| 1. |
- Bring, Arvid, et al.
(författare)
-
Effects on groundwater storage of restoring, constructing or draining wetlands in temperate and boreal climates: a systematic review
- 2022
-
Ingår i: Environmental Evidence. - : Springer Science and Business Media LLC. - 2047-2382. ; 11:1
-
Forskningsöversikt (refereegranskat)abstract
- Drainage activities have caused widespread wetland loss, groundwater drawdown and impairment of ecosystem services. There are now several national programs for wetland restoration, primarily focused on reintroducing ecosystem services such as habitats and nutrient retention. In Sweden, recent dry summers have also reinforced interest in hydrological functions such as the potential for enhanced groundwater storage, both in and around the wetland. However, there are several knowledge gaps regarding groundwater storage effects of restoration, including if they extend beyond the wetland and how they vary with local conditions. Therefore, we have systematically reviewed groundwater storage effects from the interventions of restoring, constructing or draining boreo-temperate wetlands. Drainage was included primarily to evaluate to what degree restoration can reverse drainage effects. Methods: We searched 8 databases for scientific journal publications in English, Swedish, Norwegian, Danish, French, German and Polish. Gray literature was searched in English and Swedish. Articles were included based on their relevance for Swedish conditions, i.e., in previously glaciated areas with boreal or temperate climate. Extracted outcome data were groundwater level changes, along with other variables including type of wetland and intervention and, when reported, distance between sampling point and intervention. Meta-analyses were conducted separately for studies that reported groundwater levels at different distances and studies that reported overall effects. Included studies were subject to critical appraisal to evaluate their susceptibility to bias, primarily selection bias, performance bias, and detection bias. Critical appraisal results were used in sensitivity analysis. Review findings: Out of 11,288 screened records, 224 articles fulfilled the criteria, and from these, 146 studies were included in meta-analysis. Most studies (89%) investigated peatlands, primarily from Finland, the UK and Canada. Restoration and drainage studies were equally common. Only nine studies reported measurements beyond the wetland area. Our synthesis is therefore primarily focused on effects within wetlands. In peatland restoration, the observed groundwater level rise decreased exponentially with distance from the restored ditch and was reduced to 50% after 9 [95% confidence interval: 5, 26] m. Drainage reached somewhat farther, with 50% of the groundwater drawdown remaining at 21 [11, 64] m. On average, restoration increased groundwater levels by 22 [16, 28] cm near the intervention, whereas drainage caused a drawdown of 19 [10, 27] cm. Assuming that sampling was unbiased, effects were similar for bogs, fens and mires. Restricting the meta-analysis to the 58% of studies that were of high validity did not alter conclusions. Conclusions: Effects of peatland restoration and drainage were of similar magnitudes but opposite directions. This indicates that, on average, rewetting of drained peatlands can be expected to restore groundwater levels near the ditch. However, restoration may not reach all the area affected by drainage, and there was a strong dependence on local context. For managers of wetland projects, it is thus important to follow up and monitor restoration effects and reinforce the intervention if necessary. Our results also point to a need for better impact evaluation if increased storage beyond the restored wetland area is desired.
|
|
| 2. |
- Chen, Wenjun, et al.
(författare)
-
A typological framework of non-floodplain wetlands for global collaborative research and sustainable use
- 2022
-
Ingår i: Environmental Research Letters. - : IOP Publishing. - 1748-9326. ; 17:11
-
Forskningsöversikt (refereegranskat)abstract
- Non-floodplain wetlands (NFWs) are important but vulnerable inland freshwater systems that are receiving increased attention and protection worldwide. However, a lack of consistent terminology, incohesive research objectives, and inherent heterogeneity in existing knowledge hinder cross-regional information sharing and global collaboration. To address this challenge and facilitate future management decisions, we synthesized recent work to understand the state of NFW science and explore new opportunities for research and sustainable NFW use globally. Results from our synthesis show that although NFWs have been widely studied across all continents, regional biases exist in the literature. We hypothesize these biases in the literature stem from terminology rather than real geographical bias around existence and functionality. To confirm this observation, we explored a set of geographically representative NFW regions around the world and characteristics of research focal areas. We conclude that there is more that unites NFW research and management efforts than we might otherwise appreciate. Furthermore, opportunities for cross-regional information sharing and global collaboration exist, but a unified terminology will be needed, as will a focus on wetland functionality. Based on these findings, we discuss four pathways that aid in better collaboration, including improved cohesion in classification and terminology, and unified approaches to modeling and simulation. In turn, legislative objectives must be informed by science to drive conservation and management priorities. Finally, an educational pathway serves to integrate the measures and to promote new technologies that aid in our collective understanding of NFWs. Our resulting framework from NFW synthesis serves to encourage interdisciplinary collaboration and sustainable use and conservation of wetland systems globally.
|
|
| 3. |
- Scaini, Anna, 1985-, et al.
