Norwegian Institute for Nature Research

Janik‐Superson K., Krawczyk D., Baranowska M., Królikowska K., Seweryn M., Lach J., Tończyk G., Strapagiel D., Bącela‐Spychalska K., Taugbøl A.

ABSTRACTMolecular traces are increasingly being applied to assess the presence of species and communities. Studies on environmental DNA (eDNA) have, to a large extent, become common practice in species detection, but less studies have compared biodiversity estimations with the more temporary environmental RNA (eRNA). This study compares metabarcoding results from pond water obtained from both molecule types by sequencing the V4 region in the 18S rRNA marker. Water was collected from two depths, 20 and 80 cm, and filtered sequentially through two filter porosities, 0.45 and 0.22 μm. Each filter was cut in half before fixation in either 96% ETOH or RNAlater. The results showed no differences between the fixatives for either molecule. Overall, biodiversity estimates from eDNA significantly overperformed eRNA, likely due to higher concentrations of eDNA from terrestrial sources. Comparisons of the two depths showed variation for eDNA only, with increasing levels of biodiversity found at the upper water layer. Both filter pore sizes captured distinctive compositions of taxa, where about 30% of the diversity was uniquely identified from the second, finer filter. Taken together, these findings imply that the choice of molecular marker, depth and filter pore size affects the obtained biodiversity estimations in a pond.

Martinossi‐Allibert I., Wacker S., Aparicio Estalella C., Kvarnemo C., Amundsen T.

Abstract Predicting the strength and direction of sexual selection is a challenge, as the effects of ecological factors, social environment and behavioural plasticity all need to be considered. The operational sex ratio (OSR) is a key variable, which has been shown to (i) affect the strength and direction of mating competition, as a social environment cue, and (ii) be affected itself by ecological conditions through sex‐specific environmental effects. Gaining a global view of (i) and (ii) in wild populations represents a necessary step for our understanding of sexual selection dynamics in the wild. Here, we address this challenge within the reaction norm framework. We conducted an extensive field study on the two‐spotted goby Pomatoschistus flavescens, monitoring six populations along a latitudinal gradient during an entire breeding season. We compared the temporal trajectories in social environment and sexual displays across populations, which is unprecedented. Using a reaction norm framework based on OSR theory, we show that what appears to be great variation in sexual displays across populations and sampling times, follows consistent rules. Sexual display behaviour followed behavioural reaction norms in response to the social environment that were consistent across populations, but social environment fluctuations were specific to each population. Recording behaviour not only over time, but also along a latitudinal gradient where ecological conditions vary and in turn affect OSR, was necessary to reveal the relationship between social environment and sexual displays, which in turn contributes to sexual selection dynamics.

Morten J.M., Carneiro A.P., Beal M., Bonnet‐Lebrun A., Dias M.P., Rouyer M., Harrison A., González‐Solís J., Jones V.R., Garcia Alonso V.A., Antolos M., Arata J.A., Barbraud C., Bell E.A., Bell M., et. al.

ABSTRACTAimTo identify the broad‐scale oceanic migration routes (‘marine flyways’) used by multiple pelagic, long‐distance migratory seabirds based on a global compilation of tracking data.LocationGlobal.Time Period1989–2023.Major Taxa StudiedSeabirds (Families: Phaethontidae, Hydrobatidae, Diomedeidae, Procellariidae, Laridae and Stercorariidae).MethodsWe collated a comprehensive global tracking dataset that included the migratory routes of 48 pelagic and long‐distance migrating seabird species across the Atlantic, Indian, Pacific and Southern Oceans. We grouped individuals that followed similar routes, independent of species or timings of migration, using a dynamic time warping clustering approach. We visualised the routes of each cluster using a line density analysis and used knowledge of seabird spatial ecology to combine the clusters to identify the broad‐scale flyways followed by most pelagic migratory seabirds tracked to‐date at an ocean‐basin scale.ResultsSix marine flyways were identified across the world's oceans: the Atlantic Ocean Flyway, North Indian Ocean Flyway, East Indian Ocean Flyway, West Pacific Ocean Flyway, Pacific Ocean Flyway and Southern Ocean Flyway. Generally, the flyways were used bidirectionally, and individuals either followed sections of a flyway, a complete flyway, or their movements linked two or more flyways. Transhemispheric figure‐of‐eight routes in the Atlantic and Pacific oceans, and a circumnavigation flyway in the Southern Ocean correspond with major wind‐driven ocean currents.Main ConclusionsThe marine flyways identified demonstrate that pelagic seabirds have similar and repeatable migration routes across ocean‐basin scales. Our study highlights the need to account for connectivity in seabird conservation and provides a framework for international cooperation.

