E134 Oslofjordforbindelsen - Forundersøkelser i resipienter 2022

Etter oppdrag fra Statens vegvesen har NIBIO utført forundersøkelser i bekker, tjern og marine områder som vil kunne berøres av anleggsaktivitet under bygging av E134 Oslofjordforbindelsen. Forundersøkelsene har omfattet vannkjemi, bunndyr- og fiskeundersøkelser samt prøvetaking og analyse av eDNA. Samlet omfattet forundersøkelsene 21 stasjoner fordelt på bekker og elver, tjern og marine områder.E134 Oslofjordforbindelsen - Forundersøkelser i resipienter 2022publishedVersio

Ancient origin and maternal inheritance of blue cuckoo eggs

Maternal inheritance via the female-specific W chromosome was long ago proposed as a potential solution to the evolutionary enigma of co-existing host-specific races (or 'gentes') in avian brood parasites. Here we report the first unambiguous evidence for maternal inheritance of egg colouration in the brood-parasitic common cuckoo Cuculus canorus. Females laying blue eggs belong to an ancient (∼2.6 Myr) maternal lineage, as evidenced by both mitochondrial and W-linked DNA, but are indistinguishable at nuclear DNA from other common cuckoos. Hence, cuckoo host races with blue eggs are distinguished only by maternally inherited components of the genome, which maintain host-specific adaptation despite interbreeding among males and females reared by different hosts. A mitochondrial phylogeny suggests that blue eggs originated in Asia and then expanded westwards as female cuckoos laying blue eggs interbred with the existing European population, introducing an adaptive trait that expanded the range of potential hosts

Finding the needle in the haystack: Comparison of methods for salmon louse enumeration in plankton samples

The economic and social implications of salmon louse (Lepeophtheirus salmonis) epidemics in salmon aquaculture drive focus of the dispersal dynamics of the planktonic larval stages. The vast spatial scale and high connectivity of the marine environment creates difficult conditions to monitor the infective planktonic louse stage, whereby the number of samples required for a representative description is bottlenecked by processing capacity. This study assessed five quantification methods for accuracy and precision in enumeration of lice in plankton samples, validated against the benchmark method of light microscopy. Visual-based (fluorescence microscopy and automated fluid imaging) and molecular-based (droplet digital PCR, quantitative fraction PCR and quantitative PCR) were tested using high- and low-density plankton samples spiked with louse copepodids, with spike numbers blind to assessors. We propose an approach to comparative assessment that uses the collective bias and deviation of a test method to determine whether it is acceptably similar to the benchmark method. Under this framework, no methods passed the comparative test, with only ddPCR comparable to light microscopy (87% mean accuracy and 74% precision). qfPCR and fluorescence microscopy were moderately efficient (88% and 67% accuracy, and 36% and 52% precision respectively). Molecular techniques are currently restricted in distinguishing between larval stages, which is an essential distinction for some research questions, but can be economical in processing numerous samples. Overall method suitability will depend on the research objectives and resources available. These results provide evidence for operational accuracy for the tested methods and highlight the direction for further development to optimize their use

Designing a surveillance program for early detection of alien plants and insects in Norway

Naturalized species of alien plants and animals comprise < 3% of biodiversity recorded in Norway but have had major impacts on natural ecosystems through displacement of native species. Encroachment of alien species has been especially problematic for coastal sites close to transport facilities and urban areas with high density housing. The goal of our field project was to design and test a surveillance program for early detection of alien species of vascular plants and terrestrial insects at the first phase of establishment in natural areas. In our 3-year project (2018–2020), we sampled 60 study plots in three counties in the Oslofjord region of southern Norway. Study plots (6.25 ha) were selected by two criteria: manual selection based on expert opinion (27 plots) or by random selection based on weights from a hotspot analysis of occurrence of alien species (33 plots). Vascular plants were surveyed by two experienced botanists who found a total of 239 alien species of vascular plants in 95 rounds of surveys. Insects and other invertebrates were captured with a single Malaise trap per site, with 3–4 rounds of repeated sampling. We used DNA-metabarcoding to identify invertebrates based on DNA extractions from crushed insects or from the preservative media. Over 3500 invertebrate taxa were detected in 255 rounds of sampling. We recorded 20 alien species of known risk, and 115 species that were new to Norway, including several ‘doorknocker’ species identified by previous risk assessments. We modeled the probabilities of occupancy (ψ) and detection (p) with occupancy models with repeated visits by multiple observers (vascular plants) or multiple rounds of sampling (insects). The two probabilities covaried with risk category for alien organisms and both were low for species categorized as no known or low risk (range = 0.052–0.326) but were higher for species categorized as severe risk (range = 0.318–0.651)... Arthropods · DNA-metabarcoding · Early detection · Invasive · Invertebrates · Occupancy models · Rapid response · Study design · Vascular plantsDesigning a surveillance program for early detection of alien plants and insects in NorwaypublishedVersio

Sex Allocation in Relation to Host Races in the Brood-Parasitic Common Cuckoo (Cuculus canorus)

