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Nilsson, Christer
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Publications (10 of 139) Show all publications
Nilsson, C., Muotka, T., Timm, H. & Malmqvist, B. (2022). The Fennoscandian Shield (2 uppl.ed.). In: Klement Tockner; Christiane Zarfl; Christopher T. Robinson (Ed.), Rivers of Europe: (pp. 453-494). Elsevier
Open this publication in new window or tab >>The Fennoscandian Shield
2022 (English)In: Rivers of Europe / [ed] Klement Tockner; Christiane Zarfl; Christopher T. Robinson, Elsevier, 2022, 2 uppl., p. 453-494Chapter in book (Refereed)
Abstract [en]

The Fennoscandian Shield encompasses roughly the northern half of Sweden, all of Finland, and the westernmost part of European Russia, ranging in northern latitudes between 60 and 70 degrees, and intersecting the Arctic Circle. This region also represents the westernmost extension of the taiga biome and is well within the boreal zone, covering a tetragon-shaped area between longitude 11 degrees (southwest) and 41 degrees east (northeast). Bedrock is Precambrian, dating back 1.7-1.9 billion years and including metasedimentary, metavolcanic rocks and several generations of granitoids. Even older (2.5-3.1 billion years) rocks (mainly gneisses and greenstone belts) characterize the Archean geological province in northern Finland and Kola Peninsula. These rocks often are overlaid by moraines shaped by erosion of repeated glacial events into a hilly landscape with numerous lakes and watercourses. Most rivers flow into the Baltic and its fringing bays. In Sweden, originating in the mountain chain along the border to Norway, rivers generally flow in an easterly or south-easterly direction, whereas Finnish rivers flow westward, or southward into the Gulf of Finland. The Koutajoki is the exception and drains in an easterly direction into the White Sea. At a mean annual discharge of >2500 m3/s, the Neva River, draining Lake Ladoga, the largest lake in Europe, is the largest river on the Fennoscandian Shield.

Place, publisher, year, edition, pages
Elsevier, 2022 Edition: 2 uppl.
Keywords
Biodiversity, Geological province, Geomorphology, Human colonization, Human impact, Hydrology, Land use, Physiography
National Category
Geology
Identifiers
urn:nbn:se:umu:diva-194440 (URN)10.1016/B978-0-08-102612-0.00008-0 (DOI)2-s2.0-85128571243 (Scopus ID)9780081026120 (ISBN)9780081026137 (ISBN)
Available from: 2022-05-05 Created: 2022-05-05 Last updated: 2022-05-05Bibliographically approved
Thieme, M. L., Tickner, D., Grill, G., Carvallo, J. P., Goichot, M., Hartmann, J., . . . Opperman, J. (2021). Navigating trade-offs between dams and river conservation. Global Sustainability, 4, Article ID e17.
Open this publication in new window or tab >>Navigating trade-offs between dams and river conservation
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2021 (English)In: Global Sustainability, E-ISSN 2059-4798, Vol. 4, article id e17Article, review/survey (Refereed) Published
Abstract [en]

Non-technical summary There has been a long history of conflicts, studies, and debate over how to both protect rivers and develop them sustainably. With a pause in new developments caused by the global pandemic, anticipated further implementation of the Paris Agreement and high-level global climate and biodiversity meetings in 2021, now is an opportune moment to consider the current trajectory of development and policy options for reconciling dams with freshwater system health. Technical summary We calculate potential loss of free-flowing rivers (FFRs) if proposed hydropower projects are built globally. Over 260,000 km of rivers, including Amazon, Congo, Irrawaddy, and Salween mainstem rivers, would lose free-flowing status if all dams were built. We propose a set of tested and proven solutions to navigate trade-offs associated with river conservation and dam development. These solution pathways are framed within the mitigation hierarchy and include (1) avoidance through either formal river protection or through exploration of alternative development options; (2) minimization of impacts through strategic or system-scale planning or re-regulation of downstream flows; (3) restoration of rivers through dam removal; and (4) mitigation of dam impacts through biodiversity offsets that include restoration and protection of FFRs. A series of examples illustrate how avoiding or reducing impacts on rivers is possible - particularly when implemented at a system scale - and can be achieved while maintaining or expanding benefits for climate resilience, water, food, and energy security. Social media summary Policy solutions and development pathways exist to navigate trade-offs to meet climate resilience, water, food, and energy security goals while safeguarding FFRs.

