Kandidatuppsatser, Biologi / Institutionen för biologi och miljövetenskap

Permanent URI for this collectionhttps://gupea-staging.ub.gu.se/handle/2077/69814

Browse

Now showing 1 - 20 of 62

Parkslide i Sverige. Bekämpningsmetoder och deras effektivitet
(2025-09-10) Willig, Matilda; University of Gothenburg / Department of Biological and Environmental Sciences; Göteborgs universitet / Instiutionen för biologi och miljövetenskap
Invasive Alien Species (IAS) are an increasing concern in a globalized world where more species are transported and planted beyond their native environments. Japanese knotweed (Reynoutria japonica) is notoriously difficult to eradicate and has negative effects on environment and society. Methods are continuously developed, suitable for various sites and conditions. This study investigated which eradication methods are currently used in Sweden, their efficacy, and how soil levels of glyphosate, an herbicide used for eradication, and its metabolite AMPA change over time. New measurements of Japanese knotweed communities previously treated, with three different glyphosate methods or by coverage, in a pilot study by Göteborgs Stad (2021) showed a significant reduction in community size. This demonstrates an effect of all methods in the pilot. To evaluate glyphosate’s persistence in soil, results from the pilot 2021, where soil samples were collected before and 48 hours after treatment, where compared to new follow up samples from the same location. The results revealed that glyphosate had declined below detectable levels, while AMPA concentrations had increased over time. This indicates that when glyphosate is degraded, AMPA accumulates in the soil, and that AMPA appears to have a longer degradation time than glyphosate. Through a questionnaire study with professionals in the field, coverage was found to be the widest used eradication method. However, several other methods were perceived as more effective. The discrepancy likely relates to these methods being newly developed and not widely known, with limited evidence of their long-term efficacy. As most eradication efforts have occurred between 2020 and 2025, these results should be considered preliminary. Continued monitoring is needed to assess long-term efficacy of different methods. Eradication of Japanese knotweed is complex, and many factors need to be considered. No method is effective in every case, rather, a toolbox of varied methods is needed to eradicate the species in the environments in which it grows.
Estimating poulation trend and breeding site fidelity for the Baltic grey seal (Halichoerus grypus balticus)
(2025-08-15) Dahlquist, Arvid; University of Gothenburg / Department of Biological and Environmental Sciences; Göteborgs universitet / Instiutionen för biologi och miljövetenskap
The Baltic gray seal population has for decades undergone significant changes. The extent of sea ice, which formerly was an important part of the breeding habitat, is reducing every year forcing gray seal mothers to rear pups on islands. Lacking knowledge of gray seal mothers’ site fidelity behavior, scientific methods like examine population trends and site fidelity analyses can lead to more understanding of the breeding behavior and make a huge difference in mother and pup protection. This study will therefore look upon the overall trend of the Baltic gray seal population done with the latest data from aerial surveys from 2003-2024 The study will also investigate the site fidelity behavior by monitoring a specific area in the Stockholm archipelago called Skarv, Sweden’s largest pupping site. The research question examines whether mothers return to this location, assessing its importance for pup rearing. The trend analysis was calculated with two models, exponential and logarithmic where the exponential model gave the best fit. The site fidelity assessment was done by using mark-recapture methods after identifying seals through photo-ID analysis of video material from three consecutive years, 2021-2023 that later was processed in the software Wild ID. The trend model indicates a continued exponential growth of 4.84% each year with a standard error of 0.0026. The mark recapture method resulted in a single recapture for all three years suggesting either low site fidelity behavior or limitations in the sampling. The calculations estimated the female population to N=3967 with upper CI95%=18305 and lower CI95%=1791 and by looking at the confidence intervals the conclusion can be made that uncertainty is affected by the low sample size rather than low site fidelity. Although the maximum growth for a pinniped population is at 13% the trend result suggest that the population continues to recover from historic overhunting. A conclusion for the low recapture rate however is hard to make but with a working methodology this can be used as a foundation to, with further research, establish fidelity rates.
Effect of microclimate on litter decomposition within the arctic region.
