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W dniach 15–17 marca 2022 r. w Instytucie Badawczym Leśnictwa odbyła się XII Sesja Zimowej Szkoły Leśnej, której tematem był „Wpływ zmian klimatu na środowisko leśne”. Spośród licznych propozycji, o wyborze powyższego tematu przesądziło obserwowane od wielu lat systematyczne pogorszanie się stanu zdrowotnego drzewostanów na skutek synergicznego oddziaływania wielu czynników abiotycznych i biotycznych w warunkach zmian klimatu. Współorganizatorem Sesji była Dyrekcja Generalna Lasów Państwowych. Merytoryczne aspekty XII Sesji zostały przygotowane i opracowane przez Radę Programową Zimowej Szkoły Leśnej w składzie: dr hab. Krzysztof Stereńczak, prof. IBL (przewodniczący), prof. dr hab. Bogdan Brzeziecki, mgr inż. Michał Graczyk, prof. dr hab. Andrzej Grzywacz, prof. dr hab. Andrzej Jagodziński, prof. dr hab. Janusz Olejnik, mgr inż. Jan Tabor, mgr inż. Krzysztof Rostek, prof. dr hab. Iwona Skrzecz, dr inż. Klaudia Ziemblińska. Rada Programowa określiła nie tylko zakres problematyki XII Sesji, ale także propozycje tematyczne referatów zamawianych oraz ich autorów. W trakcie trzech dni obrad prelegenci przedstawili 33 referaty. Referaty wygłosili również zaproszeni goście zagraniczni reprezentujący: Uniwersytet w Helsinkach, Czeski Uniwersytet Przyrodniczy w Pradze, Instytut Badań nad Zmianami Globalnymi (Czechy), Uniwersytet Wspólnoty Wirginii, Łotewski Państwowy Instytut Badawczy Leśnictwa oraz Integrated Carbon Observation System. W XII Sesji, która odbyła się w wersji online, wzięło udział niemal 200 osób reprezentujących m.in.: Ministerstwo Klimatu i Środowiska, jednostki organizacyjne Lasów Państwowych, ośrodki uniwersyteckie i instytuty badawcze. Liczne grono stanowili również przedstawiciele ośrodków naukowych oraz polskich uczelni leśnych.

1. There is a growing recognition that functional measures of diversity, based on quantification of functionally important species traits, are useful for explaining variation in ecosystem processes. However, the mechanisms linking functional diversity to different processes remain poorly understood, hindering development of a predictive framework for ecosystem functioning based on species traits. 2. The current understanding of how the functional traits of aquatic plants (macrophytes) affect nitrogen (N) cycling by regulating microbial communities and their activity in freshwater habitats is particularly limited. Denitrifying bacteria are typically associated with the roots of both aquatic and terrestrial plants and denitrification is the main cause of loss of N from ecosystems. Disentangling the interplay between plants and microbial denitrifiers is key to understanding variation in rates of denitrification from local to landscape scales. 3. In a mesocosm experiment, we varied the species richness (monocultures or two-species mixtures) and composition of macrophytes. We quantified effects of both macrophyte functional diversity, quantified as functional trait dissimilarity, and functional trait composition, quantified as community weighted mean trait values, on N removal in wetlands. We used structural equation modelling to disentangle the direct and indirect influences of traits on N accumulation in plant biomass, denitrification activity and abundance of key bacterial denitrification genes (nirS and nirK). 4. Both functional diversity and functional trait composition regulated N removal, explaining 70%–94% variation in the underlying ecosystem processes. Increased macrophyte functional diversity increased plant N accumulation, and indirectly enhanced denitrification by increasing denitrification gene abundance. Among traits, greater plant relative growth rates, specific leaf area and above-ground biomass increased plant N accumulation. Denitrification activity increased with increasing below-ground biomass but decreased with increasing root diameter. 5. These findings improve our understanding of N removal in freshwater wetlands dominated by macrophytes, and have broad ecological implications for wetland management targeting enhanced ecosystem services. Our results highlight the potential for optimizing denitrification and plant N accumulation in wetlands and thereby improving water purification by increasing macrophyte functional diversity and ensuring the presence of key traits in macrophyte assemblages. biodiversity, denitrification, ecosystem functioning, ecosystem service, functional diversity, functional traits, macrophytes, plant uptake

Anthropogenic changes to land use drive concomitant changes in biodiversity, including that of the soil microbiota. However, it is not clear how increasing intensity of human disturbance is reflected in the soil microbial communities. To address this issue, we used amplicon sequencing to quantify the microbiota (bacteria and fungi) in the soil of forests (n=312) experiencing four different land uses, national parks (set aside for nature conservation), managed (for forestry purposes), suburban (on the border of an urban area) and urban (fully within a town or city), which broadly represent a gradient of anthropogenic disturbance. Alpha diversity of bacteria and fungi increased with increasing levels of anthropogenic disturbance, and was thus highest in urban forest soils and lowest in the national parks. The forest soil microbial communities were structured according to the level of anthropogenic disturbance, with a clear urban signature evident in both bacteria and fungi. Despite notable differences in community composition, there was little change in the predicted functional traits of urban bacteria. By contrast, urban soils exhibited a marked loss of ectomycorrhizal fungi. Soil pH was positively correlated with the level of disturbance, and thus was the strongest predictor of variation in alpha and beta diversity of forest soil communities, indicating a role of soil alkalinity in structuring urban soil microbial communities. Hence, our study shows how the properties of urban forest soils promote an increase in microbial diversity and a change in forest soil microbiota composition. peerReviewed

