NINA Brage (Norsk institutt for naturforskning)
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Sub-arctic mosses and lichens show idiosyncratic responses to combinations of winter heatwaves, freezing and nitrogen deposition
Get PDFArctic ecosystems are increasingly exposed to extreme climatic events throughout the year, which can affect species performance. Cryptogams (bryophytes and lichens) provide important ecosystem services in polar ecosystems but may be physiologically affected or killed by extreme events. Through field and laboratory manipulations, we compared physiological responses of seven dominant sub-Arctic cryptogams (3 bryophytes, 4 lichens) to single events and factorial combinations of mid-winter heatwave (6°C for 7 days), re-freezing, snow removal and summer nitrogen addition. We aimed to identify which mosses and lichens are vulnerable to these abiotic extremes and if combinations would exacerbate physiological responses. Combinations of extremes resulted in stronger species responses but included idiosyncratic species-specific responses. Species that remained dormant during winter (March), irrespective of extremes, showed little physiological response during summer (August). However, winter physiological activity, and response to winter extremes, were not consistently associated with summer physiological impacts. Winter extremes affect cryptogam physiology, but summer responses appear mild, and lichens affect the photobiont more than the mycobiont. Accounting for Arctic cryptogam response to multiple climatic extremes in ecosystem functioning and modelling will require a better understanding of their winter eco-physiology and repair capabilities.publishedVersio
Comparing dominance relationships and movement of native marble trout (Salmo marmoratus) and introduced rainbow trout (Oncorhynchus mykiss)
Get PDFBehaviour observations of the endangered native marble trout (Salmo marmoratus,Cuvier, 1829) and introduced rainbow trout (Oncorhynchus mykiss, Walbaum, 1792)in the laboratory and in a tributary to the Idrijca River in Slovenia were combined tostudy the movements and dominance relationships between individuals of the twospecies in an open field test. Under laboratory conditions, no difference between thespecies was detected for neither time spent actively or distance moved. In speciespaired tests, rainbow trout initiated more aggressive behaviours towards marble troutthanvice versa, and rainbow trout were clearly the dominant individuals. After simul-taneous release in the river, marble trout immediately left the release area and spenttwice as long time as rainbow trout until they settled in an area of the river; there-fore, the release site was immediately occupied exclusively by rainbow trout. Thus,the dominant and aggressive behaviour of rainbow trout seen in the laboratorybefore release might have influenced marble trout's subsequent behaviour in theriver, by marble trout leaving the areas occupied by rainbow trout and moving tolocations further away from the release site. In the field, the marble trout occupiedsites individually, whereas rainbow aggregated at a few locations. Rainbow troutshowed higher movement activity in the morning compared to marble trout. Therewas a positive correlation between swimming speed in the laboratory and movementin the field for marble trout but not for rainbow trout. In conclusion, the results in thisstudy support the need to end stocking of rainbow trout in rivers with native marbletrout. To better understand the interaction between the species, and to develop effi-cient management plans to protect the native marble trout, reference behavioursshould first be understood, and future research in sites where the two species do not co-exist is needed. This is especially important for marble trout for which behaviouralresearch and data are lacking.acceptedVersio
Modellering av vanndekt areal og smoltproduksjon i Bævra
Get PDFDiserud, O.H., Bjørnås, K.L., Foldvik, A. & Ugedal, O. 2023. Modellering av vanndekt areal og smoltproduksjon i Bævra. NINA Rapport 2335. Norsk institutt for naturforskning.
Bævra er et dynamisk system med stor naturlig miljøvariasjon hvor det er utfordrende å måle fysiske og biologiske variabler på en standardisert måte og med tilstrekkelig presisjon. Det har derfor også vært utfordrende å identifisere eventuelle sammenhenger mellom vannføring og vanndekt areal, og ungfiskproduksjon. For å modellere vanndekt areal og ungfiskproduksjon er vi avhengige av vannføringstidsserier for samme periode som de fiskebiologiske undersøkelsene. En av de største utfordringene i dette prosjektet var den ujevne og usikre kvaliteten på de hydrologiske dataene fra Salsteinen målestasjon i Bævra. Den store usikkerheten gjorde at vi så oss nødt til å se bort fra målestasjonen og i stedet bruke tidsserien fra nabovassdraget Søya til å beregne variabler som beskriver variasjonen i vannføring innen og mellom år. Det å benytte data fra et sammenligningsfelt vil naturlig nok også introdusere en viss usikkerhet.
