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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
11

Blomsterlupin versus tre inhemska ärtväxtarter : Jämförelser av besöksfrekvens och pollineringseffektivitet hos olika grupper av insektspollinatörer / Garden lupin versus three native legume species : Comparisons of visitation frequency and pollination effectivity for different groups of insect pollinators

Westling, Tobias January 2023 (has links)
Red clover (Trifolium pratense) is currently used as a green fertilizer for agriculture in northern Sweden. However, due to its low resistance against diseases and a minimal benefit to local pollinators, there is a need to find alternative native species that maximize the benefits for pollinators and agriculture. Garden lupin (Lupinus polyphyllus), another legume, is an invasive alien species in Sweden that may affect the behavior of pollinators and therefore the pollination success of local plant species. The main aim of this study was to increase the knowledge of the legumes cow vetch (Vicia cracca), garden lupin, marsh pea (Lathyrus palustris) and red clover by observing their insect visitors and potential pollinators. The work was divided into subproject 1 (delprojekt 1) and subproject 2 (delprojekt 2). Delprojekt 1 studied insect visitation frequencies in one plot where garden lupin, cow vetch and red clover grew together in Burträsk, while delprojekt 2 studied insect pollination effectivity in two plots where one plot (Fäbodsanden) contained only marsh pea and the other plot (Skäret) contained both garden lupin and marsh pea. Data were collected via field observations. In ‘delprojekt 1', both bumblebees and solitary bees showed a significantly higher visit frequency to garden lupin than to cow vetch and red clover. In ‘delprojekt 2’, flies showed a significantly higher pollination effectivity on garden lupin than on marsh pea in Skäret. Both flies and bumblebees showed a significantly higher pollination effectivity on marsh pea in Fäbodsanden than in Skäret. This indicate that visitation frequencies to cow vetch and red clover as well as pollination effectivity on marsh pea may be affected by the presence/absence of garden lupin. For future studies, examples on how to extend the knowledge even further on plant-pollinator interactions are suggested.
12

Nattbelysningens påverkan på förekomsten av nattfjärilar i Halmstads urbana grönområden.

Andersson, Nelly, Lindeberg, Richard January 2023 (has links)
Sammanfattning Nattfjärilar är en utsatt grupp när det kommer till nattbelysning, eftersom nattbelysning påverkar processer som födosök och reproduktion samt ökar deras mortalitet genom stress och ökad risk för predation. Mörka och belysta lokaler i Halmstads urbana grönområden undersöktes för att studera nattbelysningens påverkan på nattfjärilars individantal och artdiversitet. I studien visade vi på signifikanta skillnader hos både nattfjärilars individantal samt artdiversitet mellan de mörka och belysta lokalerna, där tillhörande analyser visade signifikant färre antal individer och likaså negativ trend för artdiversiteten. Analyserna visade att minskad artdiversitet och individantal i belysta lokaler inte var signifikant korrelerat med belysningsstyrkan i lokalerna. Dock finns det indikationer på att belysningsstyrkan eventuellt haft en negativ påverkan på individantalet och artdiversiteten av nattfjärilar i denna studie. Det fanns en belyst lokal som utmärkte sig med ovanligt hög diversitet där artdiversiteten var det tredje högsta uppmätta värdet i hela studien. Detta kan eventuellt bero på förekomsten av blommande buskage vilket återfanns i direkt anslutning till inventeringsområdet. Vi föreslår därför att blommande växter och buskage kan implementeras som åtgärd för att förebygga nattbelysningens påverkan på nattfjärilspopulationer. Kompletterande samt uppföljande studier av ämnet kring vilka växter som passar specifikt för nattfjärilar behövs, då det i dagsläget är ett ämne som i Sverige behöver utvecklas innan implementering av passande växter kan bli en lämplig åtgärd. / Abstract Moths are a vulnerable group when exposed to night lighting, it affects their basic drives such as foraging and reproduction and increases their mortality through stress and increased risk of predation. Dark and illuminated localities in Halmstads’ urban green areas were inventoried to study the impact of night illumination on the number of individuals and species diversity of moths. In the study, significant differences were found in the individual number of moths and species diversity between the dark and illuminated localities, which could not be significantly correlated to illuminance present in the localities. However, there were indications that illuminance may still have negatively affected the number of individuals and species diversity of moths in this study. There was one illuminated locality that stood out from the rest where species diversity was the third highest measurement from the entire study, which can possibly be attributed to the presence of flowering shrubs. Therefore we suggest that flowering shrubbery can be implemented as a measure to prevent the impact of night illumination on moth populations and becomes the basis for supplementary and follow-up studies of the subject.

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