| 1. |
- Dahlgren, Jonas, et al.
(författare)
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Här trivs blåbär och lingon bäst
- 2012
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Ingår i: Skog & mark : om tillståndet i svensk landmiljö. 2012. - 9789162012939 ; , s. 24-26
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Bokkapitel (populärvet., debatt m.m.)
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| 2. |
- Dahlgren, Jonas, et al.
(författare)
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Positive feedbacks and alternative stable states in forest leaf types
- 2024
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Ingår i: Nature Communications. - 2041-1723. ; 15
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Tidskriftsartikel (refereegranskat)abstract
- The emergence of alternative stable states in forest systems has significant implications for the functioning and structure of the terrestrial biosphere, yet empirical evidence remains scarce. Here, we combine global forest biodiversity observations and simulations to test for alternative stable states in the presence of evergreen and deciduous forest types. We reveal a bimodal distribution of forest leaf types across temperate regions of the Northern Hemisphere that cannot be explained by the environment alone, suggesting signatures of alternative forest states. Moreover, we empirically demonstrate the existence of positive feedbacks in tree growth, recruitment and mortality, with trees having 4–43% higher growth rates, 14–17% higher survival rates and 4–7 times higher recruitment rates when they are surrounded by trees of their own leaf type. Simulations show that the observed positive feedbacks are necessary and sufficient to generate alternative forest states, which also lead to dependency on history (hysteresis) during ecosystem transition from evergreen to deciduous forests and vice versa. We identify hotspots of bistable forest types in evergreen-deciduous ecotones, which are likely driven by soilrelated positive feedbacks. These findings are integral to predicting the distribution of forest biomes, and aid to our understanding of biodiversity, carbon turnover, and terrestrial climate feedbacks.
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| 3. |
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| 4. |
- Nilsson, Per, et al.
(författare)
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Skogsdata 2022. Tema: Den formellt skyddade skogen
- 2022
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Rapport (övrigt vetenskapligt/konstnärligt)abstract
- SLU Riksskogstaxeringen samlar årligen in data i skog och mark i Sverige som underlag för Sveriges officiella statistik om ”Skogarnas tillstånd och förändring”. Riksskogstaxeringen påbörjades redan 1923 och har sedan dess utvecklats såväl avseende vilka geografiska områden som ingår i inventeringen, som vad som inventeras. Från och med år 2003 inkluderades formellt skyddade områden inom nationalparker och naturreservat i fältinventeringen och från och med 2016 även de delar av fjällområdet som kan förväntas innehålla trädvegetation. Genom att utnyttja Naturvårdsverkets digitala georefererade information om gränser för formellt skyddade områden kan vi nu beskriva karaktärer och egenskaper för Sveriges formellt skyddade skogsmark. SCB publicerar årligen officiell statistik avseende arealer formellt skyddad skog i Sverige (SCB 2021). I detta temanummer fokuserar vi därför på att beskriva hur dessa arealer fördelas på olika egenskaper samt kvantifierar och beskriver egenskaper för virkesförråd, tillväxt och naturlig avgång. Vi jämför även tillstånd och egenskaper för skog inom formellt skyddade områden med övrig skog.
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| 5. |
- van der Plas, F., et al.
(författare)
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Continental mapping of forest ecosystem functions reveals a high but unrealised potential for forest multifunctionality
- 2018
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Ingår i: Ecology Letters. - : Wiley. - 1461-023X .- 1461-0248. ; 21:1, s. 31-42
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Tidskriftsartikel (refereegranskat)abstract
- Humans require multiple services from ecosystems, but it is largely unknown whether trade-offs between ecosystem functions prevent the realisation of high ecosystem multifunctionality across spatial scales. Here, we combined a comprehensive dataset (28 ecosystem functions measured on 209 forest plots) with a forest inventory dataset (105,316 plots) to extrapolate and map relationships between various ecosystem multifunctionality measures across Europe. These multifunctionality measures reflected different management objectives, related to timber production, climate regulation and biodiversity conservation/recreation. We found that trade-offs among them were rare across Europe, at both local and continental scales. This suggests a high potential for win-win' forest management strategies, where overall multifunctionality is maximised. However, across sites, multifunctionality was on average 45.8-49.8% below maximum levels and not necessarily highest in protected areas. Therefore, using one of the most comprehensive assessments so far, our study suggests a high but largely unrealised potential for management to promote multifunctional forests.
