Archived project

MARS - Managing Aquatic ecosystems and water Resources under multiple Stress

Goal: + To understand the effects of multiple stressors on surface waters and groundwaters, their biota, and the services they provide to humans.
+ To understand how ecological status and ecosystem services are related – if at all.
+ To advise river basin management how to restore multiply stressed rivers and lakes.
+ To advise the revision of the Water Framework Directive on new indicators for ecological status and ecosystem services.
+ To develop methods and software for the Programmes of Measures.

Date: 1 February 2014 - 31 January 2018

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Project log

Tano Gutiérrez-Cánovas
added a research item
Freshwater ecosystems are exposed to an increasing number of stressors, challenging their biomonitoring and management. Despite recent advances in multiple-stressor research, regional-scale assessments in areas with high freshwater biodiversity and increasing anthropogenic pressure are urgently needed. We reviewed 61 studies focused on freshwater individuals, populations and communities from the Iberian Peninsula to (i) quantify the frequency of experimental approaches used (manipulative, observational), aquatic systems, biological organization levels, and types of organisms and modelled responses, (ii) identify key individual stressors and the frequency of significant positive (increase in response magnitude) and negative (decrease) effects and (iii) determine types of interacting stressors and the frequency of their combined effects. Our dataset comprised 409 unique responses to 13 types of individual stressors, 34 stressor pairs and 12 high-order interactions (3- and 4-way). We found a higher prevalence of manipulative (85 %) respect to observational studies, and a greater focus on lotic systems (59 %) and heterotrophic organisms (58 %). The most studied stressors were nutrient (Nutr), thermal (Therm), hydrologic (Hydr), ultraviolet radiation (UVR), toxic (Toxic) and salinity (Sal) stress and land-use pressure. Individual stressors showed a higher proportion of negative (34 %) than positive effects (26 %). Nutr × UVR, Toxic × Toxic, Therm × Toxic, Hydr × Toxic, Sal × Therm, and Nutr × Therm were the most studied stressor pairs. Non-interactive (50 %) and interactive responses (50 %) were balanced. Antagonistic effects (18 %) were slightly more common than synergisms (15 %), reversal or opposing (13 %) and high-order interactions (4 %). Such proportions varied within experimental approaches, biological organization levels and organism types. Our findings are helpful to manage certain stressor combinations in Iberian freshwaters. Further efforts in Iberian multiple-stressor research should be directed to (i) intensify the study of lentic systems, (ii) explore more observational data, (iii) autotrophic organisms and (vi) biodiversity-ecosystem functioning responses, and (v) cover a wider range of stressors and (vi) more complex interacting stressor scenarios.
Thomas Hein
added a research item
Sudden instream releases of water from hydropower plants (hydropeaking [HP]) can cause abrupt temperature variations (thermopeaking [TP]), typically on a daily/sub-daily basis. In alpine rivers, hydropeaking and thermopeaking waves usually overlap, which leads to a multiple stressor of flow velocity pulses and temperature alteration. Periphytic communities could give important insights into the effects of combined thermo- and hydropeaking (THP) in stream ecosystems. Thus, the study's first aim was to assess the combined effects of thermo-hydropeaking on structural (composition, biomass) and functional (photosynthesis, enzyme activity) properties of periphyton. The second aim was to assess the interaction between periphytic algae and the heterotrophic communities (bacteria) and determine how biotic and abiotic factors explain the variability of bacterial enzymatic activities in the periphyton. We assessed the effects of repeated cold and warm thermo-hydropeaking for 24 days on periphyton, by manipulating discharge and temperature in six experimental flumes directly fed by an Alpine stream. Our study revealed that THP had structural and functional effects on periphyton in oligotrophic streams, where the effects depending on the direction of the temperature change (cold/warm) and on the morphological setting (pool/riffle). The results showed that even a short-term increase in flow velocity and temperature decrease could induce better growth conditions for diatoms. Additionally, an increase in the interaction between periphytic algae and bacteria during thermo-hydropeaking was also shown, this coupling being more pronounced in pool than in riffle sections. Our results clearly showed that riffle sections develop less periphytic algal biomass and activity and therefore, THP can reduce biomass availability for primary consumers in large areas of impacted streams. These findings highlight the importance of mitigation measures, focusing on establishing heterogeneous stream bed areas, with frequent pool and riffle sequences.
Sebastian Birk
added a research item
Aquatic ecosystems are affected by man-made pressures, often causing combined impacts. The analysis of the impacts of chemical pollution is however commonly separate from that of other pressures and their impacts. This evolved from differences in the data available for applied ecology vis-à-vis applied ecotoxicology, which are field gradients and laboratory toxicity tests, respectively. With this study, we demonstrate that the current approach of chemical impact assessment, consisting of comparing measured concentrations to protective environmental quality standards for individual chemicals, is not optimal. In reply, and preparing for a method that would enable the comprehensive assessment and management of water quality pressures, we evaluate various quantitative chemical pollution pressure metrics for mixtures of chemicals in a case study with 24 priority substances of Europe-wide concern. We demonstrate why current methods are sub-optimal for water quality management prioritization and that chemical pollution currently imposes limitations to the ecological status of European surface waters. We discuss why management efforts may currently fail to restore a good ecological status, given that to date only 0.2% of the compounds in trade are considered in European water quality assessment and management.
Sebastian Birk
added a research item
Climate and land-use change drive a suite of stressors that shape ecosystems and interact to yield complex ecological responses, i.e. additive, antagonistic and synergistic effects. Currently we know little about the spatial scale relevant for the outcome of such interactions and about effect sizes. This knowledge gap needs to be filled to underpin future land management decisions or climate mitigation interventions, for protecting and restoring freshwater ecosystems. The study combines data across scales from 33 mesocosm experiments with those from 14 river basins and 22 cross-basin studies in Europe producing 174 combinations of paired-stressor effects on a biological response variable. Generalised linear models showed that only one of the two stressors had a significant effect in 39% of the analysed cases, 28% of the paired-stressor combinations resulted in additive and 33% in interactive (antagonistic, synergistic, opposing or reversal) effects. For lakes the frequency of additive and interactive effects was similar for all spatial scales addressed, while for rivers this frequency increased with scale. Nutrient enrichment was the overriding stressor for lakes, generally exceeding those of secondary stressors. For rivers, the effects of nutrient enrichment were dependent on the specific stressor combination and biological response variable. These results vindicate the traditional focus of lake restoration and management on nutrient stress, while highlighting that river management requires more bespoke management solutions.
Christine Argillier
added a research item
We studied fish size structure by using mean size, size diversity, and the slope of linear size spectra of six common European fish species along large-scale environmental gradients. We further analyzed the response of these three size metrics to environmental variables and to density-dependent effects, i.e., relative estimates of abundance (catch per unit effort, CPUE). We found differences in the strength of main predictors of size structure between the six species, but the direction of the response was relatively similar and consistent for most of the size metrics. Mean body size was negatively related to temperature for perch (Perca fluviatilis), roach (Rutilus rutilus), and ruffe (Gymnocephalus cernuus). Lake productivity (expressed as total phosphorus concentration) and lake depth were also predictors of size structure for four of six species. Moreover, we found a strong density dependence of size structure for all species, resulting in lower mean body size and size diversity and steeper size spectra slopes when density dependence increases. This suggests that density dependence is a key driver of fish size structure.
Christine Argillier
added a research item
Water resources globally are affected by a complex mixture of stressors resulting from a range of drivers, including urban and agricultural land use, hydropower generation and climate change. Understanding how stressors interfere and impact upon ecological status and ecosystem services is essential for developing effective River Basin Management Plans and shaping future environmental policy. The EU-funded project MARS (Managing Aquatic ecosystems and water Resources under multiple Stress) addressed the nature of these problems for Europe's water resources and the need to find solutions at a range of spatial scales. MARS was operating at three scales: At the water body scale, the mechanistic understanding of stressor interactions and their impact upon water resources, ecological status and ecosystem services were examined through multi-factorial experiments and the analysis of long time-series. At the river basin scale, modelling and empirical approaches was adopted to characterise relationships between multiple stressors and ecological responses, functions, services and water resources. The effects of future land use and mitigation scenarios in 16 European river basins have been assessed. At the European scale, large-scale spatial analysis were carried out to identify the relationships amongst stress intensity, ecological status and service provision, with a special focus on large transboundary rivers, lakes and fish. The project offered support to managers and policy makers in the practical implementation of the Water Framework Directive (WFD), of related legislation and of the Blueprint to Safeguard Europe's Water Resources by advising the 3rd River Basin Management Planning cycle, the revision of the WFD and by developing new tools for diagnosing and predicting multiple stressors. The final report at hand overviews the project’s objectives and provides a concise summary of the main scientific results obtained in MARS. It furthermore outlines the potential impact and the main dissemination activities. Given that the project has published about 230 scientific publications, the results presented in this report are necessarily selective and aim at a comprehensive overview of the MARS outcome illustrated by a few examples, which are described in more detail.
Florian Borgwardt
added a research item
The sustainable management of very large rivers is based on the assessment of their environmental condition. However, unlike for smaller rivers, this assessment is yet less advanced due to the specific complexities of very large river systems. In Europe, this is reflected by the lack of an international large river typology classifying these ecosystems into units with homogenous environmental features. Focussing on European rivers of >10,000 km 2 catchment size, we collated datasets describing orographic, geological, geomorphological, hydrological and climatic features of the riverine environment. These rivers were divided into segments of about 30 km length, and 40 environmental descriptors hardly modifiable by human activities were allocated to each segment. In a subsequent cluster analysis, we identified seven large river types (LRTs) across Europe: Alpine-Influenced rivers; Baltic rivers; Central Lowland rivers; Continental Lowland rivers; Mediterranean rivers; Nordic rivers; Atlantic rivers. These LRTs were compared with existing European bio-geographical classifications and tested using contemporary river sampling data of benthic invertebrates. Our study describes a systematic pan-European typology characterising different types of European very large rivers, reviewed and validated by biological data. This typology represents an essential step in fostering the implementation of bio-assessment methods tailored to very large rivers in Europe.
Mario Lepage
added a research item
Globally, there has been a decrease in dissolved oxygen in the oceans, that is more pronounced in coastal waters, resulting in more frequent hypoxia exposure for many marine animals. Managing hypoxia requires an understanding of the dynamics of dissolved oxygen (DO) where it occurs. The French coast facing the Bay of Biscay (N-E Atlantic Ocean) hosts at least a dozen tidal and turbid estuaries, but only the large estuaries of the Gironde and the Loire, are subject to a continuous monitoring. Here, we compared the DO dynamics in these two systems, in order to evaluate to what extent it is possible to predict the sensitivity to hypoxia of a tidal and turbid estuary based on its most common and easily accessible characteristics (the estuary surface area and length, liquid and solid discharge, suspended particulate load, water renewal time, presence of cities). Whereas the hyperturbid Gironde estuary is the longest (170 km), implying longer water and particle residence times, and is bordered by a large metropole (>750,000 inhabitants), only episodic summer hypoxia events (DO < 2 mg L−1) were recorded in its urban Garonne subestuary. In contrast, the turbid Loire estuary, smaller in terms of surface area and length, experiences permanent summer hypoxia. This demonstrates the inability to evaluate the susceptibility of a tidal and turbid estuary to hypoxia only by considering its general characteristics. We urge that there is a need for a pertinent DO survey strategy based on an initial assessment of DO in a specific estuary based on longitudinal investigations, in particular during the warm season (as higher water temperatures decrease DO solubility), for detecting the potential zones of minimum DO.