Robust demonstration case-studies are needed to evaluatewhether improvements in ecosystem condition are translated into improvements in ecosystem services. This research is essential for effectively scaling-up nature-based solutions across Europe and providing the evidence to support transformation agendas in society and industries, and ultimately supporting the ambitions of the European Green Deal. Clear guidance and standardised indicators help monitor the impact of freshwater and wetland restoration measures on European Green Deal goals. These monitoring indicators should include environmental indicators (e.g. for biodiversity, greenhouse gas emissions and water storage capacity) as well as socio-economic indicators such as stakeholder representation, private finance mobilisation and job creation. A combined Before-After-Control-Intervention (BACI) monitoring design is recommended to provide robust evidence and attribute change to the restoration measures. Benchmark (cost or effort) and local/regional context data (e.g. land use, governance) are also needed alongside monitoring of impacts to not just measurewhathas happened at a site but to understandwhyit has happened. &nbsp

Many zoonotic diseases are weather sensitive, raising concern how their distribution and outbreaks will be affected by climate change. At northern high latitudes, the effect of global warming on especially winter conditions is strong. By using long term monitoring data (1980–1986 and 2003–2013) from Northern Europe on temperature, precipitation, an endemic zoonotic pathogen (Puumala orthohantavirus, PUUV) and its reservoir host (the bank vole, Myodes glareolus), we show that early winters have become increasingly wet, with a knock-on effect on pathogen transmission in its reservoir host population. Further, our study is the first to show a climate change effect on an endemic northern zoonosis, that is not induced by increased host abundance or distribution, demonstrating that climate change can also alter transmission intensity within host populations. Our results suggest that rainy early winters accelerate PUUV transmission in bank voles in winter, likely increasing the human zoonotic risk in the North. Supplementary Information The online version contains supplementary material available at 10.1007/s13280-021-01594-y.

Aim Animal migrations influence ecosystem structure, dynamics and persistence of predator and prey populations. The theory of migratory coupling postulates that aggregations of migrant prey can induce large-scale synchronized movements in predators, and this coupling is consequential for the dynamics of ecological communities. The degree to which humans influence these interactions remains largely unknown. We tested whether creation of large resource pulses by humans such as seasonal herding of reindeer Rangifer tarandus and hunting of moose, Alces alces, can induce migratory coupling with Golden Eagles, Aquila chrysaetos, and whether these lead to demographic consequences for the eagles. Location Fennoscandia. Methods We used movement data from 32 tracked Golden Eagles spanning 125 annual migratory cycles over 8 years. We obtained reindeer distribution data through collaboration with reindeer herders based on satellite tracking of reindeer, and moose harvest data from the national hunting statistics for Sweden. We assessed demographic consequences for eagles from ingesting lead from ammunition fragments in moose carcasses through survival estimates and their links with lead concentrations in eagles' blood. Results In spring, eagles migrated hundreds of kilometres to be spatially and temporally coupled with calving reindeer, whereas in autumn, eagles matched their distribution with the location and timing of moose hunt. Juveniles were more likely to couple with reindeer calving, whereas adults were particularly drawn to areas of higher moose harvest. Due to this coupling, eagles ingested lead from spent ammunition in moose offal and carcasses and the resulting lead toxicity increased the risk of mortality by 3.4 times. Main conclusions We show how migratory coupling connects landscape processes and that human actions can influence migratory coupling over large spatial scales and increase demographic risks for predators. We provide vital knowledge towards resolving human-wildlife conflicts and the conservation of protected species over a large spatial and temporal scale.

‘Staggering disease’ is a neurological disorder considered a threat to European domestic cats (Felis catus) for almost five decades. However, its aetiology has remained obscure. Rustrela virus (RusV), a relative of rubella virus, has recently been shown to be associated with encephalitis in a broad range of mammalian hosts. Here, we report the detection of RusV RNA and antigen by metagenomic sequencing, RT-qPCR, in-situ hybridization and immunohistochemistry in brain tissues of 28 out of 29 cats with non-suppurative meningoencephalomyelitis and ‘staggering disease’-like neurological disorder from Sweden, Austria, and Germany, but not in non-affected control cats. Screening of possible reservoir hosts in Sweden revealed RusV infection in wood mice (Apodemus sylvaticus). Our work strongly indicates RusV as the long-sought cause of feline ‘staggering disease’. Given its broad host spectrum and considerable geographic range, RusV may be the aetiological agent of neuropathologies in further mammals, possibly even including humans.

Unravelling patterns and mechanisms of biogeographical transitions is crucial if we are to understand compositional gradientsat large spatial extents, but no studies have thus far examined breakpoints in community composition of freshwater plants acrosscontinents. Using a dataset of almost 500 observations of lake plant community composition from six continents, we examined,for the first time, if such breakpoints in geographical space exist for freshwater plants and how well a suite of ecological factors(including climatic and local environmental variables) can explain transitions in community composition from the subtropicsto the poles. Our combination of multivariate regression tree (MRT) analysis and k-means partitioning suggests that the mostabrupt breakpoint exists between temperate to boreal regions on the one hand and freshwater plant communities harbouringmainly subtropical or Mediterranean assemblages on the other. The spatially structured variation in current climatic conditionsis the most likely candidate for controlling these latitudinal patterns, although one cannot rule out joint effects of eco-evolutionary constraints in the harsher high-latitude environments and post-glacial migration lags after Pleistocene Ice Ages. Overall, ourstudy supports the foundations of global regionalisation for freshwater plants and anticipates further biogeographical researchon freshwater plant communities once datasets have been harmonised for conducting large-scale spatial analyses.

