Attributes for assessing the environmental quality of riparian zones

Seven attributes of riparian systems are proposed to be considered for assessing the ecological status of riparian zones. They can be easily evaluated by taking into consideration some features of the structure and functioning of riverine systems, largely determined by their hydromorphological dynamics. The structure of riparian zones could be characterized by the longitudinal continuity of vegetation, the lateral dimensions (width) of the channel containing natural riparian vegetation and the composition and structure of riparian vegetation communities. These attributes basically define the morphology of riparian areas, reflecting a static view of the river. They also define the spatial dimensions where riparian functions take place, indicating the possibilities of carrying on riparian restoration activities at short time scales.The functioning of riparian systems may be assessed considering the ratio of natural woody species regeneration, bank conditions, lateral connectivity and permeability of riparian soils. These attributes indicate the temporal behaviour of riparian zones, that is showed in a more dynamic or video view of the river. They are more related to the potential of achieving riparian restoration at longer time scales, representing key elements to guarantee the self-maintenance of fluvial processes and riparian biodiversity. The aforementioned attributes provide a framework to assess the ecological status of riparian zones, and offer a minimum checklist of criteria to evaluate strategies for restoring and preserving river ecosystems.El estado ecológico de las riberas fluviales puede quedar caracterizado a través de siete atributos. Dichos atributos pueden ser fácilmente evaluados teniendo en cuenta diferentes aspectos de la estructura y del funcionamiento de los sistemas riparios, los cuales están fuertemente determinados por la dinámica hidromorfológica fluvial. La estructura de las riberas queda caracterizada por la continuidad longitudinal de la vegetación, las dimensiones laterales (anchura) del espacio fluvial conteniendo vegetación riparia natural y la composición y estructura de las comunidades vegetales riparias. Estos atributos definen básicamente la morfología de las riberas, y quedan reflejados en una visión estática o fotografía del río. A su vez, dichos atributos definen las dimensiones espaciales donde tienen lugar las funciones riparias, e indican las posibilidades de llevar a cabo la restauración fluvial a corto plazo. El funcionamiento de los sistemas riparios queda reflejado a través de la tasa de regeneración natural de las especies leñosas riparias, la condición de las orillas, la conectividad lateral del cauce con sus riberas y la permeabilidad de los suelos riparios. Estos atributos indican el comportamiento en el tiempo de las riberas, y su evaluación requiere una visión dinámica, reflejada en un vídeo del río. Dichos atributos están más relacionados con las posibilidades de lograr la restauración fluvial a más largo plazo, representando elementos claves para garantizar la sostenibilidad de los procesos fluviales y la biodiversidad de los sistemas riparios. Los atributos mencionados representan en su conjunto un esquema para evaluar el estado ecológico de las riberas fluviales, y sirven como criterios para evaluar las propuestas de estrategias de restauración y conservación de los ecosistemas fluviales

Propuesta de caracterización jerárquica de los ríos españoles para su clasificación según la Directiva Marco de la Unión Europea

La clasificación de los ríos tiene un papel importante en el manejo y conservación de los ecosistemas fluviales, y representa una fase inicial en la implementación de la Directiva Marco del Agua. Según han ido evolucionando los conocimientos científicos de la ecología fluvial y las técnicas informáticas para la caracterización espacial de las regiones hidrográficas, han ido surgiendo diferentes sistemas de clasificación taxoómica y de regionalización del territorio, integrando finalmente el río en su cuenca vertiente. En este trabajo se presenta una revisión histórica de los principales sistemas de clasificación de los ríos, y se propone un esquema de caracterización jerárquica donde se contemplan diferentes escalas, de provincia biogeográfica, cuenca vertiente, segmento fluvial y tipo de hábitat, atendiendo a los principales factores que determinan las comunidades biológicas de los ecosistemas fluviales. El esquema de caracterización propuesto está diseñado para ser utilizado mediante sistemas de información geográfica, a partir de cartografías y de un trabajo de campo para la escala de hábitat fluvial. Es un método de caracterización abierto, de tipo arborescente, que admite la incorporación de nueva información y nuevas características y subclases en cada una de las escalas consideradas, permitiendo establecer un esquema de clasificación con base hidrológica y ecológica común para todo el territorio español, a la vez que contener información particularizada para las distintas regiones hidrográficas. Incluye todos los factores obligatorios de clasificación según la Directiva Marco, así como algunos de los elementos hidromorfológicos que establece la Directiva, para identificar el estado ecológico de los distintos tramos fluviales y proponer medidas para su gestión (restauración) y conservación.River classification has an important role in the management and conservation of fluvial ecosystems, and represents a first step in the implementation of the European Water Framework Directive. According to the development of scientific knowledge in fluvial ecology and computer techniques for the spatial characterisation of hydrographic regions, different systems of taxonomic and regional classification have been proposed, finally integrating the river within the context of its watershed. In this paper, the historical evolution of river characterisation schemes is reviewed, and a hierarchical characterisation approach is proposed according to different scales, biogeographic provinces, watershed, river segments, and river reaches attending to the main factors determining biological communities in river ecosystems. This proposed characterisation scheme is prepared to be used by GIS, from maps and fieldwork at the reach scale. It is an open-tree characterisation method, where new information can be incorporated and some of the criteria can be further detailed, adding new characteristics and subclasses at the different scales being considered, allowing for the development of a classification scheme based on hydrological and ecological criteria in common for the whole Spanish territory. It includes all the mandatory factors for river classification according to the Water Framework Directive, as well as some of the hydromorphological elements established by the Directive for identifying the ecological status of the different fluvial stretches, and for proposing management (restoration) and conservation measures

