Maria DOLORES Bejarano

• Biologist PhD Forest Engineering
• Professor at Technical University of Madrid (Spain)

The main goal of this study is to create a database that ultimately serves further studies on riparian vegetation and flow response guilds in the boreal region and on transferability of results across different regions. For this aim we compiled traits for all woody riparian species in northern Sweden that, directly or indirectly, underlie their res...

Thirty-six islands in the Tiétar River (Spain) were monitored through morphological and vegetation-related traits measured remotely and in the field. For the former, we used aerial photographs from 1956 to 2019. For the latter, two sampling campaigns were carried out in 2016 and 2022. Additionally, we characterized the flow regime of the last decad...

Hydropeaking, which refers to rising or falling discharges caused by the turning on or off of hydro-turbines to generate electricity, is a topic of growing interest due to its impact on fluvial ecosystems. To date, most hydropeaking studies have focused on the impact of peak fluctuations on invertebrate and fish communities, but little attention ha...

As the share of renewable energy grows worldwide, flexible energy production from peak-operating hydropower and the phenomenon of hydropeaking have received increasing attention. In this study, we collected open research questions from 220 experts in river science, practice, and policy across the globe using an online survey available in six langua...

Hydropeaking, which refers to large and rapid flow fluctuations caused by the turning on or off of hydro-turbines to generate electricity, is a topic of growing interest due to its impact on fluvial ecosystems. To date, most hydropeaking studies have focused on the impact of this hydropower operation mode on invertebrate and fish communities, but l...

Background Extreme water-level fluctuations in river reservoirs have led to ecological problems. Among those problems, the degradation of riparian vegetation has drawn much attention. Planting suitable plants to rehabilitate riparian areas in the water-level-fluctuation zone (WLFZ) of the reservoir has therefore became a focus. Methods We planted...

Hydropower globally represents the main source of renewable energy, and provides several benefits, e.g., water storage and flexibility; on the other hand, it may cause significant impacts on the environment. Hence sustainable hydropower needs to achieve a balance between electricity generation, impacts on ecosystems and benefits on society, support...

As the share of renewable energy grows worldwide, flexible energy production from peak-operating hydropower and the phenomenon of hydropeaking have received increasing attention. In this study, we collected open research questions from 220 experts in river science, practice, and policy across the globe using an online survey available in six langua...

Ensuring adequate water supply to meet social needs while maintaining good ecosystem status is becoming increasingly difficult. This task is particularly challenging in areas characterized by water scarcity and with unfavorable projections due to change climate, as is the case of Spain. The main objective of this study is to generate knowledge that...

An increase in the demand for renewable energy is driving hydropower development and its integration with variable renewable energy sources. When hydropower is produced flexibly from hydropower plants, it causes rapid and frequent artificial flow fluctuations in rivers, a phenomenon known as hydropeaking. Hydropeaking and associated hydrological al...

Hydropeaking is part of hydropower production. The discontinuous release of turbined water during hydropeaking generates sudden rise and falls of the water levels, as well as extended droughts. These artificial flow fluctuations impose challenging growing conditions for riverine vegetation. In order to identify vulnerable/resistant plant species to...

Hydropeaking research has generated unprecedented scientific discussion in the last twenty years and improved our understanding of the processes resulting from hydropeaking by strengthening the links between basic knowledge and practical applications. Given the reportedly increase in hydropeaking operations and applications in recent years, this Sp...

The general perception of small run-of-river hydropower plants as renewable energy sources with little or no environmental impacts has led to a global proliferation of this hydropower technology. However, such hydropower schemes may alter the natural flow regime and impair the fluvial ecosystem at different trophic levels. This paper presents a glo...

A novel study that focuses on the capacity of vegetation to provide shelter for fish species under hydropeaking regimes is presented. Two artificial patches mimicking the structure and density of Carex sp. mats were installed in an experimental flume to test whether submerged plants can offer flow refuge to two cyprinid species, Luciobarbus bocagei...

The computational tool InSTHAn (indicators of short-term hydrological alteration) was developed to summarize data on subdaily stream flows or water levels into manageable, comprehensive and ecologically meaningful metrics, and to qualify and quantify their deviation from unaltered states. The pronunciation of the acronym refers to the recording int...

This paper proposes a systematic procedure to identify river reaches from a geomorphic point of view. Their identification traditionally relies on a subjective synthesis of multi-dimensional information (e.g., changes of slope, changes of width of valley bottom). We point out that some of the attributes adopted to describe geomorphic characters of...

