Vascular plants in grasslands with different soil water holding capacities, Southern Brazil

Abstract

A checklist of all vascular plants was carried out in grasslands in Balsa Nova, Paraná, Brazil. The sampled area, about 4 ha, is located in the sandstones of the Itararé Group. This study was done from the premise that different pedological units and hydric regimes support different vascular floras. To achieve this, observations and collections of material were made in a biweekly basis. In the study area, with convex and concave slopes close to a floodplain, we observed three types of grasslands, differentiated by features of the vegetation type, soils and hydric regimes. They are mesófilos (Cmes), hidrófilos (Chid) e higrófilos (Chig) grasslands. The Cmes occur on Neosols on high and middle slopes, the Chid are in areas of hydric convergence on Haplic Organosols, and the Chig occur on Fluvic Cambisols in the low slopes. We recorded 582 species distributed in 80 families, of which Asteraceae (116), Poaceae (100), Cyperaceae (58), and Fabaceae (31) were the richest families, making together 52% of all species. These are usually the largest and most diverse families on south Brazilian grasslands surveys. The high number of species found is at least partially due to the habitat heterogeneity caused by soil water-holding capacity. This high diversity associated to the fragility of these environments and the accelerated habitat loss highlights the importance and urgency of conservation of these grasslands.