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Demographic correlations are pervasive in wildlife populations and can represent important secondary drivers of population growth. Empirical evidence suggests that correlations are in general positive for long-lived species, but little is known about the degree of variation among spatially segregated populations of the same species in relation to environmental conditions. We assessed the relative importance of two cross-season correlations in survival and productivity, for three Atlantic puffin (Fratercula arctica) populations with contrasting population trajectories and non-overlapping year-round distributions. The two correlations reflected either a relationship between adult survival prior to breeding on productivity, or a relationship between productivity and adult survival the subsequent year. Demographic rates and their correlations were estimated with an integrated population model, and their respective contributions to variation in population growth were calculated using a transient-life table response experiment. For all three populations, demographic correlations were positive at both time lags, although their strength differed. Given the different year-round distributions of these populations, this variation in the strength population-level demographic correlations points to environmental conditions as an important driver of demographic variation through life-history constraints. Consequently, the contributions of variances and correlations in demographic rates to population growth rates differed among puffin populations, which has implications for—particularly small—populations' viability under environmental change as positive correlations tend to reduce the stochastic population growth rate.

Layton-Matthews K., Buckingham L., Critchley E.J., Nilsson A.L.K., Ollus VMS., Ballesteros M., Christensen-Dalsgaard S., Dehnhard N., Fauchald P., Hanssen F., Helberg M., Masden E., May R.F., Sandvik H., Tarroux A. & Reiertsen T.K. 2023. Development of a Cumulative Impact Assessment tool for birds in Norwegian Offshore Waters: Trollvind OWF as a case study. NINA Report 2295. Norwegian Institute for Nature Research. There is growing interest in the economic potential of marine areas for e.g., offshore renewables, fisheries, and shipping. Thus, the cumulative stress on marine ecosystems and the species inhabiting them is increasing. This is of particular concern for migratory birds and seabirds which are undergoing global declines. In the light of an expanding global market for offshore renewables, knowledge of their cumulative impacts combined with other human-derived pressures on marine populations is crucial. This is set against the backdrop of climate change and associated large-scale changes in our oceans. Achieving sustainable development, while mitigating the effects of climate change, requires effective tools to assess the cumulative impacts of anthropogenic stressors on ecosystems. Cumulative impact assessments for the marine environment are strongly influenced by an approach developed by Halpern et al. (2008). In this report, we present and demonstrate a beta-version of a cumulative impact assessment tool for marine industrial pressures on seabirds, which is being developed through the Research Council of Norway (RCN) -funded MARCIS project. The goal of MARCIS is to assess the impacts of marine anthropogenic pressures on seabirds in the North-East Atlantic, which will both utilise and further develop the Halpern formula and provide a publicly open web-based tool that acts as a decision support for marine spatial planning. Equinor has been exploring the potential for con-structing a floating offshore wind farm, called Trollvind, in the North Sea. This proposed floating wind farm is in the early planning stages of development and is proposed to be located around the Troll offshore oil and gas platforms, approximately 65 km west of Bergen. This report presents; 1) a summary of a scoping of existing data of birds using Norwegian offshore area, 2) an assessment of bird migration through the North Sea and the Trollvind area, and the likelihood that some bird groups will be more impacted by an offshore wind farm in this area, and 3) a demonstration of the tool under development (the MARCIS web application), where we assess the potential cumulative impact of the proposed Trollvind OWF development and ocean warming on two seabird populations, as a case study. This report has specific emphasis on the demonstration of the tool. Results of the scoping study of birds using the Norwegian offshore areas indicated a below-medium to medium sensitivity of waterbirds to wind farms in the Trollvind area. However, there were strong seasonal