Population fluctuations are widespread across the animal kingdom, especially in the order Rodentia, which includes many globally important reservoir species for zoonotic pathogens. The implications of these fluctuations for zoonotic spillover remain poorly understood. Here, we report a global empirical analysis of data describing the linkages between habitat use, population fluctuations and zoonotic reservoir status in rodents. Our quantitative synthesis is based on data collated from papers and databases. We show that the magnitude of population fluctuations combined with species' synanthropy and degree of human exploitation together distinguish most rodent reservoirs at a global scale, a result that was consistent across all pathogen types and pathogen transmission modes. Our spatial analyses identified hotspots of high transmission risk, including regions where reservoir species dominate the rodent community. Beyond rodents, these generalities inform our understanding of how natural and anthropogenic factors interact to increase the risk of zoonotic spillover in a rapidly changing world.

The development of new diagnostic methods resulted in the discovery of novel hepaciviruses in wild populations of the bank vole (Myodes glareolus, syn. Clethrionomys glareolus). The naturally infected voles demonstrate signs of hepatitis similar to those induced by hepatitis C virus (HCV) in humans. The aim of the present research was to investigate the geographical distribution of bank vole-associated hepaciviruses (BvHVs) and their genetic diversity in Europe. Real-time reverse transcription polymerase chain reaction (RT-qPCR) screening revealed BvHV RNA in 442 out of 1838 (24.0%) bank voles from nine European countries and in one of seven northern red-backed voles (Myodes rutilus, syn. Clethrionomys rutilus). BvHV RNA was not found in any other small mammal species (n = 23) tested here. Phylogenetic and isolation-by-distance analyses confirmed the occurrence of both BvHV species (Hepacivirus F and Hepacivirus J) and their sympatric occurrence at several trapping sites in two countries. The broad geographical distribution of BvHVs across Europe was associated with their presence in bank voles of different evolutionary lineages. The extensive geographical distribution and high levels of genetic diversity of BvHVs, as well as the high population fluctuations of bank voles and occasional commensalism in some parts of Europe warrant future studies on the zoonotic potential of BvHVs.

Tularemia is a widely spread zoonotic disease in the northern hemisphere, caused by the bacterium Francisella tularensis. In humans, tularemia is an acute febrile illness with incidence peaks in late summer to early autumn of outbreak years, but there is no early warning system in place that can reduce the impact of disease by providing timely risk information. In this study, we revisit previously unpublished data on F. tularensis in water, sediment, soil, and small mammals from 1984 in northern Sweden. In addition, we used human case data from the national surveillance system for tularemia in the same year. In the environmental and small mammal material, bank vole (Myodes glareolus) samples from urine and bladder were the only samples that tested positive for F. tularensis. The prevalence of F. tularensis among trapped bank voles was 13.5%, although all six bank voles that were retrieved from owl nest boxes in early May tested positive. Forty-two human tularemia cases were reported from August to December in 1984. Based on these results, we encourage investigating the potential role of tularemia-infected bank voles retrieved from owl nest boxes in spring as an early warning for outbreaks of tularemia among humans in summer and autumn of the same year.

Constructed floating wetlands (CFWs) have been tested in different climatic regions and aquatic habitat types for nitrogen (N) removal from surface water, but there is limited knowledge about their applicability for N removal in cold climate regions. Most CFWs studies are conducted at the micro- or mesocosm scale, while the application of CFWs at in situ is rare. Moreover, most CFWs studies have focused on plant N accumulation without considering macrophyte root-associated denitrification as a possible N removal pathway. Here, we study the N removal potential of CFWs through N accumulation by macrophytes and potential denitrification activity (PDA) associated with plants. At a mining area in the sub-arctic region of Sweden receiving N-rich mine effluents, we tested the concept of CFWs and evaluated the performance of six native, emerging macrophyte species planted in CFWs. The CFWs were deployed in two types of systems: in situ in the recipient lake, subjected to ambient N concentrations, and CFWs placed in water-side “eco-tanks”, subjected to higher N concentrations. We showed that macrophyte establishment in CFWs is feasible under cold climatic conditions, both in situ and eco-tanks. The standing biomass of macrophytes, bulk N accumulation in plant biomass and PDA in mesocosms were 0.54–2.25 kg m−2, 7.56–24.75 mg N m−2 d−1 and 31.82–2250.77 mg N2O-N m−2 d−1, respectively. In the recipient, the variation was larger and the values were higher (standing biomass, 0.37–6.74 kg m−2; bulk N accumulation, 8.09–106.93 mg N m−2 d−1; PDA, 11.89–8446.15 mg N m−2 d−1). Macrophyte root-associated denitrification was the main N removal pathway in the CFWs. Given the demonstrated applicability of CFWs and the high denitrification rates that can be obtained, future studies should focus on designing CFWs to enhance denitrification as this process leads to permanent removal of N from the water phase.

Lemmings are a key component of tundra food webs and changes in their dynamics can affect the whole ecosystem. We present a comprehensive overview of lemming monitoring and research activities, and assess recent trends in lemming abundance across the circumpolar Arctic. Since 2000, lemmings have been monitored at 49 sites of which 38 are still active. The sites were not evenly distributed with notably Russia and high Arctic Canada underrepresented. Abundance was monitored at all sites, but methods and levels of precision varied greatly. Other important attributes such as health, genetic diversity and potential drivers of population change, were often not monitored. There was no evidence that lemming populations were decreasing in general, although a negative trend was detected for low arctic populations sympatric with voles. To keep the pace of arctic change, we recommend maintaining long-term programmes while harmonizing methods, improving spatial coverage and integrating an ecosystem perspective. ELECTRONIC SUPPLEMENTARY MATERIAL: The online version of this article (10.1007/s13280-019-01198-7) contains supplementary material, which is available to authorized users.

