Riparian quality and habitat heterogeneity assessment in Cantabrian rivers

RESUMEN. En este estudio se intentó evaluar la calidad riparia y la heterogeneidad del hábitat fluvial Como parte de la evaluación del estado de conservación de la Directiva Hábitats (CE, 1992) en los ríos incluidos en la red Natura 2000 de Cantabria, norte de España. Entre los métodos existentes elegimos los ´índices Qualitat del Bosc de Ribera (QBR) y “Riparian Quality Index” (RQI) para evaluar la calidad de la ribera, y el ´Indice de Habitabilidad fluvial (IHF) y el “Habitat Quality Assessment” (HQA) para evaluar la heterogeneidad del hábitat fluvial. El presente estudio pretende comparar el rendimiento del QBR y RQI para evaluar la calidad ribereña (RQ) y del IHF y HQA para evaluar la heterogeneidad del hábitat fluvial (RHH). Cuanto mayor sea la puntuación de los ´índices en un tramo de rio, más alta es la probabilidad de que Pertenezca a una condición de referencia, y también de que alcance una mayor integridad biológica. Por lo tanto, se utilizó la regresión logística binaria elaborando un modelo para RQ y otro para RHH, con el fin de examinar las relaciones entre los atributos evaluados por cualquiera de los cuatro ´índices y las condiciones de referencia y de no-referencia. También nos fijamos en las relaciones entre RQ y RHH y de ambos con las comunidades de macroinvertebrados. Se muestrearon la vegetación ribereña y las características del hábitat fluvial en un total de 285 tramos de 500 metros de longitud a lo largo de la red fluvial de Cantabria. Estos datos fueron comparados con datos existentes sobre la comunidad de macroinvertebrados en un total de 52 tramos de ríos y la métrica IASPT se calculó para las comparaciones. En este estudio, las condiciones de referencia se fijaron en 10 tipologías fluviales de acuerdo a los siguientes criterios: (1) régimen hidrológico inalterado, (2) usos del suelo no intensivos y (3) sin presencia o mínimos cambios morfológicos, terminando con un total de 96 tramos de río seleccionados. QBR y RQI fueron sensibles a las condiciones de referencia y a las tipologías fluviales, siendo mayor en condiciones de referencia en la mayoría de los tipos fluviales. Sin embargo, IHF y HQA sólo presentaron diferencias dependiendo del tipo fluvial y no en función de las condiciones de referencia. Por otra parte, IHF y HQA no tienen una respuesta similar a la modificación humana en todas las tipologías de río, ya que los tramos en condiciones de referencia presentaron valores más altos o más bajos que los tramos en condiciones de no-referencia en función de las tipologías fluviales. Por último, RQ se correlacionó positivamente con RHH, y el IASPT aumentó con ambos. Llegamos a la conclusión de que RQI y HQA obtuvieron ligeramente mejores resultados que el QBR y IHF para distinguir entre sitios en condiciones de referencia y no referencia en los ríos de Cantabria, y que la heterogeneidad del hábitat fluvial no debe ser utilizada para evaluar la calidad del hábitat fluvial.ABSTRACT. In this study, we attempted to assess riparian quality and river habitat heterogeneity as part of the conservation status assessment of the Habitats Directive (EC, 1992) in the rivers included in the Nature 2000 network of Cantabria, Northern Spain. We chose the Qualitat del Bosc de Ribera (QBR) and the Riparian Quality Index (RQI) to assess riparian quality and the ´Indice de Habitabilidad Fluvial (IHF) and Habitat Quality Assessment (HQA) to assess the river habitat heterogeneity. The present study aims to compare the performance of the QBR and RQI for assessing riparian quality (RQ) and of the IHF and HQA for assessing river habitat heterogeneity (RHH). With a higher score in each index, the site has a higher likelihood of belonging to a reference condition and also of reaching a higher biological integrity. Thus, we used logistic binary regressions of RQ and RHH to determine the relationships between the attributes evaluated by each of the four indices and reference/non-reference conditions. We also looked into the relationships between RQ and RHH as well as between these indices and the local macroinvertebrate communities. We surveyed riparian vegetation and river habitat characteristics in a total of 285 river reaches, each 500 m in length, along the fluvial network of Cantabria. These data were combined with previous macroinvertebrate community records from a total of 52 river reaches, and the Index of Average Score per Taxon (IASPT) metric was calculated for comparison. Reference condition sites were selected in 10 river types for the purpose of the present study on the basis of (1) unaltered discharge, (2) non-intensive land uses and (3) no or minimal morphological changes. There were 96 river reaches that matched the reference conditions. QBR and RQI were sensitive to both reference and nonreference conditions in the official river types and were larger in reference conditions than in non-reference conditions for most of the river types. However, IHF and HQA could only differentiate some of the river types and could not distinguish between reference and non-reference conditions. Moreover, IHF and HQA did not have a similar response to human modifications across river types, as reference reaches presented larger or lower values than non-reference conditions depending on the river type. Finally, RQ was positively correlated to RHH, and IASPT increased with both. We concluded that RQI and HQA performed slightly better than QBR and IHF indices to distinguish between reference and non-reference sites in the rivers of Cantabria and that river habitat heterogeneity should not be used to assess river habitat quality