differences showing above-medium values in summer in the eastern and north-eastern parts of the area. Our results also revealed that migratory bird groups differ in their type of risks of impact associated with the Trollvind development, where migrating raptors, gulls, waterfowl and owls were at greatest risk of collision, while migrating seabirds, waterbirds and waders had a higher risk of displacement and/or barrier effects. In the demo of the tool, we estimated the cumulative impact of two stressors (Trollvind OWF and ocean warming) on two study populations (kittiwake breeding at Ålesund colony and common guillemot from Sklinna colony). Both their non-breeding distribution and the cumulative impact of the two stressors was visualised in the demo of the MARCIS App. The impact of Trollvind OWF was negligible for both populations, while disturbance led to a small reduction in guillemots’ body mass and consequently their survival rates. However, ocean warming had a larger population impact, given the high emissions scenario used to quantify impact weights, particularly for guillemots. However, it is important to keep in mind that this demonstration is a case study of only two populations and should be interpreted in the larger context of the results from the scoping study and bird migration studies. The extensive range of species using this area at different times of year are much larger, and this has implementations for a potentially broader impact of such offshore developments. This also highlights the need for both spatial explicit distribution data and demographic/population data to ensure an appropriate knowledge base of population impacts before any OWF developments are conducted. Layton-Matthews K., Buckingham L., Critchley E.J., Nilsson A.L.K., Ollus V.M.S., Ballesteros M., Christensen-Dalsgaard, S., Dehnhard N., Fauchald P., Hanssen F., Helberg M., Masden E., May R.F., Sandvik H., Tarroux A. & Reiertsen T.K. 2023. Development of a Cumulative Impact As-sessment tool for birds in Norwegian Off-shore Waters: Trollvind OWF as a case study. NINA Rapport 2295. Norsk institutt for naturforskning. Presset på marine områder øker med økende økonomiske interesser for bruk av havområdene. Marine områder har blitt viktige arenaer for industriell utvikling som for eksempel havvind, petroleumsaktivitet, skipstrafikk og fiskeri. I lys av et ekspanderende globalt marked for havvind, er kunnskap om sumeffekter av både havvind, andre marine industriaktiviteter og klimaendringer avgjørende for å sikre en god sameksistens med sjøfugl og trekkfugler som benytter de samme havområdene. Økt utnyttelse av havarealene øker sumeffektene og stresset på marine økosystemer og artene som bor der, sett i lys av klima- og økosystem-endringene som skjer i marine økosystemer. Å oppnå bærekraftig utvikling, samtidig som effektene av klimaendringer reduseres, krever effektive verktøy for å vurdere sumeffektene av menneskeskapte stressfaktorer på økosystemene. Metoder for å estimere sumeffekter for havmiljøet er sterkt påvirket av en tilnærming utviklet av Halpern et al. (2008), som ser på summen av ulike stressfaktorer sin påvirkning på et miljø og miljøets sensitivitet til de ulike stressfaktorene. I denne rapporten vil vi presentere og demonstrere en betaversjon av et verktøy som kan benyttes i marin arealplanlegging og som kvantifiserer effekter av marin industri aktivitet på sjøfugler. Dette verktøyet utvikles gjennom det forskningsråds-finansierte MARCIS-prosjektet. Målet med MARCIS er å vurdere virkningene av marin industriaktivitet og klimaendringer på sjøfugler i Nordøst-Atlanteren, og vil både benytte og videreutvikle Halpern-metoden. Verktøyet vil bli gjort tilgjengelig som et offentlig åpent nettbasert verktøy, og kan fungere som beslutningsstøtte for marin arealplanlegging. Equinor har undersøkt potensialet for bygging av en flytende havvindpark, kalt Trollvind, i Nordsjøen. Denne flytende vindparken er i et tidlig planleggingsstadium og foreslås plassert rundt olje- og gassplattformene i Trollfeltet, ca. 65 km vest for Bergen. Denne rapporten presenterer: 1)en oppsummering av en scoping av eksisterende data om fugler som bruker i norsk offshore-område, 2) en vurdering av fugletrekk gjennom Nordsjøen og Trollvind-området, og sannsynligheten for at noen fuglegrupper blir mer påvirket av en havvindpark i dette området, og 3) endemonstrasjon av verktøyet som er under utvikling (MARCIS-webapplikasjonen), der vi vurdererde potensielle sumeffektene av den foreslåtte Trollvind OWF-utbyggingen og havoppvarmingenpå to sjøfuglbestander, som et casestudie. Denne rapporten har lagt spesifikk vekt på demon-strasjonen av verktøyet. Resultatene av dette studiet indikerte at trekkfugler knyttet til vann (eks. dykkere, lom