(2025-06-27) Persgården, Klara; University of Gothenburg / Department of Biological and Environmental Sciences; Göteborgs universitet / Instiutionen för biologi och miljövetenskap
Plant litter decomposition is a key process in the global carbon cycle, influencing carbon exchange between ecosystems and the atmosphere. Temperature and moisture are known climatic regulators of decomposition rate at broad spatial scales. However, their influence at finer spatial resolutions remains uncertain. Small-scale variation is particularly important to study in arctic sites, as they harbor extensive microclimatic variation. The Arctic region is predicted to experience the greatest change in climate compared to the global average, potentially causing decomposition rates to increase considerably. As arctic regions store nearly half of the terrestrial carbon, this could have profound effects on carbon cycling and the global climate. This study investigates the effects of microclimatic temperature and soil moisture on litter decomposition at three arctic sites (Latnjajaure, Disko Island and Svalbard). Decomposition rate (k), measured using the Tea Bag Index (TBI), was modeled as a function of small-scale variation in temperature and moisture using multiple linear regression. Site-specific models found no evidence that small-scale variation in moisture influenced decomposition rates at these sites, which may be due to moisture not being a limiting factor at the relatively low arctic temperatures. A combined model including all sites revealed an overall positive relationship between temperature and decomposition rate, suggesting that small-scale variation in temperature has a significant but relatively weak positive effect on decomposition rate that is constant across the Arctic. This study highlights the importance of including small-scale environmental variability into decomposition studies, but also suggests that factors other than temperature and moisture will likely have an important influence on decomposition and, by extension, carbon cycling under arctic climate change.
Osmoreglera mera - Phaseolus vulgaris under torka. Genotypiska skillnader i osmoreglering som anpassning till torka hos vanlig böna.
(2025-06-27) Sandström, Elvira; University of Gothenburg / Department of Biological and Environmental Sciences; Göteborgs universitet / Instiutionen för biologi och miljövetenskap
Torka är en av de största begränsande faktorerna för jordbruksproduktion globalt och med klimatförändringarna förväntas både förekomst och intensitet av torka öka. Detta utgör ett växande hot mot livsmedelssäkerhet samtidigt som ökade krav ställs på livsmedelsproduktionen i takt med jordens växande befolkning. Den vanliga bönan (Phaseolus vulgaris) är en vidspridd näringskälla med många olika varianter, som rankas som den mest konsumerade bönan. Den spelar en avgörande roll för kost och försörjning i låginkomstländer, särskilt i torkdrabbade länder som Rwanda. För att säkra framtida skördar behövs därför ökad förståelse för växters fysiologiska torkrespons, vilket undersökts i denna studie. En viktig mekanism växter använder för att hantera vattenbrist är osmotisk reglering, där ackumulering av lösta ämnen sänker den osmotiska potentialen i växten och möjliggör fortsatt vattenupptag från jorden runtomkring. Denna studie undersökte 22 genotyper av P. vulgaris för att kartlägga genotypisk variation i osmotisk anpassning och relatera denna till uthållighet vid torka. Genotyperna utsattes för en eller två på varandra följande perioder av torka. Osmolaritet i bladvävnad mättes före och efter behandling, samtidigt som jordfuktighet mättes varje dag och även antal dagar under torka. Resultaten visade att torka generellt ökade osmolariteten, men responsen varierade tydligt mellan genotyper. Flera uppvisade både hög osmotisk anpassning och lång uthållighet. En signifikant negativ korrelation observerades mellan osmolaritet och jordfuktighet efter bevattning. Samtidigt visade resultaten att uthållighet och osmotisk respons inte alltid samvarierade, vilket tyder på att växterna använder olika fysiologiska strategier för att hantera torka. Denna variation mellan genotyper utgör en värdefull resurs för framtida växtförädling av mer torktåliga grödor i ett föränderligt klimat.
Testing local adaption to microclimate in tundra plants. A common garden experoment with temperature treatments.
(2025-06-27) Walter, Gulis; University of Gothenburg / Department of Biological and Environmental Sciences; Göteborgs universitet / Instiutionen för biologi och miljövetenskap
One of the regions changing the fastest due to global warming is the tundra regions. This can potentially severely boost global warming due to the area containing a large majority of the worlds carbon stock, trapped under the layer permafrost existing in the ground. This change may be mediated through ecosystem changes on a community level with native plants disappearing due to the warming environment. To better understand how future tundra ecosystems may develop in regard to global warming, and whether genetic variation linked to landscape heterogeneity buffers these effects an experiment was performed. A common garden experiment was conducted using three tundra species grown in different temperature conditions to assess variation in germination, survival and early seedling growth. In Oreojuncus trifidus survival was mostly dependent on the seed mass while seedling height was significantly affected by the microclimate of origin and treatment. Amount of leaves (AOL) was significantly affect by treatment as was germination date. Site of origin had a minor effect but was mostly not relevant. The other species did not develop quickly enough to allow for measurement of Height and AOL, so were excluded from further trait analysis. The results suggest some subpopulations may be better suited to warmer conditions due to differences linkable to original microclimate. If this trait variation reflects heritable adaptation, this could help support the persistent of tundra species under climate change. Which, in turn, may contribute to slowing vegetation shifts that could otherwise affect the function of the ecosystem. Which in turn would preserve the current status quo of the area, preserving the carbon stocks in the area.
Dammen i Slottsskogen. Förekomst och förutsättningar samt åtgärdsförslag för att gynna groddjur i framtida naturvårdsarbete.
