Impact and mitigation of global change on freshwater-related ecosystem services in Southern Europe

Assembling the climate story: use of storyline approaches in climate-related science

Storylines are introduced in climate science to provide unity of discourse, integrate the physical and socioeconomic components of phenomena, and make climate evolution more tangible. The use of this concept by multiple scholar communities and the novelty of some of its applications renders the concept ambiguous nonetheless, because the term hides behind a wide range of purposes, understandings, and methodologies. This semi-systematic literature review identifies three approaches that use storylines as a keystone concept: scenarios-familiar for their use in IPCC reports-discourse-analytical approaches, and physical climate storylines. After screening peer-reviewed articles that mention climate and storylines, 270 articles are selected, with 158, 55, and 57 in each category. The results indicate that each scholarly community works with a finite and different set of methods and diverging understandings. Moreover, these approaches have received criticism in their assembly of storylines: either for lacking explicitness or for the homogeneity of expertise involved. This article proposes that cross-pollination among the approaches can improve the usefulness and usability of climate-related storylines. Among good practices are the involvement of a broader range of scientific disciplines and expertise, use of mixed-methods, assessment of storylines against a wider set of quality criteria, and targeted stakeholder participation in key stages of the process.

Exposure to global change pressures and potential impacts on ecosystem services of mountain lakes in the European Alps

Mountain lakes are increasingly affected by global change pressures. While there is growing evidence of impacts on ecosystem functioning, few studies considered changes in ecosystem services (ES). This study aimed (1) to examine the exposure of small and natural mountain lakes in the European Alps to global change pressures and (2) to estimate potential impacts on six relevant ES considering future climate projections and potential changes in water use. For 2455 lakes, we mapped the level of exposure to global change pressures, including climate change, atmospheric nutrient deposition, and anthropogenic activities (e.g., water use). Our results indicate that more than half of the Alpine mountain lakes feature a considerable level of exposure to global change. Hotspot analysis revealed spatial clusters of lakes with above-average exposure (23.7% of all lakes), mostly located in the central part of the Alps, while lakes with below-average exposure level prevailed in the south-western (19.3%) and eastern parts (10.6%). For 15 case study lakes, we quantified potential impacts on six key ES. The results revealed, in particular, potential negative effects on maintaining habitat and populations as well as aesthetic value, but contrastingly, also some positive effects for outdoor recreation, research and education. Our findings suggest the need for a comprehensive integration of mountain lakes into current management and policy frameworks to ensure the ecological integrity and ES provision of mountain lakes. Interdisciplinary mountain lake research will be important to overcome uncertainties related to the coupling of limnological parameters and ES indicators.

Evaluation of InVEST’s Water Ecosystem Service Models in a Brazilian Subtropical Basin

The biophysical modeling of water ecosystem services is crucial to understanding their availability, vulnerabilities, and fluxes. Among the most popular models, the Integrated Valuation of Ecosystem Services and Trade-offs (InVEST) models stand out. While many studies have used them, few have assessed their performance. This study evaluates the performance of InVEST’s Seasonal Water Yield, Nutrient Delivery Ratio, and Sediment Delivery Ratio models in a subtropical basin in southeastern Brazil on temporal and spatial scales, using 39 years of streamflow data, 29 for total phosphorus and total nitrogen, and 19 for total suspended solids. Statistical indicators R2, PBIAS, and NSE, were also calculated. The performance of the models varied according to the type of simulated WES and analysis scales used, with the Seasonal Water Yield model demonstrating the best performance and effectively representing the spatial and temporal variability of the average annual streamflow. All models performed well in simulating long-term mean values when compared to observed data. While one should bear in mind the study’s limitations, the results indicate that the models perform well in terms of relative magnitude, although their application in studies involving water-resource management and decision making is limited.

Impacts of Future Climate and Land Use/Cover Changes on Water-Related Ecosystem Services in Changbai Mountains, Northeast China

Sustaining ecosystem services in alpine regions is a pressing global challenge given future accelerating environmental changes. Understanding how future climate change and land use/cover change (LUCC) drive ecosystem service will be important in this challenge. However, few studies have considered the combined effects of future climate change and LUCC on ecosystem services. We assessed water yield and soil retention services and their drivers in the Changbai mountains region (CBMR) from the 2020 to 2050s using the Integrated Valuation of Ecosystem Services and Trade-offs (InVEST) model and factor control experiments. Water yield decreased by 2.80% and soil retention increased by 6.14% over the 30 years. Climate change decreased water yield and increased soil retention, while LUCC decreased both water yield and soil retention. The interactive effects between climate change and LUCC had relatively small inhibitory effects on water yield and large facilitation effects on soil retention. Changes in water yield were mainly attributed to climate change, while soil retention was largely influenced by interaction. Our study highlights the individual and interactive contributions of future climate change and land use to ecosystem service in the mountains region, which can provide important information for informed future land management and policy making for sustaining diverse ecosystem services.

