| 1. |
- Andersson, Hanna, et al.
(författare)
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Natur på skolgården för lärande, hälsa och hållbarhet
- 2024. - 2024
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Rapport (populärvet., debatt m.m.)abstract
- Gröna och artrika utemiljöer främjar barns och ungas välbefinnande och kunskap, bådegenom hälsofördelar kopplade till biologisk mångfald och genom att skapa förutsättningarför lek och lärande om natur och miljöfrågor. Skolgården skulle kunna bidra till allt detta,men är idag i hög grad en outnyttjad plats för biologisk mångfald och klimatanpassningav städer. I denna policy brief presenteras huvudsakliga motiv och möjliga åtgärder för attutveckla gröna miljöer och biologisk mångfald på skolgårdar och förskolegårdar.
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| 2. |
- Jensen, Johan Kjellberg, et al.
(författare)
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Urban tree composition is associated with breeding success of a passerine bird, but effects vary within and between years
- 2023
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Ingår i: Oecologia. - : Springer Science and Business Media LLC. - 0029-8549 .- 1432-1939. ; 201:3, s. 585-597
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Tidskriftsartikel (refereegranskat)abstract
- Birds breeding in urban environments have lower reproductive output compared to rural conspecifics, most likely because of food limitation. However, which characteristics of urban environments may cause this deficiency is not clear. Here, we investigated how tree composition within urban territories of passerine birds is associated with breeding probability and reproductive success. We used 7 years of data of breeding occupancy for blue and great tits (Cyanistes caeruleus; Parus major) and several reproductive traits for great tits, from 400 urban nest boxes located in 5 parks within the city of Malmö, Sweden. We found that tits, overall, were less likely to breed in territories dominated by either non-native trees or beech trees. Great tit chicks reared in territories dominated by non-native trees weighed significantly less, compared to territories with fewer non-native trees. An earlier onset of breeding correlated with increased chick weight in great tits. Increasing number of common oak trees (Quercus robur) was associated with delayed onset of breeding in great tits. Notably, as offspring survival probability generally increased by breeding earlier, in particular in oak-dominated territories, our results suggest that delayed onset of breeding induced by oak trees may be maladaptive and indicate a mismatch to this food source. Our results demonstrate that tree composition may have important consequences on breeding success of urban birds, but some of these effects are not consistent between years, highlighting the need to account for temporal effects to understand determinants of breeding success and inform optimal management in urban green spaces.
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| 3. |
- Dominoni, Davide M., et al.
(författare)
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Artificial light at night, in interaction with spring temperature, modulates timing of reproduction in a passerine bird
- 2020
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Ingår i: Ecological Applications. - : Wiley. - 1051-0761 .- 1939-5582. ; 30:3
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Tidskriftsartikel (refereegranskat)abstract
- The ecological impact of artificial light at night (ALAN) on phenological events such as reproductive timing is increasingly recognized. In birds, previous experiments under controlled conditions showed that ALAN strongly advances gonadal growth, but effects on egg-laying date are less clear. In particular, effects of ALAN on timing of egg laying are found to be year-dependent, suggesting an interaction with climatic conditions such as spring temperature, which is known have strong effects on the phenology of avian breeding. Thus, we hypothesized that ALAN and temperature interact to regulate timing of reproduction in wild birds. Field studies have suggested that sources of ALAN rich in short wavelengths can lead to stronger advances in egg-laying date. We therefore tested this hypothesis in the Great Tit (Parus major), using a replicated experimental set-up where eight previously unlit forest transects were illuminated with either white, green, or red LED light, or left dark as controls. We measured timing of egg laying for 619 breeding events spread over six consecutive years and obtained temperature data for all sites and years. We detected overall significantly earlier egg-laying dates in the white and green light vs. the dark treatment, and similar trends for red light. However, there was a strong interannual variability in mean egg-laying dates in all treatments, which was explained by spring temperature. We did not detect any fitness consequence of the changed timing of egg laying due to ALAN, which suggests that advancing reproduction in response to ALAN might be adaptive.
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| 4. |
- Jensen, Johan Kjellberg, et al.