Context: Community composition, environmental variation, and spatial structuring can influence ecosystem functioning, and ecosystem service delivery. While the role of space in regulating ecosystem functioning is well recognised in theory, it is rarely considered explicitly in empirical studies. Objectives: We evaluated the role of spatial structuring within and between regions in explaining the functioning of 36 reference and human-impacted streams. Methods: We gathered information on regional and local environmental variables, communities (taxonomy and traits), and used variance partitioning analysis to explain seven indicators of ecosystem functioning. Results: Variation in functional indicators was explained not only by environmental variables and community composition, but also by geographic position, with sometimes high joint variation among the explanatory factors. This suggests spatial structuring in ecosystem functioning beyond that attributable to species sorting along environmental gradients. Spatial structuring at the within-region scale potentially arose from movements of species and materials among habitat patches. Spatial structuring at the between-region scale was more pervasive, occurring both in analyses of individual ecosystem processes and of the full functional matrix, and is likely to partly reflect phenotypic variation in the traits of functionally important species. Characterising communities by their traits rather than taxonomy did not increase the total variation explained, but did allow for a better discrimination of the role of space. Conclusions: These results demonstrate the value of accounting for the role of spatial structuring to increase explanatory power in studies of ecosystem processes, and underpin more robust management of the ecosystem services supported by those processes.

AIM: To determine whether reintroduced beavers, as an example of native herbivorous megafauna, can increase freshwater biodiversity at the landscape scale and to compare effects on two contrasting taxonomic groups. LOCATION: South‐central Sweden. METHODS: We collected data on plant and water beetle composition and supporting environmental variables from 20 closely located wetlands, half created from the damming of streams by beavers—beaver ponds (BP), and half by other, mainly natural (e.g. topographic, river migration) means—other wetlands (OW). Differences in species composition and plant growth strategy (i.e. competitor, stress tolerator or ruderal) between wetland types were assessed using multivariate analyses. RESULTS: The species pool of both taxonomic groups was higher in BP than OW (plants + 17%; beetles + 15%). For both groups, the number of species unique to BP was 50% higher than those unique to OW. Plant and beetle compositions differed significantly between wetlands, most strongly for plants, while rarity scores showed no difference, and the incidence of invasive species was negligible. Plant composition was mostly influenced by open water, bare ground and woody debris in BP, and plant cover, height and leaf litter in OW. This was consistent with the characterization of BP vegetation by ruderal plants and OW by competitors and stress tolerators. A significant residual effect of wetland type on plant, but not beetle composition, suggests that beavers exert important direct effects on some biota (e.g. via herbivory) independent of the indirect effects they exert via environmental change. MAIN CONCLUSIONS: Beaver‐created ponds support novel biodiversity that is not merely a subset of that found elsewhere in the same landscape. As such, re‐establishing beaver populations where they are native should benefit freshwater biodiversity, but effects may be context and taxon specific. Beavers alone cannot solve the freshwater biodiversity crisis, but recognizing the widespread importance of herbivorous megafauna in maintaining heterogeneity and creating novel habitat will be a positive step.

This is a post-peer-review, pre-copyedit version of an article published in Ambio. The final authenticated version is available online at: http://dx.doi.org/10.1007/s13280-019-01198-7. Lemmings are a key component of tundra food webs and changes in their dynamics can affect the whole ecosystem. We present a comprehensive overview of lemming monitoring and research activities, and assess recent trends in lemming abundance across the circumpolar Arctic. Since 2000, lemmings have been monitored at 49 sites of which 38 are still active. The sites were not evenly distributed with notably Russia and high Arctic Canada underrepresented. Abundance was monitored at all sites, but methods and levels of precision varied greatly. Other important attributes such as health, genetic diversity and potential drivers of population change, were often not monitored. There was no evidence that lemming populations were decreasing in general, although a negative trend was detected for low arctic populations sympatric with voles. To keep the pace of arctic change, we recommend maintaining long-term programmes while harmonizing methods, improving spatial coverage and integrating an ecosystem perspective.

Predicting risk of zoonotic diseases, i.e., diseases shared by humans and animals, is often complicated by the population ecology of wildlife host(s). We here demonstrate how ecological knowledge of a disease system can be used for early prediction of human risk using Puumala hantavirus (PUUV) in bank voles (Myodes glareolus), which causes Nephropathia epidemica (NE) in humans, as a model system. Bank vole populations at northern latitudes exhibit multiannual fluctuations in density and spatial distribution, a phenomenon that has been studied extensively. Nevertheless, existing studies predict NE incidence only a few months before an outbreak. We used a time series on cyclic bank vole population density (1972–2013), their PUUV infection rates (1979–1986; 2003–2013), and NE incidence in Sweden (1990–2013). Depending on the relationship between vole density and infection prevalence (proportion of infected animals), either overall density of bank voles or the density of infected bank voles may be used to predict seasonal NE incidence. The density and spatial distribution of voles at density minima of a population cycle contribute to the early warning of NE risk later at its cyclic peak. When bank voles remain relatively widespread in the landscape during cyclic minima, PUUV can spread from a high baseline during a cycle, culminating in high prevalence in bank voles and potentially high NE risk during peak densities.