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| 6. |
- Aldea, Jorge, et al.
(författare)
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Current and future drought vulnerability for three dominant boreal tree species
- 2024
-
Ingår i: Global Change Biology. - 1354-1013 .- 1365-2486. ; 30
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Tidskriftsartikel (refereegranskat)abstract
- Climate change is projected to increase the frequency and severity of droughts, possibly causing sudden and elevated tree mortality. Better understanding and predictions of boreal forest responses to climate change are needed to efficiently adapt forest management. We used tree-ring width chronologies from the Swedish National Forest Inventory, sampled between 2010 and 2018, and a random forest machine-learning algorithm to identify the tree, stand, and site variables that determine drought damage risk, and to predict their future spatial–temporal evolution. The dataset consisted of 16,455 cores of Norway spruce, Scots pine, and birch trees from all over Sweden. The risk of drought damage was calculated as the probability of growth anomaly occurrence caused by past drought events during 1960–2010. We used the block cross-validation method to compute model predictions for drought damage risk under current climate and climate predicted for 2040–2070 under the RCP.2.6, RCP.4.5, and RCP.8.5 emission scenarios. We found local climatic variables to be the most important predictors, although stand competition also affects drought damage risk. Norway spruce is currently the most susceptible species to drought in southern Sweden. This species currently faces high vulnerability in 28% of the country and future increases in spring temperatures would greatly increase this area to almost half of the total area of Sweden. Warmer annual temperatures will also increase the current forested area where birch suffers from drought, especially in northern and central Sweden. In contrast, for Scots pine, drought damage coincided with cold winter and early-spring temperatures. Consequently, the current area with high drought damage risk would decrease in a future warmer climate for Scots pine. We suggest active selection of tree species, promoting the right species mixtures and thinning to reduce tree competition as promising strategies for adapting boreal forests to future droughts.
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| 7. |
- Ammenberg, Jonas, et al.
(författare)
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Sustainability Assessment of Public Transport, Part I-A Multi-Criteria Assessment Method to Compare Different Bus Technologies
- 2021
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Ingår i: Sustainability. - : MDPI. - 2071-1050. ; 13:2
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Tidskriftsartikel (refereegranskat)abstract
- This article departs from the perspective of Swedish regional transport authorities and focuses on the public procurement of bus transports. Many of these public organizations on the county level have the ambition to contribute to a transition involving the continued marginalization of fossil fuels and improved sustainability performance. However, there are several renewable bus technologies to choose between and it can be difficult to know what alternative (or combination) is preferable. Prior research and the authors experiences indicate a need for improved knowledge and supportive methods on how sustainability assessments can support public procurement processes. The purpose of this article is to develop a multi-criteria assessment (MCA) method to support assessments of public bus technologies sustainability. The method, which was established in an iterative and participatory process, consists of four key areas and 12 indicators. The article introduces the problem context and reviews selected prior research of relevance dealing with green or sustainable public procurement and sustainability assessments. Further on, the process and MCA method are presented and discussed based on advice for effective and efficient sustainability assessments. In the companion article (Part II), the MCA method is applied to assess several bus technologies involving biodiesel, biomethane, diesel, electricity, ethanol and natural gas.
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| 8. |
- Appiah Mensah, Alex, et al.