Assessing the effect of catchment characteristics to enhanced coagulation in drinking water treatment: RSM models and sensitivity analysis

Coagulation is the main process for removing natural organic matter (NOM), considered to be the major disinfection by-products (DBPs) precursor in drinking water production. In this work, k-means clusters analysis were used to classify influent waters from two different surface drinking water treatment plants (DWTPs) located in the Mediterranean region. From this, enhanced coagulation models based on response surface methodology (RSM) were then developed to optimise coagulation at two water catchments (river and reservoir). The cluster analysis classified the water quality of the raw waters into two groups related to baseline and peak organic loads. The developed enhanced coagulation models were based on the turbidity, total organic carbon (TOC) and UV₂₅₄ removals. Sensitivity analysis applied to the models (after predictors selection) determined the factors relative individual contributions for each DWTP scenario. Then, profile plots for enhanced coagulation were studied to identify the optimal levels for each case. Models mean R² were 0.85 and 0.86 in baseline and 0.85 and 0.84 in peak scenario for river and reservoir catchments, respectively. Results of this study indicate that the surface water quality variation in river DWTP is seasonal and is expressed by an increase of turbidity, while in the reservoir DWTP is related to extreme weather events showing high levels of dissolved organic load (TOC and UV₂₅₄). During baseline cases, where raw waters present low levels of organics, the three factors optimal adjustment should be ensured to optimise coagulation. Then, during peak scenarios, where influent waters present high organics, the optimal for enhanced coagulation relies on the correct adjustment of C_d. The presented work provides models for drinking water production aimed to propose the optimum conditions for enhanced coagulation, considering the influent water characteristics under different weather conditions.

Ecosystem service potential, flow, demand and their spatial associations: a comparison of the nutrient retention service between a human- and a nature-dominated watershed

Nutrient regulation is an important ecosystem regulating service in watersheds. However, systematic investigations of the spatial associations between the potential, flow, and demand of the nutrient regulation service are still lacking. Therefore, we performed a case study comparing the total phosphorus (TP) retention in the Dianchi Lake (DL) watershed (human-dominated) with that in the Lower Reach of the Zi River (LRZR) watershed (nature-dominated). We used four indicators-TP retention potential, TP retention, TP load, and TP export-to represent the potential, flow, demand, and flow-demand budget of the TP retention service, respectively. We estimated the TP retention and export using the InVEST tool, mapped the four TP indicators and calculated their correlations, and estimated the contributions of different ecosystem types and terrain ranges to TP retention and export. We determined the following: (1) the incongruity between the spatial distribution of the TP retention potential and the other three TP indicators was smaller in the LRZR watershed than in the DL watershed; (2) the TP retention potentials generally increased-while the other three TP indicators decreased-with increases in the elevation gradient in the DL watershed and the slope gradients in both study areas; and (3) paddy fields exhibited the highest TP retention intensity and residential areas exhibited the highest TP export intensity among the major ecosystem types in both study areas. Moreover, the TP retention intensities of dryland crops and residential areas in the DL watershed were much higher than they were in the LRZR watershed. Our findings imply that the flow of the nutrient retention service is influenced more by the service demand than by the service potential and that it is influenced by both landscape composition and pattern. Because of the limitations and uncertainties in the modeling outputs, our results should be carefully used in other studies or in decision-making.

Determining the contributions of climate change and human activities to vegetation dynamics in agro-pastural transitional zone of northern China from 2000 to 2015

The vegetation in the agro-pastoral transitional zone of northern China (APTZNC) was significantly restored, and both climate change and ecological restoration projects contributed to vegetation activities with varied proportion. Since few decades ago, APTZNC has undergone significant land degradation and climate change, threatening regional sustainable development, and in response to such ecological crises, multiple ecological restoration projects were implemented, which have caused a profound impact on the terrestrial ecosystem. Taking agro-pastural transitional zone of northern China (APTZNC) as the study area, this study used 16-year (2000-2015) net primary productivity (NPP) as an important indicator of the arid and semi-arid ecosystem's productivity, combing meteorological data in same period to (1) monitor the vegetation dynamics affected by both climate and ecological restoration projects; (2) detect climate changing trend, including annual precipitation, air temperature, and sunlight hours; (3) explicitly distinguish driving forces of climate change and ecological restoration projects on vegetation dynamics based on correlation analysis. The results demonstrated that (1) the annual NPP indicated overall greening (48.77% significant restoration) and partial degradation (0.39% significant degradation) in APTZNC; (2) the annual precipitation was the main factor that widely influences vegetation growth, and the area with significant influence accounted for 55.53%; however, the area with significant temperature influence only accounted for 1%, and the area affected significantly by sunshine hours accounted for 14.33%; (3) In the area of significant greening with proportion of 48.77%, of 26.93% was related to climate change, of 19.80% was related to ecological conservation programs, and of 2.05% was related to multiple factors. In the significantly degraded area with proportion of 0.39%, of 0.1% is related to climate change and of 0.29% is abnormally degraded. Our study is expected to accelerate the understanding of vegetation dynamics and its driving mechanisms, and provide support for scientifically formulating and adjusting ecological restoration projects in APTZNC.