Robertsen G., Burton T., Ugedal O., Ulvan E.M., Diserud O.H., Solem Ø., Spets M.H., Karlsson S., Fiske P.

ABSTRACTA management regulation applied in some recreational Atlantic salmon (Salmo salar) fisheries is a moratorium on harvest of female fish, which can only be effective if recreational anglers can consistently discriminate females from males. We used molecular methods to compare angler‐reported sexes of salmon captured in Norwegian populations with the true sexes of the same individuals. We made this comparison (i) among rivers that were subject to female no‐take policies or not within the same year; and (ii) within rivers before and after a female no‐take regulation was instituted. Sex was misclassified for ca. 25% of salmon that were true females, especially those that were large or captured early in the season. Furthermore, true females were misclassified more often when a female no‐take regulation was in effect. We conclude that a management regulation aimed at protecting female salmon in recreational fisheries may be less effective than expected.

Ouvrier A., Culos M., Guillerme S., Doré A., Figari H., Linnell J.D., Quenette P., Vimal R.

Abstract The recovery of large carnivores in Europe raises issues related to sharing landscape with humans. Beyond technical solutions, it is widely recognized that social factors also contribute to shaping coexistence. In this context, scholars increasingly stress the need to adopt place‐based approaches by analysing how humans and wildlife interact and co‐adapt in specific landscapes. In the burgeoning field of ‘more‐than‐human’ geography, both humans and non‐humans are considered as co‐constitutive of places. According to this tradition, animals should not simply be seen as objects under human control but approached as powerful actors in multi‐species landscapes. By tracking how brown bear recovery in the French Pyrenees has shaped different places of encounters with pastoralists (i.e. farmers and shepherds in extensive sheep farming in mountain pastures during summer), this paper discusses what coexistence means when viewed through the lens of more‐than‐human geography. We use an in‐depth, retrospective and multi‐sources approach to describe the inter‐relationships of bears and pastoralists on three mountain pastures since the return of bears at the end of the 1990s. Semi structured interviews, participant observation, administrative and institutional data about bear depredation and genetics, as well as pastoral practices form the basis of an integrated narrative analysis. Our study reveals how the return of a large carnivore has produced three different, singular, context‐specific coexistence ‘patches’. Each of these three pastures represent a distinct landscape dynamically shaped over time by bears, pastoralists and the rest of biotic and abiotic environment. Specifically, we demonstrate how various factors—the individual behaviour of bears, their movement and reproduction capacity, the number of depredations, the pastoralists' histories, their collective organization, the choices they made, the pastures' features, the available resources and surrounding vegetation—cumulatively intertwine in complex, place‐specific entanglements. Policy implications. Our results suggest that coexistence should not be conceptualized as global, top down and standardized. Instead it is shaped by patches in which humans and non‐humans interact in specific ways. Therefore, fostering coexistence means acknowledging the full diversity of situations in which people and wildlife write their own place‐based, more‐than‐human histories. Read the free Plain Language Summary for this article on the Journal blog.

Snell K., Machado dos Santos I., van Bemmelen R., Moe B., Thorup K.