Place, publisher, year, edition, pages
Cambridge University Press, 2021
Keywords
water security, ecology and biodiversity, energy, policies, politics and governance, planning and design
National Category
Environmental Sciences Ecology Oceanography, Hydrology and Water Resources
Identifiers
urn:nbn:se:umu:diva-191633 (URN)10.1017/sus.2021.15 (DOI)000684585600001 ()2-s2.0-85116315775 (Scopus ID)
Available from: 2022-01-20 Created: 2022-01-20 Last updated: 2023-10-25Bibliographically approved
Bejarano, M. D., Garcia-Palacios, J. H., Sordo-Ward, A., Garrote, L. & Nilsson, C. (2020). A New Tool for Assessing Environmental Impacts of Altering Short-Term Flow and Water Level Regimes. Water, 12(10), Article ID 2913.
Open this publication in new window or tab >>A New Tool for Assessing Environmental Impacts of Altering Short-Term Flow and Water Level Regimes
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2020 (English)In: Water, E-ISSN 2073-4441, Vol. 12, no 10, article id 2913Article in journal (Refereed) Published
Abstract [en]

The computational tool InSTHAn (indicators of short-term hydrological alteration) was developed to summarize data on subdaily stream flows or water levels into manageable, comprehensive and ecologically meaningful metrics, and to qualify and quantify their deviation from unaltered states. The pronunciation of the acronym refers to the recording interval of input data (i.e., instant). We compared InSTHAn with the tool COSH-Tool in a characterization of the subdaily flow variability of the Colorado River downstream from the Glen Canyon dam, and in an evaluation of the effects of the dam on this variability. Both tools captured the hydropeaking caused by a dam operation, but only InSTHAn quantified the alteration of key flow attributes, highlighting significant increases in the range of within-day flow variations and in their rates of change. This information is vital to evaluate the potential ecological consequences of the hydrological alteration, and whether they may be irreversible, making InSTHAn a key tool for river flow management.

Place, publisher, year, edition, pages
MDPI, 2020
Keywords
fluvial ecosystems, hydropeaking, InSTHAn tool, short-term flow regimes, subdaily flows, sustainable river management
National Category
Oceanography, Hydrology and Water Resources
Identifiers
urn:nbn:se:umu:diva-176805 (URN)10.3390/w12102913 (DOI)000582849800001 ()2-s2.0-85095969046 (Scopus ID)
Available from: 2020-11-20 Created: 2020-11-20 Last updated: 2023-08-28Bibliographically approved
Zhang, F., Nilsson, C., Xu, Z. & Zhou, G. (2020). Evaluation of restoration approaches on the Inner Mongolian Steppe based on criteria of the Society for Ecological Restoration. Land Degradation and Development, 31(3), 285-296
Open this publication in new window or tab >>Evaluation of restoration approaches on the Inner Mongolian Steppe based on criteria of the Society for Ecological Restoration
2020 (English)In: Land Degradation and Development, ISSN 1085-3278, E-ISSN 1099-145X, Vol. 31, no 3, p. 285-296Article, review/survey (Refereed) Published
Abstract [en]

