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Kan den nordliga rotgallnematoden, Meloidogyne hapla, bekämpas med svampen Clonostachys rosea? : en experimentell studie
Get PDFThe northern root-knot nematode, Meloidogyne hapla, is causing great economical losses to growers worldwide. There is a need for alternative control measures that are environmentally sustainable and effective against the nematode. Biological control is one promising control measure and there are multiple biological control agents on the market against fungal pathogens and insects. One such biocontrol agent is the fungus Clonostachys rosea. In this experiment the biocontrol effect of C. rosea against the root-knot nematode M. hapla was evaluated. The investigation included an antibiosis in vitro experiment and a pot experiment with carrot and lettuce under controlled conditions. Additionally, the effect from drought on M. hapla infection and C. rosea biocontrol was tested. Drought increased the infection by M. hapla on carrot and caused a significant (P < 0,001) decrease in fresh and dry root weight and shoot dry weight, indicating a higher parasitic effect on plant mass of infected plants during dryer periods in cultivated fields of carrot. No biological control effect from C. rosea on M. hapla was detected, nor any growth promoting effects from the fungus on the plants. However, plants treated with C. rosea showed an increased tolerance towards drought stress by not showing significant distinction between plant mass under normal and drought conditions, which was seen in the other treatments. Though, an error due to a high buildup of roots in the peat soil made it difficult to count the galls on plant roots, affecting the result of biocontrol effect and actual nematode infection. The use of sand might have simplified the rinse of the roots and a more accurate result could have been obtained
Veterinary treated cases of uterine prolapse in Swedish dairy cows : incidence and survival
Get PDFLivmoderframfall är en ovanlig komplikation som kan uppstå efter förlossning men bland våra
husdjur är kor de som drabbas oftast. Tillståndet innebär att livmodern vänds ut och in och trycks ut
genom vulvan. Komplikationer kan uppstå som slemhinneskador och infektion och i allvarligare fall
chock till följd av blodförlust och framfall av bukorgan. Tillståndet kräver snabbt insatt behandling
och även då fall hanteras omgående dör cirka 20–25 procent av korna enligt litteraturen. Behandling
går ut på att återföra livmodern, alternativt amputera, samt att behandla underliggande sjukdomar.
Det primära syftet med den här studien var att undersöka förekomsten (incidensraten) av
veterinärbehandlade livmoderframfall hos svenska mjölkkor, men även vilka åldersgrupper och
vilka raser som drabbas samt distributionen över besättningsfaktorer, så som inhysningssystem. Av
de djur som drabbats av livmoderframfall undersöktes också hur många som fanns kvar i
produktionen ett år senare. Ett ytterligare syfte med den här studien var att undersöka svenska
nötbönders attityder till livmoderframfall.
Data om veterinärbehandlade livmoderframfall, kornas laktationsnummer och ras, samt
besättningarnas inhysnings- och mjölkningssystem, besättningsstorlek och produktionsform för åren
2015 till 2020 inhämtades från Växas kodatabas, där data från cirka 70 procent av Sveriges
mjölkkobesättningar finns. En web-baserad enkät gällande attityder till och erfarenheter från kor
med livmoderframfall skickades även ut till svenska lantbrukare med mjölk- eller köttkorsbesättningar via sociala medier.
Medelincidensraten av livmoderframfall under perioden 2015 till 2020 var 8 fall per 10 000
kor och år vilket är lägre än vad som tidigare rapporterats i publicerade studier. Flest till antalet
livmoderframfall påträffades hos förstakalvare men då antalet relateras till demografin inom
populationen var incidensraten högst för sjättekalvare och äldre kor. Studien visade även att
incidensraten var högre i besättningar med uppbundet system (0,10–0,14 fall per 100 kor och år) än
kor i lösdrift (incidensrat 0,06–0,09 fall per 100 kor och år) Incidensraten var högre i små
besättningar (<50 kor) (0,06–0,12 fall per 100 kor och år). Gällande spridningen av andelen fall över
månad och år sågs inget tydligt samband.