(författare)
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Taller and slenderer trees in Swedish forests according to data from the National Forest Inventory
- 2023
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Ingår i: Forest Ecology and Management. - : Elsevier BV. - 0378-1127 .- 1872-7042. ; 527
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Tidskriftsartikel (refereegranskat)abstract
- Changes over time in annual basal area growth and mean height for Scots pine (Pinus sylvestris L.) and Norway spruce (Picea abies (L.) Karst.) over the period, 1983-2020 were studied using sample tree data from temporary plots recorded in the Swedish National Forest Inventory. The annual basal area growth was derived from the last measured full ring on increment cores. Using 20 to 60-year-old dominant trees, the mean height and annual basal area growth were examined as functions of tree, stand and site conditions, and trends were assessed mainly using residual analyses over time. A significant increase in mean height at a given age was found for both species, but the annual basal area growth level remained stable over the 38-year period. Currently, at a given age of 50 annual rings at breast height, the mean heights of pines and spruces increased on average by 10.1% (i.e. similar to 2 m), compared to 50 year-old pines and spruces in the 1980s, and the increase was similar in the different regions. The results suggest that trees have become taller and slenderer in Swedish forests. Increasing tree height over time at a given age in Northern Europe has been documented in several reports and many causes have been suggested, such as changed forest management, increasing temperatures and nitrogen deposition. We suggest that elevated CO2 in the air and improved water-use efficiency for the trees might also be strong drivers.
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| 9. |
- Aunapuu, Maano, et al.
(författare)
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Spatial patterns and dynamic responses of arctic food webs corroborate the exploitation ecosystems hypothesis (EEH)
- 2008
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Ingår i: American Naturalist. - : University of Chicago Press. - 0003-0147 .- 1537-5323. ; 171:2, s. 249-262
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Tidskriftsartikel (refereegranskat)abstract
- According to the exploitation ecosystems hypothesis (EEH), productive terrestrial ecosystems are characterized by community‐level trophic cascades, whereas unproductive ecosystems harbor food‐limited grazers, which regulate community‐level plant biomass. We tested this hypothesis along arctic‐alpine productivity gradients at the Joatka field base, Finnmark, Norway. In unproductive habitats, mammalian predators were absent and plant biomass was constant, whereas herbivore biomass varied, reflecting the productivity of the habitat. In productive habitats, predatory mammals were persistently present and plant biomass varied in space, but herbivore biomass did not. Plant biomass of productive tundra scrublands declined by 40% when vegetation blocks were transferred to predation‐free islands. Corresponding transfer to herbivore‐free islands triggered an increase in plant biomass. Fertilization of an unproductive tundra heath resulted in a fourfold increase in rodent density and a corresponding increase in winter grazing activity, whereas the total aboveground plant biomass remained unchanged. These results corroborate the predictions of the EEH, implying that the endotherm community and the vegetation of the North European tundra behaves dynamically as if each trophic level consisted of a single population, in spite of local co‐occurrence of >20 plant species representing different major taxonomic groups, growth forms, and defensive strategies.
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| 10. |
- Baeten, Lander, et al.
(författare)
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Identifying the tree species compositions that maximize ecosystem functioning in European forests
- 2019
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Ingår i: Journal of Applied Ecology. - : Wiley. - 0021-8901 .- 1365-2664. ; 56:3, s. 733-744
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Tidskriftsartikel (refereegranskat)abstract
- 1. Forest ecosystem functioning generally benefits from higher tree species richness, but variation within richness levels is typically large. This is mostly due to the contrasting performances of communities with different compositions. Evidence-based understanding of composition effects on forest productivity, as well as on multiple other functions will enable forest managers to focus on the selection of species that maximize functioning, rather than on diversity per se.2. We used a dataset of 30 ecosystem functions measured in stands with different species richness and composition in six European forest types. First, we quantified whether the compositions that maximize annual above-ground wood production (productivity) generally also fulfil the multiple other ecosystem functions (multifunctionality). Then, we quantified the species identity effects and strength of interspecific interactions to identify the "best" and "worst" species composition for multifunctionality. Finally, we evaluated the real-world frequency of occurrence of best and worst mixtures, using harmonized data from multiple national forest inventories.3. The most productive tree species combinations also tended to express relatively high multifunctionality, although we found a relatively wide range of compositions with high- or low-average multifunctionality for the same level of productivity. Monocultures were distributed among the highest as well as the lowest performing compositions. The variation in functioning between compositions was generally driven by differences in the performance of the component species and, to a lesser extent, by particular interspecific interactions. Finally, we found that the most frequent species compositions in inventory data were monospecific stands and that the most common compositions showed below-average multifunctionality and productivity.4. Synthesis and applications. Species identity and composition effects are essential to the development of high-performing production systems, for instance in forestry and agriculture. They therefore deserve great attention in the analysis and design of functional biodiversity studies if the aim is to inform ecosystem management. A management focus on tree productivity does not necessarily trade-off against other ecosystem functions; high productivity and multifunctionality can be combined with an informed selection of tree species and species combinations.
