Banco de sementes do solo em área de várzea no Parque Estadual das Várzeas do Rio Ivinhema, MS

Abstract

The floodplain areas in the Atlantic Forest have different types of vegetation called Pioneer Formations, which range from grasslands and shrub formations to alluvial forests. This vegetation variation is due to a combination of flood pulse, topography and soil types. We evaluated the seed bank in an alluvial forest area in order to record the vascular plant species, their life forms and ecological strategies to use it in the restoration of degraded areas through soil transposition. The study area is in Várzeas do Rio Ivinhema State Park where alluvial forest seed bank was sampled through 10 soil samples of 20x20x5cm randomly taken at five points along the trail, according to vegetation gradient grassland-forest-riverside totalizing 50 samples. The samples were placed in plastic trays, identified and organized to germinate in nursery under 50% shade. The emerging species were quantified to calculate the richness, species abundance and seed density. The species were classified according to their life forms, life cycles, successional categories, phytogeographic domain and vegetation typology. There were 1615 individuals, belonging to 56 species, 43 genera and 25 families. Cyperaceae, Asteraceae, Poaceae, Melastomataceae, Onagraceae and Rubiaceae were the richest families in species. Pityrogramma calomelanos (L.) Link, Erechtites hieraciifolius (L.) Raf. ex DC., Bulbostylis capillarys (L.) C.B.Clarke, Emilia sonchifolia (L.) DC. ex Wight, Clidemia urceolata DC., Ludwigia longifolia (DC.) H.Hara, Chaetogastra gracilis (Bonpl.) DC. and Cecropia pachystachya Trécul were the most important species, highlighting the contribution of herbaceous plant species in the seed bank despite the fact of the present cover is represented by shrub and woody vegetation. The dominance of herbs and shrubs in the seed bank represents a huge potential in the process of vegetation restoration after soil transposition and should be considered in revegetation strategies.