Resultaten visade också att 59 procent av korna som drabbades dog inom 12 månader, där 50
procent självdog eller avlivades och 50 procent gick till normalslakt. Resultaten konfirmeras av
enkätundersökningen där majoriteten (73 %) av djurägarna svarade att de inte inseminerar kor som
drabbats av livmoderframfall utan istället låter korna gå till slakt.
I enkätundersökningen svarade 77 procent av djurägarna att de alltid tillkallar veterinär och 92
procent att de oftast väljer att behandla kon. På frågan om hur många livmoderframfall djurägaren
hade haft de senaste tolv månaderna svarade 90 procent ett eller inget fall.
Konklusionerna från den här studien är att livmoderframfall är ovanligt förekommande hos
svenska mjölkkor, och att det framför allt är äldre kor som drabbas, även om det är mest troligt att
du som praktiserande veterinär eller djurägare kommer påträffa det hos en förstakalvare. Vidare kan
vi konkludera att majoriteten av de kor som drabbas av livmoderframfall kommer att självdö, avlivas
eller skickas till slakt inom tolv månader efter diagnos men att 40 procent av fallen lever längre än
så. Vi kan också konstatera att det generellt råder en god vilja hos djurägare tillkalla veterinär och
behandla livmoderframfall.
Nyckelord: livmoderframfall, mjölkkor, förekomst, behandling, överlevnadProlapse of the uterus is an uncommon complication following partus, in domestic animals however
it is most frequently seen in cows. Uterine prolapse means protrusion of the uterus through the vulva.
Complications may be seen as mucosal damage, infection and in more severe cases shock following
blood loss and prolapse of abdominal organs. The condition requires immediate treatment and even
with proper care around 20–25 percent of the cows die, according to literature. Treatment involves
repositioning of the uterus, or amputation, and tending to underlying diseases.
The first aim of this study was to investigate the overall incidence rate of uterine prolapse in
Swedish dairy cows during 2015 to 2020, as well as the incidence rate within different months of
the year, parities, breeds, milking-, housing- and production systems. Moreover, the portion of cows
with uterine prolapse that died, were euthanized or culled within a year after treatment were
calculated. The second aim was to examine attitudes to and experiences from cows with uterine
prolapse among Swedish farmers with dairy or meat producing cows.
By using data from the from the Swedish official milk recording scheme, dairy cows veterinary
treated for uterus prolapse between 2015 and 2020 were examined regarding incidence rate, when
the prolapse occurred, what parities were affected, production form, housing- and milking system.
Moreover, to examine the attitude to and experiences from cows with uterine prolapse, a survey was
made available on the internet (by advertisement in two Facebook groups) to Swedish farmers with
dairy or meat producing cows.
The mean incidence rate of uterus prolapse was 8 cases per 10 000 cows and year for the period
2015 to 2020. There were numerically more heifers than older cows among the cases, but when the
number of cases was related to demography within the population, the highest incidence rate was
seen in cows in their sixth lactation or higher, which published articles confirm. The study also
showed that the incidence rate was higher in herds with a tie-stall housing system (0,10–0,14 cases
per 100 cows and year) than in herds with a free-stall housing system (0,06–0,09 cases per 100 cows
and year). Moreover, the incidence rate was higher in herds with a smaller herd size (<50 cows)
(0,06–0,12 cases per 100 cows and year). Regarding the number of cases during different months
there were no clear patterns.
The results also showed that 59 percent of the treated cows died within 12 months, 50 percent
of them died or were euthanized, while 50 percent were culled. These results were confirmed by the
survey where 73 percent of the farmers replied that they don’t inseminate cows with previous uterine
prolapse but instead choose to cull them.
In the survey, 77 percent of the farmers responded that they always contact a veterinary and 92
percent that they more often than not choose to treat the cow. When answering how many cases of
uterine prolapse the farmer had had within the last twelve months, 90 percent responded zero or one
case.
To conclude, uterine prolapse is uncommon in Swedish dairy cows, and it is most frequently
seen in older cows, even though it is most likely that practicing veterinarians and farmers will
encounter cases in heifers. We can also conclude that the majority of the cows with uterine prolapse
will die, be euthanized or culled withing twelve months but 40 percent of the cases will live longer.