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| 11. |
- Billade, Bhushan, 1982, et al.
(författare)
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A Wide-band Feed System for SKA Band 1 Covering Frequencies From 350 - 1050 MHz
- 2016
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Ingår i: 10th European Conference on Antennas and Propagation, EuCAP 2016; Davos; Switzerland; 10 April 2016 through 15 April 2016. - 2164-3342. - 9788890701863 ; , s. Art. no. 7481794-
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Konferensbidrag (refereegranskat)abstract
- We present the design of a wideband feed system for the Band 1 of the Square Kilometer Array (project). The Band 1 feed system uses a quad-ridged flared horn (QRFH) optimizedfor a offset Gregorian dual reflector dish to cover RF frequencies from 350 - 1050 MHz, and a cryogenic low noise amplifier (LNA). The feed horn is optimized to achieve best Aeff/Tsys over the entire band, by making trade-off between aperture efficiency and spill over noise contribution. The optimised feed horn shows above 70% efficiency over the entire 3:1 band, with return loss better than 10 dB. The cryostat following the feed has between 9 to 14 K noise, measured at the co-axial connector of the QRFH. The estimated on-sky sensitivity of the feed system is better than specified 4.2 m2/K averaged over the entire frequency band.
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| 12. |
- Björkman, Lena, 1965, et al.
(författare)
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Neutrophil recruitment to inflamed joints can occur without cellular priming.
- 2019
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Ingår i: Journal of leukocyte biology. - 1938-3673. ; 105:6, s. 1123-1130
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Tidskriftsartikel (refereegranskat)abstract
- Recruitment of neutrophils from blood to tissues is a cardinal event in inflammation during which neutrophils switch from a resting, naive state to a preactivated, primed phenotype; the priming process is characterized by alterations in the composition of cell surface adhesins, for example, shedding of l-selectin and mobilization of granule-stored integrins to the cell surface. Ligation of chemotactic receptors and interactions with the endothelial lining are established triggers of neutrophil priming and in line with this, in vivo transmigrated neutrophils obtained from tissues are typically highly primed. We here characterize the priming of neutrophils brought about by in vivo recruitment from blood to inflamed joints by the analyses of synovial fluid and blood from patients with inflammatory arthritis. For comparisons, we used controlled in vivo models of neutrophil transmigration to skin of healthy subjects. In contrast to the residing view and in vivo transmigrated neutrophils from skin models, neutrophils from synovial fluid were often surprisingly resting and phenotypically very similar to naive cells isolated from peripheral blood; synovial fluid cells often retained l-selectin and had undergone minimal up-regulation of integrin receptors. In complete agreement with our in vivo findings, cell-free synovial fluid was potently chemotactic without triggering alteration of surface receptors also in vitro. We conclude that tissue recruitment of neutrophils does not by default trigger l-selectin shedding and granule mobilization, and the chemoattractant(s) guiding neutrophils to synovial fluid apparently operate without inducing cellular priming.
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| 13. |
- Björkman, Lena, 1965, et al.
