| 1. |
- Osvath, Gergely, et al.
(författare)
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How feathered are birds? Environment predicts both the mass and density of body feathers
- 2018
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Ingår i: Functional Ecology. - : Wiley. - 1365-2435 .- 0269-8463. ; 32:3, s. 701-712
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Tidskriftsartikel (refereegranskat)abstract
- 1.Studies modelling heat transfer of bird plumage design suggest that insulative properties can be attributed to the density and structure of the downy layer, whereas waterproofing is the result of the outer layer, comprised of contour feathers. In this study, we test how habitat and thermal condition affect feather mass and density of body feathers (contour, semiplume and downy feathers) measured on the ventral and dorsal sides of the body, using a phylogenetic comparative analysis of 152 bird species.2.Our results demonstrate that feather mass and the density of downy feathers are higher in species that inhabit colder environments, whereas total feather density is higher of species breeding under intermediate temperatures compared to the ones breeding under more extreme conditions. The density of contour feathers, depending on the body region, is either quadratically related or negatively correlated with minimum winter temperature.3.The density of contour and downy feathers, measured on both sides of the body, is higher in aquatic than in terrestrial birds. However, among the former, diving behaviour does not select for further increases in body feather mass or density.4.The results of this study provides key insights into how the plumage of birds is adapted to different environments and lifestyles and provides a basis for understanding the diverse range and the evolution of variation in these characteristics.
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| 2. |
- Forsmark, Benjamin, et al.
(författare)
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Long-term nitrogen enrichment does not increase microbial phosphorus mobilization in a northern coniferous forest
- 2021
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Ingår i: Functional Ecology. - : Wiley. - 0269-8463 .- 1365-2435. ; 35:1, s. 277-287
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Tidskriftsartikel (refereegranskat)abstract
- Nitrogen (N) deposition can enhance carbon (C) capture and storage in northern coniferous forests but it may also enhance the demand for phosphorus (P). While it is well established that long-term N enrichment can decrease decomposition and enhance the accumulation of C in soils, it remains uncertain if a higher demand and acquisition of P influence soil C. We studied microbial phosphorus mobilization and growth within a long-term N enrichment experiment in a Norway spruce forest, where N deposition was simulated by adding 0, 12.5 or 50 kg N ha−1 year−1 for 21 years (n = 12), by incubating microbial ingrowth cores with needles and humus with low and high P content, and with sand with and without mineral apatite P. Long-term N enrichment had no effect on microbial P mobilization in needles and humus and did not enhance the positive effect that apatite had on fungal growth. However, it consistently strengthened the retention of C in the soil by decreasing decomposition of needle and humus, both with low and high P content, and by increasing fungal growth in sand-filled ingrowth cores. Furthermore, we did not find any evidence that higher microbial P mobilization in response to N enrichment affected soil C storage. These results show that long-term N enrichment in relatively young soils dominated by coniferous trees and ectomycorrhizal fungi can have relatively small impact on microbial P mobilization from organic sources and on the potential to mobilize P from minerals, and subsequently that elevated P demand due to N enrichment is unlikely to lead to a reduction in the soil C accumulation rate. A free Plain Language Summary can be found within the Supporting Information of this article.
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| 3. |
- Ilardi, Marco O., et al.