Sebastian Birk
added a research item
The MARS Project aims to understand the effects of multiple stressors on the status of surface waters and groundwaters, their constituent organisms, and the ecosystem services they provide. It examines the impacts of multiple stressors through a series of multifactorial experiments, analysis of long-term monitoring datasets, sixteen case studies at the river basin scale and large-scale spatial datasets of European waters. WP6 aims to synthesise these results (from WPs 2-5) and feed this synthesis into management tools (WP7) or policy decisions (WP8). We plan to do this by pooling summary data in order to compare and synthesise results across spatial scales (experiments, individual WBs, RBs, Europe), temporal scales (months-seasons-years) and ecosystem types (rivers, lakes, reservoirs, estuaries). In order to do this it is important that common questions on regional stressor combinations are addressed across WPs 3-5, using common benchmark response indicators. Following the previous guidance document, four common questions (below) were identified across WPs 3-5 and common indicators for ecosystem services (WP2.2: Grizzetti et al. 2015 in MARS Deliverable 2.1) and common benchmark stress and response measures (WP2.3: Birk et al. 2015 in D2.1) have been recommended for adoption across the project. WP6 (Task 6.1) aims to synthesise results on the interacting effects of two stressors. There are two key outcomes of this synthesis: 1. To identify indicators (species, trait groups, metrics, services) that are sensitive or tolerant to multiple stressors (to feed into Task 6.2). 2. To identify water-body types that are sensitive or tolerant to multiple stressors (to feed into Task 6.3) The above work will help to identify indicators that can potentially be used to diagnose the cause of degradation (WP6.2), to develop tools for river basin management (WP7) and to increase knowledge needed for improved freshwater management (WP8).
Angel Borja
added a research item
Recreational fishing is considered a cultural ecosystem service, important in terms of the socio-economic benefits that it provides. In the Nerbioi estuary (northern Spain), investments in water treatment and the closure of polluting industries have led to several benefits such as improvements in water quality, fish abundance and richness, and recreational fishing activity. Currently, this activity is performed along the whole estuary including areas that previously were severely polluted. Valuing the benefits of recreational fishing is crucial to support the management of the estuary. The economic valuation is performed using a multi-site travel cost analysis. In addition, the effect on welfare measures of future scenarios where environmental conditions and accessibility change is analysed. Results indicate that each recreational trip in Nerbioi has a use value of 14.98€, with an aggregate value of 1.12 M€year−1 for the whole recreational fishers’ community. The simulated scenarios suggest that further environmental improvements would have a positive effect in the activity, increasing the current welfare by 7.5–11.5%. In contrast, worsening of environmental conditions and accessibility could translate into a welfare reduction up to 71%. The monetary use value of recreational fishing partially covers (4.7%) the costs of maintaining the environmental quality of the estuary.
Yiannis Panagopoulos
added a research item
The hydrologic regime of a river is one of the factors determining its ecological status. This paper tries to indicate the present hydrologic stress occurring across European rivers on the basis of model integration. This results in a pan-European assessment at the resolution of the functional elementary catchment (FEC), based on simulated daily time-series of river flows from the model PCR-GLOBWB. To estimate proxies of the present hydrologic stress, two datasets of river flow were simulated under the same climate, one from a hypothetic least disturbed condition scenario and the second from the anthropogenic scenario with the actual water management occurring. Indicators describing the rivers’ hydrologic regime were calculated with the indicators of hydrologic alteration (IHA) software package and the river total mean flow and the relative baseflow magnitude over the total flow were used to express the deviations between the two scenarios as proxy metrics of rivers’ hydrologic alteration or hydrologic stress. The alteration results on Europe’s FEC-level background showed that Southern Europe is more hydrologically stressed than the rest of Europe, with greater potential for hydrology to be clearly associated with river segments of unreached good ecological status and high basin management needs.
Eugenio Molina-Navarro
added a research item
There are infinite possible future scenarios reflecting the impacts of anthropogenic multiple stress on our planet. These impacts include changes in climate and land cover, to which aquatic ecosystems are especially vulnerable. To assess plausible developments of the future state of European surface waters, we considered two climate scenarios and three storylines describing land use, management and anthropogenic development (‘Consensus’, ‘Techno’ and ‘Fragmented’, which in terms of environmental protection represent best-, intermediate- and worst-case, respectively). Three lake and four river basins were selected, representing a spectrum of European conditions through a range of different human impacts and climatic, geographical and biological characteristics. Using process-based and empirical models, freshwater total nitrogen, total phosphorus and chlorophyll-a concentrations were projected for 2030 and 2060. Under current conditions, the water bodies mostly fail good ecological status. In future predictions for the Techno and Fragmented World, concentrations further increased, while concentrations generally declined for the Consensus World. Furthermore, impacts were more severe for rivers than for lakes. Main pressures identified were nutrient inputs from agriculture, land use change, inadequately managed water abstractions and climate change effects. While the basins in the Continental and Atlantic regions were primarily affected by land use changes, in the Mediterranean/Anatolian the main driver was climate change. The Boreal basins showed combined impacts of land use and climate change and clearly reflected the climate-induced future trend of agricultural activities shifting northward. The storylines showed positive effects on ecological status by classical mitigation measures in the Consensus World (e.g. riparian shading), technical improvements in the Techno World (e.g. increasing wastewater treatment efficiency) and agricultural extensification in the Fragmented World. Results emphasize the need for implementing targeted measures to reduce anthropogenic impacts and the importance of having differing levels of ambition for improving the future status of water bodies depending on the societal future to be expected.
Yiannis Panagopoulos
added a research item
Abstract The Water Framework Directive (WFD) is a pioneering piece of legislation that aims to protect and enhance aquatic ecosystems and promote sustainable water use across Europe. There is growing concern that the objective of good status, or higher, in all EU waters by 2027 is a long way from being achieved in many countries. Through questionnaire analysis of almost 100 experts, we provide recommendations to enhance WFD monitoring and assessment systems, improve programmes of measures and further integrate with other sectoral policies. Our analysis highlights that there is great potential to enhance assessment schemes through strategic design of monitoring networks and innovation, such as earth observation. New diagnostic tools that use existing WFD monitoring data, but incorporate novel statistical and trait-based approaches could be used more widely to diagnose the cause of deterioration under conditions of multiple pressures and deliver a hierarchy of solutions for more evidence-driven decisions in river basin management. There is also a growing recognition that measures undertaken in river basin management should deliver multiple benefits across sectors, such as reduced flood risk, and there needs to be robust demonstration studies that evaluate these. Continued efforts in ‘mainstreaming’ water policy into other policy sectors is clearly needed to deliver wider success with WFD goals, particularly with agricultural policy. Other key policy areas where a need for stronger integration with water policy was recognised included urban planning (waste water treatment), flooding, climate and energy (hydropower). Having a deadline for attaining the policy objective of good status is important, but even more essential is to have a permanent framework for river basin management that addresses the delays in implementation of measures. This requires a long-term perspective, far beyond the current deadline of 2027.
Angel Borja
added a research item
Recreational fishing activity has recovered in the Nerbioi estuary (Northern Spain), after water sanitation and environmental improvement. Recreational fishing is important for the local population; therefore, future management measures that could cause changes in the estuary should also consider the impacts on recreational fishing. Our objective was to analyze the effects that future management decisions and unexpected environmental changes, alone or in combination with climate change effects, can produce in recreational fishing in Nerbioi. The current recreational fishing activity was modelled using a System Dynamics Modelling (SDM). Based on those results, seven future scenarios were simulated. Results suggested that the adoption of future management measures to improve the environmental conditions could lead to additional positive changes for recreational fishing, as after water quality improvement, fish stocks will continue to recover, and these better conditions could attract more fishers and increase their satisfaction. Simulation of temporary and unexpected environmental changes resulted in quick estuarine recovery, without dramatic consequences for recreational fishing. In conclusion, analysing future scenarios on cultural ecosystem services such as recreational fishing, using SDM, can produce valuable information for decision making processes, facilitating the selection between environmental management alternatives.
Rafaela Schinegger
added a research item
The EU FP 7 project MARS – “Managing Aquatic ecosystems and water Resources un- der multiple Stress” (duration 01.02.2014 – 31.01.2018) investigated how multiple human stressors affect rivers, lakes, groundwater, transitional and coastal waters. Outcomes of this research project are more than 200 scientific publications, more than 4000 pages of deliverables, various tools and background information about multiple stressors; all available in the Freshwater Information System. This document provides recommendations and highlights relevant outcomes of the MARS project aiming to inform River Basin Managers and stakeholders in other sectors (energy, water industry, agriculture) on how to best assess and mitigate impacts of multiple stressors acting on Europe’s aquatic ecosystems. The document aims at supporting those who implement the EU Water FrameworkDirective (WFD) and who have to make recommendations or take decisions based on existing monitoring data. MARS mainly addressed pressures regarding hydromorphology, nutrients and climate change, while the focus of this document is on the most com mon and typical stressor combinations of European waters. For convenience and better readability, this document uses hyperlinks to relevant MARS results, models and tools to enable readers to directly access the respective web- sites.
Erik Jeppesen
added a research item
Important drivers of gross primary production (GPP) and ecosystem respiration (ER) in lakes are temperature, nutrients, and light availability, which are predicted to be affected by climate change. Little is known about how these three factors jointly influence shallow lakes metabolism and metabolic status as net heterotrophic or autotrophic. We conducted a pan-European standardized mesocosm experiment covering a temperature gradient from Sweden to Greece to test the differential temperature sensitivity of GPP and ER at two nutrient levels (mesotrophic or eutrophic) crossed with two water levels (1 m and 2 m) to simulate different light regimes. The findings from our experiment were compared with predictions made according the metabolic theory of ecology (MTE). GPP and ER were significantly higher in eutrophic mesocosms than in mesotrophic ones, and in shallow mesocosms compared to deep ones, while nutrient status and depth did not interact. The estimated temperature gains for ER of ~ 0.62 eV were comparable with those predicted by MTE. Temperature sensitivity for GPP was slightly higher than expected ~ 0.54 eV, but when corrected for daylight length, it was more consistent with predictions from MTE ~ 0.31 eV. The threshold temperature for the switch from autotrophy to heterotrophy was lower under mesotrophic (~ 11 C) than eutrophic conditions (~ 20 C). Therefore, despite a lack of significant temperature-treatment interactions in driving metabolism, the mesocosm's nutrient level proved to be crucial for how much warming a system can tolerate before it switches from net autotrophy to net heterotrophy.