(författare)
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The Neutrophil Response Induced by an Agonist for Free Fatty Acid Receptor 2 (GPR43) Is Primed by Tumor Necrosis Factor Alpha and by Receptor Uncoupling from the Cytoskeleton but Attenuated by Tissue Recruitment
- 2016
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Ingår i: Molecular and Cellular Biology. - : Informa UK Limited. - 0270-7306 .- 1098-5549. ; 36:20, s. 2583-2595
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Tidskriftsartikel (refereegranskat)abstract
- Ligands with improved potency and selectivity for free fatty acid receptor 2 (FFA2R) have become available, and we here characterize the neutrophil responses induced by one such agonist (Cmp1) and one antagonist (CATPB). Cmp1 triggered an increase in the cytosolic concentration of Ca2+, and the neutrophils were then desensitized to Cmp1 and to acetate, a naturally occurring FFA2R agonist. The antagonist CATPB selectively inhibited responses induced by Cmp1 or acetate. The activated FFA2R induced superoxide anion secretion at a low level in naive blood neutrophils. This response was largely increased by tumor necrosis factor alpha (TNF-alpha) in a process associated with a recruitment of easily mobilizable granules, but neutrophils recruited to an aseptic inflammation in vivo were nonresponding. Superoxide production induced by Cmp1 was increased in latrunculin A-treated neutrophils, but no reactivation of desensitized FFA2R was induced by this drug, suggesting that the cytoskeleton is not directly involved in terminating the response. The functional and regulatory differences between the receptors that recognize short-chain fatty acids and formylated peptides, respectively, imply different roles of these receptors in the orchestration of inflammation and confirm the usefulness of a selective FFA2R agonist and antagonist as tools for the exploration of the precise role of the FFA2R.
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| 14. |
- Björnsdottir, Halla, et al.
(författare)
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Phenol-soluble Modulin α Peptide Toxins from aggressive Staphylococcus aureus induce rapid Formation of neutrophil extracellular Traps through a reactive Oxygen species-independent Pathway
- 2017
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Ingår i: Frontiers in Immunology. - : Frontiers Media SA. - 1664-3224. ; 8
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Tidskriftsartikel (refereegranskat)abstract
- Neutrophils have the ability to capture and kill microbes extracellularly through the formation of neutrophil extracellular traps (NETs). These are DNA and protein structures that neutrophils release extracellularly and are believed to function as a defense mechanism against microbes. The classic NET formation process, triggered by, e.g., bacteria, fungi, or by direct stimulation of protein kinase C through phorbol myristate acetate, is an active process that takes several hours and relies on the production of reactive oxygen species (ROS) that are further modified by myeloperoxidase (MPO). We show here that NET-like structures can also be formed by neutrophils after interaction with phenol-soluble modulin alpha (PSM alpha) that are cytotoxic membrane-disturbing peptides, secreted from community-acquired methicillin-resistant Staphylococcus aureus (CA-MRSA). The PSMa-induced NETs contained the typical protein markers and were able to capture microbes. The PSMa-induced NET structures were disintegrated upon prolonged exposure to DNase-positive S. aureus but not on exposure to DNase-negative Candida albicans. Opposed to classic NETosis, PSMa-triggered NET formation occurred very rapidly, independently of ROS or MPO, and was also manifest at 4 degrees C. These data indicate that rapid NETs release may result from cytotoxic membrane disturbance by PSMa peptides, a process that may be of importance for CA-MRSA virulence.
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| 15. |
- Bohlin, Inka, et al.