Ecological restoration is becoming an increasingly common management tool worldwide. However, a challenge still exists on how to effectively monitor restoration outcomes and evaluate restoration success for ecological restoration managers. In this review, the goal is to evaluate whether the research in a degraded area has been sufficient for fostering efficient restoration measures and follow-up of restoration success based on the Society for Ecological Restoration (SER) criteria. We selected the Inner Mongolian Steppe (IMS) in China as a model system. This area has been the subject of substantial research over the most recent years to understand degradation processes and restoration outcomes. We put together the variables used to assess degradation and restoration needs in the IMS and analyzed restoration results based on SER's nine criteria for evaluating restoration success. We found that the accomplished research in the IMS only partially supplied the data needed for evaluation of restoration success. The available results were sufficient for a proper evaluation of species composition and tentatively supported assessments of another seven criteria but not self-sustainability. Grazing exclusion led to the fastest and most successful recovery of degraded steppe, but landscape-scale processes during restoration in the IMS are still incompletely known. Our review supports large-scale restoration of the IMS and emphasizes the need for long-time monitoring for a more complete evaluation of the outcome of the IMS restoration following all SER's criteria.

Place, publisher, year, edition, pages
John Wiley & Sons, 2020
Keywords
ecological processes, ecosystem degradation, evaluation criteria, grasslands, restoration assessment
National Category
Ecology
Identifiers
urn:nbn:se:umu:diva-167352 (URN)10.1002/ldr.3440 (DOI)000505557900001 ()2-s2.0-85078622109 (Scopus ID)
Available from: 2020-02-04 Created: 2020-02-04 Last updated: 2023-03-24Bibliographically approved
Polvi, L. E., Lind, L., Persson, H., Miranda-Melo, A., Pilotto, F., Su, X. & Nilsson, C. (2020). Facets and scales in river restoration: Nestedness and interdependence of hydrological, geomorphic, ecological, and biogeochemical processes. Journal of Environmental Management, 265, Article ID 110288.
Open this publication in new window or tab >>Facets and scales in river restoration: Nestedness and interdependence of hydrological, geomorphic, ecological, and biogeochemical processes
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2020 (English)In: Journal of Environmental Management, ISSN 0301-4797, E-ISSN 1095-8630, Vol. 265, article id 110288Article, review/survey (Refereed) Published
Abstract [en]

Although river restoration has increased rapidly, observations of successful ecological recovery are rare, mostly due to a discrepancy in the spatial scale of the impact and the restoration. Rivers and their ecological communities are a product of four river facets—hydrology, geomorphology, ecology and biogeochemistry—that act and interact on several spatial scales, from the sub-reach to the reach and catchment scales. The four river facets usually affect one another in predictable pathways (e.g., hydrology commonly controls geomorphology), but we show that the order in which they affect each other and can be restored varies depending on ecoregion and hydroclimatic regime. Similarly, processes at different spatial scales can be nested or independent of those at larger scales. Although some restoration practices are dependent of those at higher scales, other reach-scale restoration efforts are independent and can be carried out prior to or concurrently with larger-scale restoration. We introduce a checklist using the four river facets to prioritize restoration at three spatial scales in order to have the largest positive effect on the entire catchment. We apply this checklist to two contrasting regions—in northern Sweden and in southern Brazil—with different anthropogenic effects and interactions between facets and scales. In the case of nested processes that are dependent on larger spatial scales, reach-scale restoration in the absence of restoration of catchment-scale processes can frankly be a waste of money, providing little ecological return. However, depending on the scale-interdependence of processes of the river facets, restoration at smaller scales may be sufficient. This means that the most appropriate government agency should be assigned (i.e., national vs. county) to most effectively oversee river restoration at the appropriate scale; however, this first requires a catchment-scale analysis of feedbacks between facets and spatial scale interdependence.

Place, publisher, year, edition, pages
Elsevier, 2020
Keywords
Brazil, Fluvial geomorphology, River ecology, River restoration, Spatial scales, Sweden
National Category
Oceanography, Hydrology and Water Resources
Identifiers
urn:nbn:se:umu:diva-171804 (URN)10.1016/j.jenvman.2020.110288 (DOI)000533526800025 ()32421567 (PubMedID)2-s2.0-85084186223 (Scopus ID)
Available from: 2020-06-12 Created: 2020-06-12 Last updated: 2023-03-24Bibliographically approved
Lozanovska, I., Bejarano, M. D., Martins, M. J., Nilsson, C., Ferreira, M. T. & Aguiar, F. C. (2020). Functional Diversity of Riparian Woody Vegetation Is Less Affected by River Regulation in the Mediterranean Than Boreal Region. Frontiers in Plant Science, 11, Article ID 857.
Open this publication in new window or tab >>Functional Diversity of Riparian Woody Vegetation Is Less Affected by River Regulation in the Mediterranean Than Boreal Region
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2020 (English)In: Frontiers in Plant Science, E-ISSN 1664-462X, Vol. 11, article id 857Article in journal (Refereed) Published
Abstract [en]