Jan Lemm
added 2 research items
Interactions of multiple stressors in lotic systems have received growing interest and have been analysed in a growing number of studies using experiment and survey data. In this study, we present a protocol to identify, display and analyse stressors of rivers and their interactions (additive, synergistic or antagonistic). We used a dataset of 125 samples of central European lowland rivers comprising hydromorphological, physico-chemical and land use stressor and pressure variables as well as benthic macroinvertebrate traits as biological response variables. To identify and visualise multiple stressor combinations jointly operating in the data set, we applied social network analysis. The main co-occurring stressor combination was fine sediment accumulation (hydromorphological stress) and enhanced phosphorus concentration (nutrient stress). Agricultural (cropland) and urban land use were identified as the main large scale environmental pressures. Stressor interactions were analysed using generalised linear regression modelling (GLM) including pairwise interaction terms. Altogether, 14 macroinvertebrate response variables were tested on six stressor combinations and revealed predominantly additive effects (80% of all significant models with absolute standardised effect sizes > 0.1). Significant antagonistic and synergistic interactions occurred in almost 20% of the models. Fine sediment stress was more influential and frequent than nutrient stress. The methodology presented here is standardisable and thus could help inform practitioners in aquatic ecosystem monitoring about prominent combinations of multiple stressors and their interactions. Yet, further understanding of the mechanisms behind the biological responses is required to be able to derive appropriate guidance for management. This applies to rather complex stressors and pressures, such as land use, for which more detailed data (e.g. nutrient concentrations, fine sediment entry, pesticide pollution) is often missing.
More often than not, rivers are impacted by multiple stressors imultaneously affecting water quality, ecological flow, habitat diversity and ultimately lotic biodiversity. Identifying individual stressors as specific causes of deterioration can help inform water managers about stressor hierarchy and appropriate management options. Here, we investigate whether biological metrics from bioassessment schemes hold diagnostic capabilities to distinguish between the impact of individual stressors. We hypothesise that stressor-specific responses occur, when individual stressors showindependent ‘modes of action’ (i.e. the specific stress-induced changes of environmental factors that modify the ecological niches of the species constituting the biological community). The stress receptors comprised three aquatic organismgroups (macrophytes, benthic invertebrates, fish) represented by 437 biological metrics relevant in aquatic bioassessment. The stressor groups under investigation were physicochemical, hydromorphological and hydrological stress. The data originated from official monitoring programmes with 769 sampling sites located at three broad river types inWestern and Central Germany. Linear and non-linear variance partitioning was performed separately for each river type, with the non-linear analysis using a combination of boosted regression tree modeling and variance partitioning. We considered metrics to be potentially stressor-specific, if the corresponding models were explained predominantly by one stressor group. The linear analyses revealed 16 metrics that met our criteria. Subsequent non-linear modeling resulted in two genuinely stressor-specific metrics, both based on invertebrate data: The Index of Biocoenotic Region (specifically indicating hydromorphological stress) and the Relative abundance of alien invertebrate species (specifically indicating physico-chemical stress). We conclude that stressor-specific metrics can be empirically derived based on available monitoring data, and thus help support decision making in environmental management. However, their applicability is restricted to specific regions (e.g. river basin districts) reflecting the case-specific circumstance to which these metrics are conditioned.
Steve J. Ormerod
added 2 research items
While there is widespread recognition of human involvement in biodiversity loss globally , at smaller spatial extents, the effects are less clear. One reason is that local effects are obscured by the use of summary biodiversity variables, such as species richness, that provide only limited insight into complex biodiversity change. Here, we use 30 yr of invertebrate data from a metacommunity of 10 streams in Wales, UK, combined with regional surveys, to examine temporal changes in multiple biodiversity measures at local, metacommunity, and regional scales. There was no change in taxo-nomic or functional a-diversity and spatial b-diversity metrics at any scale over the 30-yr time series, suggesting a relative stasis in the system and no evidence for ongoing homogenization. However, temporal changes in mean species composition were evident. Two independent approaches to estimate species niche breadth showed that compositional changes were associated with a systematic decline in mean community specialization. Estimates of species-specific local extinction and immigration probabilities suggested that this decline was linked to lower recolonization rates of specialists, rather than greater local extinction rates. Our results reveal the need for caution in implying stasis from patterns in a-diversity and spatial b-diversity measures that might mask non-random biodiversity changes over time. We also show how different but complementary approaches to estimate niche breadth and functional distinctness of species can reveal long-term trends in community homogenization likely to be important to conservation and ecosystem function.
This item contributes to the 100th issue of the regular bulletin of the Chartered Institute of Ecology and Environmental Management 'In Practice'. It draws attention to the plight of global freshwater ecosystems and their biodiversity.
Yiannis Panagopoulos
added a research item
Streams and rivers are among the most threatened ecosystems in Europe due to the combined effects of multiple pressures related to anthropogenic activities. Particularly in the Mediterranean region, changes in hydromorphology along with increased nutrient loadings are known to affect the ecological functions and ecosystem services of streams and rivers with the anticipated climate change being likely to further impair their functionality and structure. In this study, we investigated the combined effects of agricultural driven stressors on the ecology and delivered services of the Pinios river basin in Greece under three future world scenarios developed within the EU funded MARS project. Scenarios are based on combinations of Representative Concentration Pathways and Shared Socioeconomic Pathways and refer to early century (2030) and mid-century (2060) representing future climate worlds with particular socioeconomic characteristics. To assess the responses of ecological and ecosystem service indicators to the scenarios we first simulated hydrology and water quality in Pinios with a process-based model. Simulated abiotic stressor parameters (predictors) were linked to two biotic indicators, the macroinvertebrate indicators ASPT and EPT, with empirical modelling based on boosted regression trees and general linear models. Our results showed that the techno world scenario driven by fast economic growth and intensive exploitation of energy resources had the largest impact on both the abiotic status (nutrient loads and concentrations in water) and the biotic indicators. In contrast, the predicted changes under the other two future worlds, consensus and fragmented, were more diverse and were mostly dictated by the projected climate. This work showed that the future scenarios, especially the mid-century ones, had significant impact on both abiotic status and biotic responses underpinning the need for implementing catchment management practices able to mitigate the ecological threat on waters in the long-term.
Angel Borja
added a research item
Well-functioning ecosystems hold high values of biodiversity and provide a wide range of ecosystem services. In 25 years, Nerbioi-Ibaizabal estuary (North Spain) has changed from a highly polluted estuary to one with a moderate/good ecological status, mainly due to the construction of a Waste Water Treatment Plant that has operated in the estuary since 1990. In recent decades, recorded biotic and abiotic parameters show a clear ecological improvement, but the concurrent response of cultural ecosystem services (e.g. recreational fishing) remains unexplored. Recreational fishers’ fishing behaviour and perceptions over environmental changes were obtained through a questionnaire and compared with recorded parameters of improvement. Results show a positive correlation between the abiotic ecological recovery and fishers’ behaviour. However, fishers’ perceptions on the biotic recovery (e.g. fish abundance) were more negative than those recorded. Despite this, fishers are satisfied with the overall experience of fishing and will probably continue fishing in the estuary. In conclusion, in better functioning estuaries the capacity to deliver cultural services (e.g. recreational fishing) increases. However, getting ecosystem services to the level of appreciation of society requires to be much better communicated.
Annette Baattrup-Pedersen
added 2 research items
• At present, scientific evidence documenting effects of weed cutting in streams as a measure to improve flood protection and run‐off from agricultural land is scarce, which is surprising considering the huge effect that it has on stream ecology. Instead, weed cutting is performed under the assumption that removal of aquatic plant biomass improves runoff from agricultural land and prevents flooding of adjacent areas provided that it is performed regularly. • In this study, we examined linkages between weed cutting practice and water level reductions in 126 small‐ and medium‐sized Danish streams (catchment size <100 km²) with continuously monitored discharge and water level data (from 1990 to 2012). Specifically, we hypothesised that (1) weed cutting reduces stream water levels more in late summer when the biomass of aquatic plants is higher than in early summer; (2) the efficiency of cutting declines with increasing cutting frequency as the aquatic plant community changes with increasing abundance of species able to regrow fast following a cutting event; (3) the high‐frequency cutting in Danish streams lowers the ecological status of the streams as evaluated from aquatic plant assemblages. • The average effect of weed cutting on the water level was largest in July, August and September with an average reduction of 16 cm and lowest in early spring and late autumn with an average reduction of 11 cm. Regrowth was largest in June, with an increase in water level of 0.41 cm/day, whereas regrowth was absent in autumn. Regrowth also varied with the frequency of weed cutting, from an average of 0.04 cm/day in streams subjected to one annual cutting to an average of 0.6 cm/day in streams subjected to >6 annual cuttings. Furthermore, we found that the ecological status was either moderate or poor/bad in streams with more than one annual cutting. • Our findings highlight that it is by no means certain that the current weed cutting practice is efficient for flood control since (1) regrowth is stimulated by frequent cuttings and a positive feedback loop may develop, necessitating even more frequent cuttings to maintain the discharge capacity of the streams, and (2) many species stimulated by weed cutting, like for instance Sparganium emersum, form dense canopy beds across the entire stream profile and therefore reduce the discharge capacity of the stream more than species growing in confined patches. We encourage more studies with the aim to identify how stream maintenance should be performed to optimise flood control without compromising the ability to reach good ecological stream quality.
The hydrology of riparian areas changes rapidly these years because of climate change‐mediated alterations in precipitation patterns. In this study, we used a large‐scale in situ experimental approach to explore effects of drought and flooding on plant taxonomic diversity and functional trait composition in riparian areas in temperate Europe. We found significant effects of flooding and drought in all study areas, the effects being most pronounced under flooded conditions. In near‐stream areas, taxonomic diversity initially declined in response to both drought and flooding (although not significantly so in all years) and remained stable under drought conditions, whereas the decline continued under flooded conditions. For most traits, we found clear indications that the functional diversity also declined under flooded conditions, particularly in near‐stream areas, indicating that fewer strategies succeeded under flooded conditions. Consistent changes in community mean trait values were also identified, but fewer than expected. This can have several, not mutually exclusive, explanations. First, different adaptive strategies may coexist in a community. Second, intraspecific variability was not considered for any of the traits. For example, many species can elongate shoots and petioles that enable them to survive shallow, prolonged flooding but such abilities will not be captured when applying mean trait values. Third, we only followed the communities for 3 years. Flooding excludes species intolerant of the altered hydrology, whereas the establishment of new species relies on time‐dependent processes, for instance the dispersal and establishment of species within the areas. We expect that altered precipitation patterns will have profound consequences for riparian vegetation in temperate Europe. Riparian areas will experience loss of taxonomic and functional diversity and, over time, possibly also alterations in community trait responses that may have cascading effects on ecosystem functioning.