(2025-06-27) Mosskull, Hanna; University of Gothenburg / Department of Biological and Environmental Sciences; Göteborgs universitet / Instiutionen för biologi och miljövetenskap
Groddjur (amfibier) är viktiga indikatorarter i både akvatiska och terrestra ekosystem, men globalt hotas denna organismgrupp av habitatförlust, försämrad vattenkvalitet och klimatförändringar. Stadsmiljöförvaltningen i Göteborg jobbar ständigt med att bevara biodiversiteten i den urbana parken Slottsskogen och att gynna groddjursdiversiteten är en del av detta arbete. Denna studie undersöker groddjursdiversiteten i Stora dammen i Slottsskogen med syfte att kartlägga artdiversiteten, att bedöma dammens lämplighet som groddjurslokal och att ge åtgärdsförslag till Stadsmiljöförvaltningen för att gynna groddjuren i Stora dammen i framtida naturvårdsarbete. Hypotesen var att förekomsten av vanlig groda (Rana temporaria), vanlig padda (Bufo bufo), större vattensalamander (Triturus cristatus), mindre vattensalamander (Lissotriton vulgaris) och ätlig groda (Pelophylax esculentus) skulle observeras. Närvaro av amfibier indikerar på hälsosamma ekosystem och god biodiversitet vilket ingår i Slottsskogens mål. Groddjursinventering genomfördes med visuell sökmetod under april-maj och kompletterades med en lokalbeskrivning av dammen samt vattenprover för att bedöma vattenkvaliteten beträffande vattnets totalfosforhalt, nitrathalt, pH, alkalinitet och syrehalt. Resultatet visade på låg groddjursdiversitet i Stora dammen då endast två individer av mindre vattensalamander (Lissotriton vulgaris) observerades. Från vattenanalyserna kunde slutsatsen dras att Stora dammen har höga näringshalter och låg syresättning vilket inte gynnar groddjursdiversiteten. pH nivåerna och alkaliniteten tros inte ligga bakom den låga diversiteten då dessa värden faller inom groddjurens preferensramar. Dammens omgivande miljö, bottenstrukturen i vattnet och kantzonerna saknar viktiga element som karaktäriserar goda groddjurslokaler. Utifrån jämförelser med artspecifika miljökrav och tidigare forskning dras slutsatsen att Stora dammen i dagsläget inte är en fungerande groddjurslokal. De åtgärder som föreslås inkluderar muddring, utplantering av vattenväxter, förändring av kantzoner och omgivande gräsmattor, utplacering av övervintringsplatser samt begränsning av predationsrisker.
Nya urbana trädarters återhämtning av fotosynteser efter värmebölja.
(2025-06-27) Blomqvist, Tove; University of Gothenburg / Department of Biological and Environmental Sciences; Göteborgs universitet / Instiutionen för biologi och miljövetenskap
Träd är viktiga för att skapa hållbara städer. De utför ekosystemtjänster som gynnar oss människor genom ökat fysiskt och psykiskt välmående samt genom att bidra positivt till vår ekonomi. Utformningen av städer medför ett flertal utmaningar för urbana träd, där värmeböljor, torka och generellt höga temperaturer är några faktorer som försvårar trädens överlevnad. Med tanke på de rådande klimatförändringarna kommer tillvaron för de stadslevande träden bli allt svårare framöver. För att framtida städer ska kunna vara ett hem åt både välmående grönska och invånare, är det nödvändigt att träden klarar av de tuffare förhållandena. I denna studie undersöktes återhämtningen av nettofotosyntes hos de urbana trädarterna K. paniculata, L. styraciflua, L. tulipifera, M. kobus, och N. sylvatica under fyra veckor efter en värmebölja på 38℃. Jämförelser gjordes mellan arterna samt mellan två behandlingsgrupper: en som utsattes för upprepad värmestress och en kontrollgrupp. Även stomatakonduktans och funktion av fotosystem II mättes för att få en uppfattning om anledningar bakom eventuella skillnader i nettofotosyntes. Nettofotosyntesen påverkades negativt av värmeböljan för L. tulipifera, M. kobus och N. sylvatica. För L. tulipifera var återhämtning möjlig på fyra veckor medan M. kobus och N. sylvatica inte kunde återhämta sig. Hos K. paniculata och L. styraciflua verkade nettofotosyntesen opåverkad av värmeböljan. När det kommer till de individuella trädarterna kunde skillnader mellan behandlingsgrupperna observeras hos alla arter utom N. sylvatica. M. kobus var den enda av dessa arter som påvisade starkare negativ påverkan vid upprepad värmestress än i kontrollgruppen. För de båda generella behandlingsgrupperna (över alla arter) minskade stomatakonduktansen under värmeböljan, med kraftigare minskning i kontrollgruppen. Vissa trädarter verkar klara av värmeböljor bättre än andra och vad trädet varit med om innan en värmebölja kan också vara av betydelse för hur det påverkas och återhämtar sig. Vid plantering av träd i urbana miljöer krävs val av rätt art för att våra städer ska förbli gröna och hälsosamma för oss och framtida generationer.
