Limiting factors in capercaillie (Tetrao urogallus) conservation

With current extinction rates comparable with the rates of previous mass extinctions and humanities necessity of biodiversity, conservation of habitat and species should be regarded as paramount whenever planning land use. In this paper we have focused on the Western capercaillie (Tetrao urogallus) an umbrella species in Eurasian boreal and temperate forests. Capercaillie numbers have been reduced in mainland Europe and British Isles during the last century mainly due to increased predator populations, habitat loss, fragmentation and degradation as a result of human development of agriculture and land use change. Human recreation in sites with capercaillie show increased levels of stress in the capercaillies which might contribute to their decline. Programs in Scotland, Germany, Spain and Poland have the aim to aid or reintroduce populations in the capercaillies historic range. Practices with the aims to reintroduce or re-stock populations often consist of releasing individuals reared in facilities or breeding centers into suitable habitat. High mortality shortly after releasing due to high predation as a result of mal adapted physical and behavior traits leads to failure in most programs. Predator management and new techniques that improve the physical and behavioral quality in reared capercaillies such as choice of rearing method, large flight pens, elevated roost and anti-predatory training have shown increased fitness and increased survival. The use of PVA tools is effective when comparing different procedures or scenarios and should be used as a decision basis.Nutidens utrotningstakt som kan jämföras med takterna under de tidigare massutdöendena och mänsklighetens behov av ekosystemtjänster som upprätthålls tack vare biodiversitet bör bevarande av habitat och arter ha en tydlig roll vid planering av markanvändning. I detta arbete har vi fokuserat på Tjäder (Tetrao urogallus) som anses vara en paraplyart i eurasiska boreala och tempererade skogar. På den europeiska kontinenten har tjäderpopulationer minskat det senaste århundradet främst på grund av ökat predationstryck samt degradering, fragmentering och förlust av habitat. Även mänsklig störning knuten till rekreation ger ökade stressnivåer hos tjädrar vilket kan vara en bidragande faktor till minskande populationer. I Skottland, Tyskland, Spanien och Polen finns program med mål att återintroducera eller bevara tjäderpopulationer. Liknande program präglas av låga framgångssiffror. Hög predation bland tjädrar kort efter utsläpp till viss del som effekt av underutvecklade fysiska- och psykiska egenskaper. Predatorkontroll samt nya metoder att föda upp tjädrar bidrar till ökad framgång i försök. PVA är ett verktyg som effektivt kan användas för att bedöma vilket scenario i människans försök att bevara tjäder som är mest slagkraftigt

Climate change, environmental threats and cybersecurity in the European High North

publishedVersio

Effects of enrichment on simple aquatic food webs

Simple models, based on Lotka-Volterra types of interactions between predator and prey, predict that enrichment will have a destabilizing effect on populations and that equilibrium population densities will change at the top trophic level and every second level below. We experimentally tested these predictions in three aquatic food web configurations subjected to either high or low nutrient additions. The results were structured by viewing the systems as either food chains or webs and showed that trophic level biomass increased with enrichment, which contradicts food chain theory. However, within each trophic level, food web configuration affected the extent to which different functional groups responded to enrichment. By dividing trophic levels into functional groups, based on vulnerability to consumption, we were able to identify significant effects that were obscured when systems were viewed as food chains. The results support the prediction that invulnerable prey may stabilize trophic-level dynamics by replacing other, more vulnerable prey. Furthermore, the vulnerable prey, such as Daphnia and edible algae, responded as predicted by the paradox of enrichment hypothesis; that is, variability in population density increased with enrichment. Hence, by describing ecosystems as a matrix of food web interactions, and by recognizing the interplay between interspecific competition and predation, a more complete description of the ecosystem function was obtained compared to when species were placed into distinct trophic levels

Deltagerdriven forskning – växtodlingsgruppen: Resultat och utvärdering av arbetet under 1998 till 2001

De ekologiska lantbrukarna i Sverige har under lång tid utfört olika typer av utvecklingsarbete på gårdsnivå (Wivstad, 1999). I den fortsatta utvecklingen av ekologiskt lantbruk är det viktigt att ta tillvara dessa erfarenheter och kunskaper. Deltagardriven forskning är en förändringsprocess (Ullmark, 1998) där aktiva lantbrukare, rådgivare och forskare arbetar i grupp utifrån gemensamma intresseområden. Syftet är att knyta ihop forskarnas, rådgivarnas och lantbrukarnas teoretiska och praktiska kunskaper och erfarenheter. Alla som medverkar i processen är lika viktiga och alla parter som berörs av resultaten har möjlighet att påverka gruppens arbete och utveckling (Ullmark, 1998). Tillsammans identifierar gruppen problem och använder/utvecklar för lantbrukaren relevanta försöks- och forskningsmetoder som kan bidra till att lösa de praktiska problem som lantbrukaren faktiskt ställs inför. Genom deltagardriven forskning kan lantbrukarna även få möjlighet till att påverka var och hur forskning bedrivs. Forskningsfrågorna kan hämtas från lantbrukssystemets olika delar samt göra gruppen medveten om hur olika delar påverkar helheten (Wivstad, 1999; Eksvärd et al, 2001). I förlängningen kan deltagarna bli informatörer och överföra idéer till andra lantbrukare (Ullmark, 1998). Centrum för uthålligt lantbruk, CUL, placerat vid SLU, har sedan 1998 ansvarat för det tvärvetenskapliga projektet ”Deltagardriven forskning” som ett verktyg för regional utveckling av det ekologiska lantbruket. Det övergripande målet har varit att öka kunskapen om hur man kan åstadkomma uthålliga lantbrukssystem. Projektet startade med sex delgrupper inriktade på följande områden: grönsaker – friland, grönsaker – växthus, höns, växtodling, biogas samt grisproduktion. Därefter har några tillkommit och några avslutats. För aktuell information se hemsidan: www.cul.slu.se. Ytterligare beskrivning kan fås i ”Deltagardriven forskning – forskningsinriktad aktörssamverkan för svenskt lantbruk” (Eksvärd, i tryck)

