NINA Brage (Norsk institutt for naturforskning)
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Behavioural responses of a trans-hemispheric migrant to climate oscillation
Get PDFLarge-scale climatic fluctuations, such as the El Niño–Southern Oscillation, can have dramatic effects on ocean ecosystem productivity. Many mobile species breeding in temperate or higher latitudes escape the extremes of seasonal climate variation through long-distance, even trans-global migration, but how they deal with, or are affected by, such longer phased climate fluctuations is less understood. To investigate how a long-lived migratory species might respond to such periodic environmental change we collected and analysed a 13 year biologging dataset for a trans-equatorial migrant, the Manx shearwater (Puffinus puffinus). Our primary finding was that in El Niño years, non-breeding birds were at more northerly (lower) latitudes than in La Niña years, a response attributable to individual flexibility in migratory destinations. Daily time spent foraging varied in concert with this latitudinal shift, with birds foraging less in El Niño years. Secondarily, we found that in subsequent breeding, a hemisphere away, El Niño years saw a reduction in foraging time and chick provisioning rates: effects that could not be attributed to conditions at their breeding grounds in the North Atlantic. Thus, in a highly migratory animal, individuals may adjust to fluctuating non-breeding conditions but still experience cascading carry over effects on subsequent behaviour. behaviour, biologging, climate, El Niño–Southern Oscillation, migration, seabirdpublishedVersio
The battle against the introduced pathogenic monogenean Gyrodactylus salaris in Norwegian Atlantic salmon rivers and fish farms
Get PDFThe introduced salmonid ectoparasite Gyrodactylus salaris has been detected on Atlantic salmon in 53 Norwegian rivers and in 39 Norwegian fish farms. In affected rivers, the mortality of Atlantic salmon juveniles is very high, estimated to a mean of 86%. G. salaris has been considered one of the biggest threats to wild Norwegian Atlantic salmon stocks. With various measures, the authorities have reduced the potential for further spread of the parasite to new rivers and fish farms, and G. salaris has been eradicated from 43 rivers and all fish farms. Furthermore, the eradication process is almost completed in five affected rivers located at the Norwegian west coast, while preparations for the eradication in the remaining five rivers in the southeastern part of Norway have begun. The goal of Norwegian management is to eradicate the introduced pathogenic G. salaris strains from all occurrences in Norway. In fish farms, the parasite has been removed by mandatory slaughter of infected fish. In rivers, G. salaris has mostly been removed by killing all the fish hosts with rotenone. The indigenous genetic Atlantic salmon stocks are re-established after eradication of the parasite. New methods are developed using chemicals that kill the parasite without killing fish in the rivers. Norwegian authorities have so far used more than NOK 1.5 billion on research, monitoring and combating G. salaris. However, the benefits are considered many times greater than the spending. Without control measures, G. salaris would likely have spread to new Atlantic salmon rivers where the same catastrophic outcome had to be expected. The Norwegian authorities seem to meet the goal in their long-term work to halt the spread of G. salaris and to eradicate the parasite in affected rivers.publishedVersio
Mapping grasslands' preservation potential: A case study from the northern Carpathians
Get PDFThe grasslands which are an important part of an ecosystem are endangered due to abandonment of traditional forms of land use. Preservation of biodiversity of seminatural grassland communities is of great importance, therefore it is important to identify threats and prepare a sustainable plan for their protection The goal of this study was to develop an approach to predict threatened grasslands hotspots, basing on multi-factor machine learning analyses. The Gorce Mountains in the Polish Carpathians were chosen as a study area, as it is region partially protected by National Park, surrounded by villages with different socio-economic conditions (agriculture or touristic oriented). The grasslands were identified and classified on Sentinel-2 multispectral imagery. As lack of regular mowing of grasslands was found as main factor promoting forest succession. Therefore, in order to find endangered grasslands areas, support vector machines' algorithm was used to classify them in mowed and unmowed categories. Then the preservation potential of grasslands was modeled with the random forest method, based on the grasslands' mowing classification, digital terrain model, land-use and population statistical data, and the historical forest extent. We found the grasslands above 750 m above sea level to be the most endangered. Also, the tourism activity and ongoing changes in employment structure from agriculture to services has had a negative influence on the grasslands preservation potential. On the other hand, the Gorce National Park's active grassland conservation by mowing and grazing was shown as a positive element in keeping with the high biodiversity of the area. Google Earth Engine, Gorce National Park, grasslands preservation, random forest, Sentinel-2 imagery, support vector machinespublishedVersio