(författare)
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Scavenging beetles control the temporal response of soil communities to carrion decomposition
- 2021
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Ingår i: Functional Ecology. - : Wiley. - 0269-8463 .- 1365-2435. ; 35:9, s. 2033-2044
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Tidskriftsartikel (refereegranskat)abstract
- Carrion is a frequent but overlooked source of nutrients to the soil. The decomposition of carrion is accelerated by invertebrate scavengers, but the impact of the scavengers on below-ground biota and its functions is scarcely known. We conducted a laboratory experiment to investigate the effects of the burying beetle Nicrophorus vespilloides on the soil community of a temperate broadleaved forest. We assembled microcosms from soil collected from an oak woodland and treated them with mouse Mus musculus carcasses and mating pairs of burying beetles (♀+♂) in a factorial design with control soils. We sampled independent replicates over time to investigate how the beetles affect soil microarthropods and microbial biomass (bacteria and fungi) in relation to soil pH and organic matter content. The beetle treatment initially reduced the total microbial biomass and abundance of major groups of microarthropods relative to the control soil. At the same time, organic matter increased in the beetle treatment and then dropped to the pre-beetle level (i.e. soil baseline) at the end of the beetle breeding cycle (2 weeks). The rapid temporal changes in organic matter were mimicked by the relative abundances of the dominant microarthropod groups, with Oribatida relatively more abundant than Collembola and predaceous mites in the beetle treatment. The overall final effect of the beetle (relative to the laboratory control) on microarthropods was negative but the beetle kept these variables within the levels observed for freshly collected soil (baseline), while the final effect on pH was positive, and most likely driven by the surplus of nutrients from the carcass and biochemical changes triggered by the decomposition process. In nature, scavenging invertebrates are widespread. Our study demonstrates that beetles breeding in carcasses regulate the dynamics of key components of the soil food web, including microbial biomass, changes in the relative abundances of dominant microarthropods and soil organic matter and pH. Given the abundance of these beetles in nature, the study implies that the distribution of these beetles is a key driver of variation in soil nutrient cycling in woodlands. A free Plain Language Summary can be found within the Supporting Information of this article.
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| 4. |
- Li, Jian, et al.
(författare)
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Root influence on soil nitrogen availability and microbial community dynamics results in contrasting rhizosphere priming effects in pine and spruce soil
- 2021
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Ingår i: Functional Ecology. - : Wiley. - 0269-8463 .- 1365-2435. ; 35:6, s. 1312-1324
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Tidskriftsartikel (refereegranskat)abstract
- The rhizosphere priming effect (RPE) is increasingly considered an important regulator of below-ground C and N cycling, with implications for terrestrial ecosystem feedback to global change. Even so, there is a lack of knowledge about the mechanisms underlying RPEs. We used novel stable isotope probing methods to investigate RPEs in an experiment with Scots pine and Norway spruce seedlings, two of the most common boreal forest species. We determined root exudation rates, RPEs on SOM decomposition and gross N mineralization, and the contribution of different microbial functional groups to the observed RPEs. Pine induced positive and spruce induced negative RPEs on SOM decomposition, while no RPE on gross N mineralization was observed. Negative RPEs in the spruce treatment were attributed to an opportunistic subset of the fungal community that was growing on root-derived 13C while depleting available N, thus reducing the activity of microbial SOM decomposers. In the pine treatment, available N was likely sufficient to support the root-induced decomposition activities of fungal decomposers, resulting in positive RPEs. The findings suggest that RPEs, promoted by root stimulation of distinct subsets of the microbial community, can either contribute to conserving the soil C stock or to depleting it, depending on plant species and soil N availability. A free Plain Language Summary can be found within the Supporting Information of this article.
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| 5. |
- Nord, Andreas, et al.
(författare)
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Heat dissipation rate constrains reproductive investment in a wild bird
- 2019
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Ingår i: Functional Ecology. - : Wiley. - 0269-8463 .- 1365-2435. ; 33:2, s. 250-259
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Tidskriftsartikel (refereegranskat)abstract
- The “heat dissipation limit” theory (HDL) posits that animals with higher capacity to dissipate metabolic heat can increase reproductive investment. This theory remains untested in the wild. We recently showed that increased workload in a small bird causally relates to maximum body temperature. Here, we have expanded this approach by experimentally facilitating sensible heat transfer rate in nestling-feeding blue tits—a small bird with high resting- and work-induced body temperatures—through removal of ventral plumage. Feather-clipped parents did not increase work rate but sired larger, and sometimes heavier, nestlings while maintaining lower body temperature and losing less body mass than controls. Thus, when relieved of the demands to dissipate metabolic heat, parents could invest more into both current (nestling condition) and future (self-maintenance) reproduction. In accordance with the HDL theory, we conclude that constraints on heat dissipation rate could be a potent mediator of life-history trade-offs in wild animals. A plain language summary is available for this article.
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| 6. |
- Svensson, Erik I.