Quantifying the performance of automated GIS-based geomorphological approaches for riparian zone delineation using digital elevation models

ABSTRACT: Riparian zone delineation is a central issue for managing rivers and adjacent areas; however, criteria used to delineate them are still under debate. The area inundated by a 50-yr flood has been indicated as an optimal hydrological descriptor for riparian areas. This detailed hydrological information is usually only available for populated areas at risk of flooding. In this work we created several floodplain surfaces by means of two different GIS-based geomorphological approaches using digital elevation models (DEMs), in an attempt to find hydrologically meaningful potential riparian zones for river networks at the river basin scale. Objective quantification of the performance of the two geomorphologic models is provided by analysing coinciding and exceeding areas with respect to the 50-yr flood surface in different river geomorphological types

Integrating monitoring, expert knowledge and habitat management within conservation organisations for the delivery of the water framework directive: A proposed approach

RESUMEN. Existe una creciente necesidad de entender mejor la naturaleza de las relaciones entre los atributos ambientales y las comunidades/especies de agua dulce para poder desarrollar acciones apropiadas que minimicen el impacto del cambio ambiental en los ecosistemas fluviales. Tal entendimiento necesitaría estar basado en investigaciones de relaciones causales más que en estudios de correlaciones estadísticas, como se acostumbra. Otro aspecto es la identificación de la escala a la cual los procesos y las características deben ser medidas para permitir un diseño de programas de monitoreo relevante. En este artículo se presenta una breve revisión de los conocimientos existentes sobre las relaciones especies/hábitat y se discuten los marcos teóricos existentes para la identificación de las características ambientales de importancia para la fauna y la determinación de la escala/s a la que deben evaluarse. Asimismo, proponemos un método para utilizar esas relaciones en el contexto de la supervisión y las prácticas de gestión en las organizaciones de conservación. Mostramos como modelos conceptuales de relaciones entre hábitats y especies pueden ser construidos usando el conocimiento existente y la opinión de expertos y como pueden ser testados utilizando datos recogidos como parte de los programas de monitoreo en las instituciones encargadas de la conservación. Sugerimos que tal marco, si aplicado, podría no sólo ayudar a identificar relaciones causales entre especies, características y procesos actuando a varias escalas, sino también para iniciar un proceso de adquisici´on de conocimiento en las instituciones responsables de la implementación de la Directiva Marco del Agua.ABSTRACT. There is a growing necessity to better understand the nature of the relationships between environmental attributes and freshwater species/communities to enable meaningful action to take place against the impacts of environmental change in river ecosystems. Such understanding would need to be based on the investigations of causal relationships rather than the study of statistical correlations or the use of expert opinion as is generally the case. Another issue is in identifying the scale(s) at which process and features should be recorded and assessed to enable the design of relevant monitoring programs. In this paper, we present a short review of existing knowledge on species/habitat relationships and discuss the importance of adequate theoretical frameworks for identifying environmental features of importance to wildlife and determining the scale/s at which they should be assessed.We further propose an approach for eliciting those relationships within the context of monitoring and management practice in conservation organisations. We show how conceptual models of habitat-species relationships can be built using existing knowledge and expert opinion and tested on data collected as part of existing monitoring programs. We suggest such framework, if applied, could not only help identify causal relationships between species, features and processes acting at various scales, but also initiate a knowledge acquisition process within organisations responsible for the delivery of the Water Framework Directive

