21603 research outputs found
Sort by
Effects of tree species richness on topsoil carbon and fungal diversity in European planted mixed forests are modulated by environmental conditions
No full textMixed-species forests have emerged as a promising approach to mitigate climate change impacts through enhanced carbon (C) sequestration while maintaining productivity, biodiversity, and other ecosystem services. However, we still have a poor understanding of the context-dependency of soil C sequestration in tree mixtures, particularly how it is influenced by plant-soil-microbe interactions and environmental conditions.Using soil samples collected from nine European sites within the global network of tree diversity experiments, TreeDivNet, we examined how tree species richness is associated with topsoil C stocks, fungal community composition and diversity, and their interactions. We further investigated the influence of biotic, edaphic, and climatic factors on the relationship between tree richness and topsoil C stocks. We hypothesised that increased tree species richness leads to increased topsoil C stocks and fungal diversity, and that this effect is modulated by site-specific interactions between biotic and abiotic factors.Overall, we found topsoil C stocks in stands with high tree diversity to be greater than in monocultures across the study sites. Lower soil fertility, cooler mean annual temperatures, and lower interannual variability of temperature and precipitation were found to correlate with positive effects of tree diversity on soil C stocks. While tree diversity did not directly influence fungal diversity, topsoil C stocks were positively correlated to fungal species richness. In addition, fungal richness showed a positive correlation with the net diversity effect of tree mixtures on topsoil C, suggesting that fungal diversity may be one of several factors contributing to the context-dependency of tree diversity effects on soil C stocks.Our study shows that tree species diversity can increase topsoil C storage across Europe, influenced both directly and indirectly by fungal diversity and environmental conditions. The mediation of direct and indirect linkages between tree diversity, fungal diversity and topsoil C stocks by local abiotic context highlights the need to improve our mechanistic understanding for site-specific management of soil C sequestration in tree mixtures to promote climate change mitigation in European forests
Commodity risk assessment of Populus alba, Populus nigra and Populus tremula plants from the UK
No full textThe European Commission requested the EFSA Panel on Plant Health to prepare and deliver risk assessments for commodities listed in Commission Implementing Regulation (EU) 2018/2019 as 'High risk plants, plant products and other objects'. This Scientific Opinion covers plant health risks posed by plants of Populus alba, Populus nigra and Populus tremula imported from the United Kingdom (UK) as: (a) 1- to 7-year-old bare root plants, (b) 3- to 15-year-old plants in pots, (c) 1- to 2-year-old cell grown plants and (d) bundles of 1- to 2-year-old cuttings/graftwood (only for P. nigra and P. tremula), taking into account the available scientific information, including the technical information provided by the UK. All pests associated with the commodity were evaluated against specific criteria for their relevance for this Opinion. Two EU protected zone quarantine pests, i.e. Bemisia tabaci (European populations) and Entoleuca mammata, fulfilled all relevant criteria and were selected for further evaluation. For the selected pests, the risk mitigation measures implemented in the technical dossier from the UK were evaluated taking into account the possible limiting factors. Expert judgements were given on the likelihood of pest freedom taking into consideration the risk mitigation measures acting on the pest, including uncertainties associated with the assessment. The age of the plants was considered, reasoning that older trees are more likely to be infested mainly due to longer exposure time and larger size. The degree of pest freedom varies between the pests evaluated, with E. mammata being the pest most frequently expected on the imported plants. The Expert Knowledge Elicitation (EKE) indicated with 95% certainty that between 9730 and 10,000 per 10,000 P. tremula rooted plants in pots (3 to 15 year old) will be free from E. mammata
The nature of a park - managing complexity and unpredictability for the long term