Children’s and Adolescents’ Use of Nature During the COVID-19 Pandemic in a Very Green Country
Get PDFPlay, physical activity, and social interaction with other children in nature are important for healthy and social development in childhood and adolescence. The extent to which lockdown policies during the COVID-19 pandemic impacted the way children engaged in outdoor activities remains unclear, especially in a country with free access to abundant nature during the pandemic. We performed a national survey of parents (n = 1002) in Norway in January 2021 to uncover changes in outdoor play for children (6–12 years, n = 396) and adolescents (13–19 years, n = 606) compared with the situation before the lockdown on 12 March 2020. Ten months after the start of the COVID-19 lockdown, 38% of the parents reported that their children played and spent time outside ‘less than usual’ in their neighborhood, compared with 15% who reported ‘more than usual’ time spent outside. Parents indicated that the children’s play activities were highly organized and institutionalized, and when the activities ceased, their children had less motivation to spend time outdoors and tended to engage more in screen-based activities indoors. We conclude that while children and adolescents had many opportunities to be outdoors in natural settings during the COVID-19 pandemic restrictions, they did so much less than before the lockdown. childhood; nature contact; natural environment; neighborhood; outdoor play; urban forestpublishedVersio
Individual quality overwrites carry-over effects across the annual cycle of a long-distance migrant
Get PDFIn seasonal environments, the fitness of animals depends upon the successful integration of life-history stages throughout their annual cycle. Failing to do so can lead to negative carry-over effects where individuals are transitioning into the next season in different states, consequently affecting their future performance. However, carry-over effects can be masked by individual quality when individuals vary in their efficiency at acquiring resources year after year (i.e. ‘quality’), leading to cross-seasonal consistency in individual performance. Here we investigated the relative importance of carry-over effects and individual quality in determining cross-seasonal interactions and consequences for breeding success over the full annual cycle of a migratory seabird (black-legged kittiwake Rissa tridactyla). We monitored the reproduction and annual movement of kittiwakes over 13 years using geolocators to estimate their breeding success, distribution and winter energy expenditure. We combined this with an experimental approach (clutch removal experiment, 2 years) to manipulate the reproductive effort irrespective of individual quality. Piecewise path analyses showed that successful breeders reproduced earlier and were more likely to breed successfully again the following year. This positive interaction among consecutive breeding stages disappeared after controlling for individual quality, suggesting that quality was dominant in determining seasonal interactions. Moreover, controlling experimentally for individual quality revealed underlying carry-over effects that were otherwise masked by quality, with breeding costs paid in higher energy expenditure and delayed onset of reproduction. We highlight the need to combine an experimental approach along with long-term data while assessing apparent carry-over effects in wild animals, and their potential impact on fitness and population demography.publishedVersio
Post-fledging movements of Atlantic Puffins Fratercula arctica from Skomer Island