Effects of landscape metrics and land-use variables on macroinvertebrate communities and habitat characteristics

ABSTRACT: The growing number of studies establishing links between stream biota, environmental factors and river classification has contributed to a better understanding of fluvial ecosystem function. Environmental factors influencing river systems are distributed over hierarchically organised spatial scales. We used a nested hierarchical sampling design across four catchments to assess how benthic macroinvertebrate community composition and lower spatial scale habitat descriptors were shaped by landscape and land-use patterns. We found that benthic macroinvertebrate community structure and composition varied significantly from catchment to habitat level. We assessed and identified fractal metrics of landscape descriptors capable of explaining compositional and functional change in the benthic faunal indicators and compared them with the traditional variables describing land use and reach level habitat descriptors within a 1 km radius of each sampling site. We found that fractal landscape metrics were the best predictor variables for benthic macroinvertebrate community composition, function, instream habitat and river corridor characteristics

Effects of landscape metrics and land-use variables on macroinvertebrate communities and habitat characteristics

The growing number of studies establishing links between stream biota, environmental factors and river classification has contributed to a better understanding of fluvial ecosystem function. Environmental factors influencing river systems are distributed over hierarchically organised spatial scales. We used a nested hierarchical sampling design across four catchments to assess how benthic macroinvertebrate community composition and lower spatial scale habitat descriptors were shaped by landscape and land-use patterns. We found that benthic macroinvertebrate community structure and composition varied significantly from catchment to habitat level. We assessed and identified fractal metrics of landscape descriptors capable of explaining compositional and functional change in the benthic faunal indicators and compared them with the traditional variables describing land use and reach level habitat descriptors within a 1 km radius of each sampling site. We found that fractal landscape metrics were the best predictor variables for benthic macroinvertebrate community composition, function, instream habitat and river corridor characteristics.El creciente número de estudios que relacionan la biota fluvial, los factores ambientales y la clasificación de los ríos, ha contribuido a comprender el funcionamiento de los ecosistemas fluviales. La organización de los factores ambientales fluviales es entendida, en la actualidad, como una jerarquía de factores con varias escalas espaciales. Para evaluar cómo la composición de los macroinvertebrados bentónicos y las características del hábitat a escala local son afectadas por el uso del paisaje y del suelo, se siguió un diseño de muestreo jerárquico en cuatro cuencas. Hemos verificado que la estructura y composición de las comunidades de macroinvertebrados bentónicos varió significativamente desde la escala de cuenca hasta la del hábitat. Fueron evaluadas e identificadas métricas fractales del paisaje que podrían explicar los cambios en la composición y funcionalidad de la fauna bentónica y se ha comparado también con la influencia de las tradicionales variables de usos del suelo y descriptores del hábitat al nivel del tramo, en un círculo de 1 km de radio alrededor de cada tramo. Encontramos que las métricas fractales del paisaje fueron las mejores variables predictoras de la composición y funcionalidad de las comunidades de macroinvertebrados y de las características del hábitat en el cauce y del corredor fluvial

Management and conservation of fish populations in mountain streams: An holistic approach in the framework of LIFE DIVAQUA project

Producción CientíficaThe recovery of threatened and endangered fish species is among the highest priorities for biodiversity conservation in national parks and fisheries management in nearby areas. Threats to fish populations are numerous and include habitat fragmentation and degradation, proliferation of invasive and pathogen species, and climate change. Moreover, mountain areas often share the most critical threats. However, there does not exist a common strategy that integrates conservation and management plans for fish populations in mountain areas. In this regard, LIFE DIVAQUA designed a conservation strategy that integrates new knowledge gained from scientific research and long-term monitoring data, and considers the main threats to fish populations in mountain areas: (1) A long term monitoring program has been already implemented for 10 years, revealing temporal trends of fish populations in mountain streams. (2) Modeling of fish population by the use of environmental DNA allowed analyzing fish distributions in areas with scarce data and evaluating habitat suitability maps. (3) Fishways construction and removal of river barriers substantially increased the distribution area of endangered species. (4) The analysis of climate change effects in water temperature and hydrology led to the implementation of environmental flows under a climate change scenario; (5) Monitoring fish diseases, their occurrence, and temporal changes (e.g., Aeromonas spp.) can be used as an early warning signal of ecosystem unbalance. A pilot study for the implementation of this conservation and management plan in the LIFE DIVAQUA project is showing promising results. However, the success of conservation and management strategies requires a broader approach. This includes the participation of a wide range of partners and stakeholders and utilizes independent scientific oversight, assessment, and project adjustments to ensure conservation goals are met.Comisión Europea - (grant LIFE18 NAT/ES/000121