The picornavirus named ‘Ljungan virus’ (LV, species Parechovirus B) has been detected in a dozen small mammal species from across Europe, but detailed information on its genetic diversity and host specificity is lacking. Here, we analyze the evolutionary relationships of LV variants circulating in free-living mammal populations by comparing the phylogenetics of the VP1 region (encoding the capsid protein and associated with LV serotype) and the 3Dpol region (encoding the RNA polymerase) from 24 LV RNA-positive animals and a fragment of the 5′ untranslated region (UTR) sequence (used for defining strains) in sympatric small mammals. We define three new VP1 genotypes: two in bank voles (Myodes glareolus) (genotype 8 from Finland, Sweden, France, and Italy, and genotype 9 from France and Italy) and one in field voles (Microtus arvalis) (genotype 7 from Finland). There are several other indications that LV variants are host-specific, at least in parts of their range. Our results suggest that LV evolution is rapid, ongoing and affected by genetic drift, purifying selection, spillover and host evolutionary history. Although recent studies suggest that LV does not have zoonotic potential, its widespread geographical and host distribution in natural populations of well-characterized small mammals could make it useful as a model for studying RNA virus evolution and transmission.

In 2012, Tigray orthohantavirus was discovered in Ethiopia, but its seasonal infection in small mammals, and whether it poses a risk to humans was unknown. The occurrence of small mammals, rodents and shrews, in human inhabitations in northern Ethiopia is affected by season and presence of stone bunds. We sampled small mammals in two seasons from low- and high-density stone bund fields adjacent to houses and community-protected semi-natural habitats in Atsbi and Hagere Selam, where Tigray orthohantavirus was first discovered. We collected blood samples from both small mammals and residents using filter paper. The presence of orthohantavirus-reactive antibodies in blood was then analyzed using immunofluorescence assay (human samples) and enzyme linked immunosorbent assays (small mammal samples) with Puumala orthohantavirus as antigen. Viral RNA was detected by RT-PCR using small mammal blood samples. Total orthohantavirus prevalence (antibodies or virus RNA) in the small mammals was 3.37%. The positive animals were three Stenocephalemys albipes rats (prevalence in this species = 13.04%). The low prevalence made it impossible to determine whether season and stone bunds were associated with orthohantavirus prevalence in the small mammals. In humans, we report the first detection of orthohantavirus-reactive IgG antibodies in Ethiopia (seroprevalence = 5.26%). S. albipes lives in close proximity to humans, likely increasing the risk of zoonotic transmission.

Background Several ungulate species are feeding and propagation hosts for the tick Ixodes ricinus as well as hosts to a wide range of zoonotic pathogens. Here, we focus on Anaplasma phagocytophilum and Borrelia burgdorferi (s.l.), two important pathogens for which ungulates are amplifying and dilution hosts, respectively. Ungulate management is one of the main tools to mitigate human health risks associated with these tick-borne pathogens. Across Europe, different species of ungulates are expanding their ranges and increasing in numbers. It is currently unclear if and how the relative contribution to the life-cycle of I. ricinus and the transmission cycles of tick-borne pathogens differ among these species. In this study, we aimed to identify these relative contributions for five European ungulate species. Methods We quantified the tick load and collected ticks and spleen samples from hunted fallow deer (Dama dama, n = 131), moose (Alces alces, n = 15), red deer (Cervus elaphus, n = 61), roe deer (Capreolus capreolus, n = 30) and wild boar (Sus scrofa, n = 87) in south-central Sweden. We investigated the presence of tick-borne pathogens in ticks and spleen samples using real-time PCR. We determined if ungulate species differed in tick load (prevalence and intensity) and in infection prevalence in their tissue as well as in the ticks feeding on them. Results Wild boar hosted fewer adult female ticks than any of the deer species, indicating that deer are more important as propagation hosts. Among the deer species, moose had the lowest number of female ticks, while there was no difference among the other deer species. Given the low number of infected nymphs, the relative contribution of all ungulate species to the transmission of B. burgdorferi (s.l.) was low. Fallow deer, red deer and roe deer contributed more to the transmission of A. phagocytophilum than wild boar. Conclusions The ungulate species clearly differed in their role as a propagation host and in the transmission of B. burgdorferi and A. phagocytophilum. This study provides crucial information for ungulate management as a tool to mitigate zoonotic disease risk and argues for adapting management approaches to the local ungulate species composition and the pathogen(s) of concern. Graphic abstract

International audience; Ljungan virus (LV), which belongs to the Parechovirus genus in the Picornaviridae family, was first isolated from bank voles (Myodes glareolus) in Sweden in 1998 and proposed as a zoonotic agent. To improve knowledge of the host association and geographical distribution of LV, tissues from 1685 animals belonging to multiple rodent and insectivore species from 12 European countries were screened for LV-RNA using reverse transcriptase (RT)-PCR. In addition, we investigated how the prevalence of LV-RNA in bank voles is associated with various intrinsic and extrinsic factors. We show that LV is widespread geographically, having been detected in at least one host species in nine European countries. Twelve out of 21 species screened were LV-RNA PCR positive, including, for the first time, the red vole (Myodes rutilus) and the root or tundra vole (Alexandromys formerly Microtus oeconomus), as well as in insectivores, including the bicolored white-toothed shrew (Crocidura leucodon) and the Valais shrew (Sorex antinorii). Results indicated that bank voles are the main rodent host for this virus (overall RT-PCR prevalence: 15.2%). Linear modeling of intrinsic and extrinsic factors that could impact LV prevalence showed a concave-down relationship between body mass and LV occurrence, so that subadults had the highest LV positivity, but LV in older animals was less prevalent. Also, LV prevalence was higher in autumn and lower in spring, and the amount of precipitation recorded during the 6 months preceding the trapping date was negatively correlated with the presence of the virus. Phylogenetic analysis on the 185 base pair species-specific sequence of the 5 ' untranslated region identified high genetic diversity (46.5%) between 80 haplotypes, although no geographical or host-specific patterns of diversity were detected.

