21603 research outputs found
Sort by
Effects of stand structural attributes on oak recruitment in mixed temperate forests
Full text linkOak-dominated forests worldwide support high levels of biodiversity and provide many important ecosystem services. However, oak forest sustainability is challenged by unsuccessful recruitment of oaks into the overstory. It is debated whether relatively shade-intolerant oaks can maintain dominance under continuous cover forestry and examples of successful recruitment of oak into the overstory in mixed, uneven-aged forests are rare. This study, set in southern Sweden, investigated the effects of selective cutting on stand structure and oak recruits and how stand density, canopy openness, and a tree species-specific shade casting index relates to the density of oak recruits. We focused on oak recruitment from the lower and middle canopy (dbh 5-10, 10-20 cm), i.e. trees that were beyond browsing height. Our findings indicate that a lower stand density was positively related to recruitment density of the smaller diameter size class, and as an indirect effect that a higher canopy openness with a lower shade-casting index was positively (but not significantly) associated with oak recruitment. Selective cutting decreased stand basal area and stand density while it increased canopy openness, but it did not have a direct short term effect on oak recruitment. These results indicate that stand structures obtained through continuous cover forestry may benefit recruiting oaks and that stand density, canopy openness and a canopy composition with high light transmission may need to be considered when ensuring the continuity of mixed, uneven-aged oak forests
Effect of bar jump height on kinetics and kinematics of take-off in agility dogs
Full text linkSport-related injuries have been reported to occur in around one-third of agility dogs. Higher bar height in competitions has been shown to increase odds of an injury. This study evaluated the effect of bar height on the kinetics and kinematics at take-off to a bar jump. Forces from fore-and hindlimb pairs were measured with force plates. A three-dimensional motion capture system was used to measure sagittal joint kinematics of the shoulder, elbow, carpus, hip, stifle, and tarsal joints, as well as limb coordination, trunk horizontal velocity, takeoff distance, and take-off angle. Data were collected for 17 Border Collies at three different bar heights: 80%, 100%, and 120% of wither height. A linear mixed model was used for statistical analysis. At higher bar height, decelerative impulses were greater and accelerative impulses decreased along with greater vertical impulses from forelimb and hindlimb pairs (p<0.001). Post-hoc analyses revealed differences between all three bar heights (p<0.01), except for forelimb decelerative impulse, which did not differ between 80% and 100% heights. Sagittal range of motion was greater, through increased peak flexion or extension, at 120% bar height than at lower bar heights (p<0.05) in almost all measured limb joints. The only exceptions were leading forelimb shoulder and elbow joints and leading hindlimb hip joint. With increasing bar height, the horizontal velocity of trunk decreased (p<0.001), and take-off angle became steeper (p<0.001), with all bar heights differing from each other (p<0.01). Temporal synchronicity between trailing and leading limbs increased and craniocaudal distance decreased in forelimbs (p<0.05) and hindlimbs (p<0.01) as bar height increased. Increased vertical and decelerative impulses, as well as the greater peak flexion and extension angles of joints, may indicate greater load on the tissues at higher bar heights, which could explain the increased odds of injury at higher bar heights in agility dogs
Integrating wind damage vulnerability into long-term forest planning: An optimisation-based model for spatial decision support
Full text linkThe vulnerability of forests to wind damage depends to a large degree on the characteristics of the specific stand and its neighboring stands, making forest management a key action in modifying the forest's wind damage vulnerability. Thus, by strategically planning where and when different forest management activities are scheduled to happen, forest managers can influence a forest's vulnerability to wind damage. In this study, we present a long-term forest planning model that identifies optimal forest management activities accounting for this specific vulnerability. The main decision in the model concerns the management of each individual stand throughout the planning horizon when the objective is to fulfil traditional long-term forest management goals and also to reduce the vulnerability to wind damage. In the model, consideration of wind damage is included by banning management activities such as final fellings in stands adjacent to highly vulnerable stands. Furthermore, the optimization model applied is specifically structured to be solvable using exact solution techniques. The model is evaluated for a case study area of 2450 hectares in southern Sweden for a 70-year planning horizon. Results suggest that it is possible to incorporate wind damage considerations into a long-term harvest scheduling problem. The proposed model excels in its ability to offer flexibility, allowing users to freely modify the settings in the model to choose their definition of vulnerability to wind damage. In addition, the model can be included in a traditional decision support system for forest planning utilizing exact solution techniques
Fiberströ till mjölkkor – inverkan på metanavgång från flytgödsellager
Full text linkFiberströ till mjölkkor kan vara ett alternativ till andra strömedel. Strömedlet består av gödselfiber som produceras på gården genom separering av orötad eller rötad flytgödsel. I denna studie jämförde vi om användning av fiberströ i stallet påverkar metanavgången vid lagring av flytgödsel och om den flytande fraktionen efter separering har lägre metanavgång än oseparerad gödsel vid lagring. Studien utfördes genom inkubering i 500 ml flaskor vid 20 o C under ca 190 dagar. Användning av fiberströ i stallet ökade metanavgången vid lagring av flytgödsel jämfört med användning av såg-/kutterspån eller halm som strömedel. Separering av flytgödsel gav lägre metanavgång från den flytande fraktionen än från oseparerad gödsel vid längre tids lagring