Steep declines in Arctic skua populations in the southern extent of their breeding range have been reported during the last half of the 20th century. We used 24 yr of ringing and re-encounter data from the Faroe Islands, North Atlantic, to investigate if patterns in survival probabilities can be explained by large-scale climatic events. Having first determined the migratory phenology and wintering regions, we estimated the effects of the North Atlantic Oscillation (NAO) index on survival during breeding and the Oceanic Niño index (ONI) during the non-breeding period within a capture-mark-recapture framework. Temporal trends along with direct and time-lagged effects of the environment on annual survival were modelled. We found support for a substantial decrease in adult annual survival, from ca. 0.93 in 1985 to ca. 0.77 in 2008, and weak support for a decrease in young (first year) survival over the duration of the study period. Furthermore, models indicated increased young survival following an El Niño winter. We suggest this time-lagged effect reflects downstream propagation of environmental conditions, particularly food availability, or a potential carry-over effect of El Niño conditions positively impacting the performance of the parents in the subsequent breeding season, leading to improved young survival prospects. While adult mortality cannot be attributed to the oceanic climate oscillations tested here, the negative trend in survival may account for the substantial population declines observed over the last decades.

August T., Balzan M., Bodesheim P., Brehm G., Cantú-Salazar L., Castro S., Chipperfield J., Ghisbain G., Gomez-Segura A., Goulnik J., Groom Q., Hogeweg L., Huijbers C., Kamilaris A., Kazlauskis K., et. al.

The InsectAI COST action will support insect monitoring and conservation at the national and continental scale in order to understand and counteract widespread insect declines. The Action will bring together a critical mass of researchers and stakeholders in image-based insect AI technologies to direct and drive the research agenda, build research capacity across Europe and support innovation and application. There is mounting evidence that populations of insects around the world are in sharp decline. Understanding trends in species and their drivers is key to knowing the size of the challenge, its causes and how to address it. To identify solutions that lead to sustainable biodiversity alongside economic prosperity, insect monitoring should be efficient and provide standardised and frequently updated status indicators to guide conservation actions. The EU Biodiversity Strategy 2030 identifies the critical challenge of delivering standardised information about the state of nature and image-based insect AI can contribute to this. Specifically, the EU Nature Restoration Law will likely set binding targets for the high resolution data that cameras can provide. Thus, outputs of the Action will contribute directly to EU policies implementation, where biodiversity monitoring is considered a key component. The InsectAI COST Action will organise workshops, conferences, short-term scientific missions, hackathons, design-sprints and much more, across four Working Groups. These groups will address how image-based insect AI technologies can best address Societal Needs, support innovation in Image Collection hardware, create standardised approaches for Image Processing and develop novel Data Analysis and Integration methods for turning data into actionable insights.

Oksanen L., Vuorinen K.E., Kyrö K., Mäkynen A., Olofsson J., Ruffino L., Tuomi M., Oksanen T.

In his classical contributions, Olavi Kalela proposed that, due to the low primary productivity of the tundra, Norwegian lemmings are locked in a strong interaction with their winter forage plants. Proposedly, Norwegian lemmings respond to the threat of critical resource depletion by conducting long‐range migrations at their population peaks. A tacit premise of this conjecture is that predation pressure on the Fennoscandian tundra is too weak to prevent runaway increases of lemming populations, creating violent boom–crash dynamics. Our results on the dynamics of Norwegian lemmings on the Finnmarksvidda tundra during 1977–2017 are in line with the predictions of Kalela's hypothesis. In contrast to the Siberian and North American tundra, densities of avian predators in our study area have been low even during lemming years, and efficient ones have been lacking from lemming habitats. Lemmings have thus increased unhinged in peak summers and crashed to densities below the trappability threshold during post‐peak winters. Each lemming crash has been accompanied by massive habitat destruction. Indications of predator activity have been concentrated to productive shrublands, where lemmings have never reached high densities. Young lemmings have responded to high densities by becoming extremely mobile: they have been trapped in large numbers on islands, including a small island in the middle of Iešjávri, a 10 × 8 km tundra lake. Many lemmings have been seen swimming across the lake, and many drowned lemmings have been observed. The dynamics and behavior of Norwegian lemmings recorded by us differ radically from those of other Lemmus spp., indicating that cycles generated by lemming–vegetation interactions have two alternative states – one with and the other without intense summer predation. We propose that the cycles of Norwegian lemmings shifted to the latter state during their unique evolutionary history, when they survived the Last Glacial Maximum in a tiny refugium archipelago.