Tularemia is a widely spread zoonotic disease in the northern hemisphere, caused by the bacterium

Documenting the patterns of biological diversity on Earth has always been a central challenge in macroecology and biogeography. However, for the diverse group of freshwater plants, such research program is still in its in- fancy. Here, we examined global variation in taxonomic, functional and phylogenetic beta diversity patterns of lake macrophytes using regional data from six continents. A data set of ca. 480 lake macrophyte community ob- servations, together with climatic, geographical and environmental variables, was compiled across 16 regions worldwide. We (a) built the very first phylogeny comprising most freshwater plant lineages; (b) exploited a wide array of functional traits that are important to macrophyte autoecology or that relate to lake ecosystem functioning; (c) assessed if different large-scale beta diversity patterns show a clear latitudinal gradient from the equator to the poles using null models; and (d) employed evolutionary and regression models to first identify the degree to which the studied functional traits show a phylogenetic signal, and then to estimate community- environment relationships at multiple spatial scales. Our results supported the notion that ecological niches evolved independently of phylogeny in macrophyte lineages worldwide. We also showed that taxonomic and phylogenetic beta diversity followed the typical global trend with higher diversity in the tropics. In addition, we were able to confirm that species, multi-trait and lineage compositions were first and foremost structured by climatic conditions at relatively broad spatial scales. Perhaps more importantly, we showed that large-scale processes along latitudinal and elevational gradients have left a strong footprint in the current diversity patterns and community-environment relationships in lake macrophytes. Overall, our results stress the need for an inte- grative approach to macroecology, biogeography and conservation biology, combining multiple diversity facets at different spatial scales. JGG appreciates financial support from the Spanish Ministry of Economy and Industry [project METAPONDS, grant CGL2017- 84176R], the Junta de Castilla y León [grant LE004G18] and from the Fundación Biodiversidad (Spanish Ministry for Ecological Transi- tion and Demographic Challenge). BAL was supported by National Research, Development and Innovation Fund [grant NKFIH, OTKA PD120775] and by the Bolyai János Research Scholarship of the Hun- garian Academy of Sciences. S.K. was supported by NWO Veni [grant 86312012]. Sampling of the coastal Brazilian lakes was financed by NWO [grant W84-549]; The National Geographic Society [grant 7864-5]; and CNPq [grants 480122, 490409, 311427]. We thank the SALGA team, especially Gissell Lacerot, Nestor Mazzeo, Vera Huszar, David da Motta Marques, and Erik Jeppesen for organizing and exe- cuting the SALGA field sampling campaign and Bruno Irgang† and Eduardo Alonso Paz for helping with identification. We thank Minne- sota and Wisconsin Departments of Natural Resources for collecting the macrophyte data. We are grateful to Carol Reschke for her work in combining and performing quality control for the Minnesota mac- rophyte data used in the analysis. This is contribution no. 607 of the Natural Resources Research Inst. of the Univ. of Minnesota Duluth. Provision of New Zealand macrophyte data was possible via NIWA SSIF funding. JGG appreciates financial support from the Spanish Ministry of Economy and Industry [project METAPONDS, grant CGL2017- 84176R], the Junta de Castilla y León [grant LE004G18] and from the Fundación Biodiversidad (Spanish Ministry for Ecological Transi- tion and Demographic Challenge). BAL was supported by National Research, Development and Innovation Fund [grant NKFIH, OTKA PD120775] and by the Bolyai János Research Scholarship of the Hun- garian Academy of Sciences. S.K. was supported by NWO Veni [grant 86312012]. Sampling of the coastal Brazilian lakes was financed by NWO [grant W84-549]; The National Geographic Society [grant 7864-5]; and CNPq [grants 480122, 490409, 311427]. We thank the SALGA team, especially Gissell Lacerot, Nestor Mazzeo, Vera Huszar, David da Motta Marques, and Erik Jeppesen for organizing and exe- cuting the SALGA field sampling campaign and Bruno Irgang† and Eduardo Alonso Paz for helping with identification. We thank Minne- sota and Wisconsin Departments of Natural Resources for collecting the macrophyte data. We are grateful to Carol Reschke for her work in combining and performing quality control for the Minnesota mac- rophyte data used in the analysis. This is contribution no. 607 of the Natural Resources Research Inst. of the Univ. of Minnesota Duluth. Provision of New Zealand macrophyte data was possible via NIWA SSIF funding.

Documenting the patterns of biological diversity on Earth has always been a central challenge in macroecology and biogeography. However, we are only beginning to generate an understanding of the global patterns and determinants of macrophyte diversity. Here, we studied large-scale variation and community-environment relationships of lake macrophytes along climatic and geographical gradients using regional data from six continents. We applied statistical routines typically used in the context of metacommunity studies to provide novel insights into macrophyte community compositional patterns within regions worldwide. We found that lake macrophyte metacommunities followed clumped species replacement structures, suggesting that two or more species groups were responding similarly to the environment within regions. Underlying such general convergence, our results also provided evidence that community-environment relationships were largely context-dependent, stressing that no single mechanism is enough to account for the complex nature of compositional variation. Surprisingly, we found no general relationships between functional or phylogenetic composition and main metacommunity types, suggesting that linking multi-trait and evolutionary information to the elements of metacommunity structure is not straightforward. Our findings highlight that global conservation initiatives and biodiversity protection need to capture environmental variation at the metacommunity level, and acknowledge the highly context-dependent patterns in the community-environment relationships of lake macrophytes. Overall, we emphasize the need to embrace the potential complexity of ecological inferences in metacommunity organization across the globe.