Eugenio Molina-Navarro
added a research item
Abstract Groundwater and surface water are often closely coupled and are both under the influence of multiple stressors. Stressed groundwater systems may lead to a poor ecological status of surface waters but to date no conceptual framework to analyse linked multi-stressed groundwater – surface water systems has been developed. In this paper, a framework is proposed showing the effect of groundwater on surface waters in multiple stressed systems. This framework will be illustrated by applying it to four European catchments, the Odense, Denmark, the Regge and Dinkel, Netherlands, and the Thames, UK, and by assessing its utility in analysing the propagation or buffering of multi-stressors through groundwater to surface waters in these catchments. It is shown that groundwater affects surface water flow, nutrients and temperature, and can both propagate stressors towards surface waters and buffer the effect of stressors in space and time. The effect of groundwater on drivers and states depends on catchment characteristics, stressor combinations, scale and management practises. The proposed framework shows how groundwater in lowland catchments acts as a bridge between stressors and their effects within surface waters. It shows water managers how their management areas might be influenced by groundwater, and helps them to include this important, but often overlooked part of the water cycle in their basin management plans. The analysis of the study catchments also revealed a lack of data on the temperature of both groundwater and surface water, while it is an important parameter considering future climate warming.
Thomas Hein
added a research item
For centuries, rivers have experienced massive changes of their hydromorphic structures due to human activities. The Danube River, the second largest river in Europe, is a case in point for long-term societal imprint. Resulting human-induced pressures are a key issue for river management, aiming to improve the ecological conditions and guarantee the provision of ecosystem services. As the most international river basin in the world, the management of the Danube is particularly challenging and needs a well-organized cooperation of 19 nations. The recent river basin management plan has identified pollution and hydromorphological alterations as most pressing problems, but it has also acknowledged newly emerging issues. In this article, we present 3 specific examples of highly relevant issues for the future river basin management of the Danube: (a) long-term impacts in the catchment such as changes in flood patterns and potential ecological consequences; (b) complex feedback loops linking the spread of neozoa with intertwined stressor responses due to river engineering for different purposes; and (c) linkages between different assessment approaches based on European legal frameworks to analyse the specific pressures at different spatial scales. These examples highlight the need for a more integrated approach in future Danube River Basin management schemes. Furthermore, large-scale effects such as climate change and interactions of multiple pressures need to be addressed in future management to increase resilience of the river system and to allow a sustainable ecosystem-based management of rivers.
Ute Mischke
added a research item
PhytoBasinRisk is a water quality model to simulate the risk of critical phytoplankton biomass and composition in large river basins. The phytoplankton of rivers is expected to be sensitive to multiple pressures driven by human activity: a) changes in nutrient emissions to and resulting concentration in surface water, b) changes in riparian land cover (i.e. shading), and c) climate change effects on discharge, radiation, and water temperature.
Meryem Beklioglu
added 2 research items
Water resources globally are affected by a complexmixture of stressors resulting from a range of drivers, including urban and agricultural land use, hydropower generation and climate change. Understanding how stressors interfere and impact upon ecological status and ecosystem services is essential for developing effective River Basin Management Plans and shaping future environmental policy. This paper details the nature of these problems for Europe'swater resources and the need to find solutions at a range of spatial scales. In terms of the latter, we describe the aims and approaches of the EU-funded project MARS (Managing Aquatic ecosystems and water Resources under multiple Stress) and the conceptual and analytical framework that it is adopting to provide this knowledge, understanding and tools needed to address multiple stressors. MARS is operating at three scales: At the water body scale, the mechanistic understanding of stressor interactions and their impact upon water resources,ecological status and ecosystem services will be examined through multi-factorial experiments and the analysis of long time-series. At the river basin scale, modelling and empirical approaches will be adoptedto characterise relationships between multiple stressors and ecological responses, functions, services and water resources. The effects of future land use and mitigation scenarios in 16 European river basinswill be assessed. At the European scale, large-scale spatial analysiswill be carried out to identify the relationships amongst stress intensity, ecological status and service provision, with a special focus on large transboundary rivers, lakes and fish. The project will support managers and policy makers in the practical implementation of theWater Framework Directive (WFD), of related legislation and of the Blueprint to Safeguard Europe's Water Resources by advising the 3rd River Basin Management Planning cycle, the revision of the WFD and by developing new tools for diagnosing and predicting multiple stressors.
In warm lakes, fish aggregate within macrophytes, thereby weakening the role of these as a daytime refuge for zooplankton and altering the zooplankton size structure, predation pressure, and water clarity. To elucidate the role of macrophytes as a refuge for zooplankton and their effect on zooplankton size distribution, we established three sets of stran-dardized artificial plant beds in 11 lakes in Turkey with contrasting fish predation risk and turbidity. Zoo-plankton were sampled within and outside of each plant beds during day and night. Fish, collected overnight in multimesh-sized gillnets, were abundant both inside and outside the artificial plant beds, impoverishing the usefulness of plants as a daytime refuge for particularly large-bodied zooplankton. Zooplankton size diversity was negatively related to fish abundance. Diel vertical migration was the frequent anti-predator avoidance behavior, but reverse migration was also observed when Chaoborus was present. In contrast to the small-bodied taxa, large-and medium-sized taxa showed intraspecific size-based migration (i.e., individuals of different sizes had different migration patterns). Predators influenced the size structure and diel movement of zooplankton, but the response changed with the size of zooplankton and water clarity.
Tuba Bucak
added 2 research items
Climate change and intense land use practices are the main threats to ecosystem structure and services of Mediterranean lakes. Therefore, it is essential to predict the future changes and develop mitigation measures to combat such pressures. In this study, Lake Beyşehir, the largest freshwater lake in the Mediterranean basin, was selected to study the impacts of climate change and various land use scenarios on the ecosystem dynamics of Mediterranean freshwater ecosystems and the services that they provide. For this purpose, we linked catchment model outputs to the two different processed-based lake models: PCLake and GLM-AED, and tested the scenarios of five General Circulation Models, two Representation Concentration Pathways and three different land use scenarios, which enable us to consider the various sources of uncertainty. Climate change and land use scenarios generally predicted strong future decreases in hydraulic and nutrient loads from the catchment to the lake. These changes in loads translated into alterations in water level as well as minor changes in chlorophyll a (Chl-a) concentrations. We also observed an increased abundance of cyanobacteria in both lake models. Total phosphorus, temperature and hydraulic loading were found to be the most important variables determining cyanobacteria biomass. As the future scenarios revealed only minor changes in Chl-a due to the significant decrease in nutrient loads, our results highlight that reduced nutrient loading in a warming world may play a crucial role in offsetting the effects of temperature on phytoplankton growth. However, our results also showed increased abundance of cyanobacteria in the future may threaten ecosystem integrity and may limit drinking water ecosystem services. In addition, extended periods of decreased hydraulic loads from the catchment and increased evaporation may lead to water level reductions and may diminish the ecosystem services of the lake as a water supply for irrigation and drinking water.
Climate change would augment water scarcity problems in Mediterranean catchments. • Future water level changes was simulated by linking SWAT model to ε-SVR model. • Climate change has a major impact on hydrology while effects of land use are minor. • Outflow management is critical to prevent Mediterranean lakes from diminishing. Inter-and intra-annual water level fluctuations and changes in water flow regime are intrinsic characteristics of Mediterranean lakes. Additionally, considering climate change projections for the water-limited Mediterranean region, increased air temperatures and decreased precipitation are anticipated, leading to dramatic declines in lake water levels as well as severe water scarcity problems. The study site, Lake Beyşehir, the largest freshwater lake in the Mediterranean basin, is – like other Mediterranean lakes – threatened by climatic changes and over-abstraction of water for irrigated crop farming. Therefore, implementation of strict water level management policies is required. In this study, an integrated modeling approach was used to predict the future water levels of Lake Beyşehir in response to potential future changes in climate and land use. Water level estimation was performed by linking the catchment model Soil and Water Assessment Tool (SWAT) with a Support Vector Regression model (ε-SVR). The projected increase in temperature and decrease in precipitation based on the climate change models led to an enhanced potential evapotranspiration and reduced total runoff. On the other hand, the effects of various land use scenarios within the catchment appeared to be comparatively insignificant. According to the ε-SVR model results, changes in hydrological processes caused a water level reduction for all scenarios. Moreover, the MPI-ESM-MR General Circulation Model outputs produced the most dramatic results by predicting that Lake Beyşehir may dry out by the 2040s with the current outflow regime. The results indicate
Raoul-Marie Couture
added a research item
Excess nutrient inputs and climate change are two of multiple stressors affecting many lakes worldwide. Lake Vansjø in southern Norway is one such eutrophic lake impacted by blooms of toxic blue-green algae (cyanobacteria), and classified as moderate ecological status under the EU Water Framework Directive. Future climate change may exacerbate the situation. Here we use a set of chained models (global climate model, hydrological model, catchment phosphorus (P) model, lake model, Bayesian Network) to assess the possible future ecological status of the lake, given the set of climate scenarios and storylines common to the EU project MARS (Managing Aquatic Ecosystems and Water Resources under Multiple Stress). The model simulations indicate that climate change alone will increase precipitation and runoff, and give higher P fluxes to the lake, but cause little increase in phytoplankton biomass or changes in ecological status. For the storylines of future management and land-use, however, the model results indicate that both the phytoplankton biomass and the lake ecological status can be positively or negatively affected. Our results also show the value in predicting a biological indicator of lake ecological status, in this case, cyanobacteria biomass with a BN model. For all scenarios, cyanobacteria contribute to worsening the status assessed by phytoplankton, compared to using chlorophyll-a alone.
Mario Lepage
added 3 research items
A community hosted by an ecosystem composed of species sharing the same characteristics i.e. species showing the same response to the environment and/or species with the same impact on their environment, can be defined as a community with high functional redundancy. Such community is supposed to be less vulnerable to species loss and the ecosystem functioning is also supposed to be less impacted than when communities are composed of species with different functional characteristics. In this work, we first described the fish communities of lakes, rivers and estuaries of France, Spain and Portugal using species richness and functional diversity. Functional diversity was a measure of the extent of complementary among species considering five characteristics previously define by different sources (literature, available database): fish size, vertical position in the water body, spawning habitat, trophic group, and swimming mode. For the three aquatic systems, the number of species and functional diversity was generally higher in northern and western France than in the Mediterranean areas; this geographical pattern was explained by historical events (recolonization after the last glacial period). Higher functional diversity found in estuaries compared to lakes and rivers was explained by the importance of the connectivity between adjacent environments. Analysing correlations between functional redundancy and species richness, results suggest that higher taxonomic richness in freshwater ecosystems is likely to increase the stability and resilience of fish assemblages after environmental disturbance because of higher species redundancy whereas it is not the case in estuaries. Studying the impact of species loss following different scenarios, we also demonstrated that, in rivers and estuaries, rare species support singular ecological functions not shared by dominant species. Our results suggest also that functional diversity of fish assemblages in rivers can be more affected by environmental disturbances than in lakes and estuaries. Finally, using functional redundancy and taxonomic vulnerability, we proposed a composite index of functional vulnerability, minimised for highly redundant assemblages composed of species with low extinction risk. Fish communities of estuarine ecosystems appear less vulnerable to species loss in comparison with assemblages of lakes and rivers. Although these latter systems obtained comparable scores, the functional vulnerability was not influenced by the same component. Fish assemblages in lakes are often redundant but composed of a large part of vulnerable species, whereas river assemblages are in general poorly redundant but composed of species with low intrinsic vulnerability. This new score is proposed to be used in conservation perspective to define management priorities.