Effekt av brand och bete på uppkomst av örtartade växter i restaurerade betesmarker. En jämförande studie
(2025-06-27) Karlsson, Mina; University of Gothenburg / Department of Biological and Environmental Sciences; Göteborgs universitet / Instiutionen för biologi och miljövetenskap
Open ecosystems, such as grasslands and pastures, have naturally been shaped by disturbances like fire and grazing. These processes play a crucial role in creating habitats with high biological diversity, particularly favourable for a wide range of herbaceous plant species. In recent years, many of these disturbances have ceased, leading to encroachment, fragmentation and habitat loss. The aim of this study was to examine and compare the effects of fire, herbivory and a combination of fire and herbivory on the emergence of herbaceous plants. The study was conducted at the Ecopark at Nordens Ark. A seed mixture was sown in plots undergoing the different treatments: fire, herbivory and their combination, in autumn 2024. In spring 2025, an inventory was done to assess total emergence, species richness and the emergence of Agrostemma githago (corncockle), a dominant species in the plots from the seed mixture. The results clearly showed that grazing was the key factor contributing to higher total emergences, greater species richness and a higher number of A. githago. The highest mean values were observed in plots with combined fire and herbivory, but no significant difference could be observed to grazing alone. Fire alone resulted in significantly lower emergence and species richness than treatments including grazing but still had a weak positive effect. These findings indicate that grazing creates favourable conditions for increased emergence of herbaceous species, likely by reducing competition from grasses and therefore increasing light availability at the soil surface. Grazing thus appears to be a more effective management tool for maintaining open ecosystems than fire, which is valuable information regarding restoration and management of open ecosystems. The study shows that herbivory, and potentially fire, act as key processes to keep open ecosystems open, thus promoting recruitment of herbaceous plants, which preserves the habitats high biodiversity, ecological function and cultural-historical value.
Mellan lag och verklighet. En studie av svenska kustkommuners förvaltning av grunda mjukbottnar i kustzonen.
(2025-06-27) Melin, Amanda; University of Gothenburg / Department of Biological and Environmental Sciences; Göteborgs universitet / Instiutionen för biologi och miljövetenskap
Grunda mjukbottnar i Sveriges kustvatten utgör biologiskt värdefulla miljöer med funktioner som näringsomsättning, erosionsskydd och viktiga livsmiljöer för fisk. Trots detta är dessa habitat kraftigt hotade av ökad exploatering kopplad till bebyggelse, turism och infrastruktur. Studien syftar till att undersöka hur svenska kustkommuner hanterar skyddet av grunda mjukbottnar i förhållande till befintlig lagstiftning och nationella riktlinjer. Fokus låg på att identifiera hur juridiska verktyg används, vilka hinder som upplevs i det lokala planeringsarbetet samt vilka drivkrafter som påverkar beslut. För att besvara frågeställningarna kombinerades kvalitativa intervjuer med tre kommuner och en representant från Havs- och vattenmyndigheten, samt en kvantitativ enkät till samtliga kustkommuner i landet. Materialet analyserades tematiskt och statistiskt, vilket möjliggjorde en integrerad förståelse av både lokala och nationella perspektiv. Resultaten visar att kommunernas planering varierar kraftigt i ambition och kapacitet. Trots insikt om miljöernas värde är skyddsarbetet ofta otillräckligt och reaktivt, och vilar främst på strandskyddsbestämmelserna. Exploatering kopplad till bostäder, båtliv och hamnar prioriteras ofta framför långsiktigt naturvårdande insatser. Kommunerna uttrycker ett behov av tydligare nationell samordning, mer vägledning och stärkta styrmedel. Kunskapsbrist och begränsade resurser försvårar tillämpningen av ekologiska perspektiv som ekosystemtjänster och styrverktyg som DAPSIR-modellen. Sammantaget visar studien på ett tydligt glapp mellan nationell policy och lokal förvaltning. Ett effektivare skydd av grunda mjukbottnar förutsätter förstärkt samverkan, konkreta verktyg och ett mer proaktivt och helhetsinriktat planeringsarbete. Studien bidrar med viktiga insikter för utveckling av nationellt anpassat stöd till kommunal planering och lyfter behovet av en sammanhållen förvaltning för att skydda våra mest sårbara marina miljöer.
Märgelgravar i Varberg. En uppföljningsstudie av småvatten i kommunen.
