The Upper Paraná River Floodplain - Brazil

The chosen area is located in the last stretch of the Parana River in Brazil without reservoirs. However, the whole dynamics of this ecosystem is influenced by the operation of a large number of reservoirs located upstream. These reservoirs also contribute to oligotrophization of the floodplain, and promote changes in the hydrological level of the river, reducing the intensity of the flood pulse and, especially, increasing the frequency of smaller pulses. These changes affect also the connectivity between the environments of the floodplain, supporting the concept of Discontinuity Serial in floodplain rivers. The reservoirs also represent propagule sources of non-native species, causing environments located downstream of these reservoirs become more susceptible to invasion. Space large-scale events and time, such as those related to the El Niño - Southern Oscillation also strongly influence the dynamics of ecosystem processes in the floodplain and are not counteracted by existing dams in the basin, unlike the seasonal flood pulses and annual recurrence.