River regulation may filter out riparian plants often resulting in reduced functional diversity, i.e., in the range of functions that organisms have in communities and ecosystems. There is, however, little empirical evidence about the magnitude of such reductions in different regions. We investigated the functional diversity patterns of riparian woody vegetation to streamflow regulation in boreal Sweden and Mediterranean Portugal using nine plant functional traits and field data from 109 sampling sites. We evaluated changes in mean plant functional traits as well as in indices of multidimensional functional traits, i.e., functional richness (FRic) and functional redundancy (FRed) within regions and between free-flowing and regulated river reaches. We found that regulation significantly reduced functional diversity in Sweden but not in Portugal. In Sweden, the increased magnitude of variations in water flow and water level in summer, the prolonged duration of extreme hydrological events, the increased frequency of high-water pulses, and the rate of change in water conditions were the likely main drivers of functional diversity change. Small riparian plant species with tiny leaves, poorly lignified stems, and shallow root systems were consistently associated with regulated sites in the boreal region. In Portugal, the similar functional diversity values for free-flowing and regulated rivers likely stem from the smaller streamflow alterations by regulation combined with the species legacy adaptations to the Mediterranean natural hydrological regimes. We conclude that streamflow regulation may reduce the functional diversity of riparian woody vegetation, but the magnitude of these effects will vary depending on the adaptations of the local flora and the patterns of streamflow disturbances. Our study provides insights into functional diversity patterns of riparian woody vegetation affected by regulation in contrasting biomes and encourages further studies of the functional diversity thresholds for maintaining ecosystems.

Place, publisher, year, edition, pages
Frontiers Media S.A., 2020
Keywords
functional diversity, functional traits, functional richness, functional redundancy, riparian woody vegetation, streamflow regulation, boreal biome, mediterranean biome
National Category
Ecology
Identifiers
urn:nbn:se:umu:diva-173776 (URN)10.3389/fpls.2020.00857 (DOI)000549207200001 ()32670322 (PubMedID)2-s2.0-85087669584 (Scopus ID)
Available from: 2020-08-04 Created: 2020-08-04 Last updated: 2024-01-17Bibliographically approved
Bejarano, M. D., Sordo-Ward, A., Alonso, C., Jansson, R. & Nilsson, C. (2020). Hydropeaking affects germination and establishment of riverbank vegetation. Ecological Applications, 30(4), Article ID e02076.
Open this publication in new window or tab >>Hydropeaking affects germination and establishment of riverbank vegetation
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2020 (English)In: Ecological Applications, ISSN 1051-0761, E-ISSN 1939-5582, Vol. 30, no 4, article id e02076Article in journal (Refereed) Published
Abstract [en]