Sammenhengen mellom vanndekt areal og vannføring er etablert for de vannføringene og fotoseriene vi har tillit til. Med gode målinger for høye vannføringer, sammen med arealestimater basert på samtidige fotoserier, kan modellen for vanndekt areal standardiseres og kalibreres for hele vannføringsintervallet, slik at vi kan lese av relative endringer i vanndekt areal som funksjon av vannføring. For modelleringen av ungfiskproduksjonen er det ikke nødvendigvis noe problem at vi ikke har komplette, modellerte tidsserier for vanndekt areal. Vi har også tilpasset generalisert additive modeller som tillater ikke-lineære transformasjoner av forklaringsvariablene så hvis det er vanndekt areal som er mest relevant for miljøpåvirkningen på ungfiskproduksjon, vil det reflekteres i den ikke-lineære transformasjonen av vannføring.
Vi fant ingen signifikante sammenhenger mellom de vannføringsvariablene vi vurderte som aktuelle (laveste ukemiddel for vannføring om vinteren og om sommeren, eller høyeste vannføring om vinteren) og ungfiskrekruttering. Unntaket var en negativ effekt av høyeste vintervannføring på 0+ tetthet etterfølgende høst. I all modellering av ungfiskrekruttering var bidraget fra variasjonen i tidligere bestandstetthet først tatt hensyn til. Bestand-rekrutteringsmodelleringen uten vannføringsvariabler ga resultater som forventet for et vassdrag som Bævra men med større residualvariasjon enn vanlig, sannsynligvis forårsaket av en kombinasjon av stor usikkerhet i grunnlagsdata og stor naturlig miljøvariasjon. Det at vi ikke fant noen signifikant sammenheng mellom lave vannføringer og ungfiskrekruttering betyr at vi ikke har grunnlag for å predikere effekten av minstevannføringene i NVE sin innstilling på smoltproduksjonen i Bævra. Men et ikke-signifikant resultat betyr ikke nødvendigvis at det ikke er noen sammenheng mellom vannføring eller vanndekt areal og ungfiskproduksjon, bare at vi ikke har klart å vise sammenhengen med tilstrekkelig presisjon. Jo større naturlig miljøvariasjon og usikkerhet i grunnlagsdata, desto mer føre-var må miljøforvaltningen være (jf. Naturmangfoldloven) i eventuelle pålegg for å unngå kritisk lave bestandsnivå.
Selv om usikkerhetene og den naturlige variasjonen her var for store til at vi kunne konkludere om effektene av vannføring og vanndekt areal på ungfiskproduksjon vil metodikken og modelleringen som har blitt presentert kunne gjenbrukes hvis datagrunnlaget forbedres slik at vi får resultater som det kan festes mer lit til
A long-established invasive species alters the functioning of benthic biofilms in lakes
Get PDF1. Invasive species often transform environmental conditions, exclude native spe-cies and alter ecosystem functioning, including key ecosystem processes un-derpinning nutrient and energy cycles. However, such impacts have been most documented during periods of invasive species dominance; their influences on functioning at lower relative abundances and after long-term establishment are less well- known.
2. We investigated the effects of Elodea canadensis, a macrophyte native to North America with a long invasion history in many regions of the world, on the biomass accrual and metabolism of littoral zone biofilms growing on organic and inorganic substrates.
3. We deployed nutrient diffusing substrates (NDS) in 18 replicate transects distrib-uted across six lakes, comprising three invaded by E. canadensis and three unin-vaded reference lakes. NDS were amended with nitrogen (N), phosphorus (P) or N + P together, or were deployed as unamended controls. E. canadensis relative abundance varied widely in the invaded transects, ranging from 13% to 93% of all macrophyte cover.
4. On control substrates, algal biomass, quantified as Chlorophyll-a, and gross pri-mary production (GPP) were 42% and 78% greater in the invaded compared to uninvaded lakes, respectively. Respiration rates, attributable to responses of both autotrophs and heterotrophs, were 45% greater on control substrates in invaded lakes. By contrast, N-limitation of both biofilm GPP and respiration was 25% and 35% greater in uninvaded compared with invaded lakes.
5. There was no evidence for differences in nutrients, light availability or grazing pressure between invaded and uninvaded transects. Rather, the observed differ-ences in metabolism suggest that the presence of E. canadensis increases availabil-ity of N at local scales, reducing N-limitation of biofilms and resulting in elevated rates of biofilm productivity.