(författare)
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Contrasting effects of tree origin and urbanization on invertebrate abundance and tree phenology
- 2022
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Ingår i: Ecological Applications. - : Wiley. - 1051-0761 .- 1939-5582. ; 32:2
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Tidskriftsartikel (refereegranskat)abstract
- The ongoing wide-scale introduction of nonnative plants across the world may negatively influence native invertebrate fauna, due to a lack of coevolved traits related to the novel plants, e.g., unique phytochemicals or shifted phenology. Nonnative plants, specifically trees, are common in urban environments, areas that already pose novel habitats to plants and wildlife through a wide array of anthropogenic factors. For example, impervious surfaces contribute to increased ambient temperatures, the so-called urban heat island effect (UHI), which can affect local plant phenology. Yet, few studies have simultaneously studied the effects of urbanization and tree species origin on urban invertebrate communities. We measured the city-level UHI and phenology of nine native and seven nonnative tree species in five city-center parks in southern Sweden, as well as four common native species in a rural control forest. We quantified the abundance of invertebrates on a subset of native and nonnative tree species through shake sampling, sticky traps, and frass collection. In the urban environment, nonnative trees hosted significantly fewer invertebrates compared to native trees. Furthermore, the nonnative trees had a delayed phenology compared to native species, while the peak of caterpillars associated with the subset of trees surveyed for this measure was significantly earlier compared to that of the native species studied. The effect of tree species origin on urban invertebrate abundance was of a greater magnitude (effect size) than the effect of urbanization on invertebrate abundance in native tree hosts. Hence, the results indicate that the impact of nonnative vegetation may be a stronger driver of invertebrate declines in urban areas than other factors. As the effect of species origin on tree phenology was at a level comparable to the urban effect, increasing prevalence of nonnative vegetation can potentially obscure effects of urbanization on phenology in large-scale studies, as well as induce mismatches to invertebrate populations. Since parks harbor a large proportion of urban biodiversity, native trees play a crucial role in such habitats and should not be considered replaceable by nonnative species in terms of conservation value.
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| 5. |
- Jensen, Johan Kjellberg, et al.
(författare)
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Migrant blackbirds, Turdus merula, have higher plasma levels of polyunsaturated fatty acids compared to residents, but not enhanced fatty acid unsaturation index
- 2020
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Ingår i: Ecology and Evolution. - : Wiley. - 2045-7758. ; 10:18, s. 10196-10206
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Tidskriftsartikel (refereegranskat)abstract
- Birds have been observed to have dietary preferences for unsaturated fatty acids during migration. Polyunsaturated fatty acids (PUFAs) may increase the exercise performance of migrant birds; however, PUFAs are also peroxidation prone and might therefore incur increased costs in terms of enhanced oxidative damage in migratory individuals. To shed light on this potential constraint, we analyzed plasma fatty acid (FA) composition and estimated the unsaturation index as a proxy for susceptibility to lipid peroxidation of migrants and residents of the partially migratory common blackbird (Turdus merula) at a stopover site during autumn migration. As predicted, migrant birds had higher relative and absolute levels of PUFAs compared to resident birds. This included the strictly dietary ?-3 PUFA a-linolenic acid, suggesting a dietary and/or storage preference for these FAs in migrants. Interestingly, the FA unsaturation index did not differ between migrants and residents. These findings suggest a mechanism where birds alter their levels of metabolic substrate without simultaneously increasing the susceptibility of the substrate to lipid peroxidation. In summary, our results are in line with the hypothesis that increased exercise performance during migration might be constrained by oxidative stress, which is manifested in changes in the composition of key FAs to retain the unsaturation index constant despite the increased levels of peroxidizable PUFAs.
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| 6. |
- Jensen, Johan Kjellberg
(författare)
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Understanding the urban ecosystem : interactions between plants, animals, and people
- 2023
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Cities are the pinnacle of human change to the environment, creating unique types of ecosystems which present many challenges to local organisms: habitat fragmentation, introduced species, and various pollutants. Being crucibles of anthropogenic effects, urban ecosystems offer opportunities to understand how humans impact nature. Moreover, since a majority of the world’s population resides in cities today, urban nature has become the most frequently encountered type of nature in everyday life. Studying urban ecology therefore has the potential to shed light on both sides of the interaction between people and nature. In this thesis, I used an interdisciplinary approach to explore the effects of urbanization on vegetation, arthropods, birds, and people. Studying several taxa, and using methods from Ecology, Physiology, Sociology, and Aerosol technology, I aimed to develop a holistic and multifaceted understanding of the urban ecosystem. Specifically, I investigated urban trophic interactions, how air pollution and nutrition may affect animal physiology, and how local wildlife influences children’s well- being and perception of nature. I outline three key findings from the six papers forming the basis of my thesis: (1) plant origin is a strong determinant for urban arthropod abundance and breeding success of birds. Namely, non-native trees show a negative effect, with a magnitude and consistency over years, which indicates that vegetation composition is a key driver limiting animal populations in cities. (2) urban birds are constrained by food quality (specific nutrients) during breeding, likely due to low abundances of certain arthropods in cities. Moreover, high quantities of low-quality food (e.g., from human sources) do not compensate for the urban birds’ dietary deficiency and may instead lead to reduced capacity to mount physiological responses to deal with air pollutants or infections. (3) children’s relation to nature (attitude and knowledge) is not impacted by urbanization but predicted instead by socioeconomic factors and the quality of nature close to their homes. These local differences call for more detailed approaches when studying cities since both social and environmental variation within urban areas can be more consequential than general divides. In this thesis, I demonstrate the importance of native vegetation in cities and food quality for urban animals. Local wildlife influences people and by better understanding the urban ecosystem, we are one step closer to building cities that will allow future generations to learn about species and enjoy nature near their homes.
