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White dwarf stars represent the last evolutionary stage of most stars in the Universe. As many of half of these stars are known to have metals in their atmospheres, that must have entered the atmosphere recently. Some also have observable debris discs, hinting that remnant exoplanets provide an important puzzle piece. However, we do not know the full extent of their role, as it is very hard to obs

This thesis explores the escalating and often underestimated issue of bird-window collisions, specifically within the Swedish context, through the lens of the built environment. Globally, hundreds of millions of birds die annually from colliding with glass surfaces, with estimates reaching nearly a billion birds in North America alone. This significant threat is compounded by modern architectural

This thesis examines how transnational mobility shapes the relationship between the sense of national belonging, European affiliation, and openness towards “others” among Polish students who have studied abroad. Based on 308 survey responses, it explores how living and studying away from one’s home country influences self-perception and impacts intergroup attitudes, applying Social Identity Theo

The growing number of offshore wind farms being constructed in the North Sea raises important questions about their potential ecological impact on marine communities. Monitoring these effects requires tools that can accurately describe biodiversity, not just in terms of species presence, but also their relative abundance. Environmental DNA analysis is a promising approach for this purpose, but the

Shrub range expansion, also known as shrubification, across arctic and subarctic ecosystems is expected to increase with climate change, with implications for vegetation structure, biodiversity, and soil carbon dynamics. Previous research has found a shrubification-induced decrease in organic matter stocks from tundra to forest in the organic horizon, prompting further investigation into whether t

Stormwater is runoff water from snow or rain events that enters a recipient shortly after the precipitations has reached the ground. Stormwater can contain heavy metals and nutrients depending on the type and size of the catchment area as well as the intensity and regularity of the precipitation. In high amounts, the pollutants can inhibit algal growth and have a negative effect in algal diversity

Life-history theory predicts a trade-off between immune defence and reproduction. If an individual needs to fight an infection during the breeding season, they may reduce their current reproductive effort and invest more resources into an immune response. Alternatively, they may invest their resources into increasing current reproductive effort at the expense of immune defence, which could reduce

Copepods play a central role in marine food webs, acting as an important link between primary producers and higher trophic levels. Predator-prey interactions between copepods and their prey drive the evolution of defense traits in phytoplankton, including chemically mediated inducible defenses. While our understanding of how predator alarm cues structure plankton communities is developing rapidly,

Understanding how organisms allocate limited resources among competing traits is a central issue in evolutionary biology. In this thesis, I test whether butterflies have an energetic trade-off between the high-cost sensory traits, compound eyes and antennae. Such a trade-off would be predicted by the Expensive Tissue Hypothesis. We used high-resolution 3D micro-CT data from 233 museum specimens (r

Growing research on ecosystem subsidies has emphasized the connection between aquatic and terrestrial ecosystems, with changes in one triggering responses in the other. In high mountain lakes, emerging aquatic insects are considered key aquatic subsidies and serve as an important nutrient resource for surrounding terrestrial ecosystem. The introduction of alien fish into these lakes, known to caus

The main focus of this case study was to assess ecological succession and restoration success after the removal of Rosa rugosa. Plant species composition and moss presence, bare ground cover, and biodiversity indices were analysed to identify patterns and differences within and between the restored and an invaded adjacent area. The complete absence of R. rugosa in restored plots confirms the effec

Sowing wildflower strips is a commonly applied agri-environmental scheme in agricultural landscapes used to mitigate the ongoing decline in pollinator diversity and abundance. Flower strips can be implemented as either annual or perennial plantings to promote biodiversity and/or ecosystem services. As different objectives may require different seed mixtures, this may impact how various pollinator

The mobility of harbor porpoise (Phocoena phocoena) makes the small, toothed whale complicated to study, especially regarding their distribution and foraging over a longer timescale. To overcome this, passive acoustic monitoring, which detects their high-frequency echolocation clicks (ranging from 125-140 kHz), offers a way to track their presence with high temporal resolution (measured as detecte

Harmful algal blooms pose a threat to public health and the economy, affecting tourism, fisheries, and aquaculture. Complex environmental factors influence their occurrence, but current forecasting models often overlook the role of grazers. Chemical cues released by zooplankton, copepodamides, can trigger the production of toxins in harmful algae. Therefore, their presence in bivalves may enhance

Migration does have a time, energy or mortality cost, and the strategy to minimise the costs shapes the migration behaviour. Depending on the relative influence of these costs in shaping the migration, an animal is expected to undertake these journeys in different ways, depending on their morphology and migration ecology. I investigated if five Tringa-type waders minimise their migration time, and

In the ocean, carbon export is driven by the biological carbon pump where organic matter is transported from the surface layer to the deep sea. The sinking particulate organic matter is mainly a product of phytoplankton aggregates and faecal pellets from zooplankton & fish, together also known as “marine snow”. Marine snow is continuously being degraded by microbial and zooplankton activities

According to sexual selection theory, males should benefit more from mating with multiple partners than females do as male investment into offspring production is typically lower. However, male reproductive success might not increase indefinitely with an increasing number of female mating partners. Male ejaculates are limited, and so mating with multiple females over a short period of time may cau