NINA Brage (Norsk institutt for naturforskning)
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Swimming behaviour of Atlantic salmon kelts migrating past a hydropower plant dam: Effects of hydraulics and dam operations
Get PDFHydropower plants commonly impede the downstream migration of Atlantic salmon (Salmo salar) kelts. Thus, understanding the effects of hydraulic conditions on kelt behaviour and passage performance at dams is crucial for developing effective mitigation measures. In this study, we investigated the influence of hydraulic conditions on kelt passage performance and swimming behaviour at a Norwegian hydropower plant. We combined biological data from 48 kelts collected via acoustic telemetry with hydraulic data modelled using computational fluid dynamics. We assessed kelt passage performance using metrics such as time-to-pass, total number of detections, and total number of detections per day. Additionally, we analysed swimming depths and speeds in relation to the hydraulic conditions created by different dam operating conditions. We found that the dam operation schedule impacted the kelts' ability to find a route past the dam. Though kelts could have passed the dam throughout the study period via a submerged pipe at the dam (which had seemingly sufficient discharge for the kelts to find), 98 % of the kelts instead waited for a spill gate to open partway through the study period. The swimming depth analysis indicated diel variation, with kelts swimming nearer to the water surface during the night. We found that swimming speed increased with increasing kelt body length, particularly under high turbulence kinetic energy and during the day. Furthermore, kelts swam faster as water velocity increased, but slowed down again as turbulence intensity increased. Our findings reveal the effects of hydraulic conditions and dam operations on the migration behaviour of Atlantic salmon kelts. This provides valuable insights for developing strategies to optimise dam operations and improve fish passage performance, including the need to spill enough water to increase passage success and will contribute to sustainable management of Atlantic salmon populations in regulated rivers.publishedVersio
Non-detriment finding for soft-shelled tortoise (Malacochersus tornieri)
Get PDFInnførsel av én levende pannekakeskilpadde (Malacochersus tornieri) født eller avlet i fangenskap fra dyrehage i Finland til dyrehage i Norge vil ikke være til skade for artens bevaringsstatus. Det konkluderer Vitenskapskomiteen for mat og miljø (VKM). Oppdraget ble gjort på vegne av Miljødirektoratet, som er forvaltningsmyndighet for Konvensjonen om internasjonal handel med truede arter av vill flora og fauna, CITES, i Norge. VKM er vitenskapelig myndighet for CITES i Norge, og utarbeider i NDF-rapporter i tråd med metodikk publisert av verdens naturvernunion (IUCN) og CITES.Non-detriment finding for soft-shelled tortoise (Malacochersus tornieri)Innførsel av én levende pannekakeskilpadde (Malacochersus tornieri) født eller avlet i fangenskap fra dyrehage i Finland til dyrehage i Norge vil ikke være til skade for artens bevaringsstatus. Det konkluderer Vitenskapskomiteen for mat og miljø (VKM). Oppdraget ble gjort på vegne av Miljødirektoratet, som er forvaltningsmyndighet for Konvensjonen om internasjonal handel med truede arter av vill flora og fauna, CITES, i Norge. VKM er vitenskapelig myndighet for CITES i Norge, og utarbeider i NDF-rapporter i tråd med metodikk publisert av verdens naturvernunion (IUCN) og CITES.publishedVersio
Black grouse (Lyrurus tetrix) population status, reasons for decline and potential conservation measures from Western and Central Europe to Fennoscandia: a literature review
Get PDFThe long-term decline of the black grouse population throughout Europe is influenced by many factors that affect populations differently depending on the distribution range, from Central Europe to the Scandinavian countries. Therefore, we analyzed available literature sources to describe the main reasons for the population decline of this species and to suggest conservation measures. In total, 228 pieces of literature from 1955 to 2024 were analyzed for this study. Based on the literature analysis, it is clear that the drivers of population decline differ across the distributional range. In Central Europe, where the population is declining rapidly, habitat loss and forest fragmentation