil) and abundance (presence of bamboos and Marantaceae) are also related to the greater environmental heterogeneity of the streams. On the other hand, in the second group the highest levels of similarity in species composition were related to the environmental homogeneity of the streams.