River regulation may filter out riparian plants often resulting in reduced functional diversity, i.e., in the range of functions that organisms have in communities and ecosystems. There is, however, little empirical evidence about the magnitude of such reductions in different regions. We investigated the functional diversity patterns of riparian wo...

This paper presents a systematic procedure for developing a characterization and classification of river reaches inspired by the River Styles Framework, through which insight can be gained about the understanding of river behavior. Our procedure takes advantage of several computer based “tools”, i.e., algorithms implemented in software packages of...

• The response of riparian vegetation to flow regulation has been a research focus for decades. Several studies have shed light on the effects of flow stabilisation on riparian woody species, but other life forms exposed to intensified inundation have been overlooked. Furthermore, studies from a functional perspective are scarce. • We evaluated the...

Operators of hydropower plants adjust electricity production in response to electricity prices variation in the energy markets. For this purpose, plants often work intermittently, creating periodic and rapid, inter- and intra-hour fluctuations in flow in the receiving water body as well as in the reservoir upstream from the dam. The term for such f...

Fluvial riparian vegetation (RV) links fluvial and terrestrial ecosystems. It is under significant pressure from anthropogenic activities, and, therefore, the management and restoration of RV are increasingly important worldwide. RV has been investigated from different perspectives, so knowledge on its structure and function is widely distributed....

Fluvial riparian vegetation (RV) links fluvial and terrestrial ecosystems. It is under significant pressure from anthropogenic activities, and, therefore, the management and restoration of RV are increasingly important worldwide. RV has been investigated from different perspectives, so knowledge on its structure and function is widely distributed....

Flow regulation affects bordering riparian plant communities worldwide, but how different plant life forms are affected by river regulation still needs further research. In northern Sweden, we selected 10 rivers ranging from free-flowing to low, moderately, and highly regulated ones. In 94 reaches across those rivers, we evaluated the relative abun...

This paper addresses the geomorphic characterization and classification of large rivers in a framework of scarce information. This is inspired by the River Styles Framework with some modifications that make the process more straightforward and accessible to practitioners and more applicable to large basins, while reducing the subjective, expert-bas...

Hydropeaking, defined as frequent and rapid variation in flow in regulated rivers with hydropower plants over a short period of time, usually sub‐daily to weekly, alters hydraulic parameters such as water levels or flow velocity and exerts strong impacts on fluvial ecosystems. We evaluated the effects of hydropeaking on riverbank vegetation, specif...

This study presents an analysis of possible policy measures to face water scarcity for agriculture in a long-term climate projection (2070–2100). Water availability was computed with the Water Availability and Adaptation Policy Analysis (WAAPA) model. WAAPA simulates water management in a basin at a monthly time scale, accounting for streamflow, re...

We evaluated different management alternatives to enhance potential water availability for agriculture under climate change scenarios. The management goal involved maximizing potential water availability, understood as the maximum volume of water supplied at a certain point of the river network that satisfies a defined demand, and taking into accou...

With the boom of hydropower industry, it has never been more important than now to re-assess approaches to a sustainable hydropower projects management. We evaluated the environmental and economic costs and benefits (namely environmental and economic effects) of implementing different hydrology-based environmental flow restrictions (i.e., environme...

Aims Many rivers across the globe are severely impacted by changed flooding regimes, resulting in drastic shifts in vegetation, but the processes driving the exchange of flood‐sensitive and flood‐tolerant species are understood less. We studied the role of long‐term and recent flooding histories for riparian plant recruitment in response to various...

In this chapter, we characterise droughts across La Plata Basin for the reference climate and future climate scenarios. La Plata Basin, located in the centre‐south of South America, stores one of the largest volumes of fresh water on the planet. However, droughts have significant impacts on agriculture, cattle rearing, water supply, natural water c...

We present the analysis of water availability under climate change in six representative basins of Southern Eu-rope: Duero-Douro, Ebro, Guadalquivir, Po, Maritsa-Evros and Struma. Water availability is computed with the Water Availability and Adaptation Policy Analysis (WAAPA) model. WAAPA performs the simulation of water management in the basin at...

Many riparian ecosystems in Mediterranean Europe are affected by land use and flow alteration by dams. We focused on understanding how these stressors and their components affect riparian forests in the region. We asked the following questions: (1) Are there well‐defined, responsive riparian guilds? (2) Do dam‐induced streamflows determine abundanc...