Alien animal introductions in Iberian inland waters: An update and analysis

Inland waters provide innumerable ecosystem services and for this reason are among the most negatively impacted ecosystems worldwide. This is also the case with invasive alien species, which have enormous economic and ecological impacts in freshwater ecosystems. The pace of alien introductions has not decreased in recent years and the first step to their management is to update checklists and to determine introduction pathways and origins of species. This study updates the list of alien animal species introduced and naturalised in inland waters of the Iberian Peninsula. Additionally, the most relevant characteristics and association patterns of these species (region of origin, taxonomic group, introduction pathway and main habitat) and introduction trends in the Iberian Peninsula, mainland Portugal and Galicia are analysed. We identified 125 alien animal species introduced in Iberian inland waters (increase of 30% compared to previous reviews) whereas 24 additional species have uncertain establishment or native status. We found marked associations among taxonomic groups and their region of origin, introduction pathway and main habitat used but less relationship between these three latter features. Considering the whole territory of the Iberian Peninsula, the introduction rates seem to be experiencing a decrease or to have achieved stabilization. However, this is not applicable to mainland Portugal and Galicia for which the historical delay in the first record dates for alien species is fading-out, suggesting increasing spread rates. Our results should facilitate early detections and the design of prevention protocols and taxon-specific management plans.

Independence of Future Changes of River Runoff in Europe from the Pathway to Global Warming

The outcomes of the 2015 Paris Agreement triggered a number of climate impact assessments, such as for floods and droughts, to focus on future time frames corresponding to the years of reaching specific levels of global warming. Yet, the links between the timing of the warming levels and the corresponding greenhouse gas concentration pathways to reach them remain poorly understood. To address this gap, we compared projected changes of annual mean, extreme high, and extreme low river discharges in Europe at 1.5 °C and 2 °C under Representative Concentration Pathways RCP8.5 and RCP4.5 from an ensemble of regional climate model (RCM) simulations. The statistical significance of the difference between the two scenarios for both warming levels was then evaluated. The results show that in the majority of Europe (>95% of the surface area for the annual mean discharge, >98% for high and low extremes), the changes projected in the two pathways were statistically indistinguishable. These results suggest that in studies of changes at global warming levels, the projections of the two pathways can be merged into a single ensemble without major loss of information. With regard to the uncertainty of the unified ensemble, the findings show that the projected changes of annual mean, extreme high, and extreme low river discharge were statistically significant in large portions of Europe.

Spatio-temporal and cumulative effects of land use-land cover and climate change on two ecosystem services in the Colombian Andes

Climate change can have marked effects on ecosystem service (ES) provision in the Andes, particularly in peri-urban areas. In addition to global-change related processes, cumulative effects such as changing socio-political dynamics, environmental policies, and conflicts are also changing type and magnitude of land use-land cover (LULC) dynamics in the Colombian Andes. Studies in the region have investigated the effects of LULC change, deforestation and extreme climatic events on the hydrology of watersheds and carbon sequestration. Yet, less is known on how the cumulative effects of climate and LULC changes will drive water yield and carbon sequestration. To investigate these cumulative effects, we study two different watersheds near Bogota, Colombia and their ES for the period 2016-2046. We use IPCC-LULC scenarios, expert elicitation, hydro-meteorological data, and integrated modelling using temporal LULC change and ESs valuation models to parse out effects of LULC versus climate change on two representative ESs. Our results show forest and shrublands remain stable during the analysis period. However, urban conversion of agricultural pastures is substantial. We found that climate change scenarios had greater effect on water yield and supply than LULC scenarios in both watersheds. However, carbon sequestration was greater in rural forest and shrubland areas farther from Bogota. In contrast to current land use zoning being promoted by local elected officials, our findings indicate that land-use development and policies in near-urban basins need to minimize urbanization in agriculture and pasture LULCs, as these can have substantial effects on water yield. Similarly, land use polices in ex-urban areas need to conserve forested and shrubland areas to maximize their carbon offset potential. Collectively, our results highlight the need to incorporate climate change conditions in decision making and land use planning processes, in order to maintain the capacity of ecosystems, both urban and rural, to provide services to society.

Assessing Freshwater Provision and Consumption in the Alpine Space Applying the Ecosystem Service Concept

A key challenge in the sustainable management of freshwater is related to non-stationary processes and transboundary requirements. The assessment of freshwater is often hampered due to small-scale analyses, lacking data and with the focus on only its provision. Based on the ecosystem service (ES) concept, this study aims at quantitatively comparing potential water supply with the demand for freshwater in the European Alps and their surrounding lowlands. We propose an easy-to-use combination of different mapping approaches, including a large-scale hydrologic model to estimate water supply and the downscaling of regional data to the local scale to map demand. Our results demonstrate spatial mismatches between supply and demand and a high dependency of the densely populated lowlands from water providing mountain areas. Under expected climate variations and future demographic changes, our results suggest increasing pressures on freshwater in the south of the Alps. Hence, sustainable water management strategies need to assure the supply of freshwater under changing environmental conditions to meet the increasing water demand of urbanized areas in the lowlands. Moreover, national water management strategies need to be optimally concerted at the international level, as transboundary policies and frameworks can strengthen future water provision.