Nenzén H.K., Moor H., O'Hara R.B., Jönsson M., Nordén J., Ottosson E., Snäll T.

AbstractUnderstanding the distribution and dynamics of species is central to ecology and important for managing biodiversity. The distributions of species in metacommunities are determined by many factors, including environmental conditions and interactions between species. Yet, it is difficult to quantify the effect of species interactions on metacommunity dynamics from observational data. We present an approach to estimate the importance of species interactions that combines data from two observational presence–absence inventories (providing colonization–extinction data) with data from species interaction experiments (providing informative prior distributions in the Bayesian framework). We further illustrate the approach on wood‐decay fungi that interact within a downed log through competition for resources and space, and facilitate the succession of other species by decomposing the wood. Specifically, we estimated the relative importance of species interactions by examining how the presence of a species influenced the colonization and extinction probability of other species. Temporal data on fruit body occurrence of 12 species inventoried twice were jointly analyzed with experimental data from two laboratory experiments that aimed to estimate competitive interactions. Both environmental variables and species interactions affected colonization and extinction dynamics. Late‐successional fungi had more colonization interactions with predecessor species than early‐successional species. We identified several species interactions, and the presence of certain species changed the probability that later‐successional species colonized by −81% to 512%. The presence of certain species increased the probability that other species went extinct from a log by 14%–61%. Including the informative priors from experimental data added two colonization interactions and one extinction interaction for which the observational field data was inconclusive. However, most species had no detectable interactions, either because they did not interact or because of low species occupancy, meaning data limitation. We show how temporal presence‐absence data can be combined with experimental data to identify which species influence the colonization‐extinction dynamics of others. Accounting for species interactions in metacommunity models, in addition to environmental drivers, is important because interactions can have cascading effects on other species.

Nyheim Ø.S., Pascual A.S., Odden J., Thorsen N.H., Bischof R.

AbstractDomestic cats (Felis catus), both feral animals and pets, are a major threat to biodiversity. While domestic cats are closely associated with human residences and activity, they also range into and impact natural areas. We still know little about how free‐ranging cats use natural and semi‐natural areas. We quantified cat occurrence at 405 forest sites in Norway over 3 years using occupancy modeling, and tested how occurrence patterns were influenced by relevant landscape variables. Cat occupancy decreased with increasing distance from residential houses, being >60% within 50 m of the nearest house, but even at 1000 m distance, occupancy still exceeded 10%. When cats were present in forests, they were more likely to be detected close to forest edges. Detection probability was lowest and declined more steeply with increased distance from the forest edge during winter, when temperature, vegetation cover, and prey availability are at their lowest. We conclude that cats may pose a threat in natural areas like forests even at considerable distances from residences. We encourage further studies that investigate the role of landscape characteristics and environmental conditions on habitat penetration by both feral and pet domestic cats.

Su X., Bejarano M.D., Jansson R., Pilotto F., Sarneel J.M., Lin F., Wang Y., Cai F., Wu S., Zeng B.