Hydropeaking, defined as frequent and rapid variation in flow in regulated rivers with hydropower plants over a short period of time, usually sub-daily to weekly, alters hydraulic parameters such as water levels or flow velocity and exerts strong impacts on fluvial ecosystems. We evaluated the effects of hydropeaking on riverbank vegetation, specifically assessing the germination and establishment of seedlings and cuttings of plant species representing a variation in traits. We used seeds and seedlings and cuttings varying in size as phytometers, and transplanted them to riverbanks both above and below dams used for hydropower production in northern Sweden, selected to represent a gradient in hydropeaking intensity, and along a free-flowing reach. We also analyzed sub-daily water-level variables modified by hydropeaking to identify variables key in explaining the observed vegetation patterns. We found that plant responses to hydropeaking varied with species, with flood-intolerant species being the most strongly affected, as early as the germination stage. In contrast, seeds of flood-tolerant species managed to germinate and survive the early establishment phase, although strong erosive processes triggered by hydropeaking eventually caused most of them to fail. The fate of flood-intolerant species identifies germination as the most critical life-history stage. The depth and frequency of the inundation were the leading variables explaining plant responses, while the duration of shallow inundation explained little of the variation. The rise and fall rates of water levels were key in explaining variation in germination success. Based on the results, we propose restoration measures to enhance establishment of riparian plant communities while minimizing the impact on hydropower electricity production. Given the strong decrease in the germination of species intolerant to prolonged flooding with hydropeaking, planting of seedlings, preferably of large sizes, together with restrictions in the operation of the power plant during the establishment phase to enhance survival would be the best restoration option. Given the high probability of plant uprooting with hydropeaking, bank protection measures have the potential to increase riparian plant survival of all species, including flooding-tolerant species.

Place, publisher, year, edition, pages
John Wiley & Sons, 2020
Keywords
drag, hydropower plant, inundation, phytometer, riverine vegetation, sub-daily water-level variables, survival
National Category
Ecology
Identifiers
urn:nbn:se:umu:diva-169077 (URN)10.1002/eap.2076 (DOI)000517314900001 ()31971649 (PubMedID)2-s2.0-85079867280 (Scopus ID)
Available from: 2020-03-23 Created: 2020-03-23 Last updated: 2023-03-24Bibliographically approved
Sarneel, J. M., Hefting, M. M., Kowalchuk, G. A., Nilsson, C., Van der Velden, M., Visser, E. J. W., . . . Jansson, R. (2019). Alternative transient states and slow plant community responses after changed flooding regimes. Global Change Biology, 25(4), 1358-1367
Open this publication in new window or tab >>Alternative transient states and slow plant community responses after changed flooding regimes
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2019 (English)In: Global Change Biology, ISSN 1354-1013, E-ISSN 1365-2486, Vol. 25, no 4, p. 1358-1367Article in journal (Refereed) Published
Abstract [en]

Climate change will have large consequences for flooding frequencies in freshwater systems. In interaction with anthropogenic activities (flow regulation, channel restoration and catchment land-use) this will both increase flooding and drought across the world. Like in many other ecosystems facing changed environmental conditions, it remains difficult to predict the rate and trajectory of vegetation responses to changed conditions. Given that critical ecosystem services (e.g. bank stabilization, carbon subsidies to aquatic communities or water purification) depend on riparian vegetation composition, it is important to understand how and how fast riparian vegetation responds to changing flooding regimes. We studied vegetation changes over 19 growing seasons in turfs that were transplanted in a full-factorial design between three riparian elevations with different flooding frequencies. We found that (a) some transplanted communities may have developed into an alternative stable state and were still different from the target community, and (b) pathways of vegetation change were highly directional but alternative trajectories did occur, (c) changes were rather linear but faster when flooding frequencies increased than when they decreased, and (d) we observed fastest changes in turfs when proxies for mortality and colonization were highest. These results provide rare examples of alternative transient trajectories and stable states under field conditions, which is an important step towards understanding their drivers and their frequency in a changing world.

Place, publisher, year, edition, pages
John Wiley & Sons, 2019
Keywords
alternative stable states, drought events, flood regime change, hydrological alterations, hysteresis, riparian vegetation, river restoration, species traits
National Category
Ecology Environmental Sciences
Identifiers
urn:nbn:se:umu:diva-157948 (URN)10.1111/gcb.14569 (DOI)000461817500013 ()30638293 (PubMedID)2-s2.0-85061011899 (Scopus ID)
Available from: 2019-04-18 Created: 2019-04-18 Last updated: 2023-03-23Bibliographically approved
Su, X., Polvi, L. E., Lind, L., Pilotto, F. & Nilsson, C. (2019). Importance of landscape context for post-restoration recovery of riparian vegetation. Freshwater Biology, 64(5), 1015-1028
Open this publication in new window or tab >>Importance of landscape context for post-restoration recovery of riparian vegetation
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2019 (English)In: Freshwater Biology, ISSN 0046-5070, E-ISSN 1365-2427, Vol. 64, no 5, p. 1015-1028Article in journal (Refereed) Published
Abstract [en]