An evaluation of freshwater monitoring programs in ILTER nodes and mountain national parks: identifying key variables to monitor global change effects

Este artículo contiene 30 páginas, 6 tablas, 4 figuras.Identifying and quantifying global change impacts on biotic and abiotic components of ecosystems is critical to promote an effective adaptation that increases the success of conservation strategies. To achieve this goal, global and regional assessment efforts require certain degree of harmonization on local monitoring programs to establish relevant comparisons at different spatio-temporal scales. Otherwise, the lack of harmonization might hinder the detection and assessment on the effects of human impacts. In this work we have compiled information on freshwater monitoring programs located in areas of intensive research and conservation interest: International Long Term Ecological Research (ILTER) nodes and mountain National Parks. We aimed at evaluating the quality and robustness of these programs to assess the impact of global change, addressing from the worldwide to the European and Spanish national scale. Results highlighted that freshwater monitoring programs lack a common strategy to monitor these ecosystems. Even at the continental and national scales, contrasting strategies and level of detail have been historically applied. Water quality, habitat and biodiversity are more commonly monitored than community structure and ecosystem functioning. Monitoring efforts on the Spanish Mountain National parks indicated differences on the targeted aquatic ecosystems. Rivers and lakes received a higher attention, while mires were rarely considered. Our results provide evidence that greater efforts should be directed towards constructing a coordinated strategy to monitor freshwater ecosystems at national, continental, and global scales. This strategy should involve a shared backbone of biophysical and biogeochemical variables for each habitat type on agreed protocols that are implemented across regions and administrative borders. Achieving this will support a substantial advance on the ecological research to further delineate proper conservation strategies to face the challenges imposed by global change.This study was carried out with the financial support of the EU LIFE programme, as part of the project LIFE-DIVAQUA (Proyecto LIFE18 NAT/ES/000121).Peer reviewe

The recovery of European freshwater biodiversity has come to a halt

Owing to a long history of anthropogenic pressures, freshwater ecosystems are among the most vulnerable to biodiversity loss$^{1}$. Mitigation measures, including wastewater treatment and hydromorphological restoration, have aimed to improve environmental quality and foster the recovery of freshwater biodiversity$^{2}$. Here, using 1,816 time series of freshwater invertebrate communities collected across 22 European countries between 1968 and 2020, we quantified temporal trends in taxonomic and functional diversity and their responses to environmental pressures and gradients. We observed overall increases in taxon richness (0.73% per year), functional richness (2.4% per year) and abundance (1.17% per year). However, these increases primarily occurred before the 2010s, and have since plateaued. Freshwater communities downstream of dams, urban areas and cropland were less likely to experience recovery. Communities at sites with faster rates of warming had fewer gains in taxon richness, functional richness and abundance. Although biodiversity gains in the 1990s and 2000s probably reflect the effectiveness of water-quality improvements and restoration projects, the decelerating trajectory in the 2010s suggests that the current measures offer diminishing returns. Given new and persistent pressures on freshwater ecosystems, including emerging pollutants, climate change and the spread of invasive species, we call for additional mitigation to revive the recovery of freshwater biodiversity

