Publications
NIBIOs employees contribute to several hundred scientific articles and research reports every year. You can browse or search in our collection which contains references and links to these publications as well as other research and dissemination activities. The collection is continously updated with new and historical material.
2022
Authors
Vilde Lytskjold Haukenes Lisa Åsgård Johan Asplund Line Nybakken Jørund Rolstad Ken Olaf Storaunet Mikael OhlsonAbstract
Knowledge about the spatial variation of boreal forest soil carbon (C) stocks is limited, but crucial for establishing management practices that prevent losses of soil C. Here, we quantified the surface soil C stocks across small spatial scales, and aim to contribute to an improved understanding of the drivers involved in boreal forest soil C accumulation. Our study is based on C analyses of 192 soil cores, positioned and recorded systematically within a forest area of 11 ha. The study area is a south-central Norwegian boreal forest landscape, where the fire history for the past 650 years has been reconstructed. Soil C stocks ranged from 1.3 to 96.7 kg m−2 and were related to fire frequency, ecosystem productivity, vegetation attributes, and hydro-topography. Soil C stocks increased with soil nitrogen concentration, soil water content, Sphagnum- and litter-dominated forest floor vegetation, and proportion of silt in the mineral soil, and decreased with fire frequency in site 1, feathermoss- and lichen-dominated forest floor vegetation and increasing slope. Our results emphasize that boreal forest surface soil C stocks are highly variable in size across fine spatial scales, shaped by an interplay between historical forest fires, ecosystem productivity, forest floor vegetation, and hydro-topography.
Abstract
No abstract has been registered
Abstract
Knowledge of the temporal variation in reproductive success and its key driving factors is crucial in predicting animal population persistence. Few studies have examined the effects of a range of explanatory factors operating simultaneously on the same population over a long period. Based on 41 years of monitoring (1979–2019), we tested prevailing hypotheses about drivers of annual variation in breeding success in two sympatric species of boreal forest grouse—the capercaillie (Tetrao urogallus) and the black grouse (T. tetrix)—in a 45 km2 boreal forest landscape. From counts in early August, we measured breeding success (chicks/hen) along with potential determining factors. We formulated five main hypotheses on causes of variation (hen condition, chick weather, chick food, predation, demographic characteristics) and derived 13 associated explanatory variables for analysis. We first tested the five hypotheses separately and then used model selection (AICc) to rank the best predictive models irrespective of hypotheses. Lastly, we used path analysis to illuminate potential causal relationships. Barring demographic characteristics, all hypotheses were supported, most strongly for chick food and predation. Among predictor variables, chick food (insect larvae and bilberry fruit crops), vole and fox abundances, the winter-NAO index, and temperature after hatching, had the strongest effect sizes in both species. Precipitation after hatching had no detectable effect. Model selection indicated bottom-up factors to be more important than predation, but confounding complicated interpretation. Path analysis suggested that the high explanatory power of bilberry fruiting was due not only to its direct positive effect on chick food quality but also to an indirect positive effect on vole abundance, which buffers predation. The two components of breeding success—proportion of hens with broods and number of chicks per brood—were uncorrelated, the former having the strongest effect. The two components had different ecological correlates that often varied asynchronously, resulting in overall breeding success fluctuating around low to moderate levels. Our study highlights the complexity of key explanatory drivers and the importance of considering multiple hypotheses of breeding success. Although chick food appeared to equal or surpass predation in explaining the annual variation in breeding success, predation may still be the overall limiting factor. Comparative and experimental studies of confounded variables (bilberry fruiting, voles, and larvae) are needed to disentangle causes of variation in breeding success of boreal forest grouse.
