Diversidad de la vegetación durante su recuperación tras una creciente extraordinaria del Río Paraná Medio (Argentina)

Abstract

Diversity of vegetation during its recovery from a catastrophic flood of the Medium Paraná River (Argentina). River floodplains have a high biological diversity that is intensely influenced by vegetation dynamics, changes in space and time scales, and the river`s hydrological regime. The vegetation composition of the medium and lower Paraná River has been analyzed previously, with different approaches and criteria that cannot be compared. The aim of this study is to analyze the diversity of the herbaceous vegetation over long time spans, from its regeneration after a catastrophic flood to its recovery, in the North and South sites of the flooding valley of the Medium Paraná River. The first sampling of a pioneer community was performed after the 1982-83 catastrophic flood, and included the surveillance of two plots in two successive recovery stages. Floristic composition and cover-abundance of all species were recorded per plot. Floristic richness, using jackknife, Shannon and Hurlbert diversity and Simpson dominance curves were calculated for each site and for each survey, using EcoSim (software). Floristic richness was higher in the North of Medium Paraná, while dominance was higher in the South. Diversity indexes did not varied significantly and resulted in relatively stable values, because its components compensate each other.

Multi-scale analysis of environmental constraints on macrophyte distribution, floristic groups and plant diversity in the Lower Paraná River floodplain

“…Regarding plant diversity, per-site alpha diversity was relatively low, but gamma diversity was relatively high due to the high beta diversity ("diversity of habitats" hypothesis, sensu Shmida and Wilson, 1985). The Shannon-Wiener diversity recorded in this area was always lower than that of the Middle Paraná River floodplain (Marchetti and Aceñolaza, 2012), even when compared to the diversity of islands in an early successional stage after an extraordinary flood (Franceschi and Lewis, 1991;Franceschi et al, 2010). Also, the gamma diversity was lower than upstream (Marchetti and Aceñolaza, 2012) but higher than downstream in the Lower Paraná River Delta (Kandus et al, 2003).…”

Macrophyte assemblages in relation to environmental, temporal and spatial variations in lakes of a subtropical floodplain-river system, Argentina

“…Although earlier studies on macrophyte assemblages of the Paraná River included successional changes in the relationship between macrophyte and physico-chemical variables (Neiff, 1975(Neiff, , 1979Franceschi and Lewis, 1979;Sabattini and Lallana, 2007), these relationships have not been studied in combination with hydrological connectivity. A recent contribution shows an association between macrophyte species richness and composition and the degree of connectivity, lake morphometry and abiotic factors (Schneider et al, 2015).…”

Vegetation and its relationship with geomorphologic units in the Parana River floodplain, Argentina

“…In spite of the importance of previous studies, it is rare to find a combined approach between the authors that have studied the vegetation of the Parana River in Argentina (Franceschi and Lewis, 1979;Neiff, 1986Neiff, , 2001Neiff, , 2004Marchetti and Aceñolaza, 2005) and those who have contributed to the knowledge of its hydrology and geomorphology (Iriondo, 1972(Iriondo, , 2007Drago, 1990;Ramonell et al, 2000;Amsler et al, 2005). Few studies have approached the interactions between the hydro-morphological matrix and the vegetation features (Lewis and Franceschi, 1979;Kandus, 1997;Malvárez, 1997;Casco et al, 2005), so this aspect continues to be major research topics for the Argentinean reach of the Parana River.…”