Effects of Degraded Optical Conditions on Behavioural Responses to Alarm Cues in a Freshwater Fish

Prey organisms often use multiple sensory cues to gain reliable information about imminent predation threat. In this study we test if a freshwater fish increases the reliance on supplementary cues when the reliability of the primary cue is reduced. Fish commonly use vision to evaluate predation threat, but may also use chemical cues from predators or injured conspecifics. Environmental changes, such as increasing turbidity or water colour, may compromise the use of vision through changes in the optical properties of water. In an experiment we tested if changes in optical conditions have any effects on how crucian carp respond to chemical predator cues. In turbidity treatments we added either clay or algae, and in a brown water colour treatment we added water with a high humic content. We found that carp reduced activity in response to predator cues, but only in the turbidity treatments (clay, algae), whereas the response in the brown water treatment was intermediate, and not significantly different from, clear and turbid water treatments. The increased reliance on chemical cues indicates that crucian carp can compensate for the reduced information content from vision in waters where optical conditions are degraded. The lower effect in brown water may be due to the reduction in light intensity, changes in the spectral composition (reduction of UV light) or to a change in chemical properties of the cue in humic waters

Optimal Swimming Speed in Head Currents and Effects on Distance Movement of Winter-Migrating Fish

Migration is a commonly described phenomenon in nature that is often caused by spatial and temporal differences in habitat quality. However, as migration requires energy, the timing of migration may depend not only on differences in habitat quality, but also on temporal variation in migration costs. Such variation can, for instance, arise from changes in wind or current velocity for migrating birds and fish, respectively. Whereas behavioural responses of birds to such changing environmental conditions have been relatively well described, this is not the case for fish, although fish migrations are both ecologically and economically important. We here use passive and active telemetry to study how winter migrating roach regulate swimming speed and distance travelled per day in response to variations in head current velocity. Furthermore, we provide theoretical predictions on optimal swimming speeds in head currents and relate these to our empirical results. We show that fish migrate farther on days with low current velocity, but travel at a greater ground speed on days with high current velocity. The latter result agrees with our predictions on optimal swimming speed in head currents, but disagrees with previously reported predictions suggesting that fish ground speed should not change with head current velocity. We suggest that this difference is due to different assumptions on fish swimming energetics. We conclude that fish are able to adjust both swimming speed and timing of swimming activity during migration to changes in head current velocity in order to minimize energy use

Replacing monocultures with mixed-species stands: Ecosystem service implications of two production forest alternatives in Sweden

Whereas there is evidence that mixed-species approaches to production forestry in general can provide positive outcomes relative to monocultures, it is less clear to what extent multiple benefits can be derived from specific mixed-species alternatives. To provide such insights requires evaluations of an encompassing suite of ecosystem services, biodiversity, and forest management considerations provided by specific mixtures and monocultures within a region. Here, we conduct such an assessment in Sweden by contrasting even-aged Norway spruce (Picea abies)-dominated stands, with mixed-species stands of spruce and birch (Betula pendula or B. pubescens), or spruce and Scots pine (Pinus sylvestris). By synthesizing the available evidence, we identify positive outcomes from mixtures including increased biodiversity, water quality, esthetic and recreational values, as well as reduced stand vulnerability to pest and pathogen damage. However, some uncertainties and risks were projected to increase, highlighting the importance of conducting comprehensive interdisciplinary evaluations when assessing the pros and cons of mixtures

Var en sovjetisk rättskultur en del av en europeisk rättskultur?

En sovjetisk rättskultur var delvis i teorin en del av en europeisk rättskultur men i praktisk tillämpning fanns det stora skillnader

Lärandemiljöer för praktiskt lärande : Var anser eleverna att de lär sig sitt yrke bäst?

Syftet med den här uppsatsen är att undersöka hur gymnasieelever på ett yrkesprogram ser på sina lärandemiljöer. Hur uppfattar eleverna lärandemiljöerna i sina yrkeslokaler på skolan och ute på deras praktikplatser? Vi vill undersöka var eleverna anser att de lär sig sitt kommande yrke bäst. Genom att utföra enkätundersökningar och djupintervjuer med elever från 5 olika yrkesprogram har vi fått fram de resultat som har varit av betydelse för vår undersökning. Den praktiska kunskapen anser de flesta eleverna att man lär sig ute på praktikplatsen men de ser också fördelarna med utbildningen inne i skolan. De ser också fördelen med att koppla den teoretiska kunskapen till den praktiska