No full textGlobal challenges of climate change and biodiversity loss increase demands on urban green infrastructure (GI) to provide increasingly wide ranges of functions and services. Academia, policy and practice call for long-term perspectives to ensure the sustainability of GI and address solutions by adopting approaches inspired by nature. Meanwhile, current trends in contracted out park management entail attention to economic and technical aspects, overlooking long-term GI development. The interface between long-term ambitions and short-term operational GI practice is addressed through the case of a planned park in Taby municipality, Sweden. The case represents an ambition to integrate design, construction and management of high biodiversity GI through a 'design-by-management' approach, resting on ideas of continuous and adaptive vegetation development after the initial construction. Workshops were conducted with responsible stakeholders in project management, park management and nature management, providing insight into current contexts and future demands of GI establishment and management. Results reveal differences in contract management approaches depending on landscape typology-namely, 'parks' and 'nature'. Project and park managers work with an approach based on adherence to rigid formal documents where dynamics and uncertainty are understood as liabilities. Conversely, nature managers work with strategic development goals as a foundation for a joint view with responsible contractors. The case suggests that existing organizational practices in park construction and maintenance make it difficult to fully embrace the complexity and uncertainty of the intended processes. However, introducing GI management in early design phases offers valuable opportunities to address these challenges strategically, supporting long term sustainability
Nature’s Master of Ceremony: The Populus Circadian Clock as Orchestrator of Tree Growth and Phenology
No full textUnderstanding the timely regulation of plant growth and phenology is crucial for assessing a terrestrial ecosystem’s productivity and carbon budget. The circadian clock, a system of genetic oscillators, acts as ‘Master of Ceremony’ during plant physiological processes. The mechanism is particularly elusive in trees despite its relevance. The primary and secondary tree growth, leaf senescence, bud set, and bud burst timing were investigated in 68 constructs transformed into Populus hybrids and compared with untransformed or transformed controls grown in natural or controlled conditions. The results were analyzed using generalized additive models with ordered-factor-smooth interaction smoothers. This meta-analysis shows that several genetic components are associated with the clock. Especially core clock-regulated genes affected tree growth and phenology in both controlled and field conditions. Our results highlight the importance of field trials and the potential of using the clock to generate trees with improved characteristics for sustainable silviculture (e.g., reprogrammed to new photoperiodic regimes and increased growth)
Microbiological control project of minced meat of wild boar (Sus scrofa L.) in approved establishments in Sweden
No full textThe aims of this study were to enhance knowledge of microbiological status of minced meat of Swedish wild boar and to evaluate its compliance with the Commission Regulation (EC) No 2073/2005 on microbiological criteria for foodstuffs. The sampling was performed by the official control staff at Swedish Food Agency during 2024. While wild boar has the capacity to harbor a diverse range of zoonotic agents there is a lack of microbiological data on the products derived from wild boar carcasses. More information concerning the microbiological status of minced meat of wild boar is needed. These results could contribute to the development of risk-based management strategies and the verification of control measures through the safe game meat chain. One sample from each of selected 33 approved establishments producing minced meat of wild boar was sent to a commercial laboratory accredited for the analyses. Process hygiene criteria Aerobic Colony Count (ACC) and Escherichia coli were analysed as well as food safety criteria Salmonella spp. and results were assessed according to the microbiological criteria for minced meat. Results show no presence of Salmonella spp. in any of the samples. The 165 units, clustered in 33 plants, had a median for ACC 5.6 log10 colony forming units, cfu/g and E. coli 1.8 log10 cfu/g. However, 25 of 33 samples (proportion 0.758, 95% Confidence interval, CI: 0.577;0.889) were unsatisfactory. In total, about one fourth of samples, (proportion 0.242, 95% C.I: 0.111;0.423) were satisfactory or acceptable. The evidence for a temporal trend from September to December was insufficient. The results show non-compliance with the process hygiene criteria for minced meat of wild boar. Hunters must be informed about the key importance of proficient shooting skills and adequate evisceration procedures. Food business operators must focus on control of incoming carcasses and hygienic handling in every stage of the production. In case of unsatisfactory results according to in-house sampling, effective corrective action should be implemented by food business operator and verified by official control. Our results show that it is possible to produce minced meat of wild boar of good bacteriological quality