Development of innovative treatment techniques for infrastructure contaminated with per- and polyfluoroalkyl substances
Full text linkPer- and polyfluoroalkyl substances (PFAS) are of growing concern due to their persistence, mobility, and toxicity. A major contamination source is aqueous film-forming foam (AFFF) used in firefighting, impacting both infrastructure and soil. This thesis explores methods for decontamination of fire suppression systems and PFAS immobilization in soil.Laboratory-scale decontamination of AFFF-contaminated stainless-steel pipes showed that butyl carbitol-based solutions removed more PFAS than tap water, with higher temperature enhancing removal. However, surface analysis using time-of-flight elastic recoil detection revealed residual fluorine, posing a risk of PFAS rebound.In another experiment, a swab sampling method was developed. It was then successfully applied on AFFF-contaminated pipe surfaces to determine total PFAS concentrations.In laboratory-scale leaching tests of PFAS-contaminated soil, the performance of cement with and without additional activated carbon (AC)- based sorbents was assessed in stabilization and solidification trials. Addition of cement showed higher PFAS leaching (µg/kg) than unsolidified soil. In contrast, the addition of AC-sorbent achieved immobilization efficiencies of >99% for most PFAS compounds. Temporal changes in Kdvalues and mass flux rates suggest a transition to diffusion-controlled release mechanisms over time.In field-deployed lysimeter experiments, PFAS immobilization using waste-derived biochars and AC-based sorbents under natural, variably saturated conditions resulted in >99% PFAS reduction in leachate for longchain PFAS and 79-99% reduction for short-chain PFAS. A 1-D transport model suggests substantial PFAS retention at the air-water interface
Assessing the impacts of EU agricultural policies on the sustainability of the livestock sector: a review of the recent literature
Full text linkHow do agricultural policies in the EU need to change to increase the sustainability of livestock production, and what measures could encourage sustainable practices whilst minimising trade-offs? Addressing such questions is crucial to ensure progress towards proclaimed targets whilst moving production levels to planetary boundaries. However, a lack of available evidence on the impacts of recent policies hinders developments in this direction. In this review, we address this knowledge gap, by collating and evaluating recent policy analyses, using three complementary frameworks. The review highlights that recent policy reforms, and especially those of the Common Agricultural Policy, have had a large impact on the sustainability of the livestock sector by contributing to intensification and simplification. This has often resulted in negative impacts (e.g. on greenhouse gas emissions and animal welfare) and while financial support has enabled production, it can also lead to a culture of dependency that limits innovation. At the same time, a lack of regulation and concrete targets, and low levels of stakeholder engagement in policy design have led to delays in the delivery of sustainability objectives. Future policies could take on-board more innovative thinking that addresses the interrelatedness of society, animals, and the environment, to deliver effective targets and support
Svensk mjölkproduktion – Vad kan vi lära av det förflutna?
Full text linkUnder de senaste trettio åren har två omfattande systemförändringar skett inom svensk mjölkproduktion: ett omfattande teknikskifte i ladugårdarna och en övergång från statligt reglerade priser och inhemskt fokus, till exponering på den internationella marknaden. Strukturrationaliseringen har av många inom sektorn setts som ofrånkomlig och effektivisering och ökad avkastning har ofta setts som den enda möjligheten att stärka de kvarvarande producenterna. Inför EU-inträdet fanns en stark tilltro till att Sverige skulle kunna ta marknadsandelar på den globala marknaden, men den svenska mjölksektorn har istället tappat marknadsandelar och självförsörjningsgraden har minskat. Den alltmer specialiserade mjölksektorn med färre men mer högavkastande kor har minskat utsläppen av växthusgaser, men bidrar mindre till att bevara de artrika naturbetesmarkerna och till inhemsk köttproduktion. Nettoeffekten på systemnivå är dock oklar eftersom specialiserade diko- och nötköttsgårdar har tagit över vissa av dessa tjänster och utsläpp. Sjukdomsförekomsten hos mjölkkor har minskat och fler mjölkkor kan nu få utlopp för fler naturliga beteenden i lösdriftssystem, som i stor utsträckning ersatt uppbundna ladugårdar. Många mjölkbönder med små besättningar har slutat och de som är kvar ökar kontinuerligt i besättningsstorlek, samtidigt som förutsättningen för kvarvarande producenter att kunna betala konkurrenskraftiga löner endast haft en svagt positiv utveckling. En stor del av arbetet på gården är fortfarande oavlönat. Generationsväxlingen är en utmaning liksom att få ökad kapacitet att anställa personal. En positiv effekt av allt större besättningar är att ensamarbetet minskat. Dock blir konsekvenserna betydande för lokalsamhället när en enskild gård läggs ner. I mötena med näringen under workshopparna betonades från handelns sida vikten av de traditionella mervärdena som svensk mjölkproduktion vanligtvis förknippas med och skulle kunna bidra med i större omfattning, nämligen god djurvälfärd, låg antibiotikaanvändning, biologisk mångfald och att korna får gå ut på bete. Handeln uttryckte att de gärna vill kunna marknadsföra dessa mervärden från svensk mjölkproduktion. De positiva värden som särskilt lyftes fram under workshopparna var mjölkproduktionens bidrag till hållbara och näringsrika livsmedel, dess bidrag till landets matförsörjning och livsmedelsberedskap, liksom en levande landsbygd. Mjölkproduktionen har också möjlighet att, i mycket större omfattning än vad som är fallet idag, bidra till ökad biologisk mångfald och fler ekosystemtjänster, men då behöver förändringar ske i produktionen och stödsystemen. För att verkligen kunna bidra till ökad livsmedelsberedskap och matförsörjning måste gårdarna spridas mer över landet och möjligheterna vidgas för mindre gårdar att vara livskraftiga. Detta är förändringar som kräver insatser från samhället och framför allt från myndigheterna