are crucial factors, as is the negative impact of tourism. In Scandinavia, where the population is gradually declining, decreasing breeding success and increasing chick mortality rates are generally considered the main negative factors. However, these factors also affect black grouse populations in Central Europe. It is crucial to acknowledge that a significant proportion of the contributing factors, such as predation and habitat loss, can be attributed to human activities. Therefore, it is necessary to emphasize that environmental protection should work hand in hand with wildlife managers to improve the situation. Tetraonidae, predation, nest success, climate change, habitat loss, biodiversity conservationpublishedVersio
Land‑based foraging by polar bears reveals sexual conflict outside mating season
Get PDFAccording to sexual selection theory, the sexes are faced with opposing evolutionary goals. Male fitness benefits from access to females, whereas female fitness is constrained by food resources and safety for themselves and their offspring. Particularly in large solitary carnivores, such as polar bears (Ursus maritimus), these divergent goals can potentially lead to conflict between the sexes. Outside the mating season, when polar bears are on the move across vast distances, the consequences of such conflict can become apparent when individuals arrive at the same food source. To investigate interrelationships between the sexes, we observed successive polar bears visiting a bird breeding colony to feed on clutches of eggs. We found that males succeeded females more frequently and more closely than expected by chance. Moreover, when males were closer to conspecifics, they walked faster, spent less time in the colony and ingested less food. In contrast, female foraging performance was not associated with proximity to other bears. Irrespective of proximity, females generally spent short periods in the colony and ingested fewer clutches than males. Our results suggest that in polar bears, there is a trade-off between the benefits of food intake and the opportunities (in males) and risks (in females) posed by encountering conspecifics. Intrasexual selection, Familiarise, Forager, Male competition, Solitary carnivorepublishedVersio
Off the conservation radar: the hidden story of Europe’s tiny pea clams (Bivalvia: Sphaeriidae)
Get PDFThis study highlights the conservation problems faced by the tiny freshwater bivalves of the family Sphaeriidae, also known as pea, pill, or fingernail clams (or mussels) in Europe. Despite their global distribution, assumed ecological importance, and potential uses, basic knowledge about their taxonomy, biology, and ecology is very limited and much lower than for the larger freshwater bivalve taxa. Immediate scientific priorities are required to fill knowledge gaps regarding their taxonomy, genetic diversity, distribution, reproductive cycle, ecosystem functions, and population trends. Such fundamental knowledge is necessary to identify specific threats and develop appropriate conservation actions. Deploying environmental DNA analysis at a large scale could be a valuable way to fill gaps in distribution and strengthen monitoring in areas where local taxonomic knowledge is lacking. Until taxon-specific management plans can be developed, we recommend that efforts concentrate on the general protection and restoration of wetland habitats, implementing pollution control measures, and managing invasive species. These actions should be complemented by community engagement through citizen science initiatives. Additionally, prioritising data collection to fill existing knowledge gaps and updating conservation statuses (Red Lists) based on comprehensive assessments will be crucial. Implementing these actions will provide a starting point for the broader protection of freshwater ecosystems, thus benefiting pea clams and other interconnected species within these habitats. Sphaeriinae · Fingernail clams · Pill clams · Conservation roadmap · Treats · Knowledge gapspublishedVersio
Climate, Hydrology, and Nutrients Control the Seasonality of Si Concentrations in Rivers