Aquatic ecosystems facing multiple stressors lead to challenging conditions for their management, as stressors can have additive, but also interactive effects on organisms, populations and communities. Accounting for these interactions is important in the assessment of the stressor’s impacts and to implement good restoration measures. Using a comparable modelling approach and large environmental and fish databases, the combined effect of water quality problems and hydrological stressors were assessed, based on characteristics of fish assemblages observed in rivers, lakes, reservoirs and estuaries of Europe. The effects of nonnative species in interaction with eutrophication and alteration of hydromorphology were also tested for fish assemblages of natural lakes and reservoirs. We show that for all the water body types, water quality problems are a major threat that impacts fish assemblages. Similarly, alteration of the hydro-morphology explains a large part of the composition of river and estuarine fish assemblages. Conversely, we fail to demonstrate an effect of this stressor on the fish community of lakes and reservoirs, as sufficient data are not available yet. However, in these standing waters the introduction of non-native species can explain the variability of some characteristics of fish assemblages. In a second step, we analysed the interactive effect of various stressors. Without interaction, the effect of two stressors on a fish assemblage characteristic corresponds to the sum of the individual effects. This additive effect was compared with the effects really observed in the assemblages to determine the type of interaction. The comparison was done for each fish assemblage characteristic impacted by stressors in each water body type. A large variability of multi-stressor impacts was observed, leading to higher or lower effects than expected in absence of interactions. These results suggest to consider all potential stressors and interactions in the development of fishbased tools dedicated to ecological status assessment or restoration monitoring whatever the water body type is.
The impact of species loss on ecosystems functioning depends on the amount of trait similarity between species, i.e. functional redundancy, but it is also influenced by the order in which species are lost. Here we investigated redundancy and sensitivity patterns across fish assemblages in lakes, rivers and estuaries. Several scenarios of species extinction were simulated to determine whether the loss of vulnerable species (with high propensity of extinction when facing threats) causes a greater functional alteration than random extinction. Our results indicate that the functional redundancy tended to increase with species richness in lakes and rivers, but not in estuaries. We demonstrated that i) in the three systems, some combinations of functional traits are supported by non-redundant species, ii) rare species in rivers and estuaries support singular functions not shared by dominant species, iii) the loss of vulnerable species can induce greater functional alteration in rivers than in lakes and estuaries. Overall, the functional structure of fish assemblages in rivers is weakly buffered against species extinction because vulnerable species support singular functions. More specifically, a hotspot of functional sensitivity was highlighted in the Iberian Peninsula, which emphasizes the usefulness of quantitative criteria to determine conservation priorities.
Eugenio Molina-Navarro
added a research item
Water pollution and water scarcity are among the main environmental challenges faced by the European Union, and multiple stressors compromise the integrity of water resources and ecosystems. Particularly in lowland areas of northern Europe, high population density, flood protection and, especially, intensive agriculture, are important drivers of water quality degradation. In addition, future climate and land use changes may interact, with uncertain consequences for water resources. Modelling approaches have become essential to address water issues and to evaluate ecosystem management. In this work, three multi-stressor future storylines combining climatic and socio-economic changes, defined at European level, have been downscaled for the Odense Fjord catchment (Denmark), giving three scenarios: High-Tech agriculture (HT), Agriculture for Nature (AN) and Market-Driven agriculture (MD). The impacts of these scenarios on water discharge and inorganic and organic nutrient loads to the streams have been simulated using the Soil and Water Assessment Tool (SWAT). The results revealed that the scenario-specific climate inputs were most important when simulating hydrology, increasing river discharge in the HT and MD scenarios (which followed the high emission 8.5 representative concentration pathway, RCP), while remaining stable in the AN scenario (RCP 4.5). Moreover, discharge was the main driver of changes in organic nutrients and inorganic phosphorus loads that consequently increased in a high emission scenario. Nevertheless, both land use (via inputs of fertilizer) and climate changes affected the nitrate transport. Different levels of fertilization yielded a decrease in the nitrate load in AN and an increase in MD. In HT, however, nitrate losses remained stable because the fertilization decrease was counteracted by a flow increase. Thus, our results suggest that N loads will ultimately depend on future land use and management in an interaction with climate changes, and this knowledge is of utmost importance for the achievement of European environmental policy goals.
Eugenio Molina-Navarro
added a research item
Automatic calibration of complex hydro-ecological models is an increasingly important issue which involves making decisions. One of the most relevant is the choice of the objective function, but its effects have been scarcely studied in complex models. We have used the SWAT model to assess the impact of the objective function for a multi-site (4 stations) and multi-variable (OrgP, OrgN, NO3⁻, PO4³⁻) calibration of the Odense catchment (Denmark). Six calibration schemes were tested, varying the objective function and the nutrient fractions targeted. The best performance metrics (R², NSE, PBIAS) were obtained when using NSE as objective function and targeting N-fractions and P-fractions separately. The scheme was validated in another SWAT set-up in northern Denmark. Although NSE is often questioned, we found it as an adequate objective function when addressing a multi-site and multi-variable calibration. Our findings may serve as guideline for hydro-ecological modellers, being useful to achieve watershed management goals.
Leoni Mack
added a research item
Part 1: This deliverable consists two manuscripts (MS) of lake time-series analysis in north-temperate region of Europe. 1st MS: ‘Is fish able to regulate filamentous blue-green dominated phytoplankton?’ submitted to ‘Hydrobiologia’, analyzes >40-year data on biota, fish catches, hydrochemistry, hydrology, and meteorological parameters in Lake Võrtsjärv, a large and shallow eutrophic lake in Estonia. The lake has intensive commercial fisheries with well documented catches for all commercial fish species. The impact of commercial fisheries on the ecological status of lakes has been poorly studied and in most cases fish as a biological quality element is omitted in water bodies with commercial fisheries. Based on our previous knowledge we assumed that the effect of different fisheries management strategies in Võrtsjärv on water quality is negligible due to the weakly operating grazing food chain. Present study showed, however, that predatory fish (pikeperch) could have a cascading impact down the food web in this lake that has to be considered in fisheries management. As we showed, the recently introduced legal requirement to sort and report on small fish in fishery statistics has caused extensive back-release of small fish by fishermen and was one of the likely reasons why the amount of small fish, including small bream, has sharply increased in the lake. The fishery management measures that could increase small plankti- and benthivorous fish biomass have to be avoided as having a cascading negative effect on the ecosystem health of Lake Võrtsjärv. 2nd MS: ‘Climate change, cyanobacteria blooms and ecological status of lakes: a Bayesian network approach’ accepted for publication in ‘Ecological Modelling’ addresses eutrophication and harmful cyanobacterial blooms as major challenges for management of aquatic ecosystems, which are expected to be reinforced by climate change. A Bayesian network (BN) modelling approach was applied to assess the impact of future scenarios of climate change and land-use management to ecological status incorporating cyanobacteria biomass as one of the indicators. The BN was able to model effects of climate change and management on ecological status of case study Lake Vansjø in Norway, by combining scenarios, process-based model output, monitoring data and the national lake assessment system. The results showed that the benefits of better land-use management were partly counteracted by future warming under these scenarios. BN demonstrated the importance of including more biological indicators in the modelling of lake status. E.g. the inclusion of cyanobacteria biomass allowed better predict the ecological status compared to assessment by phytoplankton biomass alone. Thus, the BN approach can be a useful supplement to process-based models for water resource management. Part 2: The balance between gross primary production (GPP) and ecosystem respiration (ER) determines the metabolic status of lakes. As an integrative quantity, the metabolic status is an important indicator of lake function and can have a decisive influence on the role of lakes in regional and global matter cycling. Lake metabolism is influenced by environmental conditions such as light, mixing depth, nutrients and temperature – drivers predicted to be affected by climate change. This delivery include result from two comprehensive experimental studied conducted to improve our understanding of these driving factors on the metabolic status of shallow lakes and their role in the carbon cycle. In both studies the focus is on the effects of nutrients at contrasting climate conditions. One of the studies is published in Global Change Biology (IF 8.02) in December 2015 and the other is under review after revision in the same journal. Paper 1 (under review). This study is a pan-European space-for-time mesocosm experiment running from May until November 2011 (run as part of the REFRESH project, finished during the MASRS project) and involved six lakes, covering a temperature gradient from Sweden to Greece. The experiment comprised two nutrient levels (mesotrophic or eutrophic) crossed with two water levels (1 and 2 m) to simulate different light regimes and mixing depths. In situ GPP and ER were estimated using the O2 free-water method. GPP and ER were significantly higher in the eutrophic mesocosms than in mesotrophic mesocosms, whereas the shallow mesocosms had significantly higher volumetric metabolic rates but lower area-based metabolic rates than the deep mesocosms. GPP and ER increased exponentially with temperature. Temperature gains of ~0.53 eV for GPP and ~0.65 eV for ER were comparable with those predicted by metabolic theory. All systems switched from autotrophy to heterotrophy over the investigated temperature range. The threshold temperature for the switch in metabolic status was, however, lower under mesotrophic (~16 °C) than eutrophic conditions (~22 °C). Contrary to expectations, no significant interactions between temperature, nutrients and depth were observed for GPP and ER. Overall, we quantified the differential temperature sensitivity of GPP and ER and found that trophic state is crucial for how much warming a system can tolerate before it switches from net auto- to net heterotrophy. Paper 2 published in December 2015). This study focuses on greenhouse gas (GHG) emissions, based on the fact that fresh waters make a disproportionately large contribution to greenhouse gas (GHG) emissions, with shallow lakes being particular hotspots. How GHG fluxes from shallow lakes are altered by climate change may have profound implications for the global carbon cycle. Empirical evidence for the temperature dependence of the processes controlling GHG production in natural systems is largely based on the correlation between seasonal temperature variation and seasonal change in GHG fluxes. However, ecosystem-level GHG fluxes could be influenced by factors, which whilst varying seasonally with temperature are actually either indirectly related (e.g. primary producer biomass) or largely unrelated to temperature, for instance nutrient loading. As part of the Danish Climate change effect project Deliverable 3.1: Manuscripts on time series and temperature effects (CRES) and MARS a one year study of GHG emission was conducted in the longest running shallow-lake mesocosm system. This system consists of twenty-four fully mixed, outdoor, flowthrough mesocosms (diameter 1.9 m, water depth 1 m, retention time ~2.5 months). The one year GHG study run in 2013 demonstrated that nutrient concentrations override temperature as a control of both the total and individual GHG flux. Furthermore, testing for temperature treatment effects at low and high nutrient levels separately showed only one, rather weak, positive effect of temperature (CH4 flux at high nutrients). In contrast, at low nutrients, the CO2 efflux was lower in the elevated temperature treatments, with no significant effect on CH4 or N2O fluxes. Further analysis identified possible indirect effects of temperature treatment. For example, at low nutrient levels increased macrophyte abundance was associated with significantly reduced fluxes of both CH4 and CO2 for both total annual flux and monthly observation data. As macrophyte abundance was positively related to temperature treatment, this suggests the possibility of indirect temperature effects, via macrophyte abundance, on CH4 and CO2 flux. These findings indicate that fluxes of GHGs from shallow lakes may be controlled more by factors indirectly related to temperature, in this case nutrient concentration and the abundance of primary producers. Thus, at ecosystem scale response to climate change may not follow predictions based on the temperature dependence of metabolic processes.