Global meta-analysis shows action is needed to halt genetic diversity loss
Full text linkMitigating loss of genetic diversity is a major global biodiversity challenge1, 2, 3-4. To meet recent international commitments to maintain genetic diversity within species5,6, we need to understand relationships between threats, conservation management and genetic diversity change. Here we conduct a global analysis of genetic diversity change via meta-analysis of all available temporal measures of genetic diversity from more than three decades of research. We show that within-population genetic diversity is being lost over timescales likely to have been impacted by human activities, and that some conservation actions may mitigate this loss. Our dataset includes 628 species (animals, plants, fungi and chromists) across all terrestrial and most marine realms on Earth. Threats impacted two-thirds of the populations that we analysed, and less than half of the populations analysed received conservation management. Genetic diversity loss occurs globally and is a realistic prediction for many species, especially birds and mammals, in the face of threats such as land use change, disease, abiotic natural phenomena and harvesting or harassment. Conservation strategies designed to improve environmental conditions, increase population growth rates and introduce new individuals (for example, restoring connectivity or performing translocations) may maintain or even increase genetic diversity. Our findings underscore the urgent need for active, genetically informed conservation interventions to halt genetic diversity loss
The hunt for the perfect castration in horses
Full text linkCastration is frequently performed in stallions, primarily for husbandry purposes. To ensure animal welfare, any discomfort during the procedure must be minimised. However, castration techniques and peri- and postoperative management practices vary widely, and the quality of evidence regarding their associated complications is limited. This makes it challenging to make an informed decision regarding the most appropriate method. This thesis aimed to provide evidence-based guidance to veterinarians and horse owners in selecting the optimal castration technique for individual stallions.Medical records were analysed to assess the castration techniques and perioperative medications used in Sweden. Additionally, the tissue reactions to a resorbable device, designed to facilitate ligation during standing castration, were evaluated using ultrasonography and histology. The extent of tissue trauma associated with a sutured castration technique was objectively measured using a biomarker sensitive to inflammation (SAA).In ambulatory practice, standing castration using an open, un-sutured technique was the preferred method, and perioperative antimicrobial prophylaxis was associated with a reduced risk of surgical site infection (SSI). In hospital settings, a closed, sutured technique performed under general anaesthesia and sterile conditions was the most common approach. In this setting, antimicrobial prophylaxis did not reduce SSI rates.The ligation device caused a mild and transient tissue reaction, but its mechanical properties require further refinement before clinical application.Sutured castration induced an inflammatory response with low SAA-values, minor swelling, and no SSI, indicating that the technique caused minimal surgical trauma and represents a high-quality procedure
Impact of winter warming on CO2 fluxes in evergreen needleleaf forests
Full text linkCompared to drought and heat waves, the impact of winter warming on forest CO2 fluxes has been less studied, despite its significant relevance in colder regions with higher soil carbon content. Our objective was to test the effect of the exceptionally warm winter of 2020 on the winter CO2 budget of cold-adapted evergreen needleleaf forests across Europe and identify the contribution of climate factors to changes in winter CO2 fluxes. Our hypothesis was that warming in winter leads to higher emissions across colder sites due to increased ecosystem respiration. To test this hypothesis, we used 98 site-year eddy covariance measurements across 14 evergreen needleleaf forests (ENFs) distributed from the north to the south of Europe (from Sweden to Italy). We used a data-driven approach to quantify the effect of radiation, air temperature, and soil temperature on changes in CO2 fluxes during the warm winter of 2020. Our results showed that warming in winter decreased forest net ecosystem productivity (NEP) significantly across most sites. The contribution of climate variables to CO2 fluxes varied across the sites: in southern regions with warmer mean temperatures, radiation had a greater influence on NEP. Conversely, at colder sites, air temperature played a more critical role in affecting NEP. During the warm winter of 2020, colder regions experienced larger air temperature anomalies compared to the other sites; however we did not observe a significantly larger increase at colder sites due to winter warming. The varying responses of NEP across different sites highlight the complex interactions between climate variables such as air temperature, soil temperature, and radiation. These findings underscore the importance of integrating winter warming effects to more accurately predict the impacts of climate change on forest carbon dynamics