(2025-06-17) Pettersson, Matilda; University of Gothenburg / Department of Biological and Environmental Sciences; Göteborgs universitet / Instiutionen för biologi och miljövetenskap
Märgelgravar är småvatten med ursprung i det sena 1800-talets jordbruk, då kalkrik jord grävdes upp och spreds på åkermark för att öka bördigheten. De resulterande groparna vattenfylldes med tiden och utgör idag viktiga småvattens-habitat i ett annars artfattigt jordbrukslandskap. Trots att märgelgravar omfattas av generellt biotopskydd enligt miljöbalken har dess antal minskat, vilket väcker frågor om skyddets effektivitet. Syftet med denna studie var att undersöka hur märgelgravar i Himleåns avrinningsområde i Varbergs kommun förändrats sedan en kommunal inventering 1997–98, samt att identifiera faktorer som kan förklara varför vissa märgelgravar finns kvar medan andra försvunnit. Studien baseras på material från inventeringen 97–98, flygbildsanalys, rumslig analys i QGIS, fältverifiering av svårbedömda objekt, samt statistisk analys i R med logistisk regression. Variabler som undersöktes var markanvändning, förändrad markanvändning, avstånd till väg och byggnad, vattenspegelns area 1998, samt ursprunglig skötselstatus. Av 263 märgelgravar som dokumenterades som existerande 1998 återstod 168 år 2023, vilket motsvarar en minskning med 36 %. Resultaten visade att två faktorer hade signifikant samband med bevarandestatus: större vattenspegel vid föregående inventering och klassificering som välskött. Övriga variabler uppvisade inga signifikanta samband i multivariat analys. Studien visar att små, dåligt skötta märgelgravar löper större risk att försvinna, trots lagstadgat skydd. Detta understryker vikten av riktade bevarandeinsatser, särskilt för små märgelgravar som skötts sämre. Rekommenderade åtgärder inkluderar ökad information till markägare, förbättrad uppföljning, samt restaurering som beaktar både ekologiska och kulturhistoriska värden. Framtida studier kan med fördel utökas till att omfatta hela Varbergs kommun, inventera biologiska värden, och analysera nytillkomna småvatten samt landskapsövergripande förändringstrender.
En återinventering och analys av den svenska populationen av svart nervmossa (Campylopus atrovirens)
(2025-04-04) Hultander, Erik; University of Gothenburg / Department of Biological and Environmental Sciences; Göteborgs universitet / Instiutionen för biologi och miljövetenskap
Bristly swan-neck moss (Campylopus atrovirens) is in Sweden a very rare moss that only grows on a few blocks and cliffs around Gothenburg. The species can globally only be found in areas with high precipitation. Rain fall in Gothenburg has increased with a stronger greenhouse effect. Air pollution in Gothenburg has also improved. Mosses generally benefit from these conditions and this papers hypothesis is that the population of the species has grown because of these more beneficial conditions. Data was collected through field excursions to the same locations that bristly swan-neck moss was inspected during 1977–1978. The population was measured in its entirety and information about the locations properties was collected through random placements of a grid that gave information about the species frequencies. This information combined with indicator values gives values for light, moisture, rection, nitrogen and how much heavy metals the locations have. The results of this paper show that two locations have decreased in size, two are basically the same and one has increased. The locations that have decreased in size mainly seem to be dry, but they also seem to lack suitable places to grow and are often shaded by trees. The unchanged populations have a lot of water but lack light. They seem to spread but not be able to grow large. The location where the population has grown is the most exposed to sun and is surprisingly dry. The increase might be due to low competition with other moss species, temporary wetter periods which lets the population survive and the high amount of sunlight which is only slightly obscured by the deciduous forest. The population has grown but all growth comes from one location. Light and moisture appears to be the most important factors for success.
Reproduction and adapted histology for Yellow Hedgehog sponges. A study of Polymastia boletiformis in the Koster Sea.
(2024-12-16) Börjesson, Emelia; University of Gothenburg / Department of Biological and Environmental Sciences; Göteborgs universitet / Instiutionen för biologi och miljövetenskap
The Koster Sea is Sweden's most sponge rich area, hosting around 160 sponge species. Sponges are filter feeding invertebrates that belong to one of the oldest animal phyla on earth, Porifera. Concerning their body structure, they are regarded to be the simplest of multicellular animals, built up by rather independent cells with a low degree of specialization. This study has been looking into reproduction among the Polymastia. A genus with two known species in Swedish waters – Polymastia mamillaris and Polymastia boletiformis. So far, there has been no detailed reproductive study for either of those commonly found species in this region. Also, no knowledge of specific asexual reproductive structures is documented for the species. Major aims for this study were to identify collected sponges to species and to troubleshoot a repeatable methodology for histological processing of reproductive material in Polymastia. Reproductive studies in sponges are rare, and so methodology for good histology is still cryptic. Polymastia specimens collected in the Koster Sea during 2023 were examined histologically to see if there were any differences in reproductive structures (asexual as sexual) regarding size, location in sponge bodies and seasonality. Together with Polymastia specimens from Gothenburg Museum of Natural History all sponges were examined for signs of asexual reproduction. Sponges collected in this study belonged to the same species, the yellow hedgehog sponge P. boletiformis. Three specimens were identified as reproductive females with early oocytes with significantly different sizes. They were collected in April and the presence of small oocytes indicated that the species might reproduce during summer in the Koster Sea. No signs of asexual reproduction were found among the collected specimens nor the museum specimens. This study contributes to the field of basic science within sponge reproduction with a fully adapted histology protocol for P. boletiformis. Furthermore, it contributes with the first observations of reproductive Polymastia individuals in Swedish waters.