(författare)
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Lessons learned from assessing the cover and yield of bilberry and lingonberry using the national forest inventories in Finland and Sweden
- 2021
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Ingår i: Silva Fennica. - : Finnish Society of Forest Science. - 0037-5330 .- 2242-4075. ; 55
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Tidskriftsartikel (refereegranskat)abstract
- Bilberry (Vaccinium myrtillus L.) and lingonberry (V. vitis-idaea L.) can be a part of healthy diet and are important for many animals. Two approaches are described to assessing their vegetation cover and berry yield via national forest inventory (NFI) observations. The aim was to provide estimates and predictions of the abundance and yield of the species at regional and national levels in Finland and Sweden. In Finland, the model-based predictions are used in evaluating the impacts of cutting intensity on forest berries needed in forest-related decision making. In Sweden, seasonal inventory-based estimates are used to evaluate the annual national and regional berry yields, and in a forecasting system aimed at large public and berry enterprises. Based on the NFI sample plots measured between 2014 and 2018, the total annual yields are estimated to be 208 Mkg of bilberry and 246 Mkg of lingonberry on productive forest land (increment at least 1 m3 ha–1 year–1) in Finland, and 336 and 382 Mkg respectively in Sweden (average of NFI inventories in 2015–2019). The predicted development of berry yields is related to the intensity of cuttings in alternative forest management scenarios: lower removals favoured bilberry, and higher removals lingonberry. The model-based method describes the effects of stand development and management on berry yields, whereas the inventory-based method can calibrate seasonal estimates through field observations. In providing spatially and timely more accurate information concerning seasonal berry yields, an assessment of berry yields should involve the elements of both inventory-based and model-based approaches described in this study.
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| 16. |
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| 17. |
- Bohlin, Inka, et al.
(författare)
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Predicting bilberry and cowberry yields using airborne laser scanning and other auxiliary data combined with National Forest Inventory field plot data
- 2021
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Ingår i: Forest Ecology and Management. - : Elsevier BV. - 0378-1127 .- 1872-7042. ; 502
-
Tidskriftsartikel (refereegranskat)abstract
- The increasing availability of wall-to-wall remote sensing datasets in combination with accurate field data enables the mapping of different ecosystem services more accurately and over larger areas than before. The provision of wild berries is an essential ecosystem service, and berries are the most used non-wood forest products in Nordic countries. The aim of the study was to 1) develop general prediction models for bilberry and cowberry yield based on metrics derived from airborne laser scanning (ALS) data and other existing wall-to-wall data and 2) to identify laser-based structural features of forests that can be linked to locations of the highest berry yields. We used the indirect approach where the correlation between forest structure described by the ALS data and the berry yields are utilized. Berry data collected in the Swedish National Forest Inventory (NFI) 2007–2016 were used for training the models and ALS data from 2009 to 2014 from the national ALS campaign of Sweden. Berry yields were modelled using generalised linear mixed models (GLMMs), and forest structural differences were demonstrated in histograms of presence/absence data. The ALS-based canopy cover was an important variable both in bilberry and cowberry models. Other significant variables were ALS-based height variance, shrub cover, height above sea level, slope, soil wetness and terrain ruggedness, satellite-based species-specific volume and percentage, seasonality of temperature and precipitation and annual precipitation, inventory year, soil type and land use class. In addition, the time difference between the inventory day and the Julian day when berries were expected to be ripe showed a 1.5% decrease for bilberry and a 1.1% decrease for cowberry yield per day during the season. The highest bilberry yield was identified in forests with a canopy cover of 50% and the highest cowberry yield in forests with a canopy cover close to zero. The canopy height of 15 m reflected the highest bilberry yield, whereas a canopy height close to 0 m resulted in the highest cowberry yield. The shrub cover was close to zero both with highest bilberry and cowberry yields. This is the first study combining ALS metrics with other wall-to-wall variables and NFI field data to model bilberry and cowberry yields. Prediction models can be used to produce maps showing the most potential locations for berry picking. Further, the models may, in the future, be imported into forest planning systems to obtain stand-level prognoses of berry yield development under different forest management strategies.
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| 18. |
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| 19. |
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| 20. |
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| 21. |
- Dahlgren, Claes, 1949, et al.
(författare)
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G protein coupled pattern recognition receptors expressed in neutrophils: Recognition, activation/modulation, signaling and receptor regulated functions.