Authors
Roberto Guidetti Łukasz Kaczmarek Milena Roszkowska Terje Meier Tommy Prestø K. Ingemar Jönsson James David Mervyn Speed Elisabeth Stur Ivar Gjerde Lasse Topstad Kristian Hassel Torbjørn EkremAbstract
Background: Tardigrades are common in most habitats, however few studies have focusedon large faunistic survey, specifically on tardigrade diversity in forests. Up to now, only 61 species have been recorded in different types of forest in Norway with an additional 25 found in limnic environments in forests. Although little is known about the ecological preferences of many species, previous studies have found that tardigrade diversity and community composition are significantly affected by ecological variables. In this study we associate georeferenced tardigrade species records with forest type, substrate type and substrate composition in order to see if tardigrade diversity and species communities can be associated with ecological characteristics of Norwegian forests. Methods: In total 390 moss, lichen and litter samples were collected from 12 forests in central and southern Norway in the summers of 2017 and 2018 and later stored in paper envelopes. For the identification modern literature and keys for specific genera and groups of species were used. For statistical analyses, moss and lichen substrate of each sample was classified according to the main species, life form, growth forms and habitat of substrate and associated with each tardigrade identification and sample metadata. Results: A total of 17 407 specimens were identified, encompassing in total 132 species (including some new species). Species richness increases with precipitation, but does not change with temperature or precipitation seasonality. The distribution of species richness between life forms and forest types showed considerable variation within and among the variables. Disregarding variables with low sample numbers, among life forms only acrocarpous moss samples appeared to deviate with respect to species richness, containing less species than substrates with other life forms. Conclusions: Tardigrades in Norwegian forest are extremely abundant, frequent and diverse. Moreover, it appears that that certain species and/or entire communities prefer specific microhabitats.
2021
Abstract
Old trees are important for biodiversity, and the process of their identification is a critical process in their conservation. However, determining the tree age by core extraction, ring counts, and eventually, cross-dating by means of dendrochronology is labor-intensive and expensive. Here we examine the alternative method of estimating determining tree age by visual characteristics for old Norway spruce and Scots pine trees. We used forest stands previously identified as “Old tree habitats” by visual criteria in Norwegian boreal forests. The efficiency of this method was tested using pairwise comparison of the age of core samples from trees within these sites, and within neighboring sites. Age regression models were constructed from morphological traits and site variables to investigate how accurately old trees can be detected. Cored trees in the Old-tree habitats were on average 41.9 years older than compared to a similar selection of trees from nearby mature forests. Several characteristics such as bark structure, stem taper and visible growth eccentricities can be used to identify old Norway spruce and Scots pine trees. Old trees were often found on less productive sites. Due to the wide range of environments included in the study, we suggest that these findings can be generalized to other parts of the boreal zone.
Abstract
During a three-day field trip to the Gaupne area, Luster kommune, three main localities were visited in search of lichens. A total of 35 lichens or lichenicolous fungi were found to be new to Sogn og Fjordane, most of which are also rare on a national scale. Three species on rocks, Calogaya biatorina, Lecanora gisleriana and L. subaurea, are red-listed and two species, Blastenia monticola and Caloplaca squamuleoisidiata, are new to Norway. Most of the species new to Sogn og Fjordane are calcicolous or prefer siliceous rocks containing high levels of heavy metals. The area around Gaupne is shown to be a previously unknown lichen hot-spot.
Abstract
Population fluctuations of small rodents are often synchronized over larger areas (>100 km) than what could be explained by dispersal, suggesting that the synchronizing factor is weather-related and possibly mediated through changes in food quality. Because bank vole (Myodes glareolus) populations usually peak 1 year after peaks in reproduction of the staple winter food plant bilberry (Vaccinium myrtillus), we tested for a possible link between food and spatial synchrony by comparing the synchrony in bank vole population indices and bilberry seed production indices between three study areas across about 20,000 km2 in South Norway during a four decade period (1979–2019). There were subperiods of spatial synchrony and asynchrony between the study areas in the fluctuations of bank vole numbers and bilberry seed production, with the latter part of the study period displaying more pronounced synchrony than the first and middle part. However, with a few marked exceptions, when vole fluctuations were spatially out of phase across study areas so was bilberry seed production. Thus, we conclude that bilberry seed production to a large extent explained the spatiotemporal synchronicity in bank vole population fluctuations. Although bilberry seed production seems to be a causal driver of vole fluctuations, it remains to be seen to what extent the chemical composition of bilberry plants influences vole performance. Finally, certain weather factors may still influence voles directly, or indirectly by triggering bilberry seed production.