(författare)
-
Water Availability and Land Management Control Catchment-Scale Agricultural Nitrogen and Phosphorous Use Efficiencies
- 2023
-
Ingår i: Global Biogeochemical Cycles. - 0886-6236 .- 1944-9224. ; 37:1
-
Tidskriftsartikel (refereegranskat)abstract
- In arable systems, large amounts of nutrients, particularly of nitrogen (N) and phosphorus (P), are not efficiently converted into harvestable products and are lost from agricultural systems, with negative consequences for agricultural productivity and the environment. These nutrient losses are mediated by hydroclimatic processes causing nutrient leaching and volatilization. We quantify over the period 1987-2012 how water availability through the evaporative ratio (actual evapotranspiration divided by precipitation) and irrigation, agricultural practices, and edaphic conditions jointly affect nutrient use efficiencies in 110 agricultural catchments in the United States. We consider N and P use efficiencies (nitrogen use efficiency [NUE] and phosphorous use efficiency [PUE]) defined as ratios of catchment-scale N and P in harvested products over their respective inputs, as well as the NUE/PUE ratio, as an indication of catchment-scale N and P imbalance. Both efficiencies increase through time because of changes in climate and agronomic practices. Setting all else at the median value of the data set, NUE and PUE increased with evaporative ratio by 0.5% and 0.2% when increasing the evaporative ratio by 20% and by 4.9% and 18.8% in the presence of irrigation. NUE was also higher in catchments where maize and soybean were dominant (increasing by 2.3% for a 20% increase in maize and soybean fractional area). Soil properties, represented by mineral soil texture and organic matter content, had only small effects on the efficiencies. Our results show that both climatic conditions and crop choice are important drivers of nutrient use efficiencies in agricultural catchments.
|
|
| 4. |
- Thorslund, Josefin, 1988-
(författare)
-
Hydrological spreading of metal pollution and wetlands as nature-based solutions
- 2017
-
Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- The quality of the Earth’s water resources have deteriorated due to human impacts. A key scientific challenge is to understand, quantify and predict the water-borne spreading of pollutants at relevant scales for freshwater management and water quality restoration programs. However, understanding the natural processes controlling large-scale hydrological transport of pollutants may be masked by river regulation schemes (in the form of dams and reservoirs), which are common in many large rivers. The main objective of this thesis is to increase the current knowledge regarding large-scale spreading of metals in hydrological systems. This objective is addressed through studying net impacts of mining (a main contributor to global metal pollution) on the spreading of metals in water systems and through investigating the mitigation opportunities of wetlands across the landscape. The main study region of this thesis is the Lake Baikal basin of Russia and Mongolia, which includes the large unregulated Selenga River and its delta-wetland areas. In addition, a set of global wetland sites are also studied. A multi-method approach is used in the four studies of this thesis. The methods include field-measurements, data synthesis, metal mass flow and water flow-path quantifications, as well as geochemical modelling. Results show that mining in the upstream part of the Lake Baikal basin is a significant contributor to riverine mass flows of several metals. The mass flows increased by an order of magnitude over the mining site. The observed speciation between dissolved (more bioavailable) and suspended (less bioavailable) phases could be well predicted for some metals (Fe, V, Pb and Zn) using a geochemical equilibrium model. However, the model failed to reproduce the speciation of other metals (Cr, Cu, Mn and Mo). In these cases, non-equilibrium processes may need to be considered, and adsorption databases may need to be developed, in order to make dependable predictions. Results also suggest that the concentration of dissolved organic carbon, which exhibits seasonal variability and long-term increasing trends due to climate change effects in the Arctic, can have a large impact on metal pollution transport. Further, observations showed that individual wetlands of the Selenga River delta locally retained between 77-99 % of incoming metal loads. However, a systematic analysis of current knowledge showed that large-scale net effects can differ considerably from the functions observed at individual wetlands on smaller scales. Along large-scale flow-paths, through which wetlands are connected with each other as well as with the larger landscape, key processes which can considerably contribute to such scale differences in function may occur. A survey of the current wetland research showed that relatively few studies have considered the larger scales at which key pollutant pressures and water quality changes take place. This thesis highlights the need for more research on large-scale wetland systems, which can aid in evaluating net pollution effects at landscape scales. This in turn can facilitate evaluations of how and when wetland systems may function as large-scale nature-based solutions.
|
|
| 5. |
- Thorslund, Josefin, 1988-, et al.