Do Diverse Agricultural Landscapes Lower the Risk of Biopesticide Resistance Evolution?
(2024-10-11) Boström, Hugo; University of Gothenburg / Department of Biological and Environmental Sciences; Göteborgs universitet / Instiutionen för biologi och miljövetenskap
Pesticide resistance decreases food security and leads to increased pesticide use and associated environmental damage and higher costs to farmers from increased applications. Alternative pesticide resistance management systems are needed to sustain future food security while protecting environments. Using a spatial matrix of different biopesticides instead of synthetic pesticides could possibly impose enough fluctuating selection to prevent directional resistance evolution, as long as there are trade-offs between traits that improve survival in the presence of different biopesticides. However, the scale at which divergent selection is needed to prevent evolution is unknown, and field experiments to examine the importance of gene flow are too time-consuming and logistically difficult. My project uses computer agent-based simulations to examine the effect of using two, three or four biopesticides in different landscapes to look at how diversity in agricultural land use affects resistance evolution. These simulations allow evolution in populations of digital pests with complex genomes. I further extract information from real world maps having a range of field sizes to incorporate the characteristics of realistic landscapes. My simulations showed substantial resistance evolution when only two or three biopesticides were used, but that using a larger number of biopesticides arrested resistance evolution. Surprisingly, the size of fields had no effect on resistance evolution regardless of biopesticide number: even in landscapes with large monocultures, there was enough gene flow in the computer population to prevent local resistance evolution and create sustainable pest control. I discuss my findings in the context of fundamental evolutionary principles, the demographics and dispersal abilities of pests, and the applied implications of my work for sustainable agriculture.
VEDLEVANDE BIN I SLOTTSSKOGEN - och varför deras bon är svåra att hitta
(2024-09-26) Törngren, Fideli; University of Gothenburg / Department of Biological and Environmental Sciences; Göteborgs universitet / Instiutionen för biologi och miljövetenskap
Med de minskande bestånden av vildbin över världen finns det ett behov och ett fokus att bevara och stärka populationer genom naturvårdande åtgärder, däribland att tillgodose behovet av boplatser. För de biarter som bor i död ved innebär detta att lämna kvar döda stammar, både stående och liggande. Trots den viktiga roll bin har i vår födoproduktion saknas mycket information angående bins preferenser kring boplatser och i så fall vilka faktorer som spelar in i valet. Studiens mål var att se om bin föredrar vissa boplatser före andra, med specifikt fokus på stående eller liggande död ved, mängden solexponering, träslagets hårdhet samt stammens diameter. Data samlades in i Slottsskogen under våren 2024 och den döda veden delades in i kategorier baserat på om de var stående eller liggande, hur mycket sol som träffade stammen, trädart och mätningar gjordes av trädets diameter. 36 träd slumpades fram och under juni månad 2024 räknades antal sammanlagda hål i veden samt antalet hål ockuperade av bin. För få bon hittades för att göra en statistisk analys och fokus lades i stället på att förklara det låga antalet. Orsaken är oklar, men kan möjligtvis bero på flera faktorer, bland annat ett naturligt lågt antal bon i potentiella boplatser, den döda vedens placering i parken, föda för långt ifrån potentiella boplatser, mindre populationer orsakat av ett varmare och mer ostadigt klimat samt en förändrad markanvändning. För att stärka populationerna i parken rekommenderas Slottsskogen att placera död ved i områden med mer solexponering, med närhet till föda och bomaterial.