Sex allocation theory and empirical evidence both suggest that natural selection should favour maternal control of offspring sex ratio in relation to their ability to invest in the offspring. Generalist parasites constitute a particularly interesting group to test this theory as different females commonly utilize different host species showing large variation in provisioning ability. The common cuckoo (Cuculus canorus) is a generalist brood parasite that lays its eggs in the nest of many different passerine birds, but each female tends to specialize on one particular host species giving rise to highly specialized host races. The different host species show large variation in their ability to invest in the parasitic offspring, presenting an opportunity for female cuckoos to bias offspring sex ratio in relation to host species quality. Here, we investigate host-race specific sex allocation controlling for maternal identity in the common cuckoo. We found no evidence of any significant relationship between host race and sex ratio in one sympatric population harbouring three different host races, or in a total of five geographically separated populations. There was also no significant association between host quality, as determined by species-specific female host body mass, and cuckoo sex ratio. Finally, we found no significant relationship between individual cuckoo maternal quality, as determined by her egg volume, and sex ratio within each host race. We conclude that the generalist brood-parasitic common cuckoo show no significant sex-ratio bias in relation to host race and discuss this finding in light of gene flow and host adaptations

Metodikk for kartlegging og overvåkning av fremmede marine arter i Norge - Forslag til nasjonalt program

Norge har i dag overvåkning av enkelte fremmede marine arter og en sporadisk generell kartlegging av forekomsten av slike arter langs deler av kysten. Det er derfor behov for en systematisk plan for kartlegging og overvåkning av fremmede marine arter i Norge. Når man skal lage en slik plan er det viktig å vite hvilke arter som kan forventes til landet, hvordan de kan komme seg hit, hvor de lever og hvor i landet de mest sannsynlig vil etablere seg først. Her gis en analyse av levested for etablerte arter og arter som forventes til landet, som kan danne basis for valg av metodikk. Begroing av skrog er trolig den vektoren som i dag utgjør den største risikoen for introduksjon av fremmede marine arter. Her gis en detaljert oversikt over havner som har høy risiko for slike introduksjoner basert på frekvensen av anløp direkte fra utenlandsk havn. Denne vurderingen danner basis for ett rullerende overvåkningsprogram etter internasjonale anbefalinger. Rapporten gir også en oppsummerende oversikt over eksisterende internasjonal metodikk og basert på dette gis tre alternative metodikkforslag for norskekysten. Forslagene som presenteres har ulik intensitet og vil ha store forskjeller i kostnader. Det anbefales at ulike metoder prøves ut for å vurdere effektiviteten og gi mer nøyaktige kostnadsoverslag.publishedVersio

Alien marine species in Norway - Mapping, monitoring and assessment of vectors for introductions

Norway has the second longest coastline in the world, and it is challenging to monitor non-indigenous marine species (NIMS) along the entire shore including the Norwegian areas in the Barents Sea and along Svalbard. There is currently no national program for such monitoring, however some activity is taking place on specific species and organism groups which is presented here. Historically transport of NIMS is ballast water have been the main pathway into the Norwegian coast, but with the implementation of the Ballast Water Convention this risk is minimized. Biofouling on vessels coming into the Norwegian coast is thus considered to be the most important vector for marine introduction of new species. An analysis of the frequency and origin (last port call) for 158 000 vessel arrivals into Norwegian ports in the period 2020-2021 is presented. The results show that the Oslofjord area and the west coast is the areas with highest risk for marine introductions by vessels. Other vectors for such introductions into Norway are evaluated like the increasing amount of floating debris which can carry fouling organisms, larvae and eggs to new areas. An analysis of historical data for the established NIMS in Norway show that the southern area of Norway is most susceptible to new species. This pattern is not only dependent on the vector pressure but also reflects the temperature gradient northwards along the coast. Measures for prevention of new species to arrive and management of problematic species is also discussed.publishedVersio

First-Time Migration in Juvenile Common Cuckoos Documented by Satellite Tracking

Being an obligate parasite, juvenile common cuckoos Cuculus canorus are thought to reachtheir African wintering grounds from Palearctic breeding grounds without guidance fromexperienced conspecifics but this has not been documented. We used satellite tracking tostudy naïve migrating common cuckoos. Juvenile cuckoos left breeding sites in Finlandmoving slowly and less consistently directed than adult cuckoos. Migration of the juveniles(N = 5) was initiated later than adults (N = 20), was directed toward the southwest±significantlydifferent from the initial southeast direction of adults±and included strikingly long BalticSea crossings (N = 3). After initial migration of juvenile cuckoos toward Poland, themigration direction changed and proceeded due south, directly toward the winter grounds,as revealed by a single tag transmitting until arrival in Northwest Angola where northernadult cuckoos regularly winter. Compared to adults, the juvenile travelled straighter andfaster, potentially correcting for wind drift along the route. That both migration route and timingdiffered from adults indicates that juvenile cuckoos are able to reach proper winteringgrounds independently, guided only by their innate migration programme.</p

Emerging technologies revolutionise insect ecology and monitoring

Insects are the most diverse group of animals on Earth, but their small size and high diversity have always made them challenging to study. Recent technologi- cal advances have the potential to revolutionise insect ecology and monitoring. We describe the state of the art of four technologies (computer vision, acoustic monitoring, radar, and molecular methods), and assess their advantages, current limitations, and future potential. We discuss how these technologies can adhere to modern standards of data curation and transparency, their implications for citizen science, and their potential for integration among different monitoring programmes and technologies. We argue that they provide unprecedented possibilities for insect ecology and monitoring, but it will be important to foster international standards via collaborationpublishedVersio