We can also establish that most farmers have a positive attitude towards contacting a veterinary and
treating the cow.
Keywords: uterine prolapse, dairy cow, incidence, treatment, surviva
Methodologies for training detection dogs and scent sample storing
Get PDFDogs’ spectacular sense of smell has been used as a detection tool by humans in many areas. Their
olfaction was first used as a hunting tool, but dogs’ detection skills have been shown to also be
applicable in, for example, detection of drugs, explosives, and firearms as well as disease detection.
Different types of disease detection are possible due to the body’s ability to produce volatile organic
compounds (VOCs), which reflect the metabolic state of the body. Many illnesses have been shown
to cause the body to produce a distinct pattern of VOCs, and these molecules together make up a
specific smell. Sweat is a major source of VOCs, therefore sweat samples are used for disease
detection by dogs.
The first aim of this study was to examine what track design is most beneficial for detection dogs’
learning. This was done through evaluating the performance of two trained detection dogs in three
different track shapes, when training the ability to detect individuals infected with severe acute
respiratory syndrome coronavirus 2 (SARS-CoV-2) through sweat samples. All tracks consisted of
six consoles. In Track 1 the consoles were positioned in a straight line, Track 2 was a circular track,
and in Track 3 the six consoles were placed in a slightly curved line. The track design was changed
when the trainers discovered risk factors that could potentially lead to false results. The design of
the straight track caused the dogs to have a high level of curiosity which subsequently made them
skip the first couple of consoles in many searches. The design of the circular track made it possible
for the dogs to pick up on visual cues the handlers were unaware of.
Both dogs’ sensitivity was the highest in the first track (96.4% and 97.8% respectively), and the
lowest in the third track (62.9% and 82.6%). The sensitivity for Track 2 was 78.9% and 85.1%.
Similarly, the specificity was also the highest in the first track (99.3% and 99.8%) and the lowest in
the third track (94.3% and 98.5%). The specificity for Track 2 was 96.6% and 99.2%. However, the
results may have been influenced by prerequisites that differed between the tracks, which makes the
results difficult to interpret.
The second aim of the study was to examine if Falcon centrifuge tubes are suitable as storage
containers for scent samples. This was tested through keeping 50 sealed Falcon tubes together in a
freezer for one week, out of which three contained pieces of natural rubber that give off a particular
smell. Three detection dogs trained to detect that smell searched through all sealed tubes. The results
of the study indicate that the scent did not escape the sealed containers as no dog could detect the
scent. Falcon tubes are therefore a promising alternative for storing scent samples since scent
contamination between samples would not be possible if the containers do not leak the scent. Further
studies would be valuable as this could potentially facilitate storing scent samples in a spaceefficient way.
Keywords: detection dogs, scent training, canine scent detection, search dogs, scent samples in a spaceefficient way
Factors Influencing Farmers’ Adoption of Climate Change Adaptation Practices : Evidence from Vietnam, Laos, and Cambodia
Get PDFSoutheast Asia is among the most vulnerable regions to climate change, and its high dependence on agriculture imposes significant challenges on its farming systems. Given these challenges, farmers’ climate change adaptation is becoming increasingly important. Therefore, this thesis explored the interlinkages among – and the influence of – social support, knowledge, and various aspects of farmers’ perceptions on their adoption of climate change adaptation practices. Previous research in Southeast Asia has thus far focused on farmers’ attitudes towards – or barriers to – adaptation. This thesis goes a step further by providing insights into the underlying factors and how their interlinkages influence adaptation. Structural Equation Modelling was employed to account for the complexity of farmers’ adaptation behaviour. The results show that social support, knowledge, and perceived usefulness of adaptation practices have small positive direct effects on farmers’ adoption of adaptation practices. Perceived ease of use had a medium-sized positive direct effect, and also mediated the relationship between knowledge and adoption. Perceptions of climate change and its impacts were not found to have significant direct or indirect effects. The thesis concludes that perception should not be studied as a single latent construct when investigating Southeast Asian farmers’ adoption of adaptation practices but rather as multiple constructs. The findings contribute to the crucial research efforts needed in the region to understand how farmers’ adaptive capacity and food systems’ resilience can be strengthened. Thus, the findings also add to policy-relevant literature and provide a good foundation for future research on the development of climate change adaptation policies