ANALYSIS OF VENTRICULAR MORPHOLOGY AND ARTERIAL ANATOMY IN THE HEARTS OF FARMED RAINBOW TROUT (Oncorhynchus mykiss)
(2024-08-23) Grote, Johanna; University of Gothenburg / Department of Biological and Environmental Sciences; Göteborgs universitet / Instiutionen för biologi och miljövetenskap
Oxygenation of the cardiac muscle tissue is essential for survival in both fish and mammals. Unlike mammals, most fish rely on oxygen-poor luminal venous blood flowing through the spongy myocardium to oxygenate the cardiac tissue. However, athletic salmonids such as rainbow trout (Oncorynchus mykiss) possess an additional layer of myocardial cells outside of the spongy myocardium known as the compact myocardium. This layer is associated with increased cardiac muscle mass and volume, but it also distances individual cells from the luminal oxygen supply. Consequently, the compact myocardium depends on the development of a coronary circulation to supply the cardiac cells with oxygen-rich blood. This supply is essential for maintaining cardiac function. Notably, farmed salmonid fish exhibit deviations in heart morphology compared to their wild counterparts, making them susceptible to decreased cardiac performance and cardiac diseases. In this study, microscopic and macroscopic traits of hearts in farmed rainbow trout were investigated. The results are discussed in relation to cardiac performance and farming conditions. Consistent with other studies, a high prevalence of rounded ventricles and misaligned bulbus arteriosus was observed in our samples. Furthermore, this project identified cases of excess collagen distribution within the compact myocardium, which suggest an old injury caused by myocardial ischemia, presence of coronary anatomy anomaly, and ventricular hypoplasia. These findings underscore the variability of cardiac abnormalities found in farmed salmonid fish compared to their wild counterparts and contributes further to the discussions about cardiac health in farmed fish from a fish welfare and economic perspective.
NATURMINNENS FÖRVALTNING OCH SKYDD: Inventering i Västra Götaland
(2024-08-22) Fredriksson, Stina; University of Gothenburg / Department of Biological and Environmental Sciences; Göteborgs universitet / Instiutionen för biologi och miljövetenskap
Natural monuments are natural objects with special protection due to their high natural value or cultural significance. The natural value is determined by the occurrence of signal species found on and near the natural monument. The law surrounding natural monuments has evolved a lot since the first ones were declared, and today the title natural monument can be replaced with the title tree with high conservation value. The title has come later and can sometimes overlap natural monument. Some natural monuments lack the qualities required to be classified as a natural monument or a tree with high conservation value, but have a cultural importance. These can instead be classified as a biological cultural heritage. In this study, I have obtained an inventory of 30 natural monument trees around Västra Götaland. The inventory answers how well these are taken care of based on what can be assumed from their condition. During the inventory, it was noted if the object remained, whether it was marked with a sign, shading and its natural value class based on the presence of signal species. All data from the inventories was collected in field documents and an inventory log containing pictures of the objects. Based on the collected data, a χ2-test was made from the number of signal species found per natural monument and degree of shade, to investigate the effect of shading from surrounding fauna. The results showed no significant correlation between the degree of shading and the number of signal species found.
HÅRNERVMOSSANS PÅVERKAN PÅ LJUNGHEDENS ARTMÅNGFALD: En fältstudie från Sandsjöbackas naturreservat
(2024-08-22) Arkheden, Linda; University of Gothenburg / Department of Biological and Environmental Sciences; Göteborgs universitet / Instiutionen för biologi och miljövetenskap
Campylopus introflexus is a moss species that originates from the southern hemisphere and has spread worldwide during the 20th century. Today it is classified as an invasive alien species in many countries, and it has been seen during inventories that it has become widespread in Sweden as well. The purpose of this essay is to contribute to new knowledge about how this moss affects species diversity on Calluna heathlands in Sweden. The study includes both fieldwork and an analysis of scientific literature on the subject, and the question that is answered is if C. introflexus has an impact on species richness in the heather peat. Field data were collected on an Calluna heathland in Sandsjöbacka nature reserve outside Gothenburg, where species in the heather peat were counted and identified, both in places where C. introflexus was present and not. The collected data were tested for normal distribution and equal variances, after which a two-tailed ttest was performed. The result showed a significant difference in the mean number of species found when C. introflexus was present and not. Average number of species found in 0,25m2 squares with C. introflexus was 6,1, while the number of species in squares without C. introflexus was 7.4. When it comes to the number of species found, this is almost a 20% decrease. That indicates that C. introflexus has a negative impact on species richness on Calluna heathlands, but to establish this more comprehensive field studies are required. The literature survey also showed that C. introflexus has a negative impact on species diversity as it forms dense mats that make it difficult for other species to grow there. The invasive moss can also establish itself very quickly in disturbed environments, such as on clearcuts, root rolls or burned ground, which gives it an additional competitive advantage on Calluna heathlands.