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| 7. |
- Kjellberg Jensen, Johan, et al.
(författare)
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Quantifying the influence of urban biotic and abiotic environmental factors on great tit nestling physiology
- 2023
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Ingår i: Science of the Total Environment. - : Elsevier B.V.. - 0048-9697 .- 1879-1026. ; 859
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Tidskriftsartikel (refereegranskat)abstract
- There is a long history of avian studies investigating the impacts of urbanization. While differences in several life-history traits have been documented, either between urban and rural populations or across generalized urbanization gradients, a detailed understanding of which specific environmental variables cause these phenotypic differences is still lacking. Here, we quantified several local environmental variables coupled to urbanization (air pollution, tree composition, ambient temperature, and artificial light at night [ALAN]) within territories of breeding great tits (Parus major). We linked the environmental variables to physiological measures of the nestlings (circulating fatty acid composition [FA], antioxidant capacity and an oxidative damage marker [malondialdehyde; MDA]), to garner a mechanistic understanding of the impact of urbanization. We found that the antioxidant capacity of nestlings decreased with higher numbers of oak trees and levels of PM2.5 (airborne particulate matter with a diameter < 2.5 μm). Furthermore, the ratio of ω6:ω3 polyunsaturated FAs, important for immune function, was positively correlated with PM2.5 concentration, while being negatively associated with ambient temperature and number of non-native trees in the territory. Body mass and wing length both increased with the number of local oak trees. We also show, through a principal component analysis, that while the environmental variables fall into an urbanization gradient, this gradient is insufficient to explain the observed physiological responses. Therefore, accounting for individual environmental variables in parallel, and thus allowing for interactions between these, is crucial to fully understand of the urban ecosystem. © 2022 The Authors
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| 8. |
- Persson, Anna S., et al.
(författare)
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Främja biologisk mångfald i städer och tätorter
- 2024
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Ingår i: Movium Fakta. - 2001-2357. ; 2024:1
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Tidskriftsartikel (övrigt vetenskapligt/konstnärligt)abstract
- Trots att urbaniseringen är negativ för biologisk mångfald lyfts urbana miljöer ofta fram som en möjlig tillflyktsort för arter. Dessutom har kunskapen om hur biologisk mångfald bidrar till goda livsmiljöer för människor blivit allt tydligare. I detta nummer av faktabladet kommer vi att utforska hur urbana miljöer kan gynna biologisk mångfald och skapa goda livsmiljöer för vissa arter och människor.
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| 9. |
- Ziegler, Ann Kathrin, et al.
(författare)
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Dietary fatty acids modulate oxidative stress response to air pollution but not to infection
- 2024
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Ingår i: Frontiers in Physiology. - 1664-042X. ; 15
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Tidskriftsartikel (refereegranskat)abstract
- Anthropogenic changes to the environment expose wildlife to many pollutants. Among these, tropospheric ozone is of global concern and a highly potent pro-oxidant. In addition, human activities include several other implications for wildlife, e.g., changed food availability and changed distribution of pathogens in cities. These co-occurring habitat changes may interact, thereby modulating the physiological responses and costs related to anthropogenic change. For instance, many food items associated with humans (e.g., food waste and feeders for wild birds) contain relatively more ω6-than ω3-polyunsaturated fatty acids (PUFAs). Metabolites derived from ω6-PUFAs can enhance inflammation and oxidative stress towards a stimulus, whereas the opposite response is linked to ω3-derived metabolites. Hence, we hypothesized that differential intake of ω6-and ω3-PUFAs modulates the oxidative stress state of birds and thereby affects the responses towards pro-oxidants. To test this, we manipulated dietary ω6:ω3 ratios and ozone levels in a full-factorial experiment using captive zebra finches (Taeniopygia guttata). Additionally, we simulated an infection, thereby also triggering the immune system’s adaptive pro-oxidant release (i.e., oxidative burst), by injecting lipopolysaccharide. Under normal air conditions, the ω3-diet birds had a lower antioxidant ratio (GSH/GSSG ratio) compared to the ω6-diet birds. When exposed to ozone, however, the diet effect disappeared. Instead, ozone exposure overall reduced the total concentration of the key antioxidant glutathione (tGSH). Moreover, the birds on the ω6-rich diet had an overall higher antioxidant capacity (OXY) compared to birds fed a ω3-rich diet. Interestingly, only the immune challenge increased oxidative damage, suggesting the oxidative burst of the immune system overrides the other pro-oxidative processes, including diet. Taken together, our results show that ozone, dietary PUFAs, and infection all affect the redox-system, but in different ways, suggesting that the underlying responses are decoupled despite that they all increase pro-oxidant exposure or generation. Despite lack of apparent cumulative effect in the independent biomarkers, the combined single effects could together reduce overall cellular functioning and efficiency over time in wild birds exposed to pathogens, ozone, and anthropogenic food sources.
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