The Medina del Campo groundwater body (MCGWB) is located in the Spanish side of the Duero River Basin (central western Spain) and extends over 3,700 km 2 (Fig. 1). It has a Mediterranean climate that combined with the soils and land uses lead to an annual average potential evapotranspiration of 750 mm, implying an average annual rainfall deficit of...

Medina del Campo groundwater body (MCGWB) is located in the Duero river basin (Spain, Fig. 1). It is an inland area located to the south of the Duero River and is composed of about 130 municipalities with a total area of 3,700 km2 which is 3.77 % of the total area of the Duero basin. MCGWB is an almost flat region with an elevation descending from...

We identified and analysed droughts in the La Plata Basin (divided into seven sub-basins) for the current period (1961–2005) and estimated their expected evolution under future climate projections for the periods 2011–2040, 2041–2070, and 2071–2099. Future climate projections were analysed from results of the Eta Regional Climate Model (grid resolu...

Hydropeaking refers to frequent, rapid and short-term fluctuations in water flow and water levels downstream and upstream of hydropower stations. Such fluctuations are becoming increasingly common worldwide and are known to have far-reaching effects on riverine vegetation. Novel hydrology caused by hydropeaking has no natural correspondence in fres...

River regulation affects riparian systems world‐wide and conservation and restoration efforts are essential to retain biodiversity, and the functioning and services of riverine ecosystems. Effects of regulation on plant species richness have been widely addressed, but the filtering effect of regulation on guilds has received less attention. We used...

A characterization of short-term changes in river flow is essential for understanding the ecological effects of hydropower plants, which operate by turning the turbines on or off to generate electricity following variations in the market demand (i.e., hydropeaking). The goal of our study was to develop an approach for characterizing the effects of...

One effect of hydropower is hydropeaking, caused by sub-daily fluctuations of water-level because of variable turbine operation. We aim to investigate the effects of hydropeaking on the recruitment and performance of riparian vegetation, in order to identify (1) the stages in the plants’ life-cycle critically affected by hydropeaking, (2) hydropeak...

Many hydropower installations are producing electricity using hydropeaking. Hydropeaking refers to rising or falling discharges caused either by the turning on or off of hydro-turbines to generate electricity according to variations in the market demand. As a result, downstream and upstream river hydrology is altered due to unnatural, rapid and sig...

Geomorphic responses to damming are primarily determined by the magnitude of sediment transport and sediment supply alteration and by the resulting change in the balance between the two. The former change is caused by alterations in the flow regime that are caused by reservoir operations. Flow regime changes also affect the distribution and amount...

The evaluation of the effects of regulated stream-flows on riparian areas was addressed from the species-based and functional-based approaches. On the one hand, we stressed variations of diversity of species in riparian communities (i.e., species richness and composition) following regulation. Then, we moved away from individual species to function...

We characterized droughts in La Plata Basin by using the SPEI (Standardized Precipitation-Evapotranspiration Index) for the period 1961 – 2100. La Plata Basin is located in the Centre-South of South America and comprises 3.100.000 km2 and five countries. It storages one of the largest volumes of fresh water on the planet. Despite of the significant...

Over the past decades, we have assisted to an increasing understanding of the effects of regulated-flow conditions on aquatic ecosystems. However, the responses to altered flows of the ecotonal ecosystems remain a long-standing chal-lenge in the Mediterranean regions. This is probably due to the multiple pressures that in-fluence directly and indir...

Background: Stream flow is a fundamental driver of riparian plant communities. The increasing need for water resources to manifold purposes (hydropower energy, agriculture, industry, urban use) resulted in a widespread disturbance of flow regimes, with regulation by dams having a major impact in fluvial and riparian landscapes. There is increasing...

Background & Aim: Alteration of flow regimes by dams causes shifts in the composition and diversity as well as the trait syndromes of streamside plant communities [1]. There is still a limited knowledge of riparian strategies to streamflow regulation and moreover to different dam operations. Such an understanding would enable us to more strategical...

Dams and reservoirs are the most intensive human alterations of the fluvial system. In most cases, sediment flux and flow regimen are interrupt and modified. Consequently, modification of the main channel form controls-sediment and water- implies a potential alteration of the hierarchy of channel variables. In this paper we evaluate the effect of...

Despite being considered a renewable and clean energy source, hydropower also causes significant environmental losses. Hydropeaking constitutes a major impact from hydropower dam operation. It refers to frequent changes in river flow occurring within the span of a day caused either by turning the turbines on or off in response to varying demand in...