Assessing the Establishment and Implementation of Environmental Flows in Spain

The alteration of natural flows due to water withdrawals and the presence of hydraulic infrastructure poses significant threats to the integrity of riverine ecosystems. The establishment of environmental flows (EF) has been conceived as a water management tool to mitigate the impact of in-stream flows alteration. To date, a large body of literature has focused on methods to define EF, but less attention has been paid to documenting and assessing their actual implementation on the ground. This article provides a framework to describe and assess the process of design, application, and monitoring of EF at a river basin level. The framework is applied to Spain, where significant efforts have been made during the past decade to define and implement EF across the country. The goal of the paper is to identify strengths and opportunities for improving the implementation of EF at country level. The Spanish legislation establishes that EF should contribute to the achievement of the good ecological status of surface water bodies as required by the European Union Water Framework Directive. Several pitfalls in the design, application, and monitoring of this important river management measure constrain the ability of the existing EF to deliver that fundamental outcome

Analysis of the Evolution of Climatic and Hydrological Variables in the Tagus River Basin, Spain

During the second half of the 20th century, several Spanish rivers experienced a decrease in the availability of water resources which coincided with an increase in human water demands. This situation is expected to be exacerbated by climate change. This study analyses the evolution of annual streamflow in 16 sub-basins of the Tagus River basin (Spain) during the 1950–2010 period and its relationship with selected variables. Our main objective is to characterize changes in in-stream flows and to identify what factors could have contributed to them. First, we used non-parametric tests to detect trends in the hydro-climatic series. Then, we analyzed changes in the runoff coefficient and applied regression-based techniques to detect anthropic drivers that could have influenced the observed trends. The analysis revealed a general decreasing trend in streamflow and an increasing trend in air temperature, while trends in precipitation are less clear. Residuals from regression models indicate that the evolution of several non-climatic factors is likely to have influenced the decline in streamflow. Our results suggest that the combination of the expansion of forested areas (a 60% increase from 1950 to 2010) and irrigated land (a 400% increase since 1950) could have played an important role in the reduction of streamflow in the Tagus basin

Riparian Quality Index (RQI): a methodology for characterising and assessing the environmental conditions of riparian zones

This paper presents a new version of the Riparian Quality Index (RQI). This index serves to assess the ecological status of riparian systems. The paper provides recommended field forms for the collection of the data used to characterise riparian systems prior to their assessment. The RQI considers the main sources of riparian ecological functions and environmental services. It represents a useful tool for monitoring and evaluating the structure of riparian zones, an element of the river morphological conditions considered by the Water Framework Directive. The Index was applied to the Guadiana Basin and other Spanish rivers providing helpful criteria for not only evaluating the present status of riparian systems but also formulating diagnosis and rehabilitation options. It represents a checklist of riparian natural characteristics and possible human-impacted riparian features, and it has valuable potential applications for post-project appraisals.En este trabajo se presenta una nueva versión del índice RQI, conjuntamente con una propuesta de estadillos de campo para la toma de datos y la caracterización de las riberas, que debe ser previa a la interpretación y valoración de su estado. Esta nueva versión del RQI considera los principales componentes de las riberas de los ríos que desarrollan las funciones ecológicas y los servicios ambientales de los corredores fluviales, y representa una herramienta útil para el control y seguimiento de la estructura riparia, la cual forma parte de las condiciones morfológicas de los ríos consideradas por la Directiva Marco del Agua. El índice ha sido aplicado en la Cuenca del Guadiana y en otras regiones españolas, suministrando criterios útiles no solo para la evaluación del estado ecológico de las riberas, sino también para la formulación de diagnosis y opciones de rehabilitación o restauración, representando una lista de características naturales y posibles impactos derivados de actividades humanas de las zonas riparias, con un uso potencial para la evaluaci'on post-proyecto

