NINA Brage (Norsk institutt for naturforskning)
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Snowmobile noise alters bird vocalization patterns during winter and pre-breeding season
Get PDFNoise pollution poses a significant threat to ecosystems worldwide, disrupting animal communication and causing cascading effects on biodiversity. In this study, we focus on the impact of snowmobile noise on avian vocalizations during the non-breeding winter season, a less-studied area in soundscape ecology. We developed a pipeline relying on deep learning methods to detect snowmobile noise and applied it to a large acoustic monitoring dataset collected in Yellowstone National Park. Our results demonstrate the effectiveness of the snowmobile detection model in identifying snowmobile noise and reveal an association between snowmobile passage and changes in avian vocalization patterns. Snowmobile noise led to a decrease in the frequency of bird vocalizations during mornings and evenings, potentially affecting winter and pre-breeding behaviours such as foraging, predator avoidance and successfully finding a mate. However, we observed a recovery in avian vocalizations after detection of snowmobiles during mornings and afternoons, indicating some resilience to sporadic noise events. Synthesis and applications: Our findings emphasize the need to consider noise impacts in the non-breeding season and provide valuable insights for natural resource managers to minimize disturbance and protect critical avian habitats. The deep learning approach presented in this study offers an efficient and accurate means of analysing large-scale acoustic monitoring data and contributes to a comprehensive understanding of the cumulative impacts of multiple stressors on avian communities.Snowmobile noise alters bird vocalization patterns during winter and pre-breeding seasonpublishedVersio
Metapopulation regulation acts at multiple spatial scales: Insights from a century of seabird colony census data
Get PDFDensity-dependent feedback is recognized as important regulatory mechanisms of population size. Considering the spatial scales over which such feedback operates has advanced our theoretical understanding of metapopulation dynamics. Yet, metapopulation models are rarely fit to time-series data and tend to omit details of the natural history and behavior of long-lived, highly mobile species such as colonial mammals and birds. Seabird metapopulations consist of breeding colonies that are connected across large spatial scales, within a heterogeneous marine environment that is increasingly affected by anthropogenic disturbance. Currently, we know little about the strength and spatial scale of density-dependent regulation and connectivity between colonies. Thus, many important seabird conservation and management decisions rely on outdated assumptions of closed populations that lack density-dependent regulation. We investigated metapopulation dynamics and connectivity in an exemplar seabird species, the Northern gannet (Morus bassanus), using more than a century of census data of breeding colonies distributed across the Northeast Atlantic. We developed and fitted these data to a novel hierarchical Bayesian state-space model, to compare increasingly complex scenarios of metapopulation regulation through lagged, local, regional, and global density dependence, as well as different mechanisms for immigration. Models with conspecific attraction fit the data better than the equipartitioning of immigrants. Considering local and regional density dependence jointly improved model fit slightly, but importantly, future colony size projections based on different mechanistic regulatory scenarios varied widely: a model with local and regional dynamics estimated a lower metapopulation capacity (645,655 Apparently Occupied Site [AOS]) and consequently higher present saturation (63%) than a model with local density dependence (1,367,352 AOS, 34%). Our findings suggest that metapopulation regulation in the gannet is more complex than traditionally assumed, and highlight the importance of using models that consider colony connectivity and regional dynamics for conservation management applications guided by precautionary principles. Our study advances our understanding of metapopulation dynamics in long-lived colonial species and our approach provides a template for the development of metapopulation models for colonially living birds and mammals. connectivity, conspecific attraction, dispersal, immigration, latent process, long-term population monitoring, marine conservation, metapopulation dynamics, Monte Carlo Markov Chain, Morus bassanus, Northern gannet, regulatory feedbackpublishedVersio
Iteroparity and its contribution to life-history variation in Atlantic salmon
Get PDFEvolution of iteroparity is shaped by the trade-off between current and future reproduction.We studied variation in iteroparity among 205 050 individual Atlantic salmon caught in 179 rivers spanning 14◦ of latitude. The proportion of repeat spawners (iteroparous individuals) averaged 3.8% and ranged from 0% to 26% across rivers. Females were more often repeat spawners than males and had lower cost of reproduction in terms of lost body mass between spawning events. Proportion of repeat spawners for a given sea age at maturity, and the ratio of alternate to consecutive repeat spawners, increased with increasing population mean sea age at maturity. By combining smolt age, sea age at maturity, and age at additional spawning events, we identified 141 unique life-history types, and repeat spawners contributed 75% of that variation. Our results show that repeat spawners are important for life-history variation and suggest that the association between mean sea age and the frequency of repeat spawning is adaptive rather than a pleiotropic side effect arising from selection on sea age. age at maturity, life-history evolution, local adaptation, repeat spawning, trade-offpublishedVersio
Quantitative fatty acid signature analysis reveals a high level of dietary specialization in killer whales across the North Atlantic
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Restaurerbar natur i Nordre Follo
Get PDFSkrindo, A.B., Simensen, T., Jansson, U., Bakkestuen, V., Dervo, B., Hagen, D., Mehlhoop, A.C., Museth, J. & Singsaas, F.T. 2023. Restaurerbar natur Nordre Follo. NINA Rapport 2314. Norsk institutt for naturforskning
Nordre Follo kommune har vedtatt et politisk mål om arealnøytralitet. Dette innebærer at planprosesser videre skal sikre at det er null netto tap av natur kommunen til nedbygging og andre arealbruksendringer. Som ledd i oppfølgingen av kommunedelplan for naturmangfold samt målsettinger i kommuneplanen, ønsker kommunen en oversikt over restaurerbare arealer. Formålet med oppdraget er å bidra til definisjon av - og kartlegging av - restaurerbar natur som viktig kunnskapsgrunnlag for kommunens arbeid med arealnøytralitet og arealregnskap.