Get PDF* Seasonal variations in annual riverine dissolved silica concentrations (DSi regime) were correctly classified 80% of the time • Climate and primary productivity emerge as the most important drivers in differentiating among average DSi regimes • Median nitrogen and phosphorus concentrations strongly predicted minimum and maximum DSi concentration, regardless of regime The seasonal behavior of fluvial dissolved silica (DSi) concentrations, termed DSi regime, mediates the timing of DSi delivery to downstream waters and thus governs river biogeochemical function and aquatic community condition. Previous work identified five distinct DSi regimes across rivers spanning the Northern Hemisphere, with many rivers exhibiting multiple DSi regimes over time. Several potential drivers of DSi regime behavior have been identified at small scales, including climate, land cover, and lithology, and yet the large‐scale spatiotemporal controls on DSi regimes have not been identified. We evaluate the role of environmental variables on the behavior of DSi regimes in nearly 200 rivers across the Northern Hemisphere using random forest models. Our models aim to elucidate the controls that give rise to (a) average DSi regime behavior, (b) interannual variability in DSi regime behavior (i.e., Annual DSi regime), and (c) controls on DSi regime shape (i.e., minimum and maximum DSi concentrations). Average DSi regime behavior across the period of record was classified accurately 59% of the time, whereas Annual DSi regime behavior was classified accurately 80% of the time. Climate and primary productivity variables were important in predicting Average DSi regime behavior, whereas climate and hydrologic variables were important in predicting Annual DSi regime behavior. Median nitrogen and phosphorus concentrations were important drivers of minimum and maximum DSi concentrations, indicating that these macronutrients may be important for seasonal DSi drawdown and rebound. Our findings demonstrate that fluctuations in climate, hydrology, and nutrient availability of rivers shape the temporal availability of fluvial DSi.publishedVersio
Miljø-, klima- og samfunnsendringer i Målselv- Malangen, og lokalt prioriterte forskningsområder
Get PDFArneberg, M.K., Engen, S., Weber, C.T., Gross, L. 2024. Miljø-, klima- og samfunnsendringer i Målselv-Malangen, og lokalt prioriterte forskningsområder. NINA Rapport 2501. Norsk institutt for naturforskning.
Denne rapporten er første del av en samproduksjonsprosess i prosjektet Fra fjell til fjord (Catchment to Coast – C2C). Her presenterer vi observerte klima-, miljø- og samfunnsendringer gjort av forskere og lokale aktører i Målselv-Malangen området, samt lokalt identifiserte kunnskapsbehov og forskningsspørsmål. For å kartlegge klima- miljø- og samfunnsendringer gjennomførte vi semistrukturerte intervjuer med 10 lokale kunnskapsholdere og fem forskere våren 2023. Kartlagte endringer ble deretter presentert for deltakerne under et arbeidsseminar som vi arrangerte i Målselv på Høgtun 1. november 2023. Her diskuterte deltakerne observerte endringer i fellesskap og valgte ut lokalt viktige forskningsområder og forskningsspørsmål.
Lokalt viktige forskningsområder inkluderte i) endringer i kulturlandskap og matproduksjon, ii) klimaendringer på tvers av økosystem, iii) endringer i vassdrag og fjord, samt iv) forsvarets aktivitet. Datakvalitet- og tilgang ble også fremhevet. Vi fant også at på enkelte områder etterspurte lokale aktører kunnskap som allerede eksisterer.
Basert på erfaringer fra dette arbeidet så langt, har vi følgende anbefalinger til forskere som ønsker å produsere lokalt relevant kunnskap:
kartlegg hvilken kunnskap som etterspørres lokalt.
identifiser hva som allerede finnes av kunnskap på disse områdene. Finnes det eksisterende kunnskap om det som etterspørres, må denne kunnskapen formidles bedre.
gjennomfør forskning i samarbeid med lokale aktører på tema som står igjen som lokalt relevante kunnskapshull
Evaluering av «Krypsiv på Sørlandet». En kvalitativ studie av et samarbeidsprosjekt
Get PDFSutcliffe, T. E. 2024. Evaluering av «Krypsiv på Sørlandet». En kvalitativ studie av et samarbeidsprosjekt. NINA Rapport 2509. Norsk institutt for naturforskning.
I over 20 år har prosjektet «Krypsiv på Sørlandet» (KPS) jobbet med å identifisere årsakene til masseveksten av krypsiv (Juncus bulbosus) i vassdrag og elver, og utvikle løsninger for fjerning. Krypsiv er en flerårig vannplante som er stedegen i norske vassdrag, men masseveksten har blitt et problem for rekreasjon og bruk av vassdrag. Evalueringen er basert på 17 intervjuer med aktører tilknyttet KPS og gir en oversikt over måloppnåelse, læringspunkter og fremtidige alternativer.