Optimising power-to-gas integration with wastewater treatment and biogas: A techno-economic assessment of CO2 and by-product utilisation
Get PDFProduction of electrolytic hydrogen and its conversion to methane, also known as power-to-gas (PtG), could play a key role in the transition towards a defossilised energy system. Integration of PtG technology with wastewater treatment and co-digestion presents an opportunity to produce low-carbon methane while simultaneously upgrading biogas, recycling biogenic carbon dioxide and utilising process by-products (heat and oxygen). A model of such an integrated system was developed using real plant data to assess the techno-economic performance through simulation of hourly operation and configuration optimisation. The integrated concept was demonstrated to be a promising option for increasing efficiency and reducing costs and emissions in the PtG system. By-product utilisation increased net energy efficiency from 52.3 to 59.7 %(HHV), leading to a reduction in levelised cost of PtG (LCOPtG) of 1.0 % and in net specific emissions of 28.3 % and 2.2 % based on average and marginal grid emission factors respectively. Minimum LCOPtG of 194.6 /MWh(CH4) was achieved, which entailed average and marginal net specific emissions of 37.2 and 635.2 gCO(2)/kWh(CH4), respectively. In the investigated conditions, the optimised PtG configuration produced heat in excess, but could not fulfil oxygen demand at the wastewater treatment plant. Heat integration yielded considerable performance improvements, while oxygen integration provided only minor benefits and slightly increased overall production costs. However, improved economic performance of oxygen integration was shown to be possible depending on local conditions. Although integrating several independent systems introduced the challenge of managing fluctuating heat and oxygen demand, alongside the varying supply of biogas and renewable electricity, the difference in magnitude between by-product generation and demand meant that their utilisation had only a minor impact on system operation
Diplodia tip blight (Diplodia sapinea) and site conditions shape Scots pine (Pinus sylvestris) endophytic mycobiome
Get PDFDiplodia sapinea (Fr.) Fuckelis is an opportunistic pathogen of Scots pine (Pinus sylvestris (L.) that causes Diplodia tip blight following host stress. The factors driving its shift from endophyte to pathogen are not well understood, particularly in relation to the surrounding fungal community. The objective of the current study was to determine the association of D. sapinea and the composition of the general endophyte community with symptomatic and asymptomatic sites, trees, twigs and tissues in an ongoing outbreak of Diplodia tip blight. The endophytic fungal community was characterized using metabarcoding of the ribosomal ITS2 region. We found that variation in fungal community composition was most influenced by differences between sites, highlighting the importance of site-specific environmental conditions such as previous drought impact and associated crown dieback. However, the fungal communities also varied between symptomatic and asymptomatic trees indicating the significance of tree health. The fungal communities of symptomatic trees, especially in twigs with tip blight symptoms, included D. sapinea, Therrya pini, and Lophodermium arboricola. These results are consistent with the balanced antagonism hypothesis, suggesting that shifts in community composition under stress may facilitate the transition of D. sapinea from a latent endophyte to a pathogen. D. sapinea was found in both healthy and symptomatic twigs, with a similar to 60-fold increase in symptomatic tissues. Site differences accounted for 42.6 % of fungal community variation. In contrast, taxa from the order Phaothecales were more abundant in asymptomatic twigs and in healthy tissues of of symptomatic twigs - suggesting potential antagonism. Our findings provide insights into early disease detection and underscore the importance of monitoring endophyte community shifts to support Scots pine forest resilience under climate stress
Rekryteringsindex för ål
