Person: De Stefano, Lucia
Universidad Complutense de Madrid
Faculty / Institute
Geodinámica, Estratigrafía y Paleontología
Now showing 1 - 3 of 3
PublicationShedding light on the decline of Iberian freshwater fish species over the period 1980–2020(Wiley, 2022-08-09) Valerio, Carlotta; Baquero, Rocío A.; Gómez Nicola, Graciela; Garrido, Alberto; De Stefano, LuciaFreshwater fish biodiversity is experiencing an alarming decline worldwide. Understanding the main factors behind its deterioration is a key step for ecosystem restoration. In this work, large-scale and long-term data were used to identify the causes of the decline of native species richness in Castilla-La Mancha. This region in central Spain covers part of six river basins belonging to four of the 11 biogeographical provinces for freshwater fish in the Iberian Peninsula. Firstly, we built a dataset that associates the presence of several fish species and a wide range of environmental variables (e.g. hydrological and hydromorphological indicators, land use classes, presence of alien fish species) at selected river sites for two different time periods (1980–2000 and 2001–2020). Secondly, we conducted an exploratory data analysis to identify possible temporal trends in the dataset. Finally, we applied the random forest algorithm to predict the response of different ecological guild-based metrics of fish richness to the selected variables. The exploratory data analysis revealed a decrease in native fish species richness in 74% of the area studied. There was no sustained temporal trend for stressor variables, except for the number of alien species, which increased in most river sites (63%). The models of the richness of native rheophilic, native intolerant, alien rheophilic, and alien limnophilic species performed satisfactorily. Magnitude of maximum discharge, presence of alien species, land use in the catchment area and altitude were the most important predictors of richness of native intolerant and rheophilic species. Alien limnophilic species proved to be sensitive to variables related to flow regime alteration, such as the presence of dams and the number of river flow reversals, while a less degraded habitat was found to be favourable to alien rheophilic species. The results suggest that the cumulative effect of persistent altered flow regimes and water pollution, coupled with a strong increase in the number of alien species, have led to the decline of native species in the area studied. The restoration of near-natural magnitudes of high flows when implementing environmental flows emerged as a key measure to restore ecosystem integrity. Starting from a long-term and large-scale dataset, this study provides new, quantitative insights into stressor–ecosystem relationships in rivers and could inform future environmental policy initiatives because it has identified the main factors leading to native fish decline and alien fish proliferation. Our findings emphasise the importance of considering metrics based on fish assemblage composition and ecological functional groups in order to disentangle the effects of stressors on fish communities. PublicationA Methodology for the Evaluation of Water Policies in European Countries(Springer, 2010) De Stefano, Lucia; Pedraza Gilsanz, Javier de; Villarroya, FermínPeriodic assessment of progress toward established policy goals is crucial to understanding whether the applied efforts are effective. In Europe, the Water Framework Directive (WFD) adopted in year 2000 set ambitious environmental objectives to be achieved by the end of 2015 through the implementation of Integrated Water Resources anagement (IWRM) principles. While at this stage it is premature to measure the impact of this Directive in terms f environmental outcomes, it is nonetheless important to develop indicators in order to monitor whether water management practices throughout Europe are aligning towards IWRM. This article presents the methodological development of the Water and Wetland Index, a comparative water policy assessment by environmental NGOs that was carried out in 2002–2003, and highlights the interest of repeating it in 2015, when the first WFD planning cycle will be completed. PublicationWetland Restoration in the Mancha Occidental Aquifer, Spain: A Critical Perspective on Water, Agricultural, and Environmental Policies(Wiley, 2008) Martínez Santos, Pedro; De Stefano, Lucia; Llamas Madurga, Ramón; Martínez Alfaro, Pedro E.Conflicts between intensive groundwater use and wetland conservation are widespread throughout arid and semiarid regions worldwide. These have become more significant wherever there has been a synchronism between pumping- based human development and the awakening of an environmental awareness in society. The Mancha Occidental aquifer provides an example of such an occurrence, which has given rise to noteworthy social conflicts. This paper presents a cross-policy analysis for wetland restoration measures, establishing the main reasons why fundingintensive agricultural, environmental, and water policies have only attained marginal success in recovering the area’s aquatic ecosystems.