Så langt vi kjenner til, er dette det første forsøket på en slik sammenstilling i en norsk kommune, og metodeutvikling en viktig del av oppdraget. Her inngår identifisering av kriterier for når et areal er restaurerbart, innledende geografiske analyser basert på eksisterende data for å kartlegge potensielt restaurerbare områder, samt drøfting av prinsipper for prioritering av tiltak. Rapporten inneholder også en gjennomgang av sentrale begreper som naturrestaurering, forringet natur, økologisk tilstand og restaurerbar natur.
Følgende arealtyper er inkludert i den geografiske analysen:
• Naturlige arealer som myr, skog på våtmark, skog på fastmark, bekker og dammer
• Kulturmarksarealer som kantsoner langs vassdrag, kantsoner langs terrestriske områder og semi-naturlige enger
• Konstruerte arealer som dammer og skrotemark
I tillegg drøftes enkelte økologiske funksjoner og naturgoder.
Litteraturstudien viste at det ikke finnes et omforent kriteriesett i vitenskapelig litteratur for når et areal kan ansees for å være restaurerbart, men noen studier har sett på kriterier for prioritering. EU har foreslått et rammeverk som definerer nivåer av forringet natur, mulighet for restaurering og potensiell effekt av restaurering. Vi har tatt utgangspunkt i dette rammeverket, og operasjonalisert mulige kriterier tilpasset tilgjengelige data for Nordre Follo kommune. Forslag til kriterier er utviklet i dialog med kommunen slik at resultatene skal bli relevante for arealforvaltningen.
Prosjektleveransen er både en database med kartlag over potensielle restaurerbare arealer i Nordre Follo kommune og denne rapporten. Oversikten over restaurerbare arealer gir ikke et komplett kunnskapsgrunnlag for kommunen, ettersom det eksisterende datagrunnlaget over arealtyper i kommunen ikke er tilstrekkelig kartlagt og oppdatert. Likevel gir det et godt grunnlag for å igangsette arbeidet med arealnøytralitet og videreutvikle kunnskapsgrunnlaget.
Før eventuelle tiltak iverksetter må det gjennomføres feltundersøkelser og prioriteringer mellom lokaliteter. Effekten av tiltakene vil variere mellom naturtyper og økologisk tilstand, og grad av usikkerhet knyttet til slike effekter bør inngå i vurderinger av endelige prioriteringer.