- 2022
-
Ingår i: Immunological reviews. - : Wiley. - 1600-065X .- 0105-2896. ; 314:1, s. 69-92
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Forskningsöversikt (refereegranskat)abstract
- Neutrophils, the most abundant white blood cell in human blood, express receptors that recognize damage/microbial associated pattern molecules of importance for cell recruitment to sites of inflammation. Many of these receptors belong to the family of G protein coupled receptors (GPCRs). These receptor-proteins span the plasma membrane in expressing cells seven times and the down-stream signaling rely in most cases on an activation of heterotrimeric G proteins. The GPCRs expressed in neutrophils recognize a number of structurally diverse ligands (activating agonists, allosteric modulators, and inhibiting antagonists) and share significant sequence homologies. Studies of receptor structure and function have during the last 40years generated important information on GPCR biology in general; this knowledge aids in the overall understanding of general pharmacological principles, governing regulation of neutrophil function and inflammatory processes, including novel leukocyte receptor activities related to ligand recognition, biased/functional selective signaling, allosteric modulation, desensitization, and reactivation mechanisms as well as communication (receptor transactivation/cross-talk) between GPCRs. This review summarizes the recent discoveries and pharmacological hallmarks with focus on some of the neutrophil expressed pattern recognition GPCRs. In addition, unmet challenges, including recognition by the receptors of diverse ligands and how biased signaling mediate different biological effects are described/discussed.
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| 22. |
- Dahlgren, Claes, 1949, et al.
(författare)
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Neutrophil Signaling That Challenges Dogmata of G Protein-Coupled Receptor Regulated Functions
- 2020
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Ingår i: ACS Pharmacology and Translational Science. - : American Chemical Society (ACS). - 2575-9108. ; 3:2, s. 203-220
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Forskningsöversikt (refereegranskat)abstract
- Activation as well as recruitment of neutrophils, the most abundant leukocyte in human blood, to sites of infection/inflammation largely rely on surface-exposed chemoattractant receptors. These receptors belong to the family of 7-transmembrane domain receptors also known as G protein-coupled receptors (GPCRs) due to the fact that part of the downstream signaling relies on an activation of heterotrimeric G proteins. The neutrophil GPCRs share significant sequence homologies but bind many structurally diverse activating (agonistic) and inhibiting (antagonistic) ligands, ranging from fatty acids to purines, peptides, and lipopeptides. Recent structural and functional studies of neutrophil receptors have generated important information on GPCR biology in general; this knowledge aids in the overall understanding of general pharmacological principles, governing regulation of neutrophil function and inflammatory processes, including novel leukocyte receptor activities related to ligand recognition, biased/functional selective signaling, allosteric modulation, desensitization mechanisms and reactivation, and communication (cross-talk) between GPCRs. This review summarizes the recent discoveries and pharmacological hallmarks with focus on neutrophil GPCRs. In addition, unmet challenges are dealt with, including recognition by the receptors of diverse ligands and how biased signaling mediates different biological effects. © 2020 American Chemical Society.
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| 23. |
- Dahlgren, Jonas
(författare)
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Beyond mean fitness: Demographic stochasticity and resilience matter at tree species climatic edges
- 2023
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Ingår i: Global Ecology and Biogeography. - : Wiley. - 1466-822X .- 1466-8238. ; 32, s. 573-585
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Tidskriftsartikel (refereegranskat)abstract
- Aim: Linking local population dynamics and species distributions is crucial to predicting the impacts of climate change. Although many studies focus on the mean fitness of populations, theory shows that species distributions can be shaped by demographic stochasticity or population resilience. Here, we examine how mean fitness (measured by invasion rate), demographic stochasticity and resilience (measured by the ability to recover from disturbance) constrain populations at the edges compared with the climatic centre. Location: Europe: Spain, France, Germany, Finland and Sweden. Period: Forest inventory data used for fitting the models cover the period from 1985 to 2013. Major taxa: Dominant European tree species; angiosperms and gymnosperms. Methods: We developed dynamic population models covering the entire life cycle of 25 European tree species with climatically dependent recruitment models fitted to forest inventory data. We then ran simulations using integral projection and individual-based models to test how invasion rates, risk of stochastic extinction and ability to recover from stochastic disturbances differ between the centre and edges of the climatic niches of species. Results: Results varied among species, but in general, demographic constraints were stronger at warm edges and for species in harsher climates. Conversely, recovery was more limiting at cold edges. In addition, we found that for several species, constraints at the edges were attributable to demographic stochasticity and capacity for recovery rather than mean fitness. Main conclusions: Our results highlight that mean fitness is not the only mechanism at play at the edges; demographic stochasticity and population capacity to recover also matter for European tree species. To understand how climate change will drive species range shifts, future studies will need to analyse the interplay between population mean growth rate and stochastic demographic processes in addition to disturbances.