A good trainer is a committed trainer : a study of riders' experiences of and expectations on trainers
Get PDFAtt vara tränare inom ridsport skiljer sig på många sätt i förhållande till andra sporter. För att lyckas uppnå optimal utveckling hos de ekipage som tränas krävs djupgående kunskap inom åtskilliga områden. Ryttare har olika förväntningar på sina tränare vilket kräver stor vetskap kring vilka områden de aktiva värdesätter högst och vilka de anser mest väsentliga. Syftet med denna studie är att kartlägga och analysera ryttares upplevelser av och förväntningar på Svenska Ridsportförbundets diplomerade tränare inom dressyr och hoppning. Studien genomfördes genom att besvara frågeställningarna: Vilka förväntningar har ryttare på sina tränare? Inom vilka områden önskar ryttare få kunskap av sin tränare? På vilket/vilka sätt önskar ryttare få hjälp av sin tränare? Vilka upplevelser och erfarenheter har ryttare av att träna för tränare? Den metod som använts var kvantitativ enkätundersökning i kombination med kvalitativa semistrukturerade intervjuer. Enkäten besvarades av totalt 602 ryttare som tränar på storhäst inom disciplinerna dressyr och hoppning för diplomerad A-, B- eller C- tränare. Åtta intervjuer genomfördes, fyra inom hoppning och fyra inom dressyr. Materialet som samlades in transkriberades och analyserades därefter genom innehållsanalys. Enkätens resultat har sammanställts under tre huvudteman: upplägg på träning, vad karaktäriserar en bra tränare samt hjälp och kunskap. Intervjuernas resultat landade i tre övergripande teman som sedan specificerades. Dessa var ryttarnas definition av bra tränare, tränarrollen kräver bred kompetens och ryttarnas upplevelser och erfarenheter. Resultatet påvisade att 82,4 procent ansåg engagemang som en av huvudfaktorerna för vad som karaktäriserar en bra tränare. Resultat framhåller tydligt att det fanns en stor efterfrågan på bred kompetens hos tränare. Ryttare önskar få hjälp med helhetskoncept runt sitt ekipage samt värdesätter coachande och pedagogiska undervisningsmetoder. Sammanfattningsvis visar denna studie att ryttare idag förväntar sig en tränare som är engagerad och ärlig. De värdesätter en tränare med erfarenhet som innehar mångsidig kompetens. Ryttare önskar få hjälp med ett helhetsupplägg kring ekipaget där i huvudsak tävlingsmomentet är en central del. Vid undervisning önskar ryttarna att det finns ett coachande och ett pedagogiskt förhållningssätt. Studien konstaterar att tränarens roll är vital för utveckling och undervisning av ryttare och häst. Relationen mellan tränare och elev kan vara både av professionell eller vänskaplig karaktär. Oavsett typ av relation så framgår det dock att tränaren är en nyckelperson för att uppnå framsteg. En ryttares tränare är således en väldigt viktig del av ryttarens idrottsliga prestation.Being a trainer in equestrian sports differs in many ways compared to other sports. In order to succeed in achieving optimal development in the equestrians that are trained, in-depth knowledge is required in several areas. Riders have different expectations of their trainers, which requires a great deal of knowledge about which areas the active people value most and which they consider most important. The purpose of this study is to map and analyze riders' experiences of and expectations of the Swedish Equestrian Federation's certified trainers in dressage and jumping. The study was conducted by answering the questions: What expectations do riders have of their trainers? In which areas do riders want to get knowledge from their trainer? In what way (s) do riders want help from their trainer? What experiences and events do riders have from training for trainers? The method used was a quantitative survey in combination with qualitative semi-structured interviews. The questionnaire was answered by a total of 602 riders who train on horses in the disciplines of dressage and jumping for certified A-, B- or C-trainers. Eight interviews were conducted, four in jumping and four in dressage. The material collected was transcribed and then analyzed by content analysis. The results of the survey can be compiled under three main themes: the structure of training, what characterizes a good trainer and help and knowledge. The results of the interviews landed in three overarching themes which were then specified. These were the riders 'definition of a good trainer, the trainers role requires broad competence and the riders' experiences and events.The results showed that 82.4% considered commitment as one of the main factors for what characterizes a good trainer. The results clearly indicate that there was a great demand for broad competence among trainers. Riders want help with a holistic concept around their equipage and value coaching and pedagogical teaching methods. In summary, this study shows that riders today expect a trainer who is committed and honest. They value a trainer with experience who possesses versatile skills. Riders want help with a comprehensive plan, where the competition part is mainly a central part. When teaching, the riders want there to be a coaching and pedagogical approach. The study states that the trainer's role is vital for the development and teaching of riders and horses. The relationship between trainer and student can be both of a professional or friendly nature. Regardless of the type of relationship, however, it is clear that the trainer is a key person to achieve progress. A rider's trainer is thus a very important part of the rider's athletic performance