6. Our results demonstrate that invasive elodeids might have significant impacts on biofilms and processes associated with the cycling of nutrients, even when long- established and present at lower relative abundancespublishedVersio
Hunting for ecological indicators: are large herbivore skeleton measures from harvest data useful proxies for monitoring?
Get PDFHunter-collected data and samples are used as indices of population performance, and monitoring programs often take advantage of such data as ecological indicators. Here, we establish the relationships between measures of skeleton size (lower jawbone length and hind-leg length) and autumn carcass mass of slaughtered individuals of known age and sex of the high Arctic and endemic Svalbard reindeer (Rangifer tarandus platyrhynchus). We assess these relationships using a long-term monitoring dataset derived from hunted or culled reindeer. The two skeleton measures were generally strongly correlated within age class. Both jaw length (R2 = 0.78) and hind-leg length (R2 = 0.74) represented good proxies of carcass mass. These relationships were primarily due to an age effect (i.e. due to growth) as the skeleton measures reached an asymptotic size at 4–6 years of age. Accordingly, strong positive correlations between skeleton measures and carcass mass were mainly evident at the young age classes (range r [0.45–0.84] for calves and yearlings). For the adults, these relationships weakened due to skeletal growth ceasing in mature animals causing increased variance in mass with age—potentially due to the expected substantial impacts of annual environmental fluctuations. As proxies for carcass mass, skeleton measurements should therefore be limited to young individuals. Although body mass is the ‘gold standard’ in monitoring large herbivores, our results indicate that skeleton measures collected by hunters only provide similar valuable information for young age classes, particularly calves and yearlings. In sum, jaw length and hind-leg length function as proxies identical to body mass when documenting the impacts of changing environmental conditions on important state variables for reindeer and other herbivores inhabiting highly variable environments. Arctic · Citizen science · Hunter-collected data · Life history · Terrestrial large herbivoreHunting for ecological indicators: are large herbivore skeleton measures from harvest data useful proxies for monitoring?publishedVersio
Seasonal variation in urban pollen resource use by north temperate European honeybees
Get PDFUrban green infrastructure can provide important habitats for pollinators and support urban ecosystem services. Therefore, these areas must be managed to maximize biodiversity and density of pollinating insects. We used DNA metabarcoding to study honeybee pollen resource use over time and space in the city of Oslo, Norway, and to assess the role of green infrastructure as a resource for pollinators and the services they generate. Urban honeybees used diverse pollen resources throughout their active season. There was considerable seasonal turnover in pollen resource use that reflected flowering phenology. Non-native plants (including invasive species) were an important resource early in the season but were replaced by native plants later in the season. Hive location was not strongly correlated with resource use, likely indicating effective long-distance foraging in the fragmented urban landscape. However, flower visitation rates and floral resource density in public urban green spaces were coupled to pollen use. Honeybees collected pollen from a small number of preferred species but also visited other species, likely for nectar. To preserve pollinator services, urban planning should consider flower resource management, with particular focus on planting native species that can act as early season resources for bees. Public campaigns and other incentive mechanisms to promote the cultivation of native plants that are resources for pollinators and the protection of urban semi-natural habitats have the potential to enhance the value of green infrastructure to support urban pollinators and pollination services. Urban ecology · Pollination · Seasonality · Pollen diversity · Flower resources · Urban green infrastructure · Citizen sciencepublishedVersio
Tidlig oppdagelse av nye landlevende fremmede arter. Årsrapport for feltsesongen 2023. Morfologisk verifisering av enkelte DNA-funn fra 2022 og 2021
Get PDFJacobsen, R.M., Andreasen, M., Davey, M., Endrestøl, A., Fossøy, F., Laugsand, A.E., Staverløkk, A., Åström, J. 2023. Tidlig oppdagelse av nye landlevende fremmede arter. NINA Rapport 2370. Norsk institutt for naturforskning.