ABSTRACTOver two‐thirds of global rivers are subjected to flow regulation. Although it is widely recognized that flow regulation can adversely affect riparian vegetation—a critical component of river ecosystems—the specific roles of various drivers remain poorly understood. To address this gap, we conducted a broad‐scale meta‐analysis, aiming to elucidate how different factors mediate the adverse impacts of flow regulation on riparian vegetation. This meta‐analysis encompassed 59 papers, spanning 278 dams constructed on 146 rivers. We extracted data on four key indices of riparian vegetation: species richness and abundance of all riparian species, and those indices exclusively for non‐native species. Indices were compared between regulated and free‐flowing or pre‐damming rivers to quantify the impact of flow regulation. Our meta‐analysis revealed a moderate but significant reduction in the richness and abundance of all riparian species under flow regulation, coupled with a strong increase in the abundance of non‐native species. Riparian vegetation in arid and continental climate regions experienced stronger negative impacts than those in tropical and temperate climates. Furthermore, the adverse effects on riparian vegetation were more pronounced downstream of dams than upstream. Considering climate region, study identity, and relative position to the dam as random variables, it became evident that years since flow regulation emerged as the most important factor influencing species richness. Over time, richness gradually recovered from initially low levels. However, this recovery was slowed by increasing flow regulation intensity (percentage of annual runoff stored). Additionally, the impact was more evident in larger rivers. To support regulated river management, we recommend prioritizing the protection of riparian vegetation in arid and continental climates, with emphasis on areas downstream of dams, limiting flow regulation intensity, particularly in larger rivers, and monitoring non‐native species to prevent disproportionate spread.

Bårdsen B., Tømmervik H., Næss M.W., Bjerke J.W.

AbstractIn an era marked by accelerating climate change, habitat loss, and shifting land use patterns, it is crucial to understand the intricate effects of multiple stressors on ecosystems. This long‐term study sheds light on the complex interplay between grazing and habitat characteristics on pasture dynamics and offers insights into how various stressors affect ecosystems facing environmental challenges. Our experimental study documents that manipulation in restricting reindeer grazing and trampling through fencing led to higher ground‐lichen biomass, volume, height (particularly in one habitat), and cover compared with open‐control plots. The effect of fencing varied depending on habitat, and for lichen biomass, volume, and height, the lowest values were observed in windswept exposed ridges and mountain heaths (exposed/mountain), and the highest values were observed in forested and leeward‐heath (forest/leeward) habitat. The average (past five years) number of reindeer per square kilometer had indirect effects that varied across habitats. We observed negative density dependence in the open plots for height in the exposed/mountain habitats. Fencing reduced this effect, which was also valid for biomass except that habitat did not affect the effect of density. Surprisingly, in the forest/leeward areas, the estimated effects of reindeer density on biomass, volume, and height were positive for the fenced plots. Negative density dependence was evident for lichen cover irrespective of habitats and manipulation, even though this effect had little biological significance, whereas cover at the initiation of the experiment positively affected later recordings (particularly for the controls). Our models showed high explanatory power, highlighting the significance of reindeer density and habitat as predictors of ground‐lichen dynamics. Overall, negative density‐dependent effects were observed in the open plots in the most exposed areas, and fencing mitigated the negative impact of reindeer on lichens, particularly in less exposed areas. We challenge the “equilibrium” and “nonequilibrium” frameworks for explaining livestock‐pasture dynamics. We propose future studies to estimate the relative importance of density‐dependent and density‐independent factors, such as climate, using models considering both mechanisms simultaneously.

Finne E.A., Bjerke J.W., Stordal F., Tallaksen L.M.

Abstract Extreme weather events influence carbon cycling and lead to pervasive changes in ecosystem structure and function. Vegetation at high latitudes and in alpine bioclimatic zones can be particularly sensitive to winter warming events, which are short‐lived climatic events where temperatures are unusually high and often include rainfall. With climate change the frequency and severity of winter warming events are increasing. We report here from a field experiment on a lichen‐dominated ridge at a high mountain plateau in central Norway. This is a common vegetation type at high latitudes and altitudes, yet little is known about ecophysiological responses to winter warming events in lichens, and how it may differ from responses in bryophytes and vascular plants. We ran a week‐long simulation of vegetation stress from winter warming events through thaw–freeze and ice encasement, during late winter in 2021 and 2022. The thaw–freeze treatment had minor effects on summer ecophysiology in lichens (Cladonia mitis, Cetraria islandica and Nephromopsis nivalis), while the species N. nivalis and to a lesser extent, C. mitis had reduced vitality after the ice encasement treatment. Contrastingly, the bryophyte Polytrichum juniperinum, and vascular plant Empetrum nigrum had reduced photosynthetic efficiency and seasonal growth in both thaw–freeze and ice encasement treatments. The ice encasement treatment was overall more lethal and led to reduced NDVI (Normalised Difference Vegetation Index). However, reduction in vitality of vascular and non‐vascular plants was not enough to impact overall ecosystem carbon flux. Synthesis: The lichen's stronger tolerance against thaw–freeze and ice encasement than co‐existing plants oppose the general effects of summer climate warming, where lichens may succumb under greater plant‐growth and warmer soils. This study advocates for the importance of year‐round ecology to understand vegetation change under climate change.