Greenhouse gas fluxes from restored peatland : a comparison between a restored extracted peatland and a pristine mire in Store Mosse national park 7 years after rewetting
Get PDFDen globala uppvärmningen ökar. För att dämpa denna ökning behöver världens växthusgasutsläpp minska. När torvmarker dikas ut för industrier går de från att vara kolsänkor till att vara kolkällor. För att få tillbaka torvmarkers funktion som kolsänka restaureras dem, främst genom återvätning. Denna studie bidrar med underlag för hur restaurering av torvtäkter påverkar växthusgasutsläppen, vilket går att koppla till miljökvalitetsmålen Begränsad klimatpåverkan och Myllrande våtmarker. Studien jämför metan- och koldioxidutsläpp från en restaurerad torvmark mot en orörd myr. Fältarbetet genomfördes med en gasanalysator och en 50x50x50 cm transparent- och opak kammare under dagtid i april och maj 2022. Kolflödesmätningarna relateras till mikrotopografi, vattennivå, fotosyntetiskt aktiv strålning, vegetationstäckning och marktemperatur, eftersom dessa faktorer påverkar kolflödet. Resultatet åskådliggör att både det restaurerade- och det orörda området har ett nettoupptag av kol. Detta innebär att återvätning snabbt återställer torvtäkters funktion som kolsänka. Resultatet påvisar också att det restaurerade området är en starkare kolsänka än det orörda området. Det här beror på att Sphagnum i det restaurerade området har betydligt snabbare tillväxthastighet och därmed högre fotosyntes än Sphagnum i det orörda området. Hur kolflödet i de undersökta områdena ser ut under resten av året och i framtiden kan studien endast spekulera om. Ytterligare studier krävs för att kunna besvara detta. Denna studie bidrar med underlag för hur återvätning och restaurering påverkar växthusgasutsläppen ifrån torvtäkter.Global warming is increasing. To lower this increase, the greenhouse gas emissions need to be reduced. When peatlands are drained for industries, they go from being carbon sinks to becoming carbon sources. To get back the function of peatlands as a carbon sink, they are restored, mostly by rewetting. This study contributes to knowledge of how restauration of extracted peatlands affects greenhouse gas emissions. The study does this by comparing methane- and carbon dioxide emissions from a restored peatland with the emissions from a pristine mire. The field work was conducted with a gas analyzer and a 50x50x50 cm transparent- and opaque chamber, during daytime in April and May 2022. The carbon flux measurements are related to microtopography, water table, photosynthetic active radiation, vegetation cover and soil temperature, since these factors influence carbon flux. The result show that both sites have a net carbon uptake, which imply that rewetting quickly restore the function of peatlands as carbon sinks. The study also show that the restored area is a bigger carbon sink than the pristine area. This is caused by the higher growth rate, and therefore higher photosynthesis of the Sphagnum at the restored area. To know how the carbon flow in the areas develop the rest of the year and in the future, more studies are needed. This study contributes knowledge to how rewetting and restauration affects the greenhouse gas emissions from extracted peatlands
How precipitation can affect activity patterns and livestock depredation of lion (Panthera leo)
Get PDFAfrican lions (Panthera Leo) are classified as vulnerable according to the International Union for Conservation. The presence of predators as lion, is crucial for a functioning ecosystem worldwide, which makes the decline a serious problem. Wildlife conflicts between people and lions are a major threat for the lion population. The conflicts occur when lions prey on livestock and people respond by killing them. Exploitation of natural resources has caused habitat losses and reductions in wild prey, which tend to increase the risk of lions predating on livestock. Knowledge of how different factors can affect the conflict between human and the lion, can be an important tool for developing effective conservation strategies for lions. The main objective in this study was to examine general activity and movement patterns of the African lion and livestock predation caused by lion, in relation to different amounts and periods of precipitation in Ol Pejeta Conservancy, Kenya. Data was collected in Ol Pejeta Conservancy. Activity and movement patterns were analyzed using camera traps at three wildlife corridors in the reserve and depredation was mapped using available data on site. Meteorological data and weather conditions was collected from 10 weather stations near Ol Pejeta. The results revealed that lion movement patterns differ according to the amount and period of precipitation. The results also indicates that the depredation on livestock is affected by a higher amount of precipitation. Overall, the results imply that the risk of wildlife conflicts are higher during more wet periods when wild prey is inaccessible for lion to overcome