2020
Abstract
Red-listed species are often used as target species in selection of sites for conservation. However, limitations to their use have been pointed out, and here we address the problem of expected high spatio-temporal dynamics of red-listed species. We used species data (vascular plants, bryophytes, macrolichens and polypore fungi) from two inventories 17 years apart to estimate temporal turnover of red-listed and non-red-listed species in two forest areas (147 and 195 ha) and of plots (0.25 ha) within each area. Furthermore, we investigated how turnover of species afected the rank order of plots regarding richness of red-listed species, using two diferent national Red List issues (1998 and 2015). In both study areas, temporal turnover was substantial, despite minor changes in the overall number of species. At plot level, temporal turnover in red-listed species was higher than in non-red-listed species, but similar to non-red-listed species of the same frequency of occurrence. Adding the efect of changing identities of species red-listed according to the two Red List issues, further increased the estimated spatio-temporal dynamics. Recorded spatio-temporal turnover also resulted in substantial changes in the rank order of plots regarding richness of red-listed species. Using rare red-listed species for site selection may therefore be accompanied by a higher loss of conservation efectiveness over time than for more common species, and particularly at fner scales. Red-listed species · Site selection · Spatio-temporal dynamics · Temporal turnover
Authors
N.G. Hodgetts Lars Söderström T.L. Blockeel S. Caspari M.S. Ignatov N.A. Konstantinova N. Lockhart B. Papp C. Schröck M. Sim-Sim D. Bell N.E. Bell Hans Blom M.A. Bruggeman-Nannenga M. Brugués J. Enroth Kjell Ivar Flatberg R. Garilleti L. Hedenäs D.T. Holyoak V. Hugonnot I. Kariyawasam H. Köckinger J. Kučera F. Lara R.D. PorleyAbstract
Introduction. Following on from work on the European bryophyte Red List, the taxonomically and nomenclaturally updated spreadsheets used for that project have been expanded into a new checklist for the bryophytes of Europe. Methods. A steering group of ten European bryologists was convened, and over the course of a year, the spreadsheets were compared with previous European checklists, and all changes noted. Recent literature was searched extensively. A taxonomic system was agreed, and the advice and expertise of many European bryologists sought. Key results. A new European checklist of bryophytes, comprising hornworts, liverworts and mosses, is presented. Fifteen new combinations are proposed. Conclusions. This checklist provides a snapshot of the current European bryophyte flora in 2019. It will already be out-of-date on publication, and further research, particularly molecular work, can be expected to result in many more changes over the next few years.
Authors
L.T. Ellis Olga M. Afonina I.V. Czernyadjeva L.A. Konoreva A.D. Potemkin V.M. Kotkova M. Alataş Hans Blom M. Boiko R.A. Cabral S. Jimenez D. Dagnino C. Turcato L. Minuto P. Erzberger T. Ezer Olga Galanina N. Hodgetts M.S. Ignatov Elena A. Ignatova S.G. Kazanovsky T. Kiebacher H. Köckinger E.O. Korolkova J. Larraín A.I. Maksimov D. Maity A. Martins M. Sim-Sim F. Monteiro L. Catarino R. Medina M. Nobis Arkadiusz Nowak Ryszard Ochyra I. Parnikoza V. Ivanets V. Plášek M. Philippe P. Saha Md. N. Aziz A.V. Shkurko S. Ştefănuţ G.M. Suárez A. Uygur K. Erkul M. Wierzgoń A. GraulichAbstract
No abstract has been registered