Resultatene fra intervjuene viser tydelig en bred enighet om at KPS har vært en suksess når det gjelder å skape en samarbeidsarena for utveksling av kunnskap og erfaringer på tvers av forvaltningsnivåer, forskere, regulanter, tiltaksgrupper og fagråd. Dette samarbeidet beskrives som unikt og et eksempel til etterfølgelse. Evalueringen viser at måloppnåelsen er nådd når det gjelder å finne årsakene til masseveksten. Forskningen viser at årsakene til masseveksten er sammensatt og at det skyldes menneskelig aktivitet og arealbruk som kalking av forsurede vassdrag, vannkraftregulering, eutrofiering og global oppvarming. Når det gjelder å finne og iverksette tiltak for å begrense masseveksten, så er deltagerne mer ambivalente. Dette har å gjøre med at man også ønsket at tiltakene skal ha en mer permanent effekt. Tiltak som harving, klipping og mudring må gjentas hvert andre til tredje år og er dermed symptombehandlende. Resultatene fra evalueringen peker på kunnskapsproduksjonen i KPS som en suksess og som en viktig brobygger mellom de ulike aktørene. Dette er det et sterkt ønske om at skal kunne fortsette i fremtiden.
Finansieringen av KPS er et spleiselag der aktørene har betalt inn til en felles pott, og her har summen i hovedsak blitt delt likt mellom forskning på årsakene til massevekst av krypsiv og tiltak for fjerning av krypsiv. Evalueringen viser at det er frustrasjon over statens beslutning om å kutte støtten over statsbudsjettet, noe som skaper usikkerhet rundt fremtidig organisering og finansie-ring. Konsekvenser kan være at møteplassen for erfaringsutveksling og samproduksjon av kunnskap forsvinner, noe som igjen svekker beslutningsgrunnlaget i vannforvaltningen. Videre kan masseveksten fortsette å begrense bruken av vassdragene hvis reduserte midler til å gjennomføre tiltak opphører.
Diskusjonen som er basert på intervjuene løfter frem viktige temaer for hvordan krypsivproblemet kan håndteres videre. Blant annet diskuteres det hvordan energipolitikk over tid har påvirket utbygging av vassdragene, og hvordan internasjonale rammeverk som EUs vanndirektiv og nyere klima- og miljøavtaler, som Konvensjonen om biologisk mangfold, er relevante i krypsivsammenheng. Evalueringen peker også på viktigheten av å integrere krypsivkunnskap i forvaltningen. Evalueringen avsluttes med fire alternativer for veien videre:
Integrering i fylkeskommunens vannforvaltning – KPS integreres i Agder vannregion, med styringsgruppen som overtar FoU-gruppens arbeid for å sikre overvåking og tiltak. Det foreslås en 50 % stilling for å koble krypsivarbeidet med eksisterende oppgaver.
Videreføring av dagens organisering – KPS fortsetter uten statlig støtte, ledet av fylkeskommunen. Tiltak fokuserer på områder med høy bruksverdi, og forskning prioriteres for mer effektive tiltaksmetoder.
Økt bidrag fra aktører – Kommuner, regulanter og andre foreslås som større økonomiske bidragsytere. Dette møtes med skepsis grunnet kommunenes økonomiske press, men kan styrkes ved lokal forankring gjennom brukerfinansiering.
Nedleggelse – Nedleggelse vil stoppe tiltak og kunnskapsproduksjon, noe som kan ha negative konsekvenser for lokalbefolkningen og beslutninger i vannforvaltningen. Samtidig frigjøres midler til andre samfunnstjenester, men presset for å håndtere krypsivproblemet kan øke over tid.Sutcliffe, T. E. 2024. Evaluation of «Krypsiv på Sørlandet». A qualitative study of a collaboration project. NINA Report 2509. Norwegian Institute for Nature Research.
For over 20 years, the collaborative project "Krypsiv på Sørlandet" (hereafter KPS) has worked to identify the causes of the mass growth of bulbous rush (Juncus bulbosus) in rivers and water-ways and to find solutions and removal strategies. Bulbous rush is a perennial aquatic plant native to Norwegian rivers and streams, but the mass proliferation of this plant has gained attention as it impedes recreational use of water bodies. This evaluation is based on 17 qualitative interviews with stakeholders involved in KPS, providing an overview of achievements, lessons learned, and future pathways.
