Author(s): I. Boavida; J. Santos; R. Cortes; M. T. Ferreira; A. Pinheiro
Linked Author(s):
Keywords: River2D; Rehabilitation; Nase; WUA; Cumulative effect
Abstract: Mediterranean rivers are especially susceptible to deterioration due to high human settlement and intensive agricultural production. Consequently, there has been a significant effort to maintain and restore the dynamic nature of aquatic ecosystems, habitat connectivity and species biodiversity. However, little research has been focused on quantifying the cumulative effects on the habitat improvement by considering simultaneously different rehabilitation scenarios on a single river segment. A rehabilitation program was undertaken in a modified Mediterranean river segment, to assess the effect of potential enhancement measures on the habitat of different life-history stages of the Iberian nase Iberochondrostoma almacai, a critically endangered cyprinid species. Two potential enhancement scenarios, previously simulated by changing the actual riverbed topography, were considered: the introduction of islands in the middle of the channel and the creation of lateral bays in opposite banks. Potential habitat improvement, as measured by gains in the weighted usable area (WUA) relative to the control condition, was assessed by means of a two-dimensional hydraulic model, the River2D. The results indicated that both scenarios produced a WUA improvement for all life-history stages. In addition, the simultaneous modelling of both physical interventions yielded a higher WUA relative to the same scenarios modelled individually. This study showed that simultaneous multi-interventions can be more effective in enhancing fish habitat than considering implementation of single rehabilitation scenarios.
Year: 2009