We tested whether the recovery of riparian vegetation along rapids that have been restored after channelisation for timber floating can be predicted based on floristic and geomorphic characteristics of surrounding landscape units. Our study was located along tributary stream networks, naturally fragmented in rapids, slow-flowing reaches, and lakes (i.e. process domains), in the Vindel River catchment in northern Sweden.

We tested whether landscape characteristics, specifically to what extent the geomorphology (affecting local abiotic conditions), species richness, and species composition (representing the species pool for recolonisation), as well as the proximity to various upstream process domains (determining the dispersal potential), can predict post-restoration recovery of riparian vegetation.

Our results indicate that post-restoration recovery of riparian vegetation richness or composition is not strongly related to landscape-scale species pools in these streams. The restored rapids were most similar to upstream rapids, geomorphically and floristically, including plant traits. Species richness of adjacent landscape units (upstream process domains or lateral upland zone) did not correlate with that of restored rapids, and proximity of upstream rapids or other process domains was only weakly influential, thus diminishing support for the hypothesis that hydrochory or other means of propagule dispersal plays a strong role in riparian vegetation community organisation after restoration in this fragmented stream network.

We conclude that, in these naturally fragmented stream systems with three discrete process domains (rapids, slow-flowing reaches and lakes), hydrochory is probably not the main predictor for short-term riparian vegetation recovery. Therefore, other factors than landscape context can serve in prioritising restoration and, in these systems, local factors are likely to outweigh landscape connectivity in the recovery of riparian vegetation.

Place, publisher, year, edition, pages
John Wiley & Sons, 2019
Keywords
hydrochory, plant dispersal, riparian zone, species pool, streams
National Category
Ecology
Identifiers
urn:nbn:se:umu:diva-159391 (URN)10.1111/fwb.13282 (DOI)000466805700016 ()2-s2.0-85063265512 (Scopus ID)
Available from: 2019-06-10 Created: 2019-06-10 Last updated: 2023-03-24Bibliographically approved
Balke, T. & Nilsson, C. (2019). Increasing Synchrony of Annual River‐Flood Peaks and Growing Season in Europe [Letter to the editor]. Geophysical Research Letters, 46(17-18), 10446-10453
Open this publication in new window or tab >>Increasing Synchrony of Annual River‐Flood Peaks and Growing Season in Europe
2019 (English)In: Geophysical Research Letters, ISSN 0094-8276, E-ISSN 1944-8007, Vol. 46, no 17-18, p. 10446-10453Article in journal, Letter (Refereed) Published
Abstract [en]

In a changing climate, time sensitive ecological interactions such as pollination and predation are vulnerable to temporal mismatch with direct consequences for ecosystem functioning. It is not known if synchrony and asynchrony of ecological and physical processes such as flood disturbance and plant phenology may similarly be affected by climate change. Here, by spatially merging temperature and flood peak data, we show for the first time that in Central and Eastern Europe, annual river flood peaks increasingly occur within the thermal growing season. This is due to the combined effect of earlier spring onsets and later flood peaks. Such increased physical‐phenological synchrony may especially impact river biogeomorphology and riparian floodplain ecosystem functioning through uprooting of seedlings and increased hydraulic roughness during major flood events.

Place, publisher, year, edition, pages
American Geophysical Union (AGU), 2019
Keywords
biogeomorphology, flood, phenology, climate change, river, riparian
National Category
Climate Research
Identifiers
urn:nbn:se:umu:diva-167621 (URN)10.1029/2019GL084612 (DOI)000508385500027 ()2-s2.0-85074077747 (Scopus ID)
Available from: 2020-02-05 Created: 2020-02-05 Last updated: 2020-02-05Bibliographically approved
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