The results reveal broad agreement that KPS has been successful as a collaborative platform for knowledge exchange among administrative levels, researchers, regulators, and action groups. The project is described as unique and exemplary for cross-disciplinary cooperation. The evaluation shows that the goal of identifying causes has been achieved, with research pointing to factors such as liming of acidified watercourses, hydropower regulation, eutrophication, and global warming. However, there is ambivalence pertaining to the measures implemented—such as harrowing, cutting, and dredging—because they only have temporary effects, requiring repetition every two to three years, making them symptomatic treatments. The evaluation highlights knowledge production as a success and an important bridge-builder between the various actors. There is a strong desire to continue this in the future.
Funding has been a joint effort, with resources divided primarily between research on the causes of bulbous rush proliferation and practical management measures. However, there is frustration over the government’s decision to withdraw state budget support, creating uncertainty about future organisation and funding. This could lead to the loss of the collaborative platform for experience sharing and knowledge co-production and weakening decision-making in water management. Moreover, the proliferation of bulbous rush may continue to restrict waterway use due to reduced funding for control measures.
The discussion highlights critical themes for managing bulbous rush going forward. These include the impact energy policies have had over time on watercourses and how bulbous rush issues can be linked to international frameworks such as the EU Water Framework Directive and recent climate and environmental agreements like the Convention on Biological Diversity. The evaluation also emphasises the importance of integrating knowledge about bulbous rush into management practices. The evaluation concludes with four potential pathways for KPS:
Integration into regional water management – KPS becomes part of Agder's water region management, with the steering group absorbing the R&D group to ensure continued monitoring and measures. A 50% position is proposed to connect bulbous rush efforts with existing management tasks.
Continuation with existing structure – Maintain the current organisation of KPS without state funding, with the county municipality leading and providing the secretariat. Efforts would target high-use areas, prioritising monitoring and intervention-focused research for more effective methods.
Continuation with increased contributions – Retaining KPS’s structure but with greater financial contributions from municipalities, regulators, and other stakeholders. While municipal budget constraints make this challenging it could be strengthened through local anchoring via user financing.
Discontinuation – Ending KPS would halt interventions and knowledge production, negatively affecting local populations, visitors, and future water management decisions. potentially harming local communities and future water management decisions. While it would free resources for other societal needs, pressure to address bulbous rush is likely to grow over time
Sensitivity to network perturbations in the randomized shortest paths framework: theory and applications in ecological connectivity
Get PDFThe randomized shortest paths (RSP) framework, developed for network analysis, extends traditional proximity and distance measures between two nodes, such as shortest path distance and commute cost distance (related to resistance distance). Consequently, the RSP framework has gained popularity in studies on landscape connectivity within ecology and conservation, where the behavior of animals is neither random nor optimal. In this work, we study how local perturbations in a network affect proximity and distance measures derived from the RSP framework. For this sensitivity analysis, we develop computable expressions for derivatives with respect to weights on the edges or nodes of the network. Interestingly, the sensitivity of expected cost to edge or node features provides a new signed network centrality measure, the negative covariance between edge/node visits and path cost, that can be used for pinpointing strong and weak parts of a network. It is also shown that this quantity can be interpreted as minus the endured expected detour (in terms of cost) when constraining the walk to pass through the node or the edge. Our demonstration of this framework focuses on a migration corridor for wild reindeer (Rangifer rangifer) in Southern Norway. By examining the sensitivity of the expected cost of movement between winter and calving ranges to perturbations in local areas, we have identified priority areas crucial for the conservation of this migration corridor. This innovative approach not only holds great promise for conservation and restoration of migration corridors, but also more generally for connectivity corridors between important areas for biodiversity (e.g. protected areas) and climate adaptation. Furthermore, the derivations and computational methods introduced in this work present fundamental features of the RSP framework. These contributions are expected to be of interest to practitioners applying the framework across various disciplines, ranging from ecology, transport and communication networks to machine learning. corridors, linear response theory, migration, sensitivity analysis, spatial conservation prioritization, susceptibilitypublishedVersio