Get PDFThe movements of seabirds during the immature period generally remain poorly understood, primarily due to the challenges involved with tracking birds that do not regularly return to a nest. This knowledge gap prevents us from gaining a full understanding of the areas used by seabird populations. Here, we attempted to track the post-fledging movements of Atlantic Puffins Fratercula arctica from Skomer Island (Wales), by deploying geolocators on chicks ready to leave the nest. Despite our very small return rate (just two loggers out of 54, recording 485 and 196 days of data after fledging, respectively), our results provide a first glimpse into the distribution and scale of movements of young Puffins after fledging. The young Puffins undertook movements comparable in scale to those of post-breeding adults, and there were considerable differences between the two individuals. New initiatives to track juvenile seabirds in much larger numbers will hopefully soon provide more insight into seabird post-fledging movements.Post-fledging movements of Atlantic Puffins Fratercula arctica from Skomer IslandpublishedVersio
Forensic geochemistry identifies the illegal introduction of Walleye into Lake Cascade, Idaho
Get PDFObjective: The illegal introduction of fish species can disrupt ecosystems, collapse food webs, and undermine recreational fishing opportunities. Determining whether introduced fish are locally reproducing is important for resource managers. Here, we used the geochemical analysis of otoliths to investigate the potential illegal introduction of a Walleye Sander vitreus caught in 2022, in Lake Cascade, Idaho. Lake Cascade is known for its recreational Yellow Perch Perca flavescens fishery and has no documented resident population of Walleye. Methods: To determine if the Walleye was spawned in Lake Cascade or introduced from elsewhere, we analyzed otoliths for strontium isotopes (87Sr/86Sr) and compared them to local water samples and three locally caught Yellow Perch. Result: The Walleye otolith revealed a shift from higher 87Sr/86Sr values (0.70878) in its early life to a period of intermediate value (0.70842) equal to Payette Lake water, then finally to a lower value (0.70807) comparable to the Lake Cascade water and resident Yellow Perch otoliths. Conclusion: These results suggest that the Walleye was initially transplanted to the Payette Lake area from a currently unknown source in 2020, 2 years before its capture. It resided there briefly before migrating south into Lake Cascade. This study further highlights the benefit of geochemical analyses to identify the illegal introduction of fish and to provide resource managers with a powerful tool for early detection and prevention of the establishment of illegally introduced fish species. distribution, fisheries, nonindigenous species, otolithspublishedVersio
Dynamics of cold-water dinoflagellates in the northern Baltic Sea based on 18S rRNA gene metabarcoding
Get PDFCold-water dinoflagellates contribute significantly to spring blooms in temperate coastal waters. In the northern Baltic Sea, Peridiniella catenata, Apocalathium malmogiense, Gymnodinium corollarium, and Biecheleria baltica predominate the dinoflagellate spring blooms. Spring dynamics of cold-water dinoflagellates have been previously studied using cyst sedimentation data. Here, we utilize time-series data based on amplicons of the V4 region of the 18S rRNA gene spanning from autumn 2012 to spring 2013 and describe dynamics and habitat preferences of the relatively most abundant dinoflagellates in the northern Baltic Sea. Our results indicate that these species preferred either sea ice, under-ice water, or deeper water columns during the ice-covered season and that they shifted in temporal dominance during our sampling period. Succession · Sea ice · Phytoplankton · Niche · Habitat preferencepublishedVersio
Long-term impacts of the Smøla wind farm on a local population of white-tailed eagles (Haliaeetus albicilla)
Get PDFStokke, B.G., Dahl, E.L., Kleven, O., May, R., Nygård, T., Pavón-Jordán, D. & Sandercock, B.K. 2024. Long-term impacts of the Smøla wind farm on a local population of white-tailed eagles (Haliaeetus albicilla). NINA Report 2333. Norwegian Institute for Nature Research.
In the period 2020–2023, a full annual inventory of white-tailed eagle territories at Smøla was undertaken. In addition, searches for collision victims at Smøla wind farm were conducted with standardized protocols. Feathers from nestlings and adults at nest sites, and tissue from collision victims were used in subsequent DNA analyses and population modelling procedures. The main aim was to obtain knowledge of the status of the local population of white-tailed eagles.
The results from the present study indicate that the breeding population of white-tailed eagles at Smøla has been rather stable in the period 1998–2023. There have been no obvious long-term changes in reproductive output or number of active territories. Two years with particularly low reproductive output were likely due to adverse weather conditions (2012) and an outbreak of avian flu (2022). Interestingly, exposure to avian flu did not seem to impact adult survival in 2022–2023.