(författare)
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Eco-evolutionary dynamics of sexual selection and sexual conflict
- 2019
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Ingår i: Functional Ecology. - : Wiley. - 0269-8463 .- 1365-2435. ; 33:1, s. 60-72
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Tidskriftsartikel (refereegranskat)abstract
- The research framework of eco-evolutionary dynamics is increasing in popularity, as revealed by a steady stream of review articles and a recent and influential book, but primary empirical research is lagging behind. Moreover, the few empirical case studies demonstrating eco-evolutionary dynamics might not be entirely representative. Much current research on eco-evolutionary dynamics is focused on how ecological interactions lead to natural selection on phenotypic traits (“eco-evo”), and in turn how the evolutionary change in such traits feed back on ecological dynamics (“evo-eco”). A key feature of eco-evolutionary dynamics is thus a feedback loop between ecology (e.g., population dynamics) and evolution (i.e., genetic change). In contrast to previous research on eco-evolutionary dynamics driven by natural selection, the role of eco-evolutionary feedbacks in sexual selection and sexual conflict is largely unknown. Here, I review theory and the limited empirical evidence in this area and identify some promising future lines of research. I update a past review on contemporary evolution of secondary sexual traits in natural populations and formulate six explicit and rigorous criteria for contemporary evolution of secondary sexual traits by natural or sexual selection or sexual conflict. I then discuss the other key prediction of eco-evolutionary dynamics (i.e., evolution by sexual selection or sexual conflict shapes ecological dynamics). My overview reveals that our current knowledge in this area is limited and mainly come from theoretical models and laboratory experiments. A major challenge in eco-evolutionary dynamics is therefore to link ecological and population dynamics with sexual selection and sexual conflict. This is not an easy task but might be possible with carefully chosen study systems and methods. A plain language summary is available for this article.
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| 7. |
- White, Hannah J., et al.
(författare)
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Ecosystem stability at the landscape scale is primarily associated with climatic history
- 2022
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Ingår i: Functional Ecology. - : Wiley. - 0269-8463 .- 1365-2435. ; 36:3, s. 622-634
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Tidskriftsartikel (refereegranskat)abstract
- There is an increasing interest in landscape-scale perspectives of ecosystem functioning to inform policy and conservation decisions. However, we need a better understanding of the stability of ecosystem functioning (e.g. plant productivity) at the landscape scale to inform policy around topics such as global food security. We investigate the role of the ecological and environmental context on landscape-scale stability of plant productivity in agricultural pasture using remotely sensed enhanced vegetation index data. We determine whether four measures of stability (variability, magnitude of extreme anomalies, recovery time and recovery rate) are predicted by (a) species richness of vascular plants, (b) regional land cover heterogeneity and (c) climatic history. Stability of plant productivity was primarily associated with climatic history, particularly a history of extreme events. These effects outweighed any positive effects of species richness in the agricultural landscape. A history of variable and extreme climates both increased and decreased contemporary ecosystem stability, suggesting both cumulative and legacy effects, whereas land cover heterogeneity had no effect on stability. The landscape scale is a relevant spatial scale for the management of an ecosystem's stability. At this scale, we find that past climate is a stronger driver of stability in plant productivity than species richness, differing from results at finer field scales. Management should take an integrated approach by incorporating the environmental context of the landscape, such as its climatic history, and consider multiple components of stability to maintain functioning in landscapes that are particularly vulnerable to environmental change. A free Plain Language Summary can be found within the Supporting Information of this article.
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| 8. |
- Binyameen, Muhammad, et al.
(författare)
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Co-localization of insect olfactory sensory cells improves the discrimination of closely separated odour sources
- 2014
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Ingår i: Functional Ecology. - : Wiley. - 1365-2435 .- 0269-8463. ; 28:5, s. 1216-1223
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Tidskriftsartikel (refereegranskat)abstract
- 1. The sense of smell is crucial for fitness of most animals, enabling them to find mates, food and egg laying sites and to stay away from danger. Hence, odour molecules are detected by sensitive and specific olfactory sensory neurons (OSNs). In insects, the OSNs are stereotypically grouped into olfactory sensilla located mainly on the antennae. The functional significance of this co-localization principle is poorly understood, but it has been hypothesized that it allows for coincidence detection of odour filaments, improving discrimination of closely separated odour sources. 2. Using an insect in its natural environment, we conducted the first experimental test of the hypothesis. We manipulated the distance between odour sources of an attractive pheromone and either of two host-derived attraction antagonists (1,8-cineole and verbenone) and investigated the effect on trap catches of the bark beetle, Ips typographus (Coleoptera). 1,8-Cineole is detected by an OSN co-localized with an OSN for one of the pheromone components, while verbenone is detected by OSNs in other sensilla, not co-localized with pheromone OSNs. 3. Consistent with the hypothesis, trap catch increased with distance between odour sources more for 1,8-cineole than for verbenone. The strongest effect was found among the males, that is the sex that first locates and attacks the host tree. 4. Our data from the beetle provide, for the first time, direct experimental support for the hypothesis that co-localization of OSNs in sensilla improves the discrimination of closely separated odour sources. Thus, selection for improved odour source discrimination could well be one of the factors explaining the strict co-localization of OSNs that is seen across the Insecta class.