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| 24. |
- Dahlgren, Jonas
(författare)
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Climate- and successional-related changes in functional composition of European forests are strongly driven by tree mortality
- 2017
-
Ingår i: Global Change Biology. - : Wiley. - 1354-1013 .- 1365-2486. ; 23, s. 4162-4176
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Tidskriftsartikel (refereegranskat)abstract
- Intense droughts combined with increased temperatures are one of the major threats to forest persistence in the 21st century. Despite the direct impact of climate change on forest growth and shifts in species abundance, the effect of altered demography on changes in the composition of functional traits is not well known. We sought to (1) quantify the recent changes in functional composition of European forests; (2) identify the relative importance of climate change, mean climate and forest development for changes in functional composition; and (3) analyse the roles of tree mortality and growth underlying any functional changes in different forest types. We quantified changes in functional composition from the 1980s to the 2000s across Europe by two dimensions of functional trait variation: the first dimension was mainly related to changes in leaf mass per area and wood density (partially related to the trait differences between angiosperms and gymnosperms), and the second dimension was related to changes in maximum tree height. Our results indicate that climate change and mean climatic effects strongly interacted with forest development and it was not possible to completely disentangle their effects. Where recent climate change was not too extreme, the patterns of functional change generally followed the expected patterns under secondary succession (e.g. towards late-successional short-statured hardwoods in Mediterranean forests and taller gymnosperms in boreal forests) and latitudinal gradients (e.g. larger proportion of gymnosperm-like strategies at low water availability in forests formerly dominated by broad-leaved deciduous species). Recent climate change generally favoured the dominance of angiosperm-like related traits under increased temperature and intense droughts. Our results show functional composition changes over relatively short time scales in European forests. These changes are largely determined by tree mortality, which should be further investigated and modelled to adequately predict the impacts of climate change on forest function.
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| 25. |
- Dahlgren, Jonas
(författare)
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Colonization and extinction dynamics and their link to the distribution of European trees at the continental scale
- 2022
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Ingår i: Journal of Biogeography. - : Wiley. - 0305-0270 .- 1365-2699. ; 49, s. 117-129
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Tidskriftsartikel (refereegranskat)abstract
- Aim The population processes that drive tree species distribution are still widely debated. We test the hypotheses that metapopulation processes of colonization and extinction are linked to predictions of species distribution models. Location Europe: Spain, France, Germany, Finland and Sweden. Taxon Angiosperms and Gymnosperms. Methods For 17 tree species analysed, we fitted species distribution models (SDM) relating environmental variables to presence-absence data across Europe. Then, using independent data from national forest inventories across Europe, we tested whether colonization and extinction probabilities are related to SDM occurrence probabilities. Finally, we assessed the probability of presence at metapopulation equilibrium depending on colonization and extinction probabilities. Results We found that for most species at least one process (colonization/extinction) is related to SDM occurrence probability, but rarely both (only two species). Depending on the species, the link was either for colonization or for extinction, but relationships were generally weak. In addition, the metapopulation models tended to overestimate the occurrence probability at equilibrium. Main conclusions Our study shows that metapopulation processes are only weakly related to SDM occurrence probability and call for caution in extrapolating SDM models to metapopulation dynamics.
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