Abras de Mantequilla wetland vegetation. Floristic composition. Grounds for its restauration

Abstract

Abras de Mantequilla wetland and its surroundings’ major plant groups were obtained from a 61inventory matrix (Two-way Indicator Species Analysis; TWINSPAN), which evidenced the existence of four most important biotopes characteristic associations, resulting from strong water eutrophication (low levels of dissolved oxygen (DO) ppm and higher for total dissolved solids (TDS) mg / L).  Aquatic vegetation, floating or rooted, (VAG) is the most extensive, with two dominant species, Ludwigia helminthorrhyza and Eichhornia crassipes, typical of aquatic habitats with a high degree of eutrophication and three variants depending on the water level in floating meadows (VAPF). It consists of grass (Panicum maximum, P. mertensii, and Paspalum repens) with long rhizomes that interweave to prevent disintegration, what favors birds. Peripheral formation, subjected to periods of recurrent flooding (VBSI), is characterized by the presence of dry forest shrubs and trees (Xylosma benthamii, Hematoxylum campechianum), tolerant to prolonged flooding, and weed remains associated in crops during the dry season. The principal component analysis (PCA) shows a strong anthropic alteration. The first two factors with values of 10.28 and 5.11, assume only 25.60% of the variance. Biodiversity indices obtained, stress that natural marsh vegetation (Albidella nymphaeifolia, Sagittaria sagittifolia, S. lancifolia) is the one prevailing in areas with emerging underground aquifers. Surrounding dry forest vegetation (DFV) presents a relative floristic homogeneity and low biodiversity index.