osv) hadde en under middels til middels følsomhet for havvindparker i Trollvind-området. Det var imidlertid sterke sesongforskjeller som viste over middels verdier om sommeren i østlige og nordøstlige deler av området. Resultatene våre avdekket også at grupper av trekkfugl hadde ulik risiko for å bli påvirket av en havvind-utbygging knyttet Trollvind-området. Trekkende rovfugler, måker, gjess og ender, og ugler hadde størst risiko for kollisjon med turbiner, mens trekkende sjøfugler, andre fugler knyttet til vann og vadefugler hadde høyere risiko for å bli fordrevet fra området eller utsatt for barriereeffekter av havvind-installasjoner. Sum-effektene av to ulike stressfaktorer (Trollvind havvindpark og havoppvarming) ble estimert for to studiepopulasjoner (krykkje og lomvi fra hhv Ålesund og Sklinna) og visualisert i betaversjonen av MARCIS-appen. Effekten av en potensiell havvind-installasjon i Trollvind området var ubetydelig for begge popu-lasjoner, mens fordrivelse fra området førte til en liten reduksjon i lomviens kroppsmasse og dermed effekt på bestandens overlevelsesrate. Havoppvarmingen hadde imidlertid en større påvirkning på bestandene, og spesielt for lomvi. Det er imidlertid viktig å huske på at denne demonstrasjonen er en casestudie av bare to populasjoner og bør tolkes i en større kontekst i lys av resultatene fra scoping-studiet og fugletrekkstudiet. Begge disse viser det omfattende spekteret av arter som bruker dette området, og hvordan mengde og sammensetning av arter varierer til ulike tider av året. Effekten av en offshore havvind utbygging i Trollvind området har dermed en potensielt større effekt. Dette fremhever også behovet for gode data, både romlige distribusjonsdata og data på demografiske rater eller bestandstall for å sikre et godt nok kunnskapsgrunnlag om effekter på populasjoner før eventuelle havvind-utbygginger tar til.

A global analysis recently showed that seabird breeding phenology (as the timing of egg-laying and hatching) does not, on average, respond to temperature changes or advance with time (Keogan et al. 2018 Nat. Clim. Change 8, 313–318). This group, the most threatened of all birds, is therefore prone to spatio-temporal mismatches with their food resources. Yet, other aspects of the breeding phenology may also have a marked influence on breeding success, such as the arrival date of adults at the breeding site following winter migration. Here, we used a large tracking dataset of two congeneric seabirds breeding in 14 colonies across 18° latitudes, to show that arrival date at the colony was highly variable between colonies and species (ranging 80 days) and advanced 1.4 days/year while timing of egg-laying remained unchanged, resulting in an increasing pre-laying duration between 2009 and 2018. Thus, we demonstrate that potentially not all components of seabird breeding phenology are insensitive to changing environmental conditions.

Annual migration between breeding- and wintering grounds is a common behavior that is found in a range of taxa, including many seabird-species such as alcids. Within-population-differences in migration strategies, including high or low fidelity in routes, wintering destination and timing, might have a strong impact on survival and later breeding success due to potential differences in e.g. threat exposure and environmental conditions during the inter-breeding season. Knowledge of such is therefore crucial in order to understand the population dynamics of a taxa as well as to improve conservation strategies within environmental management. Through the usage of light based geolocators equipped with saltwater immersion sensors, this study investigated spatial distribution and activity patterns of razorbills breeding in the southern Barents Sea during their non-breeding season of 2018/19. The razorbills were found to divide into at least two main groups depending on their choice of wintering destination. One group migrated south to overwinter in Skagerrak while the other stayed resident in the Barents Sea. The razorbills wintering in the Barents Sea significantly lowered their activity during the main winter-months, spending less time foraging and in flight. The razorbills wintering in Skagerrak did not lower their activity to the same extent, leading to a seasonal difference of time spent foraging and in flight, depending on migration strategy. No difference on body condition between the two groups was found during the following breeding season, suggesting that both strategies might be a viable alternative. However, further research is needed in order to establish an understanding of consistency and drivers of migration in the Barents Sea razorbills as well as any possible long term-fitness consequences.