The importance of aquatic plant diversity in regulating nutrient cycling in wetlands remains poorly understood. We investigated how variation in macrophyte growth form (emerging, submerged and bryophyte) combinations and species mixtures affect nitrogen (N) removal from the water and N accumulation in plant biomass. We conducted a wetland mesocosm experiment for 100 days during July–September 2015. Twelve species were grown in mono- and in two-species mixed cultures for a total of 32 single and two-growth form combinations. Nitrogen removal from the water was quantified on three occasions during the experiment, while N accumulation in plant biomass was determined following termination of the experiment. The number of species and growth forms present increased N removal and accumulation. The growth form combinations of emerging and bryophyte species showed the highest N accumulation and N removal from water, followed by combinations of emerging species. By contrast, submerged species growing in the presence of emerging or other submerged species showed the lowest levels of N accumulation and N removal. Temporal variation in N removal also differed among growth form combinations: N removal was highest for emerging-bryophyte combinations in July, but peaked for the emerging-submerged and emerging-bryophyte combinations in August. Indeed, the occurrence of complementarity among macrophyte species, particularly in combinations of bryophyte and emerging species, enhanced N removal and uptake during the entire growing season. Our study highlights the importance of bryophytes, which have been neglected in research on nutrient cycling in wetlands, for aquatic N cycling, especially given their worldwide distribution across biomes. Overall, our findings point towards the potential important role of the diversity of macrophyte growth forms in regulating key ecosystem processes related to N cycling in wetlands.

Bryophytes and macroalgae have frequently been used as indicators of trace elements and organic pollutants, but their potential as indicators of eutrophication has not been accurately evaluated. Here, I used frequency data of aquatic macrophytes (vascular plants, charophytes, bryophytes and macroalgae) from 233 Swedish lakes to assess the additive value of bryophytes and macroalgae for the assessment of ecological status in lakes. Applying an established approach for boundary setting of total phosphorous (Tot-P) concentrations, 18 of the studied 31 macroalgae and bryophyte species (58.1%) were classified as sensitive species, two as indifferent (6.5%) and 11 as tolerant species (35.5%). Several cryptogam species showed sudden drops in their frequency along the Tot-P gradient (e.g. Aegagropila linnaei, Drepanocaldus sordius and Fontinalis antipyretica). The correlation between a macrophyte-based trophic index and Tot-P concentrations was only marginally higher when calculated with compared to without macroalgae and bryophytes. However, the differences between the trophic index calculated with and without these species, respectively, was significantly higher at Tot-P concentrations

Mining and related industries are a major source of metal pollution. In contrast to the well-studied effects of exposure to metals on animal physiology and health, the impacts of environmental metal pollution on the gut microbiota of wild animals are virtually unknown. As the gut microbiota is a key component of host health, it is important to understand whether metal pollution can alter wild animal gut microbiota composition. Using a combination of 16S rRNA amplicon sequencing and quantification of metal levels in kidneys, we assessed whether multi-metal exposure (the sum of normalized levels of fifteen metals) was associated with changes in gut microbiota of wild bank voles (Myodes glareolus) from two locations in Finland. Exposure to increased metal load was associated with higher gut microbiota species diversity (α-diversity) and altered community composition (β-diversity), but not dispersion. Multi-metal exposure and increased levels of several metals (Cd, Hg, Pb and Se) were associated with differences in the abundance of microbial taxa, especially those within the families Clostridiales vadinBB60 group, Desulfovibrionaceae, Lachnospiraceae, Muribaculaceae and Ruminococcaceae. Our data indicate that even low-level metal pollution can affect the diversity of microbiota and be associated with deterministic differences in composition of host gut microbiota in wild animal populations. These findings highlight the need to study a broader range of metals and their cocktails that are more representative of the types of environmental exposure experienced by wild animals.

Background To predict the risk of infectious diseases originating in wildlife, it is important to identify habitats that allow the co-occurrence of pathogens and their hosts. Puumala hantavirus (PUUV) is a directly-transmitted RNA virus that causes hemorrhagic fever in humans, and is carried and transmitted by the bank vole (Myodes glareolus). In northern Sweden, bank voles undergo 3–4 year population cycles, during which their spatial distribution varies greatly. Methods We used boosted regression trees; a technique inspired by machine learning, on a 10 – year time-series (fall 2003–2013) to develop a spatial predictive model assessing seasonal PUUV hazard using micro-habitat variables in a landscape heavily modified by forestry. We validated the models in an independent study area approx. 200 km away by predicting seasonal presence of infected bank voles in a five-year-period (2007–2010 and 2015). Results The distribution of PUUV-infected voles varied seasonally and inter-annually. In spring, micro-habitat variables related to cover and food availability in forests predicted both bank vole and infected bank vole presence. In fall, the presence of PUUV-infected voles was generally restricted to spruce forests where cover was abundant, despite the broad landscape distribution of bank voles in general. We hypothesize that the discrepancy in distribution between infected and uninfected hosts in fall, was related to higher survival of PUUV and/or PUUV-infected voles in the environment, especially where cover is plentiful. Conclusions Moist and mesic old spruce forests, with abundant cover such as large holes and bilberry shrubs, also providing food, were most likely to harbor infected bank voles. The models developed using long-term and spatially extensive data can be extrapolated to other areas in northern Fennoscandia. To predict the hazard of directly transmitted zoonoses in areas with unknown risk status, models based on micro-habitat variables and developed through machine learning techniques in well-studied systems, could be used. Electronic supplementary material The online version of this article (doi:10.1186/s12879-017-2618-z) contains supplementary material, which is available to authorized users.