HÅRNERVMOSSA I SANDSJÖBACKA NATURRESERVAT: Analys av hårnervmossans invasivitet på ljunghedens vegetationstyper
(2024-08-22) Fredman, Amanda; University of Gothenburg / Department of Biological and Environmental Sciences; Göteborgs universitet / Instiutionen för biologi och miljövetenskap
Heath star moss (Campylopus introflexus) is an alien species in Sweden and is currently classified as composing a "very high risk” of becoming invasive in the country according to SLU, and has in several parts of the world taken over large areas in a short time. The moss is characterized by its preference for disturbed and burned land, something that occurs on the heathland in the Sandsjöbacka nature reserve, when burning for nature conservation purposes is carried out annually. Sandsjöbacka's heathland is a valuable ecosystem and is one of the few heathlands in a favorable condition that remains in Sweden after strong reforms in modern agriculture in the last century, which led to forest succession of these cultural environments. Heathlands are one of the most threatened environmental types in Europe, of which 95 % are estimated to have disappeared from Sweden since the 1800’s and around 200 red-listed species have been linked to the environment that heathlands offer, which means that heathlands need to be prioritized within nature conservation. C. introflexus is today established in the reserve and the question is the following: does the moss pose a threat to the heathland at the present time - and if so, is there any preferred type of vegetation that is particularly vulnerable to the invasion? By sampling random replicates from three commonly occurring vegetation types (heather type on shallow peat soils, heather type on moraine soil, Agrostis capillaris type) in Sandsjöbacka nature reserve, the frequency of heath star moss was calculated and in statistical analysis it could be deduced that there was a strong statistically significant difference for the Agrostis capillaris type compared to the two other vegetation types where the frequency of heath star moss on Agrostis capillaris type was significantly much lower. The null hypothesis could therefore be rejected, and the conclusion was drawn that C. introflexus poses no threat to grasslands (of Agrostis capillaris type), but for heather and heather peat no further conclusions can be drawn.
THE EFFECT OF DIET BREADTH ON BIOPESTICIDE SUSCEPTIBILITY
(2024-08-22) Petersson, Malin; University of Gothenburg / Department of Biological and Environmental Sciences; Göteborgs universitet / Instiutionen för biologi och miljövetenskap
Pesticide resistance has evolved in insects for as long as the use of insecticides, and has caused us to continually develop new ones. An alternative to synthetic pesticides is biopesticides, which can consist of either living organisms or substances from organisms. Biopesticides containing living organisms can include bacteria, virus, fungi, as well as predators and parasites. They can be preferable to synthetics since they usually are less dangerous to humans, disintegrate faster and tend to be more targeted to specific pest species. Pest species ability to develop resistance to a synthetic insecticide seems to vary depending on the number of plant families the species feed on. The reason for this can be that polyphagous insects are better adapted to handling secondary metabolites from more or different plant species than do specialist insects. In this meta-analysis, I investigate whether a similar relationship exists among living biopesticides. The underlying hypothesis is that since plants have microorganisms in and on them, an insect feeding on several plants can have a history of being exposed to more diverse microbial communities compared to insects feeding on just one plant species throughout its life. I used a Bayesian multilevel regression model to answer the question: Are polyphagous pests less susceptible to novel pathogens and living biopesticides than specialist pests? The result showed no evidence for polyphagous pests to be more resilient against novel biopesticides. However, the posterior distribution is not mean centred, which can indicate a small effect of polyphagia on mortality. Further and more detailed studies of this question are strongly needed.
NEDKYLNING HOS VANLIG BÖNA, PHASEOLUS VULGARIS
(2024-08-19) Sjöndin, Camilla; University of Gothenburg / Department of Biological and Environmental Sciences; Göteborgs universitet / Instiutionen för biologi och miljövetenskap
Beans are a global source of plant-based protein, and in some countries, they constitute a primary source of protein intake. With ongoing climate change, including rising temperatures, it is necessary to adapt beans to ensure a reliable food supply. An important mechanism that many plants have, to cope with high temperatures, is cooling through transpiration. During transpiration, stomata open and release water vapor. Water molecules use heat energy from the leaf to convert into gas, thereby cooling the leaf. The aim of this study was to investigate the extent of cooling in common bean, Phaseolus vulgaris, and how cooling differs between various bean varieties. This was done by comparing differences in leaf and air temperatures from existing field data from Rwanda and a selection of five bean varieties in a laboratory setting. Additionally, the lab examined how an increase in air temperatures and an increase in light intensity affect the cooling process. In both the field and lab studies, the plants were watered so that water availability did not limit transpiration. Both field and lab results show that common beans lower leaf temperature by an average of 3.3°C relative to air temperature and that cooling is greater at higher air temperatures than at lower ones. This is likely due to increased VPD (Vapor Pressure Deficit) and increased stomatal conductance. The lab results also showed that cooling decreased with increased light intensity. In the field data, no significant differences between the bean varieties were observed. The lab data did not provide conclusive results but showed a trend where one variety often cooled better than the others. The study demonstrates that transpirational cooling is an important mechanism in common beans to avoid high temperatures. The increased cooling protects against the harmful effects of heat and allows continued photosynthesis even at high air temperatures.

Browse

Recent Submissions