Leoni Mack
added 12 research items
Summary D5.1-1 Part 1: Multi-stressors on surface water and effects on ecological statusHumans have increased the discharge of pollution, altered water flow regime and modified the morphology of rivers. All these actions have resulted in multiple pressures on freshwater ecosystems, undermining their biodiversity and ecological functioning. The European Union has adopted an ambitious water policy to reduce pressures and achieve a good ecological status for all water bodies. However, assessing multiple pressures on aquatic ecosystemsand understanding their combined impact on the ecological status is challenging, especially at the large scale, though crucial to the planning of effective policies. Here, for the first time, we quantify multiple human pressures and their relationship with the ecological status for all European rivers. We considered ecological data collected across Europe and pressures assessed by pan-European models, including pollution, hydrological and hydromorphological alterations. We estimated that in one third of EU’s territory rivers are in good ecological status. We found that better ecological status is associated with the presence of natural areas in floodplains, while urbanisation and nutrient pollution are important predictors of ecological degradation. We explored scenarios of improvement of rivers ecological status for Europe. Our results strengthen the need to halt urban land take, curb nitrogen pollution and maintain and restore nature along rivers. Summary D5.1-1 Part 2: Analysis of pressure -response relations: classification of multiple pressures on broad river typesFor this deliverable a unique and comprehensive collation of input data were derived. Information from different data sources, in varying formats, spatial resolution, comprising information on hydrology, physico-chemical water quality, geo-morphological characteristics, ecological status and other, were harmonized and merged to an extended database. The data were derived for about 100,000 sub-catchments (FECs) covering Europe, EFTA states and further, hydrologically connected areas to the east. From this database pressure indicators were deduced and statistically compared to the ecological status reported by the EU-countries. An important and novel indicator is the impact of hydrological alteration on major flow characteristic like base flow, floods or duration of low flows. These were derived by comparing modelled flows for current conditions and for seminatural conditions. The goal was identifying the most explanatory pressure indicators impeding a good ecological status. First, the general statistics on the distribution of all pressure indicators were conducted, secondly, the pressure indicators were compared to the ecological status as assessed in 1st River Basin Management Plan (RBMP). Importance of pressures for supportinggood ecological state varies a lot among river types and regions in Europe. On large rivers, chemical stressors, percentage of broad leaved forest and share of agricultural land in floodplain are three most important pressures. On lowland, medium to largerivers, high flow hydrological characteristics become very important also. Share of coniferous forest in floodplain is important pressure in mid altitude rivers, whereas base flow and oxygen demanding substances are important for highland rivers. Our results also suggest, that diffuse pollution of nutrients and decrease of riparian vegetation at present do not support good ecological status mainly in the Mediterranean and Atlantic regions. In the Central and Baltic region, the most important cause for a deterioration of ecological status is the combination of diffuse pollution of nutrients and hydrological alterations. In the Eastern Continental region all three types of pressures, namely, hydrological, morphological and chemical are equally important. Classification of multiple pressures on European broad rive types presented here is closely related to JRC work (Grizzetti et al., 2017) and NTUA work (MARS, 2017) in the same work package of the MARS project. JRC has unveiled patterns between human pressures and ecological status of European rivers in non -stratified manner. NTUA has analysed relation of low flows and ecological flows (E-flows) to ecological status and contributed data for hydrological pressures. This contribution is very important, sincein our study we indeed show that hydrological pressures are very important, and in some regions and river types even prevail over morphological pressures. Our results serve as an input to scenario analysis tool at the European scale (namely work package 7.4) and will be expanded with additional data and expert knowledge. Summary D5.1-1 Part 3: Multiple stressors and groundwater status analysis and statistical modelling at the European scaleThe aim of the work is to analyse groundwater status and stressors (pressures) relevant for groundwater using available data at European scale reported by European countries (WISE-WFD and WISE-SoE datasets managed by the EEA). In particular, a definition of spatial extent of ground waters in poor status, acting single stressors (pollution, abstraction, saltwater intrusion) and stressor combinations including an identification of prevailing pollutants causing failure of good groundwater status. The aim of the statistical analysis is to use simple statistical models to investigate the large-scale pressures on the chemical status and quantitative status of groundwater reported by European Union Member states. In particular, to see if it is possible to use these models to investigate and understand any interactions between different pressures on groundwater status. The analysis of stressors and status shows that prevailing stressor causing failure of good groundwater status is pollution, followed by groundwater abstraction. Pollution in combination with groundwater abstraction appears to be most common stressor combination in Europe. Salt water intrusion is almost always associated with groundwater abstraction or/and pollution, but it does not take place in all coastal areas. The most common type of groundwater pollutants are agrochemicals (nutrients and pesticides) affecting whole Europe and especially agricultural areas. When assessing pesticide pollution at European scale, one must take into account a bias induced by various monitoring strategies used by countries, there is lack of comparable data on pesticide metabolites that may occur more frequently and in higher concentrations than parentpesticides. EU WFD common implementation strategy does not assure sufficient harmonization of monitoring strategies among EU member states preventing comparable pan-European assessments. The study demonstrated how ‘data-led’ methods, such as stepwise regression, can be used to suggest and estimate models of groundwater status. However, we note that they should be used with caution as such approaches can include spurious relationships which result from not accounting for multiple hypothesis tests. Only limited interactions have been investigated to date, however, there is some evidence for a synergistic interaction between arable farming and winter precipitation (when the regression does not include country as a random effect) on the chemical status of groundwater. There is, however, less confidence in the results of models of groundwater quantitative status which appears, as may be expected, to be largely driven by weather variables. Summary D5.1-2: Relation of low flows, E-flows, and Ecological StatusThe present report ‘Relation of low flows, E-flows, and Ecological Status’ presents a European scale analysis of hydrologic data at the resolution of the Functional Elementary Catchment (FEC). Simulated daily time-series of river flows from the PCR-GLOBWB global model were used based on a hypothetic near-natural scenario where water abstractions from water bodies do not exist and an anthropogenic scenario with water abstractions occurring.The latter practically represents the reality. Many hydrologic indicators expressing the characteristics of the rivers’ hydrologic regime were calculated for all FECs with the Indicators of Hydrologic Alteration (IHA) methodology and software package and the deviations of the indicators’ values between the two scenarios were used as proxy metrics of hydrologic alteration or hydrologic stress of rivers. Regressions between indicators with the rather limited dataset of EQR values of two BQEs (macroinvertebrates and phytobenthos) showed insignificant or very weak relationships when processed with the entire dataset for Europe or separately for each of the 20 Broad River Types (BRTs). However, by conducting two examples at smaller scales (catchment or region) with better ecological response datasets clearer relationships were found.Hydrologic alteration metrics were averaged per BRT without reference to any ecological response not showing remarkable hydrologic stress in certain BRTs or considerable differences in the degree of alteration among the various BRTs. Clearer results could be indicated by mapping the hydrologic alteration on Europe’s geographical background. The mapped indicators, especially some of those connected with low flow conditions were the most informative showing that Southern Europe is more hydrologically stressed due to groundwater abstractions for irrigation. In the rest of Europe hydrologic conditions change less frequently within a single year and a multi-year period. The determination of a minimum ecological flow connected with good ecological status needs further research with updated datasets, but the water community can already take advantage of the results produced herein to obtain a view of hydrologic stress in Europe, identify significant hydrologic stress on a local basis and try to interpret the impacts of this stress on river’s ecology with the use of appropriate response data. Summary D5.1-3: Impact of multi-stressors on ecosystem services and their monetary valueWhich are the ecosystem services (i.e. the contribution of nature to human well-being) provided by European rivers, lakes, and coastal waters? Can we map and quantify them? Do enhanced ecosystem conditions and biodiversity support higher benefits for people? These are the questions addressed in this research. We quantify the main ecosystem services provided by aquatic ecosystems at the European scale, including fish provisioning, water provisioning, water purification, erosion prevention, flood protection, coastal protection, and recreation. These services are provided by aquatic ecosystems, such as lakes, rivers, groundwater and coastal waters. We show European maps of ecosystem service capacity, flow (actual use), sustainability or efficiency and, when possible, benefit. Our results indicate that the ecosystem services are mostly positively correlated with the ecological status of European water bodies (that is a measure of the ecosystem integrity and biodiversity), except for water provisioning, which strongly depends on the climatic and hydrographic characteristics of river basins. We also highlight how provisioning services can act as pressures on the aquatic ecosystems. Based on the relationship between ecosystem status and delivery of services, we explore qualitatively the expected changes of ecosystem services under scenarios of increase in different pressures. Finally, we perform an economic valuation of the ecosystem services provided by European lakes, considering the current conditions and scenarios of improvement of the ecological status. Using a benefit transfer approach, we estimate that the average economic value of ecosystem services delivered by a European lake is 2.92 million EUR per year. We also demonstrated that the ecological status of lake has an impact on valuation. The expected benefit from restoring all European lakes into at least a moderate ecological status is estimated to be 5.9 billion EUR per year, which corresponds to 11.7 EUR per person and per year. Quantifying and valuing ecosystem services helps to recognise all the benefits that humans receive from nature, offering stronger arguments to protect and restore ecosystems and thus fostering the implementation of the European water policy. This study offers scientific evidence to this aim. Summary D5.1-4: Effects of multiple stressors on ecosystem structure and services of phytoplankton and macrophytes in European lakesThe aim of this deliverable was to assess the impacts of multiple stressors on lake ecosystems at the European scale. We have examined ecological responses of two main biological groups (quality elements), namely algae (phytoplankton) and other aquatic plants (macrophytes), to a range of stressor combinations in large populations of lakes. Moreover, the impacts of future multiple stressor scenarios -future climate and nutrient concentrations -have been assessed for a phytoplankton communtity index. While nutrients are a key stressor in all regions of Europe, MARS also focuses on the following key environmental changes for specific regions: water scarcity and flow alterations (Southern Europe); changes in hydrology and morphology (Central Europe); and changes in hydrology and temperature (Northern Europe). More specifically, the stressors that have been investigated in this report are related to increased air temperature and precipitation, hydropower and water abstraction for irrigation and public water supply, hydrological changes (flushing or water level changes), salinisation, or increase in humic substances (“brownification”). We have analysed effects on ecological status (ecological quality ratio values), and in addition a set of