Resumen

BARUCH, Zdravko. Trachypogon plumosus (poaceae), un caso de alta diversidad interpoblacional en sabanas neotropicales. INCI [online]. 2005, vol.30, n.8, pp.488-494. ISSN 0378-1844.

Savannas comprise a large segment of Northern South America. In Venezuela, they extend over a wide range of habitats with differing soils and climate, and the C4 grass Trachypogon plumosus is dominant, which suggests considerable interpopulational diversity. Several life history and ecophysiological traits were investigated in 9 populations of T. plumosus. Quantitative traits vary significantly among populations and are related to geographic and environmental features of the local habitats. Plant biomass and size were related to water availability whereas leaf nutrient content was more closely related to soil fertility. Specific leaf area decreased at the driest sites contributing to minimize drought effects. Under uniform greenhouse conditions, the interpopulational differences were maintained, which suggest that they were genetically based ecotypes. These phenotypic variations in T. plumosus represent a useful tool for restoration of degraded savannas. The conservation of local populations is also important for the maintenance of ecosystem function and stability. Although the forage quality of T. plumosus is limited, it is important for the local cattle industry. The possibility to select ecotypes that respond to fertilization by increasing its nutritive quality is an option for Venezuelan savannas as well as those in Colombia, Brazil and Guyana. Given that almost 25% of Venezuelan savanna species share the wide geographic distribution of T. plumosus, if most of them show similar phenotypic and genotypic diversity as the one described, the total diversity for the savannas should be significantly larger than the relatively low values found in the literature.

Palabras clave : Area foliar específica; Biomasa; Crecimiento; Ecofisiología; Genética; Isoenzimas; Nutrientes.