The biodiversity of aquatic ecosystems is under threat and there is an urgent need to quantify the various facets of biodiversity to assess the conservation value of freshwater ecosystems. The effects of taxonomic relatedness have so far not been taken into account in biodiversity assessments of lake macrophytes. We therefore tested the response of species richness and average taxonomic distinctness (AvTD) of aquatic macrophytes along environmental gradients using linear regression models and Bayesian Information Criterion variable selection method. We selected data from four regions, each with 50–60 lakes, situated in northern Europe (Finland and Sweden) and northern America (Minnesota and Wisconsin). We separately studied all macrophyte species, hydrophytes and helophytes. Species richness and AvTD of aquatic macrophytes were generally negatively related in all regions, although it was not statistically significant. Both biodiversity measures responded to environmental gradients to various degrees among the studied macrophyte groups and regions. Species richness was best explained by alkalinity and lake area in Finland, by elevation, annual mean temperature and total phosphorus in Minnesota, and by alkalinity in Wisconsin. AvTD was best explained by alkalinity, annual mean temperature and total phosphorus in Finland and by alkalinity in Wisconsin. Very weak relationships were found in Sweden. Our findings strongly suggest that complementary indices are needed to indicate more comprehensively the effects of environmental conditions on freshwater biodiversity. Species richness was found to be a better measure than AvTD to account for conservation value in freshwaters. However, further research is required to evaluate the usefulness of AvTD to indicate conservation value (e.g. randomisation tests), because alternative measures are clearly needed for those freshwater taxa lacking complete information on true phylogenetic diversity.

Different species' niche breadths in relation to ecological gradients are infrequently examined within the same study and, moreover, species niche breadths have rarely been averaged to account for variation in entire ecological communities. We investigated how average environmental niche breadths (climate, water quality and climate-water quality niches) in aquatic macrophyte communities are related to ecological gradients (latitude, longitude, altitude, species richness and lake area) among four distinct regions (Finland, Sweden and US states of Minnesota and Wisconsin) on two continents. We found that correlations between the three different measures of average niche breadths and ecological gradients varied considerably among the study regions, with average climate and average water quality niche breadth models often showing opposite trends. However, consistent patterns were also found, such as widening of average climate niche breadths and narrowing of average water quality niche breadths of aquatic macrophytes along increasing latitudinal and altitudinal gradients. This result suggests that macrophyte species are generalists in relation to temperature variations at higher latitudes and altitudes, whereas species in southern, lowland lakes are more specialised. In contrast, aquatic macrophytes growing in more southern nutrient-rich lakes were generalists in relation to water quality, while specialist species are adapted to low-productivity conditions and are found in highland lakes. Our results emphasise that species niche breadths should not be studied using only coarse-scale data of species distributions and corresponding environmental conditions, but that investigations on different kinds of niche breadths (e.g., climate vs. local niches) also require finer resolution data at broad spatial extents.

Background Anaplasma phagocytophilum is currently regarded as a single species. However, molecular studies indicate that it can be subdivided into ecotypes, each with distinct but overlapping transmission cycle. Here, we evaluate the interactions between and within clusters of haplotypes of the bacterium isolated from vertebrates and ticks, using phylogenetic and network-based methods. Methods The presence of A. phagocytophilum DNA was determined in ticks and vertebrate tissue samples. A fragment of the groEl gene was amplified and sequenced from qPCR-positive lysates. Additional groEl sequences from ticks and vertebrate reservoirs were obtained from GenBank and through literature searches, resulting in a dataset consisting of 1623 A. phagocytophilum field isolates. Phylogenetic analyses were used to infer clusters of haplotypes and to assess phylogenetic clustering of A. phagocytophilum in vertebrates or ticks. Network-based methods were used to resolve host-vector interactions and their relative importance in the segregating communities of haplotypes. Results Phylogenetic analyses resulted in 199 haplotypes within eight network-derived clusters, which were allocated to four ecotypes. The interactions of haplotypes between ticks, vertebrates and geographical origin, were visualized and quantified from networks. A high number of haplotypes were recorded in the tick Ixodes ricinus. Communities of A. phagocytophilum recorded from Korea, Japan, Far Eastern Russia, as well as those associated with rodents had no links with the larger set of isolates associated with I. ricinus, suggesting different evolutionary pressures. Rodents appeared to have a range of haplotypes associated with either Ixodes trianguliceps or Ixodes persulcatus and Ixodes pavlovskyi. Haplotypes found in rodents in Russia had low similarities with those recorded in rodents in other regions and shaped separate communities. Conclusions The groEl gene fragment of A. phagocytophilum provides information about spatial segregation and associations of haplotypes to particular vector-host interactions. Further research is needed to understand the circulation of this bacterium in the gap between Europe and Asia before the overview of the speciation features of this bacterium is complete. Environmental traits may also play a role in the evolution of A. phagocytophilum in ecotypes through yet unknown relationships.