The recovery of European freshwater biodiversity has come to a halt

Owing to a long history of anthropogenic pressures, freshwater ecosystems are among the most vulnerable to biodiversity loss1. Mitigation measures, including wastewater treatment and hydromorphological restoration, have aimed to improve environmental quality and foster the recovery of freshwater biodiversity2. Here, using 1,816 time series of freshwater invertebrate communities collected across 22 European countries between 1968 and 2020, we quantified temporal trends in taxonomic and functional diversity and their responses to environmental pressures and gradients. We observed overall increases in taxon richness (0.73% per year), functional richness (2.4% per year) and abundance (1.17% per year). However, these increases primarily occurred before the 2010s, and have since plateaued. Freshwater communities downstream of dams, urban areas and cropland were less likely to experience recovery. Communities at sites with faster rates of warming had fewer gains in taxon richness, functional richness and abundance. Although biodiversity gains in the 1990s and 2000s probably reflect the effectiveness of water-quality improvements and restoration projects, the decelerating trajectory in the 2010s suggests that the current measures offer diminishing returns. Given new and persistent pressures on freshwater ecosystems, including emerging pollutants, climate change and the spread of invasive species, we call for additional mitigation to revive the recovery of freshwater biodiversity.publishedVersio

Multi-decadal improvements in the ecological quality of European rivers are not consistently reflected in biodiversity metrics

Humans impact terrestrial, marine and freshwater ecosystems, yet many broad-scale studies have found no systematic, negative biodiversity changes (for example, decreasing abundance or taxon richness). Here we show that mixed biodiversity responses may arise because community metrics show variable responses to anthropogenic impacts across broad spatial scales. We first quantified temporal trends in anthropogenic impacts for 1,365 riverine invertebrate communities from 23 European countries, based on similarity to least-impacted reference communities. Reference comparisons provide necessary, but often missing, baselines for evaluating whether communities are negatively impacted or have improved (less or more similar, respectively). We then determined whether changing impacts were consistently reflected in metrics of community abundance, taxon richness, evenness and composition. Invertebrate communities improved, that is, became more similar to reference conditions, from 1992 until the 2010s, after which improvements plateaued. Improvements were generally reflected by higher taxon richness, providing evidence that certain community metrics can broadly indicate anthropogenic impacts. However, richness responses were highly variable among sites, and we found no consistent responses in community abundance, evenness or composition. These findings suggest that, without sufficient data and careful metric selection, many common community metrics cannot reliably reflect anthropogenic impacts, helping explain the prevalence of mixed biodiversity trends.We thank J. England for assistance with calculating ecological quality and the biomonitoring indices in the UK. Funding for authors, data collection and processing was provided by the European Union Horizon 2020 project eLTER PLUS (grant number 871128). F.A. was supported by the Swiss National Science Foundation (grant numbers 310030_197410 and 31003A_173074) and the University of Zurich Research Priority Program Global Change and Biodiversity. J.B. and M.A.-C. were funded by the European Commission, under the L‘Instrument Financier pour l’Environnement (LIFE) Nature and Biodiversity program, as part of the project LIFE-DIVAQUA (LIFE18 NAT/ES/000121) and also by the project ‘WATERLANDS’ (PID2019-107085RB-I00) funded by the Ministerio de Ciencia, Innovación y Universidades (MCIN) and Agencia Estatal de Investigación (AEI; MCIN/AEI/10.13039/501100011033/ and by the European Regional Development Fund (ERDF) ‘A way of making Europe’. N.J.B. and V.P. were supported by the Lithuanian Environmental Protection Agency (https://aaa.lrv.lt/) who collected the data and were funded by the Lithuanian Research Council (project number S-PD-22-72). J.H. was supported by the Academy of Finland (grant number 331957). S.C.J. acknowledges funding by the Leibniz Competition project Freshwater Megafauna Futures and the German Federal Ministry of Education and Research (Bundesministerium für Bildung und Forschung or BMBF; 033W034A). A.L. acknowledges funding by the Spanish Ministry of Science and Innovation (PID2020-115830GB-100). P.P., M.P. and M.S. were supported by the Czech Science Foundation (GA23-05268S and P505-20-17305S) and thank the Czech Hydrometeorological Institute and the state enterprises Povodí for the data used to calculate ecological quality metrics from the Czech surface water monitoring program. H.T. was supported by the Estonian Research Council (number PRG1266) and by the Estonian national program ‘Humanitarian and natural science collections’. M.J.F. acknowledges the support of Fundação para a Ciência e Tecnologia, Portugal, through the projects UIDB/04292/2020 and UIDP/04292/2020 granted to the Marine and Environmental Sciences Centre, LA/P/0069/2020 granted to the Associate Laboratory Aquatic Research Network (ARNET), and a Call Estímulo ao Emprego Científico (CEEC) contract.Peer reviewe