indicators of environmental stressors for both biological quality elements. For phytoplankton, the main indicators analysed were chl-a, abundance of cyanobacteria (a group of potentially harmful algae) and PTI (phytoplankton trophic index). For macrophytes, the main indicators were the water-drawdown index (WIc) for regulated lakes, a proportion of macrophyte coverage (%PVI), and other indices based on specific species or species groups. Interactions within the lake community, including also zooplankton (small crustaceans), were addressed by analysis of data from mesocosms across Europe.Potential effects of multiple stressors on ecosystem services (e.g. nutrient retention, nutritional value of fish, and cultural services to lake visitors) have also been investigated by case studies and national datasets. The main large-scale data sourcesused in our studies include the European Environment Agency's WISE-SoE datasets (Waterbase), data compiled during previous EU projects (WISER), and national monitoring data. Moreover, information on lake and catchment characteristics (such as land use) was obtained from the MARS geodatabase. The natural characteristics of lakes (such altitude, surface area, mean depth, alkalinity and humic level) were explicitly considered in most of the studies, either as co-variables or as determinands of lake types. The analysis of EEA's water quality data in combination with land use data showed that, not surprisingly, total phosphorus (P) concentration in lakes clearly increased and Secchi depth (transparency) generally decreased with increasing proportion of arable and pasture lands in lake catchments across Europe. Total P was the stressor that correlated best with ecological status of phytoplankton, while Secchi depth better explained the ecological status of macrophytes. Climatic variables such as air temperature and precipitation, in contrast, had apparently no effect on the ecological status. This result does not contradict that climate change may cause additional stress for lake ecosystem. Instead, the space-for-time approach (using geographic variation in climate as a substitute for temporal variation) in these analyses may not be the most appropriate for detecting real effects of climate change. For the individual phytoplankton indicators (cyanobacteria and PTI), interactions between effects of nutrients and climatic stressors (temperature and/or precipitations) were found for some of the lakes or lake types. For example, the analysis of time series indicated that cyanobacteria are most favoured by nutrient stress in lakes of low nutrient status and sensitive to summer rainfall in short residence time lakes. However, the studies also revealed large variation in the combined stressor effects among the different lakes types. It was therefore difficult to generalise such results across lake types. For the PTI index(Northern Europe), the strongest interaction between nutrients and temperature stress was found for lowland siliceous lakes. We used this empirical relationship to predict the future PTI scores for this lake type under the MARS future climate scenarios. According to our model, increased temperature and precipitation will result in higher PTI scores, indicating impaired ecological status. In the short term (2030), however, climate-induced changes in PTI will probably not be sufficient to change the ecological status class of lakes (e.g., from Good to Moderate). The analysis of Mediterranean (Turkish) lakes suggest that warming together with expected changes in land use in this regions may result in higher salinisation and eutrophication with more frequent cyanobacteria blooms and loss of biodiversity. Consequently, under such conditions, the ecosystem services potential (e.g. drinking and irrigation water, biodiversity etc.) are likely to be deteriorated if not lost completely. To counteract, stricter control of nutrients emissions and human use of water is urgently needed. The interactions between nutrients and climatic stressors could most clearly be interpreted from the experimental data based on former mesocosm experiments. For example, these experimental results indicate that global climate warming might favour growth of macrophytes at moderate water level decrease southern regions, even under relatively eutrophic conditions. However, if the water level decrease becomes so extreme that macrophytes are directly negatively affected, and longer and intense drought periods become more common, the combined effects of eutrophication and extreme water level reductions may adversely affect the development of macrophytes. In contrast, warmer temperatures in northern regions may hamper macrophyte growth due to increased precipitation and, thus increased water levels and nutrient loading. The MARS project have resulted in much new information on the combined effect of eutrophication and climate change and their interactions on trophic structure and dynamics -showing that combined effects through a series of cascading events can lead to deterioration in water quality and ecological status -there are still some knowledge gaps to be filled. Knowledge on differences ininteractions along altitude, latitude and other biogeographical gradients are needed before firm and safe conclusions relevant for managers and WFD can be drawn. We also need more knowledge on the resilience of lake community structure and dynamics to extreme climatic events such as heat waves, drought, and heavy rainfall, since we can expect an increase of such events. Summary D5.1-5: New functional diversity indices allowing assessing vulnerability in abiotic multi-stressor contextA community hosted by an ecosystem composed of species sharing the same characteristics i.e. species showing the same response to the environment and/or species with the same impact on their environment, can be defined as a community with high functional redundancy. Such community is supposed to be less vulnerable to species loss and the ecosystem functioning is also supposed to be less impacted than when communities are composed of species with different functional characteristics. In this work, we first described the fish communities of lakes, rivers and estuaries of France, Spain and Portugal using species richness and functional diversity. Functional diversity was a measure of the extent of complementary among species considering five characteristics previously define by different sources (literature, available database): fish size, vertical position in the water body, spawning habitat, trophic group, and swimming mode. For the three aquatic systems, the number of species and functional diversity was generally higher in northern and western France than in the Mediterranean areas; this geographical pattern was explained by historical events (recolonization after the last glacial period). Higher functional diversity found in estuaries compared to lakes and rivers was explained by the importance of the connectivity between adjacent environments. Analysing correlations between functional redundancy and species richness, results suggest that higher taxonomic richness in freshwater ecosystems is likely to increase the stability and resilience of fish assemblages after environmental disturbance because of higher species redundancy whereas it is not the case in estuaries. Studying the impact of species loss following different scenarios, we also demonstrated that, in rivers and estuaries, rare species support singular ecological functions not shared by dominant species. Our results suggest also that functional diversity of fish assemblages in rivers can be more affected by environmental disturbances than in lakes and estuaries. Finally, using functional redundancy and taxonomic vulnerability, we proposed a composite index of functional vulnerability, minimised for highly redundant assemblages composed of species with low extinction risk. Fish communities of estuarine ecosystems appear less vulnerable to species loss in comparison with assemblages of lakes and rivers. Although these latter systems obtained comparable scores, the functional vulnerability was not influenced by the same component. Fish assemblages in lakes are often redundant but composed of a large part of vulnerable species, whereas river assemblages are in general poorly redundant but composed of species with low intrinsic vulnerability. This new score is proposed to be used in conservation perspective to define management priorities.
Deliverable D4.1 is a synthesis report of the 16 regional case studies being undertaken in WP4 (Multi-stressors at the river basin scale. The report is composed of 3 parts. Part 1: Task 4.2 - Southern Basins region Part 1 reports the background to, and results and conclusions from Task 4.2 on four case studies from the Southern Basins region. The four Southern Basins included in this report are: Lower Danbe (Romania); Lake Beyşehir (Turkey), Pinios (Greece), Sorraia (Portugal). In fact, the Southern group includes also the Nervión case study (Spain), which however will be reported in another Deliverable of MARS due to the special focus of the work on estuaries. The work described in this report was undertaken between February 2013 and July 2016. Part 2: Task 4.3 - Central Basins region Part 2 reports the background to, and results and conclusions from Task 4.3 on the 6 case studies from the Central Basins region. The six Central Basins are: the Drava (Austria); Elbe, Haval and Saale (Germany), Odense (Denmark); Thames (United Kingdom); Regge and Dinkel (Nederland); and, the Ruhr (Germany). The work described in this report was undertaken between February 2013 and July 2016. Part 3: Task 4.4 - Northern Basins region Part 3 reports the background to, and results and conclusions from Task 4.4 on the 6 case studies from the Northern Basins region. The Northern Basins are: the Otra and the Vansjø-Hobøl Norway), the Kokemäenjoki river basin, the Lepsämänjoki and Lake Pääjärvi catchments (Finland), lake Võrtsjärv (Estonia) and the Welsh basins (Wales). The work described in this report was undertaken between February 2013 and July 2016.
This deliverable investigates the impacts of changes in hydrology and nutrients on ecosystem structure and function of Mediterranean shallow lakes by using long term monitoring data of two lakes (Lakes Mogan and Eymir) and paleolimnological records of six lakes from Turkey. The first two papers are on Lakes Eymir and Mogan, which are two inter-connected lakes in Central Anatolia situated in a cold dry steppe climate. Both papers used 20 years of monitoring data. Manuscript 1 focused on annual and seasonal water and nutrient (TP, SRP, DIN, TN) budgets of the two lakes and highlighted the impacts of water balance on eutrophication of Mediterranean shallow lakes. It was published in Science for the Total Environment in April 2016. Manuscript 2 focused on understanding the impacts of nutrient concentrations and hydrological conditions (e.g. water level fluctuation and hydraulic retention time) on lake restoration efforts, which included sewage effluent diversion and biomanipulation in a relatively deep and shallow Mediterranean lake. This paper is out online in February 2017 in the open access journal Water. The third and fourth manuscirpts provide long-term paleoecological data to infere the impact of past environmental changes using a paleolimnological approach with single or multiple proxies. In Manuscript 3, the Cladocera sub-fossils community assemblage was used to explain ecological changes that took place in three Anatolian lakes (Lakes Eymir, Mogan and Gölhisar), which are located in Mediterranean climatic zones. Sub-fossil cladoceran remains provide a good indicator of key environmental changes including water level, eutrophication and salinization. This manuscript has been published in Hydrobiologia in November 2015. Manuscript 4 used multi- proxy data of Cladocera, Diatom, pigment, plant macrofossil as well as XRF-determined minerals to trace the impacts of lake-level changes on benthic-pelagic primary and secondary productions over the last 50-100 years in three Turkish shallow lakes. It was published in Palaeogeography, Palaeoclimatology, Palaeoecology in March 2016.
Raoul-Marie Couture
added 3 research items
We constructed a model chain into which regional climate-related variables (air temperature, precipitation) and a lake’s main tributary hydrological indicators (river flow, dissolved inorganic carbon) were employed for predicting the evolution of planktonic blue-green algae (cyanobacteria) and zooplankton (rotifer) biomass in that lake for the mid-21st century. Simulations were based on the future climate predicted under both the Representative Concentration Pathways 4.5 and 8.5 scenarios which, combined with three realistic policy-making and basin land-use evolution lead to six scenarios for future water quality. Model outputs revealed that mean annual river flow is expected to decline between 3 to 20%, depending of the scenario. Concentration of river dissolved inorganic carbon is predicted to follow the opposite trend and might soar up to twice the 2005-2014 average concentration. Lake planktonic primary producers will display quantitative changes in the future decades whereas zooplankters will not. A 2 to 10% increase in mean cyanobacteria biomass is accompanied by a stagnation (-3 to +2%) of rotifer biomass. Changes in cyanobacteria and rotifer phenology are expected: a surge of cyanobacteria biomass in winter and a shortening of the rotifer biomass spring peak. The expected quantitative changes on the biota were magnified in those scenarios where forested area conversion to cropland and water abstraction were the greatest.