Riparian zones - from policy neglected to policy integrated

[EN] 1. Riparian zones are vital areas of interaction between land and rivers and are often degraded by several pressures such as urbanisation, intensive agriculture and river engineering works. 2. This policy brief provides five key policy messages and recommendations to be considered by policy-makers, scientists, managers, and stakeholders to enhance riparian zone management. 3. Adopting an integrated socio-economic and environmentally dynamic view will ensure the sustainable management of riparian zones. 4. In light of climate change, it is critically important to conserve and/or restore the ecological integrity of riparian zones. 5. European Union Directives and national-scale legislation and regulations need updating to ensure coordinated implementation of riparian zone-related policies. 6. Stakeholder knowledge exchange, policy co-creation and adaptive management are key to enhancing riparian zone functions.Funding was provided by COST Action CONVERGES (CA16208) and by the Horizon 2020 Framework Programme of the European Union. GU was partially supported by the Slovenian Research Agency. PR-G was supported by the Portuguese Foundation for Science and Technology (FCT) through the CEEC Individual Programme (2020.03356. CEECIND), and Forest Research Centre was supported through the FCT UIDB/00239/2020. Portuguese Foundation for Science and Technology (FCT) funded Inês Gomes Marques through a PhD scholarship (SFRH/BD/133162/2017). AA was supported by the Ministry of Education, Science and Technological Development of the Republic of Serbia (Grant No. 451-03-68/2022-14/200010).Urbanic, G.; Politti, E.; Rodríguez-González, PM.; Payne, R.; Schook, D.; Alves, MH.; Andelkovic, A.... (2022). Riparian zones - from policy neglected to policy integrated. Frontiers in Environmental Science. 9(5):1-8. https://doi.org/10.3389/fenvs.2022.868527189

Flow regime patterns and their controlling factors in the Ebro basin (Spain)

Natural intra-annual flow fluctuations vary between rivers, being a determining factor for aquatic insects, fish and riparian communities which are adapted to the habitat conditions and different flows throughout the seasons. Moreover, restoration of seasonal flow patterns plays an important role in achieving good ecological status of rivers, through the preservation and/or recovery of components and processes of natural river ecosystems. In this work we: (a) classify fluvial segments in the Ebro basin (North-Eastern Spain) according to the intra-annual variability of flows under natural conditions using statistical cluster analysis of monthly mean flow data; (b) characterise the resulting flow typologies according to several ecologically important hydrological variables; (c) analyse the relationships between flow regimes of fluvial segments and physical variables from their catchments; and finally (d) predict the most probable natural flow regime using logistic models based on the most determinant physical characteristics. Fifteen natural flow typologies were described in the Ebro basin, which were characterised in terms of flow fluctuation through the year as well as timing, flow ratio and duration of the maximum and minimum flows. Precipitation, biogeography and geology of catchments showed the highest correlations with flow regimes. Basin size, mean elevation and slope were also correlated. The logistic model we developed had a prediction success of 72% in the Ebro basin. The definition of the natural hydrological conditions (to which the biological communities are tailored), even when flow data are not available, is an important support in the management of river ecosystems. It is especially suitable for setting goals in aquatic ecosystem conservation or restoration projects

River Restoration in Spain: Theoretical and Practical Approach in the Context of the European Water Framework Directive.

River restoration is becoming a priority in many countries because of increasing the awareness of environmental degradation. In Europe, the EU Water Framework Directive (WFD) has significantly reinforced river restoration, encouraging the improvement of ecological status for water bodies. To fulfill the WFD requirements, the Spanish Ministry of the Environment developed in 2006 a National Strategy for River Restoration whose design and implementation are described in this paper. At the same time many restoration projects have been conducted, and sixty of them have been evaluated in terms of stated objectives and pressures and implemented restoration measures. Riparian vegetation enhancement, weir removal and fish passes were the most frequently implemented restoration measures, although the greatest pressures came from hydrologic alteration caused by flow regulation for irrigation purposes. Water deficits in quantity and quality associated with uncontrolled water demands seriously affect Mediterranean rivers and represent the main constraint to achieving good ecological status of Spanish rivers, most of them intensively regulated. Proper environmental allocation of in-stream flows would need deep restrictions in agricultural water use which seem to be of very difficult social acceptance. This situation highlights the need to integrate land-use and rural development policies with water resources and river management, and identifies additional difficulties in achieving the WFD objectives and good ecological status of rivers in Mediterranean countries

Riparian Zones—From Policy Neglected to Policy Integrated

1. Riparian zones are vital areas of interaction between land and rivers and are often degraded by several pressures such as urbanisation, intensive agriculture and river engineering works. 2. This policy brief provides five key policy messages and recommendations to be considered by policy-makers, scientists, managers, and stakeholders to enhance riparian zone management. 3. Adopting an integrated socioeconomic and environmentally dynamic view will ensure the sustainable management of riparian zones. 4. In light of climate change, it is critically important to conserve and/or restore the ecological integrity of riparian zones. 5. European Union Directives and national-scale legislation and regulations need updating to ensure coordinated implementation of riparian zone-related policies. 6. Stakeholder knowledge exchange, policy co-creation and adaptive management are key to enhancing riparian zone functions