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| 9. |
- Eikenaar, Cas, et al.
(författare)
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Oxidative damage to lipids is rapidly reduced during migratory stopovers
- 2020
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Ingår i: Functional Ecology. - : Wiley. - 0269-8463 .- 1365-2435. ; 34:6, s. 1215-1222
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Tidskriftsartikel (refereegranskat)abstract
- Most migrating birds need to stopover in between flights in order to refuel. Lately, additional purposes of stopover have been suggested, including physiological recovery from metabolically demanding migratory flight. One apparently unavoidable, but harmful physiological effect of migratory flight is increased oxidative damage to lipids and proteins. We here, for the first time, tested whether migrating birds are able to reduce their oxidative damage during stopover. To be able to collect longitudinal data on a large number of individual birds, we temporarily caged wild northern wheatears, a long-distance migrant which does not suffer stress when caged during migration. Around noon on the first and third day at stopover, the birds were blood-sampled to determine malondialdehyde (MDA) concentration, a commonly used marker of oxidative damage to lipids. We found that MDA concentrations significantly decreased during stopover, a result unchanged when correcting for the peroxidizability of the substrate. The extent of the decrease was unrelated to the amounts of food consumed or of fuel accumulated. Our findings support the hypothesis that stopovers serve reduction of oxidative damage, warranting re-thinking of how birds accomplish their migrations. They also highlight the need to include physiological recovery as a driver of the (temporal) organization of migration. A free Plain Language Summary can be found within the Supporting Information of this article.
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| 10. |
- Hasper, Thomas Berg, et al.
(författare)
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Water use by Swedish boreal forests in a changing climate
- 2016
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Ingår i: Functional Ecology. - : Wiley. - 0269-8463 .- 1365-2435. ; 30:5, s. 690-699
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Tidskriftsartikel (refereegranskat)abstract
- The rising levels of atmospheric carbon dioxide concentration ([CO2]) and temperature have the potential to substantially affect the terrestrial water and energy balance by altering the stomatal conductance and transpiration of trees. Many models assume decreases in stomatal conductance and plant water use under rising [CO2], which has been used as a plausible explanation for the positive global trend in river run-off over the past century. Plant water use is, however, also affected by changes in temperature, precipitation and land use, and there is yet no consensus about the contribution of different drivers to temporal trends of evapotranspiration (ET) and river run-off. In this study, we assessed water-use responses to climate change by using both long-term monitoring and experimental data in Swedish boreal forests. Historical trends and patterns in ET of large-scale boreal landscapes were determined using climate and run-off data from the past 50 years, while explicit tree water-use responses to elevated [CO2] and/or air temperature were examined in a whole-tree chamber experiment using mature Norway spruce (Picea abies (L.) Karst.) trees. The results demonstrated that ET estimated from water budgets at the catchment scale increased by 18% over the past 50 years while run-off did not significantly change. The increase in ET was related to increasing precipitation and a steady increase in forest standing biomass over time. The whole-tree chamber experiment showed that Norway spruce trees did not save water under elevated [CO2] and that experimentally elevated air temperature did not increase transpiration as decreased stomatal conductance cancelled the effect of higher vapour pressure deficit in warmed air. Our findings have important implications for projections of future water use of European boreal coniferous forests, indicating that changes in precipitation and standing biomass are more important than the effects of elevated [CO2] or temperature on transpiration rates.
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