Tidlig oppdagelse av nye fremmede arter kan bidra til å unngå store økonomiske og økologiske konsekvenser, gitt at man følger opp med en rask utryddelse eller kontroll av potensielle problemarter. I 2018 og 2019 ble det derfor utviklet og testet metodikk for kartlegging av landlevende fremmede karplanter og insekter, der hovedmålet var oppdagelse av nye fremmede arter i tidlig etableringsfase i norsk natur. Fra 2020 ble det igangsatt årlig kartlegging av 25 ruter på 250x250m i Sørøst-Norge, og fra 2022 ble det foretatt gjenbesøk av ruter fra tidligere år, i henhold til opprinnelig overvåkingsdesign. Her rapporteres resultatene fra gjenbesøk i 2023 av de 25 rutene tidligere kartlagt i 2020, med unntak av resultatene fra DNA-metastrekkodingen som vil komme i en egen rapport i 2024 for å få tid til bioinformatikk og gjennomgang av artslistene før publisering.
Plantekartlegging og insektinnsamling ble utført på hver rute etter samme metodikk som tidligere år. Dette innebærer en fri kartlegging av alle fremmede plantearter, med særlig fokus på nye eller mindre vanlige arter, innen en tidsgrense på maks. 5 timer per rute. Planteartene ble i hovedsak identifisert i felt av erfarne botanikene. Forekomster av fremmede arter ble registrert med høypresisjons-GPS. Insekter ble samlet inn med en malaisefelle på hver rute, som ble satt opp i slutten av mai og tømt månedlig til slutten av september (fire tømminger totalt). Ved hver malaisefelle ble det montert dataloggere som registrerte temperatur, lysintensitet og luftfuktighet. Hver felleprøve er blitt veid (våtvekt), og gjennomsnittlig biomasse tilsvarer det som er blitt samlet inn tidligere år. Det er tydelig at mikroklima rundt fellen har en signifikant effekt på hvor mange insekter som fanges, da biomasse er sterkt korrelert med temperatur, lysintensitet og luftfuktighet registrert av dataloggerne. Artsidentifisering ved DNA-metastrekkoding vil rapporteres i 2024.
Totalt 145 fremmede plantearter ble registrert, samt to rødlistearter. Da dette er gjenbesøk av ruter kartlagt for tre år siden, var det færre nye eller usedvanlige arter. Et par nye fremmedarter er likevel verdt å nevne. Brasilsøtvier (Solanum sarrachoides) var kun registrert en gang i Norge i 1930 før den ble registrert på Øra i 2012, og igjen i dette prosjektet i 2023. Arten er ikke vurdert til fremmedartslista da den anses som for varmekrevende til å overleve i Norge, men vil med stor sannsynlighet bli registrert oftere i de kommende årene, i takt med klimaendringene. Brasilsøtvier kommer fra Sør-Amerika, men forekommer i Nord-Amerika som en relativt skadelig fremmedart i potetåkre. Karpatspirea (Spirea media) er også en mindre vanlig fremmedart, med kun seks tidligere funn, som ble funnet i dette prosjektet i 2023 på ruta Hyggen i Asker kommune. Karpatspirea er en østlig art som foreløpig er vurdert til å ha lav økologisk risiko, men som kan ha et økende potensiale for spredning og økologisk effekt med flere introduksjoner til og fra hager.
I tillegg til basiskartleggingen beskrevet over har vi i år forsøkt å verifisere tidligere DNA-baserte funn av potensielle nye fremmede insektarter, ved å finne individene i felleprøver fra 2022 og 2021, og identifisere dem morfologisk. Dette ble utprøvd for Hymenoptera, der egnede arter ble lett etter i ti malaisefelleprøver. Metodisk fungerte morfologisk verifisering godt for Hymenoptera, da individene var i relativt god stand etter lyseringen. Fire DNA-baserte identifiseringer ble verifisert, en art ble ansett som feilbestemt ved DNA-metodikken, og en ny fremmedart ble funnet som ikke var blitt påvist med DNA-metastrekkoding. Morfologisk verifisering kan være et verdifullt bidrag til overvåkingen og burde utarbeides som en standardisert del av DNA-basert overvåking av nye, fremmede insektarter.Jacobsen, R.M., Andreasen, M., Davey, M., Endrestøl, A., Fossøy, F., Laugsand, A.E., Staverløkk, A., Åström, J. 2023. Early detection of new terrestrial alien species. NINA Report 2370. Norwegian Institute for Nature Research.
