Current projects

FRESHTRESS: Comprehensive assessment of multi-stressor impacts on freshwater ecosystems and organisms

Freshtress aims to provide a comprehensive framework that allows assessing the joint ecological impacts of major stressors affecting freshwater ecosystems and organisms. There is an urgent need for advancing our knowledge on how human-induced environmental and biological changes such as climate change, pollution or biodiversity loss, are altering natural ecosystems and biological communities. Even if these issues have received considerable scientific attention in the last few decades, there are still important knowledge gaps that preclude a comprehensive understanding of how ecosystems and organisms are affected by the many stressors that often occur simultaneously. These deficiencies could be partly explained by (1) the difficulty of finding sufficient replication to study interactions among multiple stressors in nature, and (2) the complexity of experimental studies where several factors are manipulated at the same time and multiple variables are measured. In Freshtress, we address these issues through the use of mesocosm experiments that partly reproduce the complexity of natural systems while allowing the concomitant manipulation of several stressors and the measurement of multiple responses at different levels of biological complexity, from ecosystem functioning to organism physiology.

Conservation biology of the Pyrenean desman

The Pyrenean desman (Galemys pyrenaicus) is a water mole endemic of the Pyrenees and the north of the Iberian Peninsula that mostly lives in fast-flowing mountain streams. Its distribution area has shrunk severely in the last decades, even in areas where stream ecological status has improved, thus making managers wonder what is causing this decline. To elucidate the drivers of this decline, the stream ecology group is combining different approaches in collaboration with other research groups: metabarcoding analyses of faeces to characterize desman diet, radiotracking of animals to describe habitat preferences, genomic analyses to quantify inbreeding, and use of artificial latrines to monitor changes in distribution and abundance. We hope to give managers clues to improve the conservation status of this animal.

CITYPOLL. City runoff pollution impacts on river biodiversity under extreme climatic events

Urban areas are growing throughout the world, with important consequences on surrounding natural ecosystems and on the global biodiversity and climate. In addition to domestic and industrial wastewater, runoff from impervious urban surfaces alters local hydrology and can contribute a diverse array of pollutants, whose effects on receiving river ecosystems are poorly known, but likely to increase as a consequence of ongoing climate change. CityPoll will address this information gap by means of multidisciplinary research combining hydrology, environmental chemistry, ecotoxicology and ecology, in contrasting case studies. To that aim, it will first create a hydrological model of both case studies, integrating the sewer and the receiving river systems, to jointly analyze and monitor the path of water and contaminants between urban areas and receiving rivers during rainfall events. Second, it will combine automatic sampling of natural rain events with the follow-up of experimental rainfall and with the most advanced analytical tools to monitor the chemical characteristics of urban runoff, including suspended materials, nutrients, regulated and emerging microcontaminants, and microplastics. It will prioritize the contaminants according to their occurrence and toxicity, and associate specific pollutants with specific types of urban areas. Third, by means of micro- and mesocosm studies, it will study the ecotoxicological effects of these runoffs on a range of organisms, from microbes to invertebrates. It will also analyze the ecological effects of urban runoff by measuring the structural and functional response of receiving rivers looking at biofilm, invertebrates, as well as at a range of ecosystem processes, from nutrient dynamics to greenhouse gas emissions. With this information, CityPoll will produce multimetric indices of the ecological impact of urban runoff. Fourth, it will assess the capacity of buffer zones (urban parks, riparian vegetation, etc.) to mitigate the pollution derived from urban runoff, thus pointing to the most adequate Nature-Based Solutions to that end. Finally, CityPoll will devote a large effort to the transfer and dissemination of the multi-layered evidence collected to a wide range of targets, from urban and water managers to scientists and to the general public, by producing guidelines, protocols, scientific papers, press releases and a video documentary. These guidelines and protocols will be of use beyond the specific case studies of CityPoll. Also, it will contribute to the development of new digital solutions for runoff monitoring, strengthening the European industry once new procedures and strategies become transposed into worldwide standards. CityPoll is a "Strategic Project Oriented towards the Ecological Transition and the Digital Transition", funded by the European Union, under the NextGenerationEU program.

A) A urban stream emerging after a wide concrete bridge. B) A big storm-water pipe bringing urban runoff to a stream. C) Creating experimental rainfall in collaboration with local firefighters. D) Anchoring wooden sticks and biofilm carriers to assess the ecological effects of urban runoff. E) The UPV/EHU crew during a sampling day. F) A pond created as a Nature-Based Solution to mitigate urban runoff pollution.