The spatial distribution of territories, however, has changed after construction of the wind farm. The construction area used to hold many territories prior to construction, but in the period 2020–2023 there was only one nest located within the wind farm.
In the period 2005–2023, a total of 133 white-tailed eagles have been found killed by collision with turbine blades at the Smøla wind farm. In general, central areas of the wind farm have caused more collisions than peripheral turbines in the period 2020–2023. No collisions have occurred at the four turbines with rotor blades painted black to increase visibility, suggesting that the mitigation measure should be expanded to other turbines, especially locations that can be described as collision “hot-spots” with multiple collisions recorded in the last 4-year period. Furthermore, most collision victims were adult birds, probably in search for a vacant breeding terri-tory.
Based on results from DNA analyses and population modelling, the white-tailed eagle population at Smøla seems to consist of a mix of transient and resident individuals. Furthermore, proximity to the wind farm had a pronounced effect on apparent survival of adult white-tailed eagles. The apparent survival of transient individuals declined from the centre of the wind farm. The pattern could be explained by many vacant territories near or within the wind farm, or more occupied territories at distances further away from the wind farm. In contrast, the apparent survival of residents showed the opposite pattern, with increasing survival with greater distance from the wind farm. The pattern might be expected if mortality rates are higher due to collisions at the wind farm, if mate loss leads to an increased probability of emigration, or because collision rates are low near nests because resident individuals learn to avoid nearby turbines.
We evaluated the status of the white-tailed eagle population at Smøla for two time periods with intensive monitoring effort that provided good quality DNA- and comparable inventory data (2006–2011 versus 2020–2023). We found no significant differences in the number of territories occupied, number of fledglings produced per occupied territory, or adult survival. We combined our new estimates of demographic rates in an age-structured matrix population model for female sea eagles.
In 2006–2011, the estimate of the finite rate of population change () and 95% confidence interval (CI) of the estimate were both greater than one, and the eagle population was predicted to grow at ca. 3.1% per year. In 2020–2023, the estimate of was less than one and the population would be predicted to decline at ca. 1.1% year. However, the 95%CI included one so that the finite rate of population change was not significantly different from the rate predicted for a sta-tionary population. Estimates of the net reproductive rate (R0) in the two time periods were > 1, indicating that females were successfully replacing themselves each generation. The confidence intervals of R0 were greater than one in 2006–2011 but included one in 2020–2023. Hence, it would be interesting to undertake a new investigation of the population status in approximately 15 years’ time (one eagle generation).Stokke, B.G., Dahl, E.L., Kleven, O., May, R., Nygård, T., Pavón-Jordán, D. & Sandercock, B.K. 2024. Langtidseffekter av Smøla vindpark på den lokale bestanden av havørn (Haliaeetus albicilla). NINA Rapport 2333. Norsk institutt for naturforskning.
I perioden 2020-2023 ble det foretatt årlige inventeringer av havørn-territorier på Smøla. I tillegg ble det gjennomført systematiske søk etter kollisjonsofre i Smøla vindpark. Fjær fra unger og voksne ved ulike reir samt vev fra kollisjonsdrepte individer ble benyttet i molekylære analyser og bestandsmodellering for å bedømme tilstanden til havørnbestanden på Smøla.
Resultatene indikerer at hekkebestanden hos havørn på Smøla har vært relativt stabil i perioden 1998–2023. Det har ikke vært noen store endringer i perioden hverken med hensyn til antall aktive territorier eller ungeproduksjon. To år med relativt lav ungeproduksjon skyldtes svært ugunstige værforhold (2012) og utbrudd av fugleinfluensa (2022). Resultatene tyder imidlertid på at overlevelsen til voksne fugler ikke ble påvirket av fugleinfluensa i 2022-2023 i noen betydelig grad.