‘Good Farmer’ Values and How They Affect the Path to a Sustainable Agriculture
Get PDFConventional agriculture is unsustainable on several levels and therefore a change has to take place. This study focuses on the central ’good farmer’ values of conventional farmers and how these values affect the path to a sustainable agriculture. An analysis of ’good farmer’ values of conventional farmers was carried out on the basis of a literatur study and interviews with conventional Gotlandic farmers. The analysis showed that some of these values conflicted with sustainable agriculture, while others did not. It was mainly the visible symbols of being a ’good farmer’ that inhibited the implementation of sustainable practices along with the small economic margins most conventional farmers have. The study concludes that ’good farmer’ values can be a key element in the change of conventional agriculture, if these values are shifted towards sustainable ones. This shift can be facilitated by establishing new social contexts for the farmers and changing the structures of the current food systems
Validering av grundytetillväxtfunktioner för lärk i Heurekasystemet
Get PDFLarch is getting more common in Sweden. This highlights the need of reliable growth models for
larch species in Heureka DSS. Precise and accurate growth models are essential for long-term forest
planning. The risk of using under- or overpredicted basal area growth in forest planning is that longterm
projections could get more and more imprecise over time. This could, in turn, lead to
suboptimal forest management and decision-making, leading to non-optimal choice of tree-species,
early- or late timing of silvicultural treatments and ultimately to economic loss. The aim of this
thesis was to validate Heureka’s basal area growth function for Siberian larch (Larix sibirica),
European larch (Larix decidua) and hybrid larch (Larix x eurolepis). To validate the growth
function, field trials of larch from all over Sweden were used to compare basal area growth
prediction errors between Heureka predicted growth and basal area measured in the field. A sample
of plots were also chosen for simulation in Heureka StandWise for further analysis of basal area,
height and volume growth. Age-related prediction errors along with ground vegetation type were
tested and compared for the Heureka basal area function.
The results showed that basal area growth of Siberian larch was underpredicted at early age and
overpredicted at old age, regardless of vegetation type. European larch basal area growth was neither
under- nor overpredicted for the vegetation types but showed random error at young age. Basal area
growth of Hybrid larch showed a general underpredicted with vegetation type bilberry while no such
trend was seen for vegetation type no field vegetation. Heureka simulations showed a slightly higher
underpredicted basal area growth than predictions from the growth function. This could be explained
by that the predicted growth gets more imprecise over time or due to a too small sample size. There
are possibilities to increase the precision of Heureka’s growth predicted where one strategy would
be to develop and apply species specific growth models in Heureka DSS
Effects of vegetation and nutrients on methanotroph abundance and methane emissions from constructed wetlands
Get PDFAgriculture is the largest anthropogenic source of nitrogen and phosphorous (P) leakage to Swedish coastal seas, causing eutrophication which threatens marine ecosystems. Constructing wetlands is one way to improve nutrient retention in the modern agricultural landscape. However, constructed wetlands can emit substantial amounts of methane (CH4). Methanotrophs facilitate aerobic oxidation of CH4, which transforms the CH4 into less potent carbon dioxide. However, the factors controlling the methanotrophs and their effect on CH4 emissions are poorly understood. The aim of this thesis was to investigate the effect of vegetation and nutrient status on the CH4 emissions and abundance of methanotrophs from constructed wetlands in agricultural areas in Sweden. Water samples for DNA extraction and quantification by qPCR and gas samples for concentrations of dissolved CH4 was taken at 34 wetlands in southwest and middle Sweden. At 5 of the wetlands CH4 fluxes were measured using floating chamber technique. At each wetland samples were taken at one point with and one without vegetation. In addition, water chemistry and nutrient status were measured.