Early detection of new alien species can result in prevention of great economic and ecological costs, provided it is followed up by rapid extermination or control of potentially problematic species. This was the rationale for developing (in 2018) and initiating (from 2019) a yearly survey of terrestrial alien vascular plants and insects (including Arachnida and Collembola), with the main goal being detection of new alien species in early establishment phase in Norwegian nature. From 2020, the standard for the yearly survey was 25 plots (250x250 meters) in Southeast Nor-way, with new plots being surveyed each year until 2021. Starting in 2022, we returned to previously surveyed plots to repeat the mapping of alien species of plants and insects. In this report, we present the results from resurveys in 2023 of plots previously surveyed in 2020. However, the results from DNA-metabarcoding of insects will be presented in a report in 2024, to get enough time for bioinformatics and quality control of species lists.
Plant surveys and insect sampling was conducted at each plot following the same methodology as previous years. For plants, this entails a free survey of all alien species, focusing on new or uncommon species, within a maximum timeframe of 5 hours per plot. Plant species were mainly identified in field by expert botanists. Occurrence of alien species was registered with high-precision GPS. Insects were sampled with one malaise trap in each plot, which was put up in the end of May and emptied monthly until the end of September (four sample periods in total). Loggers for temperature, light intensity and humidity were installed at each malaise trap. Each sample was weighed (wet weight) for biomass, which corresponds to catches in previous years. It was clear that microclimate around the trap significantly affected the catches, as biomass was strongly correlated with temperature, light intensity and humidity as registered by the loggers.
In total 145 alien plant species were registered in 2023, as well as two redlisted species. Since we are now revisiting plots surveyed three years ago, there are fewer new discoveries. Still, a couple of less common alien species are worth mention. Hairy nightshade (Solanum sarrachoides) had only been registered in Norway in 1930, and in Øra in Fredrikstad municipality in 2012, before it was again registered at Øra in this project in 2023. This South-American species has not been risk assessed for the Norwegian alien species list, since it is considered too de-
pendent on high temperatures to survive in Norway. However, it could very well become more frequent in the future following climate change, and in North-America it is a problematic alien species invading potato fields. Another uncommon alien species, Russian spirea (Spirea media), was registered in 2023 in Hyggen in Asker municipality. This is an Eurasian species with a distribution towards the east, which had only six previous registrations from Norway. It is considered low risk on the alien species list, but has a potential for increasing spread and ecological effect if it is frequently introduced to gardens and from there further into Norwegian nature.
This year, we have also attempted to verify DNA-based registrations of potentially new alien species of insects from previous years. We have searched for selected species of potentially new alien species of Hymenoptera in ten malaise trap samples from 2022 and 2021, and attempted to identify the individuals (if found) morphologically. Four DNA-based identifications were verified, one species was determined to be incorrectly identified based in DNA, and one new alien species was found that had not been detected by DNA-metabarcoding. Morphological verification proves to be a valuable addition to DNA-based surveillance of new, alien species, and should be developed into a standardised part of the survey
Recommendations for quantitative uncertainty consideration in ecology and evolution
Get PDFEcological and evolutionary studies are currently failing to achieve complete and
consistent reporting of model-related uncertainty. We identify three key barriers –
a focus on parameter-related uncertainty, obscure uncertainty metrics, and limited recognition of uncertainty propagation – which have led to gaps in uncertainty
consideration. However, these gaps can be closed. We propose that uncertainty
reporting in ecology and evolution can be improved through wider application of
existing statistical solutions and by adopting good practice from other scientific
fields. Our recommendations include greater consideration of input data and
model structure uncertainties, field-specific uncertainty standards for methods
and reporting, and increased uncertainty propagation through the use of hierarchical models.publishedVersio
The evolving story of catadromy in the European eel (Anguilla anguilla)
Get PDFAnguillid eels were once considered to be the classic example of catadromy. However, alternative life cycles have been reported, including skipping the freshwater phase and habitat shifting between fresh, brackish, and saltwater throughout the growth phase. There is a lack of knowledge regarding these alternate life strategies, for example, the proportion of individuals in the population that adopt them compared to classic catadromy. We provide a description of these alternate life cycle strategies in temperate anguillids, their possible drivers, and the methods available to investigate them. These methods (lethal and non-lethal), include otolith microchemistry, fatty acid and stable isotope analyses, parasite identification, blood transcriptomics, and electronic tags. We argue that since the current management framework for the European eel and other temperate eels is based mainly on the freshwater component of the population, it ignores eels growing in saline waters. Many of the factors that are thought to be responsible for the precipitous decline of the eel population are more prevalent in freshwater systems. Therefore, the contribution of saline eels may be more important than currently estimated. The habitat-shifting ability of eels may be all the more crucial for the persistence and recovery of those species that are endangered.publishedVersio