Vi anbefaler Nordre Follo kommune å igangsette restaureringsprosjekter basert på dette oppdragets leveranse. Vi anbefaler videre en ny gjennomgang når erfaringer ved restaurering basert på denne kartleggingen foreligger. Datagrunnlaget bør oppdateres fortløpende ettersom nye data blir tilgjengelige. Vi anbefaler også at andre kommuner kan benytte denne metoden, slik at den videreutvikles på grunnlag av andre tilgjengelige data, andre økosystemer og annen type arealbruk
A retrospective investigation of feather corticosterone in a highly contaminated white-tailed eagle (Haliaeetus albicilla) population
Get PDFExposure to persistent organic pollutants (POPs), such as organochlorines (OCs) and polybrominated diphenyl
ethers (PBDEs), is associated with adverse health effects in wildlife. Many POPs have been banned and conse quently their environmental concentrations have declined. To assess both temporal trends of POPs and their
detrimental impacts, raptors are extensively used as biomonitors due to their high food web position and high
contaminant levels. White-tailed eagles (WTEs; Haliaeetus albicilla) in the Baltic ecosystem represent a sentinel
species of environmental pollution, as they have suffered population declines due to reproductive failure caused
by severe exposure to dichlorodiphenyltrichloroethane (DDT) and polychlorinated biphenyls (PCB) during the
1960s through 1980s. However, there is a lack of long-term studies that cover a wide range of environmental
contaminants and their effects at the individual level. In this study, we used 135 pooled samples of shed body
feathers collected in 1968–2012 from breeding WTE pairs in Sweden. Feathers constitute a temporal archive for
substances incorporated into the feather during growth, including corticosterone, which is the primary avian
glucocorticoid and a stress-associated hormone. Here, we analysed the WTE feather pools to investigate annual
variations in feather corticosterone (fCORT), POPs (OCs and PBDEs), and stable carbon and nitrogen isotopes
(SIs; dietary proxies). We examined whether the expected fluctuations in POPs affected fCORT (8–94 pg. mm− 1
)
in the WTE pairs. Despite clear temporal declining trends in POP concentrations (p 0.05 in all cases). Our results do not support fCORT as
a relevant biomarker of contaminant-mediated effects in WTEs despite studying a highly contaminated popu lation. However, although not detecting a relationship between fCORT, POP contamination and diet, fCORT
represents a non-destructive and retrospective assessment of long-term stress physiology in wild raptors other wise not readily available.publishedVersio
Scavenging patterns of an inbred wolf population in a landscape with a pulse of human-provided carrion
Get PDFScavenging is an important part of food acquisition for many carnivore species that switch between scavenging and predation. In landscapes with anthropogenic impact, humans provide food that scavenging species can utilize. We quantified the magnitude of killing versus scavenging by gray wolves (Canis lupus) in Scandinavia where humans impact the ecosystem through hunter harvest, land use practices, and infrastructure. We investigated the cause of death of different animals utilized by wolves, and examined how the proportion of their consumption time spent scavenging was influenced by season, wolf social affiliation, level of inbreeding, density of moose (Alces alces) as their main prey, density of brown bear (Ursus arctos) as an intraguild competitor, and human density. We used data from 39 GPS-collared wolves covering 3198 study days (2001–2019),including 14,205 feeding locations within space–time clusters, and 1362 carcasses utilized by wolves. Most carcasses were wolf-killed (80.5%) while a small part had died from other natural causes (1.9%). The remaining had either anthropogenic mortality causes (4.7%), or the cause of death was unknown (12.9%). Time spent scavenging was higher during winter than during summer and autumn. Solitary wolves spent more time scavenging than pack-living individuals, likely because individual hunting success is lower than pack success. Scavenging time increased with the mean inbreeding coefficient of the adult wolves, possibly indicating that more inbred individuals resort to scavenging, which requires less body strength. There was weak evidence for competition between wolves and brown bears as well as a positive relationship between human density and time spent scavenging. This study shows how both intrinsic and extrinsic factors drive wolf scavenging behavior, and that despite a high level of inbreeding and access to carrion of anthropogenic origin, wolves mainly utilized their own kills. Canis lupus, consumption time, human density, inbreeding, intraguild competition, prey density, social affiliationpublishedVersio
Global analysis of seasonal changes in trematode infection levels reveals weak and variable link to temperature