Proyecto TED2021-129966B-C32 financiado por:

RIBER: Restauración de riberas en ríos del norte de España: el papel de la biodiversidad vegetal en los servicios ecosistémicos fluviales

Las riberas fluviales juegan un papel fundamental en el correcto funcionamiento del ecosistema fluvial, pero el aspecto funcional rara vez se tiene en cuenta cuando se realizan actividades de restauración de riberas. En RIBER, proponemos un marco de actuación que tiene en cuenta un conjunto de indicadores fisicoquímicos, estructurales y funcionales a la hora de ejecutar una restauración de riberas fluviales y de evaluar su éxito. Además, destacamos la importancia de la diversidad y la composición de la comunidad vegetal de la ribera restaurada a la hora de restaurar el funcionamiento fluvial y de mitigar los impactos de otros estresores tales como el cambio climático, fragmentación de hábitat o las enfermedades emergentes. RIBER cuenta con dos paquetes de trabajo, en los cuales (i) estableceremos la situación actual de las riberas restauradas en nuestra área de estudio (Comunidad Autónoma del País Vasco) y (ii) definiremos, mediante experimentos de laboratorio, los umbrales mínimos de diversidad vegetal necesarios para mantener niveles adecuados de funcionamiento fluvial, proponiendo estrategias concretas de restauración para nuestra área de estudio. Los resultados de RIBER supondrán no sólo un avance científico debido a su enfoque novedoso de integración de múltiples indicadores en un contexto de biodiversidad-funcionamiento del ecosistema, sino una herramienta para los gestores que permita diseñar y evaluar el éxito de los proyectos de restauración cumpliendo con la Directiva Marco del Agua y otras normativas relevantes a nivel europeo y estatal.

Proyecto TED2021-129966B-C32 financiado por:

LandComp: The interactions between land use, substrate quality and consumers on global patterns of leaf litter decomposition in stream ecosystems

The primary cause of biodiversity decline worldwide is habitat degradation. Given the tight relationship between biodiversity and various ecosystem processes, it is reasonable to predict that habitat degradation should also lead to changes in ecosystem functioning. However, this has not been explored on a large scale. An important ecosystem process in stream ecosystems is the processing of terrestrially-derived leaf litter from stream side vegetation. Breakdown of this material is largely a function of its chemistry (nutrients, secondary/structural compounds), macro- and micro-consumers, and environmental conditions. In stream ecosystems, changes in watershed land use from forest to agriculture, urban and plantation results in habitat changes in the stream environment. This is due to various factors. Changes in sediment mobility on the landscape due to agricultural activity leads to shifts in substrate distribution, which is important to species composition of invertebrate communities known to be important to regulating the processing of leaf litter. Impervious cover that characterizes urban landscapes disrupts the dynamic equilibrium of sediment flux, exporting more than that imported, driving river channels down and, as in agricultural streams, shifting substrate distribution. In addition, flow dynamics are altered, resulting in much more intense, shorter duration disturbance events than that experienced by forested streams. Furthermore, thermal regimes are altered in summer months as warm water is heated dramatically from impervious surfaces before exported to the stream environment. This has implications not only for the tolerances of invertebrate taxa, but also microbial decomposers as well. Taken together, it is expected that upstream land use should drive shifts in the processing of leaf litter decomposition, owing mainly to:

1. Altered flow regimes
2. Elevated temperatures
3. Shifts in habitat
4. Interactions with substrate (litter) chemistry

As such, we seek to answer the following questions:

1. Does leaf litter breakdown shift with land use — agriculture, urban, plantation, forest — systematically across the globe?
2. Do these patterns vary consistently with leaf litter quality?
3. Is there an interaction with exclusion of consumers?

Our approach is a large scale, distributed study embracing a network of more than 50 collaborators across the globe. Leaf litter breakdown of the same leaf species plus a local dominant species will be estimated in streams experiencing the impacts of four land use types: urban, agriculture, plantation (if available), and forest. Breakdown of leaf litter with and without access by leaf shredding invertebrates will be estimated, as will characterization of the local shredder communities. Results will be placed in the context of consistently measured environmental conditions (water physical, chemical conditions) and biome.



