Original paper

Effects of extraordinary floods on the dynamics of tall grasslands of the river Parana valley

Lewis, J.P.; Franceschi, E. A.; Prado, D.E

Phytocoenologia Band 15 Heft 2 (1987), p. 235 - 251

32 references

published: Aug 7, 1987

DOI: 10.1127/phyto/15/1987/235

BibTeX file

ArtNo. ESP024001502004, Price: 29.00 €

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Abstract

The river Paraná has a yearly pulse, by which the water reaches its highest level in autumn and its lowest in spring. Each few years there are great floods, and there are records of extraordinary floods in 1905 and 1983. The Panicum prionitis tall grassland is a community of low floristical diversity widespread all over the river valley, and most authors supposed that it is an advanced state in the plant succession towards a wet forest. The 1983 extraordinary flood destroyed completely this community. In this paper the phytosociological analysis of the communities which appeared in its place is given. These are floristically rich and composed fundamentally by the rare species of the Panicum prionitis tall grassland. It is supposed that they will evolve towards that last community, and thus the floristical diversity will decrease. New evidence of Panicum prionitis mature grassland being a steady state community which does not evolve further is added.

Abstract

Las aguas del Rio Paraná tienen un pulso anual que alcanza su máximo en otono y su minimo en primavera. En ciclos breves, de pocos anos, hay grandes inundaciones, y hay registros de crecientes extraordinarias en 1905 y 1983. El pajonal de Panicum prionitis es una comunidad de baja diversidad floristica ampliamente distribuida en todo el valle del rio, y muchos autores suponen que es una etapa avanzada en la sucesión vegetal hacia un bosque húmedo. La creciente extraordinaria de 1983 destruyó completamente esta comunidad. En este trabajo presentamos el análisis fitosociológico de las comunidades que aparecieron en su lugar. Estas son floristicamente ricas y compuestas fundamentalmente por las especies raras del pajonal de Panicum prionitis. Suponemos que evolucionarán hacia esta última comunidad y entonces la diversidad floristica decrecerá. Aportamos nuevas evidencias de que el pajonal maduro de Panicum prionitis es una comunidad estable que no evoluciona posteriormente.

Keywords

tall grasslandsriver Paraná valleyPanicum prionitis