The results show that vegetation had no effect on the abundance of methanotrophs or on the dissolved CH4 and CH4 fluxes. This contradicts previous studies and may be explained by even conditions throughout the wetland and the off-vegetative season. Of the nutrients and hydrochemical factors, P and the increased fraction of P in relation to carbon and nitrogen was significantly correlated to the abundance of methanotrophs, which is in line with previous studies. None of the studied variables were correlated to the dissolved CH4. The total fluxes corresponded to fluxes reported in previous studies and indicated that ebullitive fluxes can be large even during winter season. Except the relationship between increased abundance of methanotrophs and increased P concentrations, the lack of significant results in this study may indicate that the abundance of methanotrophs, dissolved CH4 and CH4 fluxes depend on multiple direct and indirect variables that interactively control CH4 emissions and the bacterial community involved in CH4 oxidation.I Sverige är jordbruket den största mänskliga källan till läckage av kväve och fosfor till kustnära vatten, vilket orsakar övergödning och hotar marina ekosystem. Att bygga anlagda våtmarker är ett sätt att förbättra näringsretentionen i det moderna jordbrukslandskapet. I våtmarker kan det dock bildas och avgå en betydande mängs metangas (CH4). En särskild grupp av mikroorganismer, så kallade metanotrofer, omvandlar CH4 till den mindre starka växthusgasen koldioxid genom oxidation, men de faktorer som kontrollerar metanotroferna och deras påverkan på CH4-avgången är dåligt studerade. Syftet med det här masterarbetet var att undersöka effekten av våtmarksvegetation och näringsstatus på mängden metanotrofer och utsläppen av CH4 från konstruerade våtmarker i svenska jordbrukslandskap. Vattenprover för DNA-extraktion och kvantifiering av metanotrofer genom qPCR samt gasprover för CH4 löst i vatten togs på en plats med och en plats utan vegetation i 34 våtmarker i Halland och Mälardalen. I fem av våtmarkerna mättes också metangasavgången med hjälp av flytande kamrar. På alla platser mättes vattenkemi och koncentration av näringsämnen.
Resultaten visar en stor variation inom och mellan våtmarker, men vegetationen hade ingen signifikant effekt på varken mängden metanotrofer, löst CH4 eller CH4-avgång. Detta är i motsats till tidigare studier och kan möjligen förklaras av en jämn fördelning av näringsämnen i hela våtmarken samt att proverna togs när det inte var växtsäsong. Av de näringsämnen och vattenkemiska faktorer som mättes visade fosfor (P) samt en ökande mängd P i förhållande till kol och kväve ett signifikant, positivt samband till mängden metanotrofer men inga signifikanta samband till löst CH4 kunde påvisas. CH4-avgången som mättes i kamrarna var av samma storleksordning som tidigare studier rapporterat men visade också, tvärtemot vad tidigare studier antytt, att avgången kan vara stor även vintertid. Förutom korrelationen mellan P och metanotrofer antyder avsaknaden av signifikanta resultat och samband i den här studien att mängden metanotrofer och utsläppen av CH4 inte kan förklaras av en eller ett fåtal faktorer, utan sannolikt beror på flera både direkta och indirekta samverkande faktorer som kontrollerar CH4-avgång och mikrobsamhällena involverade i CH4-oxidation