(författare)
-
Salinity impacts on irrigation water-scarcity in food bowl regions of the US and Australia
- 2022
-
Ingår i: Environmental Research Letters. - : IOP Publishing. - 1748-9326. ; 17:8
-
Tidskriftsartikel (refereegranskat)abstract
- Irrigation water use and crop production may be severely limited by both water shortages and increased salinity levels. However, impacts of crop-specific salinity limitations on irrigation water scarcity are largely unknown. We develop a salinity-inclusive water scarcity framework for the irrigation sector, accounting for crop-specific irrigation water demands and salinity tolerance levels and apply it to 29 sub-basins within two food bowl regions; the Central Valley (CV) (California) and the Murray–Darling basin (MDB) (Australia). Our results show that severe water scarcity (levels >0.4) occurs in 23% and 66% of all instances (from >17 000 monthly crop-specific estimates) for the CV and MDB, respectively. The highest water scarcity levels for both regions occurred during their summer seasons. Including salinity and crop-specific salinity tolerance levels further increased water scarcity levels, compared to estimations based on water quantity only, particularly at local sub-basin scales. We further investigate the potential of alleviating water scarcity through diluting surface water with lower saline groundwater resources, at instances where crop salinity tolerance levels are exceeded (conjunctive water use). Results from the CV highlights that conjunctive water use can reduce severe water scarcity levels by up to 67% (from 946 monthly instances where surface water salinity tolerance levels were exceeded). However, groundwater dilution requirements frequently exceed renewable groundwater rates, posing additional risks for groundwater depletion in several sub-basins. By capturing the dynamics of both crops, salinity and conjunctive water use, our framework can support local-regional agricultural and water management impacts, on water scarcity levels.
|
|
| 6. |
- Van Vliet, Michelle T. H., et al.
(författare)
-
Global river water quality under climate change and hydroclimatic extremes
- 2023
-
Ingår i: Nature Reviews Earth & Environment. - 2662-138X. ; 4, s. 687-702
-
Forskningsöversikt (refereegranskat)abstract
- Climate change and extreme weather events (such as droughts, heatwaves, rainstorms and floods) pose serious challenges for water management, in terms of both water resources availability and water quality. However, the responses and mechanisms of river water quality under more frequent and intense hydroclimatic extremes are not well understood. In this Review, we assess the impacts of hydroclimatic extremes and multidecadal climate change on a wide range of water quality constituents to identify the key responses and driving mechanisms. Comparison of 965 case studies indicates that river water quality generally deteriorates under droughts and heatwaves (68% of compiled cases), rainstorms and floods (51%) and under long-term climate change (56%). Also improvements or mixed responses are reported owing to counteracting mechanisms, for example, increased pollutant mobilization versus dilution during flood events. River water quality responses under multidecadal climate change are driven by hydrological alterations, rises in water and soil temperatures and interactions among hydroclimatic, land use and human drivers. These complex interactions synergistically influence the sources, transport and transformation of all water quality constituents. Future research must target tools, techniques and models that support the design of robust water quality management strategies, in a world that is facing more frequent and severe hydroclimatic extremes.
|
|
| 7. |
- Åhlén, Imenne, et al.
(författare)
-
Wetland position in the landscape : Impact on water storage and flood buffering
- 2022
-
Ingår i: Ecohydrology. - : Wiley. - 1936-0584 .- 1936-0592. ; 15:7
-
Tidskriftsartikel (refereegranskat)abstract
- On-going climatic changes and land-use changes may impact water storage dynamics within wetlandscapes (defined as the entire hydrological catchments of interconnected wetland systems). These dynamics are closely linked to many wetland ecosystem services including flood buffering, nutrient retention and biodiversity support. Here, we investigate if and how current water storage dynamics can differ between wetlands within the same wetlandscape. Based on continuous monitoring of water levels in multiple wetlands throughout a growing season (spring, summer, autumn) in Vattholma, Sweden, we show that there are two distinct storage behaviours depending on the position of the wetland within the landscape. Headwater wetland regions were active in temporary storage of surplus water from regular summer rains while water levels of downstream wetlands dropped to seasonal low values without responding to individual summer precipitation events. Thereby, the downstream wetlands maintained capacity to buffer extreme floods. We also found that headwater wetlands were associated with complex and patchy inundation, which causes habitat conditions to vary over short time scales both within and among these wetlands, in contrast to the prolonged low-water state of the downstream wetlands. These differences between headwater-downstream wetlands imply that the functionality of an entire wetlandscape cannot be assessed by simple extrapolation of data from monitoring stations that typically are located downstream of headwater regions. Increased understanding of these differences can support wetland management practices that target location-specific nature-based solutions and ecosystem services.
|
|