Olve K., Helene F., Bjørn K.

Abstract This study explores the impact of NIMBY (Not In My Backyard) sentiments on local resistance to wind power developments in Norway. With a reopening of concession processing for new onshore wind power projects in 2022, a significant number of applications await evaluation, provoking substantial local opposition. This research assesses the prevalence and impact of NIMBY attitudes among the Norwegian public and to critically examine the theoretical validity and practical utility of the NIMBY concept. Using data from an online survey, which yielded 1220 complete responses, we analyzed general attitudes toward wind power in Norway and specific attitudes toward local wind power installations. While 37% of respondents support wind power construction in Norway, only 27% favor it near their homes. Based on the relationship between these two attitudes, we identified the proportion of NIMBYs in the data using two approaches. A strict definition requires individuals to support wind power in Norway but oppose its presence in the natural areas near their own homes. A less strict definition also includes those who expressed a neutral stance toward wind power in Norway among the NIMBYs. In both cases, a relatively small segment of respondents exhibit classic NIMBY characteristics, i.e., support (or claim neutrality) to wind power in general but opposing it locally. Further analysis reveals that direct experience with wind power installations is associated with increased acceptance rather than opposition, challenging the NIMBY narrative. Our study argues that labeling local resistance as NIMBYism oversimplifies the issue and ignores other significant factors like environmental identity, place attachment, and broader environmental attitudes. Hence, the study suggests that blaming wind power opponents as “Nimbys” often is misplaced and unjust.

Davis S., Grainger M., Pfeifer M., Pattison Z., Stephens P., Sanderson R.

Abstract Background Riparian zones are vital transitional habitats that bridge the gap between terrestrial and aquatic ecosystems. They support elevated levels of biodiversity and provide an array of important regulatory and provisioning ecosystem services, of which, many are fundamentally important to human well-being, such as the maintenance of water quality and the mitigation of flood risk along waterways. Increasing anthropogenic pressures resulting from agricultural intensification, industry development and the expansion of infrastructure in tropical regions have led to the widespread degradation of riparian habitats resulting in biodiversity loss and decreased resilience to flooding and erosion. Considering climate change and its associated effects on freshwater systems, the need to build resilience and adaptive capacities is pertinent. This has prompted the need to protect existing riparian habitats and the implementation of solutions to restore these degraded habitats to recover their functional capacity. This systematic map will aim to identify and collate existing literature on approaches for riparian restoration implemented in tropical regions and identify what indicators have been used to measure outcomes for biodiversity and human well-being. The resulting collation of evidence will help to identify current knowledge gaps and inform the direction of future research. Methods To address the aims of this systematic map, a search of pre-identified bibliographic databases will be undertaken using a set string of search terms. In addition to this, a grey literature search will be conducted using Google Scholar and by searching for references using specialist websites. All literature that is gathered will be screened by title, abstract and full text using a two-phase screening process which adheres to a pre-determined eligibility criteria. Data will then be coded from the collated group of articles using a pre-designed data coding sheet. Heterogeneity will likely be present in the data; therefore, studies will be grouped appropriately based on the restoration strategy implemented and, on the type of outcome measured. These will be presented as sub-groups. A narrative synthesis of map findings will be produced, this will outline the distribution and frequency of restoration interventions, and outcomes measured, and will highlight evidence gaps to direct future research.