Get PDFÅlbeståndets minskning i Sverige började uppmärksammas i början av 1970-talet då fångsterna av adult ål i yrkesfisket minskade kraftigt. I övriga Europa märktes en nedgång i fångsterna av glasål i början av 1980-talet. Som en del av arbetet med att förbättra situationen för europeisk ål utfärdade EU en förordning år 2007, som bland annat innebär att alla medlemsstater ska ta fram förvaltningsplaner för ål. Dessa ska innehålla åtgärder för återhämtning av beståndet av europeisk ål, med beaktande av regionala och lokala förhållanden. Sveriges ålförvaltningsplan fokuserar främst på ökad kontroll, inskränkningar i fisket, förbättrade möjligheter för blankål att vandra ut i havet, och stödutsättningar av importerade ålyngel. För att följa beståndets utveckling, och övervaka om åtgärderna får önskad effekt, används bland annat ett internationellt rekryteringsindex. Arbetet med att ta fram ett rekryteringsindex för Sverige påbörjades år 2010. Som ett första steg behövdes en lämplig metod för att skatta mängd ålyngel i ett vattendrag eller på en plats tas fram. En annan viktig aspekt är att rekryteringsindex inte ska vara påverkade av ålutsättningar. I Sverige märks alla importerade ålyngel sedan 2009 kemiskt med strontium (Sr) innan de sätts ut, vilket skapar en permanent Sr-märkning i ålarnas hörselstenar (otoliter) vilket gör det möjligt att skilja på utsatta ålar och naturliga rekryter. Eftersom denna provtagning är dödande (ålen måste dissekeras för att otoliterna ska kunna användas) så kan även annan viktig biologisk data samlas in, så som längd, vikt, parasitförekomst, och ålder.Denna rapport sammanfattar resultaten från arbetet med att ta fram ett rekryteringsindex för ål i Sverige. Metodutvecklingsförsök för att skatta mängd ålyngel och för att samla in ål för vidare provtagning, gjordes med fallfälla, nättingfälla och elfisken. Fallfälla och nättingfälla användes på sammanlagt 19 platser (2010–2013). Elfiske utfördes i 5-16 vattendrag årligen mellan 2010-2020, . Två av vattendragen valdes ut som ”referensvattendrag”, vattendrag som ligger långt från platser där importerad ål satts ut, där de rekryterande ålynglen borde bestå av naturliga rekryter. Detta för att kunna jämföra storleks- och åldersfördelning hos rekryter mellan vattendrag där populationen endast består av naturliga rekryter, med vattendrag där ålynglen både kan härstamma från importerade utsatta (Sr-märkta) ålyngel och naturligt invandrade.Försöken att samla in yngel med fallfälla i grunda kustområden, respektive med nättingfälla i rinnande vatten, resulterade i ett fåtal fångster. De låga fångsterna kan dels förklaras av praktiska problem med fällorna och dels att den låga tätheten av ålyngel gjorde att fällorna inte fungerade effektivt. Elfiske är den metod som ansågs mest framgångsrik, Största problemet med denna metod var att den inte fungerade tillfredställande vid låga tätheter vilket leder till att skattningar, och därmed jämförelser mellan lokaler blir osäkra.På alla platser som undersöktes (oavsett metod) fann vi ålyngel av naturligt rekryterat ursprung. Importerade utsatta (Sr-märkta) ålyngel återfanns endast på totalt fyra av de undersökta platserna Dessa fyra ligger i närheten av områden där man årligen sätter ut importerade yngel, varför förekomst av utsatta ålyngel var förväntat. Många platser där importerad utsatt ål inte återfanns ligger dock också i närheten av områden där ål sätts ut. Resultatet kan förklaras med att de utsatta ålynglen direkt simmar långt upp i vattendragen (uppströms de lokaler som undersökts), hellre än att stanna kvar i kustnära områden, alternativt att de av någon anledning simmar ut till havs igen, eller att dödligheten är hög. Detta i sig kan tyda på att de rör sig på ett annat sätt än de naturliga rekryterna. Resultatet innebär också att man inte enbart kan använda data över utsättningar för att få ett säkert svar på om ett rekryteringsindex är påverkat av utsättningar eller inte.Sammantaget visar dessa undersökningar att elfiske är den metod (av de tre metoder som undersökts) som lämpar sig bäst för att skatta mängd ål och för att samla in ålrekryter. Undersökningen visar också att flera av de undersökta lokalerna lämpar sig väl för att skapa rekryteringsindex, eftersom många områden inte hade någon förekomst av importerade och utsatta ålyngel
Tales of catastrophe: the authenticity of Mediterranean palaeo-disasters in films
Get PDFThis article explores the enduring allure of ruins from ancient civilizations and the depiction of catastrophic events in cinema, focusing on the portrayal of natural disasters in antiquity and prehistoric times. A reflection from an archaeological and environmental point of view is based on literary and scientific sources of natural events that inspire the film synopses. Using films from the Peplum genre’s “Golden Age” in the mid-20th century, we analyze how cinema reimagines historical calamities, ranging from the destruction of the Colossus of Rhodes to the demise of Pompeii. While some palaeo-disasters in these films are scientifically plausible, such as the Vesuvius eruption in Pompeii, others, like the Black Sea deluge hypothesis in Noah and The Ten Commandments’ multi-disaster scenario, persist as enduring myths. The article also addresses debated hypotheses, including the meteoritic impact in Sodom and Gomorrah and the speculative cataclysm in 10,000 BC, emphasizing their reliance on myths and pseudo-archaeological theories. This exploration contributes to understanding the complex interplay between cinematic imagination, historical events, natural disasters and enduring cultural myths