Get PDFSeasonal changes in environmental conditions drive phenology, i.e., the annual timing of biological events ranging from the individual to the ecosystem. Phenological patterns and successional abundance cycles have been particularly well studied in temperate freshwater systems, showing strong and predictable synchrony with seasonal changes. However, seasonal successional changes in the abundance of parasites or their infection levels in aquatic hosts have not yet been shown to follow universal patterns. Here, using a compilation of several hundred estimates of spring-to-summer changes in infection by trematodes in their intermediate and defnitive hosts, spanning multiple species and habitats, we test for general patterns of seasonal (temperature) driven changes in infection levels. The data include almost as many decreases in infection levels from spring to summer as there are increases, across diferent host types. Our results reveal that the magnitude of the springto-summer change in temperature had a weak positive efect on the concurrent change in prevalence of infection in first intermediate hosts, but no efect on the change in prevalence or abundance of infection in second intermediate or defnitive hosts. This was true across habitat types and host taxa, indicating no universal efect of seasonal temperature increase on trematode infections. This surprising variation across systems suggests a predominance of idiosyncratic and species-specifc responses in trematode infection levels, at odds with any clear phenological or successional pattern. We discuss possible reasons for the minimal and variable efect of seasonal temperature regimes, and emphasise the challenges this poses for predicting ecosystem responses to future climate changepublishedVersio
Managing small populations—using genetic data and trial translocations to help inform suitable conservation measures for the alpine blue-sowthistle (Cicerbita alpina) in Scotland
Get PDFHabitat fragmentation is causing an increasing amount of species loss around the world and creates problems at the population level. Many species are left as only small and isolated populations, which are vulnerable to genetic erosion and inbreeding depression. Here we present a study on the alpine blue-sowthistle (Cicerbita alpina). Due to intensive grazing the species is very rare in Scotland, where it occurs at only four small, montane sites, has never been reported to reproduce and is in need of conservation interventions. As the species can grow clonally it is unknown how many individuals remain and whether populations are affected by genetic isolation. We (1) quantified genetic diversity, inbreeding and between-population differentiation in Scotland and Norway using 15 microsatellite loci, and (2) experimentally translocated plants to new sites. Genetic diversity in Scotland was low (HE: 0.35; Allelic Richness: 1.84; 4 sites) compared to Norway (HE: 0.52; Allelic Richness: 2.56; 5 sites). The transplants were able to grow at new sites and are therefore not restricted to steep, montane ledges. While grazing is likely to be the main factor preventing range expansion, long-term genetic isolation has possibly further lowered population viability. To avoid local extinction of this species, conservation translocations and genetic rescue might be appropriate conservation interventions, but this needs to be further tested in a controlled environment and away from wild sites to avoid potential risks of outbreeding depression. conservation genetics, translocations, gene flow, microsatellites, grazing, Scotland, AsteraceaepublishedVersio
Innslag av rømt oppdrettslaks i Altaelva og Repparfjordelva i 2023
Get PDFAltaelva
Av 485 innsendte skjellprøvene fra sportsfisket i Altaelva i 2023 var 481 (99,2 %) villaks, mens fire laks (0,8 %) var av ukjent opphav basert på skjellanalyse grunnet erstatningsskjell. Innslaget av oppdrettslaks i sportsfiskefangsten er 0 % og dermed i samme størrelsesorden som i de siste fem årene (variasjon: 0-0,7 %).
Fangsten av villaks i sportsfisket i 2023 var dominert av smålaks (< 3 kg) og storlaks (≥ 7 kg), som utgjorde henholdsvis 34 % og 42 % av den fangede villaksen. Mellomlaksen (3-7 kg) utgjorde 24 % av fangsten.
Skjellanalysene viste at smoltalder hos villaksen varierte mellom tre og seks år, hvor størsteparten (63 %) hadde vandret ut i sjøen etter fire år i elva. Sjøalder hos villaksen varierte mellom ett og syv år, hvor 45 % av fisken hadde vært ett år og 32 % hadde vært tre år i sjøen før tilbakevandring.
Totalt sett ble det fanget flere hanner enn hunner i sportsfisket (58 % hannfisk og 42 % hunnfisk).
I 2023 ble det gjennomført ordinært høstfiske med sportsfiskeutstyr i Altaelva i den siste uken i september. Det ble fisket i alle sonene unntatt Sautso. Totalt ble det sendt inn skjellprøver fra 35 laks, hvorav 34 var villaks og en var av usikkert opphav basert på skjellanalysen grunnet erstatningsskjell. Innslaget av sikker rømt oppdrettslaks (0 %) i den ordinære høstfiskefangsten i 2023 er i lik som i de siste fire foregående årene (va riasjon: 0-0,7 %).
Årsprosenten basert på prosentvist innslag av rømt oppdrettslaks i sport- og høstfisket i 2023 ble beregnet til 0 %. Dette er likt det i 2021 og 2022 (0 %), og lavere enn i 2013-2019 (variasjon: 0,3–10,6 %).
Repparfjordelva
Av 547 innsendte skjellprøver fra sportsfisket i Repparfjordvassdraget i 2023 var 540 (98,7 %) villaks, tre (0,5 %) rømt oppdrettslaks, én (0,2 %) kultivert laks og tre (0,7 %) laks var av ukjent opphav basert på skjellanalyse grunnet erstatningsskjell. Innslaget av oppdrettslaks i sportsfiskefangsten er dermed i samme størrelsesorden som i de siste fem årene (variasjon: 0 – 1 %).
Den ene av de tre rømte oppdrettslaksene veide 4,1 kg og var 65 cm lang og hadde mest sannsynlig rømt inneværende år. De to andre oppdrettslaksene veide henholdsvis 2 kg og 7,1 kg og var 57 og 85 cm lange. Den minste av disse to hadde vært et år i havet etter rømming, mens den største hadde vært minimum ett år i havet etter rømming.
Smålaks ( 7 kg) utgjorde henholdsvis 22 % og 5 % av fangsten.
Skjellanalysen viste at smoltalder hos villaksen varierte mellom tre og syv år, hvor størsteparten av laksen hadde vandret ut i sjøen etter fire (36 %) eller fem år (42 %) i elva. Sjøalder hos villaksen varierte mellom ett og fem år, hvor 71 % av fisken hadde vært ett år i sjøen før tilbakevandring.
Blant villaksen ble det totalt fanget flere hanner enn hunner i sportsfisket (60 % hannfisk og 40 % hunnfisk). De rømte oppdrettslaksene var to hanner og en hunnlaks