Den romlige fordeling av havørnterritorier har derimot endret seg betydelig etter ferdigstillingen av Smøla vindpark. I årene før vindparken ble etablert var det mange territorier i dette området, men i perioden 2020–2023 ble det kun funnet ett aktivt territorium i vindparken.
Til sammen 133 havørner er blitt funnet drept grunnet kollisjon med vindturbinblader i Smøla vindpark i perioden 2005–2023. I perioden 2020–2023 ble det funnet flest kollisjonsofre i de sentrale delene av vindparken. Ingen kollisjoner ble påvist ved fire turbiner hvor ett av tre turbinblad var malt svart for å øke synligheten, noe som tilsier at dette avbøtende tiltaket bør benyttes også på andre turbiner i vindparken. Dette gjelder spesielt for de turbinene hvor man har påvist flest kollisjoner. Undersøkelsene viste også at det var flest voksne individer som ble funnet kollisjonsdrept. Dette var trolig individer som var på utkikk etter ledige territorier.
På bakgrunn av resultatene fra de molekylære analysene og bestandsmodelleringen består havørnbestanden på Smøla av en blanding av stasjonære (territorielle) og ikke-stasjonære individer. Det ble funnet at avstand fra vindparken hadde en tydelig effekt på voksenoverlevelsen. Overlevelsen til ikke-stasjonære individer avtok med avstand fra vindparken. Dette kan forklares med at det er mange potensielt ledige territorier i eller nær vindparken, eller mange okkuperte territorier lenger bort fra vindparken. Overlevelsen til stasjonære individer viste et motsatt mønster, med økende overlevelse med økende avstand fra vindparken. Dette kan forklares med høyere dødelighet i vindparken enn lenger unna, økt sannsynlighet for at stasjonære individer kan emigrere til andre områder dersom ett av individene i et par dør, eller lave kollisjonsrater ved reir-områdene dersom stasjonære individer unngår å oppholde seg nær turbinene i vindparken.
Vi evaluerte statusen til havørnbestanden på Smøla i to tidsperioder der det eksisterer gode nok data til å gjennomføre bestandsmodellering (2006–2011 versus 2020–2023). Det ble ikke funnet noen statistisk signifikant forskjell hverken med hensyn til antall aktive territorier, antall unger produsert per aktivt territorium eller voksenoverlevelse.
I perioden 2006–2011 var bestandens vekstrate (), inklusive 95 % konfidensintervall, større enn 1, og bestanden var estimert til å vokse med ca. 3,1 % per år. I perioden 2020–2023 var vekst-raten mindre enn 1, og estimert til å avta med 1,1 % per år. 95 % konfidensintervallet inkluderte imidlertid 1, noe som tilsier at bestandens vekstrate ikke er signifikant forskjellig fra det som er forventet for en stabil bestand. Estimatene for netto reproduksjonsrate (R0) i de to tidsperiodene var større enn 1, noe som indikerer at hunnene produserte nok avkom til å resultere i en stabil eller økende bestand. Konfidensintervallene for R0 var høyere enn 1 i perioden 2006–2011, men inkluderte 1 i perioden 2020–2023. Det ville derfor vært interessant å gjenta havørninventering på Smøla om ca. 15 år (én ørnegenerasjon)
Ærfugl rundt Vega – fordeling og nye bestandstall fra 2022/2023
Get PDFDehnhard, N. & Follestad, A. 2024. Ærfugl rundt Vega – fordeling og nye bestandstall fra 2022/2023. NINA Rapport 2351. Norsk institutt for naturforskning.
Ærfugl (Somateria mollissima) er vanlig hekkefugl langs hele fastlandskysten i Norge, og sanking av egg og dun var en viktig inntektskilde for kystsamfunnet i Nord-Norge. I dag sliter bestanden av ærfugl langs hele Norskekysten, og arten er listet som «sårbar» på den Norske rødlista. Ærfugldrift for dun er ikke lenger vanlig, og lever videre bare på Vega, hvor den var avgjørende for å få status som UNESCO verdensarv i 2004. Eggsankingen har stoppet for lengst, men andre trusler har dykket opp, bla. introdusert mink (Neovison vison), redusert mattilgang pga. klimaendringer, økt båttrafikk og økt arealbeslag til havs. Åpning av områder sør for Vega for industriell tarehøsting i 2022 førte med seg bekymring for at dette kunne ytterligere påvirke ærfuglbestanden rundt Vega negativt.