Global environmental change threatens biodiversity, ecosystem functioning and, ultimately, the sustainability of human activities on Earth.Rivers and streams are among the most threatened ecosystems. While effects of environmental change on ecosystems are most usuallystudied with space-for-time approaches, data series from monitoring networks are becoming long enough to directly describe and interpretthe complex effects of climate and other environmental changes. Nevertheless, stream data are noisy, as they are subjected to frequentlocal disturbances; therefore, to obtain sound spatiotemporal patterns, it is essential to analyse highly spatially detailed time series fromthe perspective of metacommunity dynamics. Using a time series with a high spatial and temporal resolution, RiMSECisinvestigating the response of riverine metacommunities to environmental changeduring the last three decades to identify changes and drivers of the diversity, stability and the food web energetics of river ecosystems.RiMSEC will also study the spatial turnover of diversity and food web energetics in headwater fluvialnetworks, which are underrepresented on monitoring schemes, unravelling the role of landuse and organic matter availability and quality. Additionally, we will assess the effect of metacommunity dynamics on diversity and foodweb energetics by comparing isolated small catchments that flow to the sea with similar catchments that are connected tolarger fluvial networks. The project RiMSEC will yield a significantleap towards disentangling the dynamics of freshwater metacommunities facing global environmental change.

Sampling organic matter availability and qualityin headwater fluvialnetworks

MERLIN. Mainstreaming Ecological Restoration of freshwater-related ecosystems in a Landscape context: Innovation, upscaling and transformation

The MERLIN project (Mainstreaming Ecological Restoration of freshwater-related ecosystems in a Landscape context: Innovation, upscaling and transformation) is an international river restoration project in which the UPV/EHU and the Provincial Council of Gipuzkoa are collaborating. This project seeks new widely applicable formulas to restore the functions of European river ecosystems, for example, to reduce flooding and store carbon dioxide, or to facilitate natural water flow and fish migration through nature-based solutions (NbS). At the European scale, MERLIN identifies landscapes with high potential for transformative restoration and analyses the cost-benefit ratio of restoration scenarios. Overall, the MERLIN Academy and virtual marketplace will multiply innovations for the community of practice, investors and policy makers across Europe and beyond. MERLIN is focused on pursuing a sustainable, climate-neutral and resilient, inclusive and transformative path, incorporating restoration as a cornerstone of systemic change. In Gipuzkoa, 10 disused dams that fragment the connectivity of the Deba River are planned to be removed. During the first 18 months of the project, 4 dams have been removed. Dam removal effects on the structure and functioning of fluvial ecosystem are being investigated following a before-after design. In both periods, fish community, GHG emissions, or nutrient uptake are being sampled.

Santa Ana - Mendaro, Gipuzkoa, Basque Country

Matxategi - Bergara, Gipuzkoa, Basque Country

Alzolabea - Alzola, Gipuzkoa, Basque Country

San Prudentzio - Arrasate/Mondragon, Gipuzkoa, Basque Country

MERLIN project | MERLIN Gipuzkoa

GLoBE Network

GLoBE is an international network of freshwater ecologists, which main aim is to explore ecological patterns and processes in stream ecosystems at the global scale. Originally designed to specifically study one key stream ecosystem process, leaf litter breakdown (hence its name, which stands for 'Global Lotic Breakdown Experiments'), it has now expanded in order to consider a wide variety of ecological issues that are globally relevant. The network currently counts with collaborators from approximately 50 research teams from >30 countries across 6 continents.

Decomposition and Diversity in streams: a global experiment (DecoDiv)

A key question in contemporary ecology is how the loss of biological diversity affects ecosystem functioning. Plant litter decomposition is a fundamental ecosystem process with major consequences for the carbon cycle, but it is unclear how the loss of plant diversity affects decomposition rates. In a global-scale stream study, Boyero et al. ( examined decomposition rates of litter mixtures differing in phylogenetic diversity across latitudes and found that more diverse mixtures decomposed faster in the tropics, while less diverse mixtures decomposed faster at high latitudes. This suggested that different mechanisms could operate at different latitudes, possibly because different biological assemblages decompose litter at these different latitudes. While detritivores (key decomposition agents at high latitudes) might benefit from the concentration of particular resources in less diverse mixtures, microbes (dominant in the tropics) might be more efficient when using more varied resources (in more diverse mixtures) as they can optimize nutrient acquisition. We aim to explore the above question by examining decomposition rates in 3-spp litter mixtures differing in phylogenetic diversity (and hence in the concentration of different resources) at multiple sites across climatic zones. Although phylogenetic diversity and the diversity of functional traits do not always show a linear relationship (given that not all traits are phylogenetically conserved and due to the existence of convergent evolution and phenotypic plasticity), the usefulness of a phylogenetic proxy for trait diversity is maximized in studies with broad taxonomic scale. This approach can be particularly useful because phylogeny can represent a great deal of information that is not encompassed in the few traits that are generally measured.