AbstractMany surface waters in Europe suffer from the adverse effects of multiple stresses. The Otra River, southernmost Norway, is impacted by acid deposition, hydropower development and increasingly by climate change. The river holds a unique population of land-locked salmon and anadromous salmon in the lower reaches. Both populations have been severely affected by acidification. The decrease in acid deposition since the 1980s has led to partial recovery of both populations. Climate change with higher temperatures and altered precipitation can potentially further impact fish populations. We used a linked set of process-oriented models to simulate future climate, discharge, and water chemistry at five sub-catchments in the Otra river basin. Projections to year 2100 indicate that future climate change will give a small but measureable improvement in water quality, but that additional reductions in acid deposition are needed to promote full restoration of the fish communities. These results can help guide management decisions to sustain key salmon habitats and carry out effective long-term mitigation strategies such as liming. The Otra River is typical of many rivers in Europe in that it fails to achieve the good ecological status target of the EU Water Framework Directive. The programme of measures needed in the river basin management plan necessarily must consider the multiple stressors of acid deposition, hydropower, and climate change. This is difficult, however, as the synergistic and antagonistic effects are complex and challenging to address with modelling tools currently available.
Tano Gutiérrez-Cánovas
added 6 research items
Networks of protected areas represent one of the main strategies to reduce the rapid loss of biodiversity. However, most of these protected areas have been designed by considering only charismatic groups of vertebrates and plants, most linked to terrestrial environments. Thus, little is known about how well protected areas perform in representing aquatic biodiversity. This study analyses the suitability of national and European protected area networks (Natural Protected Areas and Natura 2000) in representing such biodiversity. For this purpose, we studied the different components of diversity (α, β and γ) using water beetles from the Segura River Basin as surrogates of overall macroinvertebrate biodiversity. Our results revealed no significant differences in α-diversity between protected and non-protected areas. Similarly, we did not find significant differences in β-diversity components (species replacement and nestedness, i.e., differences in among-site richness without species replacement) between protected and non-protected areas. The species replacement contributed more than nestedness to explain overall β-diversity changes. Finally, we found that the γ-diversity component was significantly higher in both protected areas, when compared to an equivalent number of randomly selected locations. Thus, the protected area networks from the Segura River Basin currently seem to have gaps in embracing the different aquatic biodiversity components. These results for river management and biodiversity conservation are discussed, providing some guidelines for future research.
Leoni Mack
added 3 research items
The implementation of successful external communication is a key to achieving the main objectives of the MARS project. In particular, the cooperation with related EU funded research projects plays a central role. In the first project months, a list of external projects relevant to MARS was prepared, aiming at maintaining this list over the full project duration. Amongst these external activities we identified three partner projects of specific importance to MARS, as their aims particularly match with the objectives of our project: GLOBAQUA, SOLUTIONS and OpenNESS. The contact with these projects was established at an early stage, inviting the coordinators to the MARS kick-off workshop in February 2014. Extensive consultations with each project coordinator resulted in detailed plans for cooperation. These plans are descripted in this report. Another objective of the MARS communication and dissemination is to provide clear answers to major stakeholders on how to manage water bodies exposed to multiple pressures. To close the gap between science and policy, and to avoid information overload, the MARS dissemination strategy aims to combine target groups, suitable products and arenas for dialogue and communication. The key stakeholders are river basin managers (particularly in the 16 case study catchments), national environmental agencies responsible for WFD implementation, WFD-CIS groups and MAES freshwater group, DG Environment and EEA. As an external information channel for a broader audience a project website was set up, together with state-of-the-art communication tools and intranet facilities for storing all project-relevant files. A popular science blog, reaching up to 3,000 readers per month, with weekly posts was successfully taken over from the BioFresh project, and is now operated by the project. Additionally, new and social media channels are fed to reach the public. Finally, the draft for a general information platform for the freshwater scientific community is presented. In this contribution we present a future outlook on establishing a ‘global network for freshwater scientists’, targeting at the sustainable onward use of already developed tools and data collections. The principal objective is to merge and synthesise the available information generated by various EU funded projects related to freshwater research.
This deliverable is composed of four chapters describing products of the MARS project, which will contribute to harmonize the outcome of the experiments (WP3), of the catchment modelling (WP4) and of the large-scale data analysis (WP5). All these work areas address the effects of multiple stressors on water resources and aquatic ecosystems, but are using different approaches, targeting different stressor combinations and response variables. To ensure that the outcome is suited for a meta-analysis across approaches, scales, stressors and variables several underlying procedures were harmonized; that’s what this deliverable is about. Part 1: Review of multiple stressors and their effects on European surface waters Part 1 reviews the effects of multiple stressors on rivers, lakes, groundwaters and coastal ecosystems, based on a thorough literature analysis. Despite the existence of a huge conceptual knowledge base in aquatic ecology, only few studies provide quantitative evidence on multiple stress effects. Two-stressor combinations were addressed most frequently. Over all biological groups analyzed, the strength of the pressure-response relationships increased with increasing number of stressors considered in lakes and rivers, but the response remained unclear in transitional and coastal waters. Biological groups responded generally very differently to increasing complexity of stress. Part 2: Cook-book for ecosystem service assessment and valuation in European water resource management Part 2 first addresses current approaches towards ecosystem service assessment and valuation and provides an overview of ecosystem services evaluated in the MARS experiments, catchment models and large-scale data analysis. Finally, a procedure towards ecosystem service assessment to be applied in MARS is described, which comprises four steps: Scoping of the analysis, development of the integrated assessment framework, biophysical quantification of ecosystem services, and economic valuation of ecosystem services. The procedure is exemplified for a number of case study catchments. Part 3: Framework to select indicators of multi-stressor effects for European river basin management Part 3 describes a set of “benchmark indicators”, i.e. response variable to be addressed in the experiments, catchment modelling and large-scale data analysis. These indicators allow for a streamlined analysis of multi-stressor effects across the different spatial scales and environmental conditions targeted in MARS. The benchmark indicators mainly comprise simple metrics and indices of abiotic and biotic ecosystem properties, covering physico-chemical, hydrological and riparian features of the water body and selected attributes of its biological community. The indicators are known to respond to anthropogenic pressure. They are applicable in various geographical contexts and to different water categories and types of water bodies. Part 4: Report on the MARS scenarios of future changes in drivers and pressures with respect to Europe’s water resources Part 4 describes storylines outlining future changes regarding (i) main drivers in the economy, (ii) economic growth, (iii) policies regarding the environment, and (iv) public concern about the environment and protection of ecosystem services. This contribution establishes the baseline for simulating future scenarios at both basin and European scale. Various future climatic and socio- economic scenarios were chosen to define three storylines at the European level. Several projects and modeling tools were reviewed with the aim of identifying quantitative data fitting the selected storylines. Suitable data were collated and can now be used by the subsequent MARS work packages to drive the simulations of the three storylines.
The implementation of successful external communication is a key to achieving the main objectives of the MARS project. In particular, the cooperation with related EU funded research projects plays a central role. In the first project months, a list of external projects relevant to MARS was prepared, aiming at maintaining this list over the full project duration. Amongst these external activities we identified three partner projects of specific importance to MARS, as their aims particularly match with the objectives of our project: GLOBAQUA, SOLUTIONS and OpenNESS. The contact with these projects was established at an early stage, inviting the coordinators to the MARS kick-off workshop in February 2014. Extensive consultations with each project coordinator resulted in detailed plans for cooperation. These plans are descripted in this report. Another objective of the MARS communication and dissemination is to provide clear answers to major stakeholders on how to manage water bodies exposed to multiple pressures. To close the gap between science and policy, and to avoid information overload, the MARS dissemination strategy aims to combine target groups, suitable products and arenas for dialogue and communication. The key stakeholders are river basin managers (particularly in the 16 case study catchments), national environmental agencies responsible for WFD implementation, WFD-CIS groups and MAES freshwater group, DG Environment and EEA. As an external information channel for a broader audience a project website was set up, together with state-of-the-art communication tools and intranet facilities for storing all project-relevant files. A popular science blog, reaching up to 3,000 readers per month, with weekly posts was successfully taken over from the BioFresh project, and is now operated by the project. Additionally, new and social media channels are fed to reach the public. Finally, the draft for a general information platform for the freshwater scientific community is presented. In this contribution we present a future outlook on establishing a ‘global network for freshwater scientists’, targeting at the sustainable onward use of already developed tools and data collections. The principal objective is to merge and synthesise the available information generated by various EU funded projects related to freshwater research.
Mario Lepage
added 4 research items
The life history strategies of fishes can be defined by specific combinations of demographic traits that influence species performances depending on environmental features. Hence, the constraints imposed by the local conditions restrict the range of successful strategies by excluding species poorly adapted. In the present study, we compared the demographic strategies of fish caught in 47 estuaries of the North East Atlantic coast, aiming to determine the specific attributes of resident species and test for changes in trait associations along the environmental gradients. Eight demographic traits were considered to project our findings within a conceptual triangular model, composed on three endpoint strategies: (i) periodic (large size, long generation time, high fecundity); (ii) opportunistic (small size, short generation time, high reproductive effort); and (iii) equilibrium (low fecundity, large egg size, parental care). We demonstrated that various life history strategies co-exist in estuaries, but equilibrium species were scarce and restricted to euhaline open-water. Resident species form a specialised assemblage adapted to high spatiotemporal variability of estuarine conditions, i.e. opportunistic attributes associated with parental care. Even with these singular attributes, our findings revealed changes in distribution of resident species across the estuarine gradients linked to their life history traits. Among other patterns, the diversity of life history strategies significantly decreased from euhaline to oligohaline areas and along gradient of human disturbances. These trends were associated with a convergence of species traits toward short generation times, suggesting that long-lived species with late maturation are more severely impacted by disturbance and environmental stress.
Estuaries are subjected to multiple anthropogenic stressors, which have additive, antagonistic or synergistic effects. Current challenges include the use of large databases of biological monitoring surveys (e.g. the European Water Framework Directive) to help environmental managers prioritizing restoration measures. This study investigated the impact of nine stressor categories on the fish ecological status derived from 90 estuaries of the North East Atlantic countries. We used a random forest model to: 1) detect the dominant stressors and their non-linear effects; 2) evaluate the ecological benefits expected from reducing pressure from stressors; and 3) investigate the interactions among stressors. Results showed that largest restoration benefits were expected when mitigating water pollution and oxygen depletion. Non-additive effects represented half of pairwise interactions among stressors, and antagonisms were the most common. Dredged sediments, flow changes and oxygen depletion were predominantly implicated in non-additive interactions, whereas the remainder stressors often showed additive impacts. The prevalence of interactive impacts reflects a complex scenario for estuaries management; hence, we proposed a step-by-step restoration scheme focusing on the mitigation of stressors providing the maximum of restoration benefits under a multi-stress context.
Sebastian Birk
added a project goal
+ To understand the effects of multiple stressors on surface waters and groundwaters, their biota, and the services they provide to humans.
+ To understand how ecological status and ecosystem services are related – if at all.
+ To advise river basin management how to restore multiply stressed rivers and lakes.
+ To advise the revision of the Water Framework Directive on new indicators for ecological status and ecosystem services.
+ To develop methods and software for the Programmes of Measures.