I 2022 og 2023 gjennomførte vi fem flytellinger for å kartlegge forekomst av ærfugl i områder som ble åpnet for taretråling i 2022 sør for Vega, og for å få nye bestandstall for ærfugl i hele Vegaområdet i hekke-, myte- og vinterperioden. Målet var videre å koble lokasjonsdata av ærfugl med miljødata, spesielt dybde og modellert forekomst av tareskog, for å forstå bedre hvilke områder blir brukt av arten.
Resultater fra tellinger i 2022 og 2023 viser lav forekomst av ærfugl i området som ble åpnet for taretråling i hekke- og myteperioden og sent høst. Dette området ble ikke fullstendig dekket i vinterperioden, og vi kan dermed ikke uttale oss om betydningen av dette området for ærfugl gjennom vinteren. Sammenliknet med tidligere tellinger i hele Vegaområdet fra starten og midten av 1980-tallet er bestanden av ærfugl kraftig redusert både i hekke-, myte- og vinterperioden (> 86 %). Ærfuglbestanden rundt Vega følger dermed den nasjonale trenden.
Ved alle tellinger året rundt observerte vi at ærfugl i stor grad opphold seg i grunne områder med en vanndybde mindre enn 20 m, og i områder med tareskog, noen viser viktigheten av denne habitattypen for ærfugl i Vegaområdet. Vi avslutter rapporten med en anbefaling for videre forskning for å tette fortsatt eksisterende kunnskapshull.Dehnhard, N. & Follestad, A. 2024. Common eiders around Vega – distribution and new population counts from 2022/2023. NINA Report 2351. Norwegian Institute for Nature Research.
The common eider (Somateria mollissima) is a common breeding bird along the coast of mainland Norway, and collection of eggs and down was an important income for coastal communities in Northern Norway. Today, populations of common eiders are in decline along the entire Norwegian coastline, and the species is listed as “vulnerable” on the Norwegian Redlist. Caring for common eiders and the collection of down is no longer a common practice, and is today only present on around Vega, where this tradition was critical to obtain the status as UNESCO World Heritage Center in 2004. The collection of eggs has ceased a long time ago, but other threats have turned up, among others the introduced American mink (Neovison vison), reduced access to food due to climate change, increased boat traffic and increased area use at sea. The opening of areas south of Vega for industrial harvesting of kelp in 2022 led to concern for a further negative impact on the common eider population around Vega.
We conducted five flight counts in 2022 and 2023 to map the occurrence of common eiders in the area that was opened for kelp harvesting in 2022 south of Vega, and to obtain new population counts for the entire Vega-area during the breeding, moulting and wintering period. A further aim was to couple location data of common eiders with environmental data, specifically depth and modelled presence of kelp forests, to gain a better understanding about which areas are used by the species.
The results of the counts in 2022 and 2023 show low numbers of common eiders in the area that was opened for kelp harvesting during the breeding and moulting period as well as during late autumn. The area was not covered entirely during the winter count, and we can therefore not draw conclusions about the importance of this area for common eiders during winter. Compared to earlier counts conducted in the entire area around Vega during the early and mid-1980s, the population of common eiders has declined strongly (> 86%) during the breeding, moulting and wintering periods. The population of common eiders around Vega thus follows the national trend.
During all counts throughout the year, we observed that common eiders were distributed in shallow areas with a water depth of less than 20 m, and in areas with kelp forests, which shows the importance of these habitat types for common eiders around Vega. We conclude the report with recommendations for further research to close remaining knowledge gaps.Miljødirektoratet og Stiftelsen Vegaøyan Verdensar