EThe semantic root for " engineer " comes from the Latin term " ingenium " : " ability " , " mental power " , " genius " , or " clever device ". Nowadays, an engineer is an expert in creating useful tools by combining intelligence, skill and technical knowledge. Thus, creativity must be encouraged in engineering degrees. Since 1999, when Bologna De...

In this paper we evaluate the effect of large dams on several Spanish rivers. Measurements of active channel and riparian corridor dimensions downstream from the dams were done in gravel-bed, sandy and silty-clay rivers. Hydrological alteration and geomorphic responses were analysed comparing pre and post-dam flow regimes and pre and post-dam aeria...

The expected recovery of the natural conditions of large regulated rivers over the distance downstream from a dam is limited by relative tributary size according to the Serial Discontinuity Concept; however, geomorphology may also influence the recovery process. We examined the woody vegetation of the riparian zone in seven river segments distribut...

In this study the flood abatement effect at dams with gated spillways under a wide range of extreme floods is analysed (100 < return period < 10,000 years). A group of integrated models (rainfall generator, hydrological model and dam operation model) interacting within a Monte Carlo simulation framework is used for producing numerous hydrologic eve...

As florestas ripárias são componentes fundamentais da paisagem mediterrânica. Para além do elevado contributo para o incremento da biodiversidade regional, estas comunidades de écotono desempenham várias funções físicas, ecológicas, sociais e económicas. Os sistemas fluviais estão sujeitos a severas alterações no regime hidrológico, devido à regula...

Riparian or streamside forests are key-components of river systems generally adapted to natural flow dynamics and disturbance regimes. Changes in the natural flows and fragmentation of riparian corridors by river regulation interfere in the ecological processes of riparian zones and may induce compositional shifts in species and functional traits o...

RESUMEN: En este artículo se analiza y discute la situación actual del Uruguay en cuanto a la estimación de caudales ambientales en sus cursos de agua. En particular, se analizan los casos de cuencas cuya superficie es inferior a 1000 Km 2 , que para Uruguay tienen principal interés, ya que en muchas de ellas existe una fuerte regulación debido a l...

En este artículo se analiza y discute la situación actual del Uruguay en cuanto a la estimación de caudales ambientales en sus cursos de agua. En particular, se analizan los casos de cuencas cuya superficie es inferior a 1000 Km2 , que para Uruguay tienen principal interés, ya que en muchas de ellas existe una fuerte regulación debido a la existenc...

El presente artículo describe la metodología EFI+ cuyo objetivo es obtener el estatus ecológico de las masas de agua europeas basándose en variables descriptoras de las comunidades piscícolas. Partiendo de una base de datos paneuropea de inventarios de pesca eléctrica, se ha seleccionado un conjunto de variables descriptoras relativas a la riqueza,...

Do Mediterranean riparian guilds show distinct responses to stream water declines? If observed, which are the most sensitive and resilient guilds and their most affected attributes? Tiétar river below the Rosarito dam, central-western Spain. We identified riparian guilds based on key woody species features and species distribution within this Medit...

Water development accompanying mankind development has turned rivers into endangered ecosystems. Improving the understanding of ecological responses to river management actions is a key issue for assuring sustainable water management. However, few studies have been published where ecological metrics have been quantified in response to various degre...

1. Flow dynamics is a major determinant of riparian plant communities. Therefore, flow regulation may heavily affect riparian ecosystems. Despite the large number of dams worldwide, little specific information is available on the longitudinal impacts of dams on vegetation, for example how far downstream and at what degree of regulation a dam on a r...

Soil compaction and light availability influence plant growth via different mechanisms. In general, soil compaction has a direct effect on roots, whereas light affects leaves and stems. Although plants in nature are exposed to variable levels of soil compaction and light, no study on the potential mutual interactions of these limiting factors in wo...

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, throu...

Las pautas naturales de fluctuación intranual de los caudales varían de unos ríos a otros condicionando, tanto de forma directa como de forma indirecta mediante su efecto dinamizador de las características físicas que subyacen las comunidades biológicas, la distribución de las especies, su capacidad adaptativa, su capacidad de supervivencia, de dis...

This study presents the application of LIDAR data to the evaluation and quantification of fluvial habitat in river systems, coupling remote sensing techniques with hydrological modeling and ecohydraulics. Fish habitat studies depend on the quality and continuity of the input topographic data. Conventional fish habitat studies are limited by the fea...