| 1. |
- Lembrechts, Jonas J., et al.
(författare)
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SoilTemp : A global database of near-surface temperature
- 2020
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Ingår i: Global Change Biology. - : Wiley. - 1354-1013 .- 1365-2486. ; 26:11, s. 6616-6629
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Tidskriftsartikel (refereegranskat)abstract
- Current analyses and predictions of spatially explicit patterns and processes in ecology most often rely on climate data interpolated from standardized weather stations. This interpolated climate data represents long-term average thermal conditions at coarse spatial resolutions only. Hence, many climate-forcing factors that operate at fine spatiotemporal resolutions are overlooked. This is particularly important in relation to effects of observation height (e.g. vegetation, snow and soil characteristics) and in habitats varying in their exposure to radiation, moisture and wind (e.g. topography, radiative forcing or cold-air pooling). Since organisms living close to the ground relate more strongly to these microclimatic conditions than to free-air temperatures, microclimatic ground and near-surface data are needed to provide realistic forecasts of the fate of such organisms under anthropogenic climate change, as well as of the functioning of the ecosystems they live in. To fill this critical gap, we highlight a call for temperature time series submissions to SoilTemp, a geospatial database initiative compiling soil and near-surface temperature data from all over the world. Currently, this database contains time series from 7,538 temperature sensors from 51 countries across all key biomes. The database will pave the way toward an improved global understanding of microclimate and bridge the gap between the available climate data and the climate at fine spatiotemporal resolutions relevant to most organisms and ecosystem processes.
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| 2. |
- Cavieres, Lohengrin A., et al.
(författare)
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Facilitative plant interactions and climate simultaneously drive alpine plant diversity
- 2014
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Ingår i: Ecology Letters. - : Wiley. - 1461-0248 .- 1461-023X. ; 17:2, s. 193-202
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Tidskriftsartikel (refereegranskat)abstract
- Interactions among species determine local-scale diversity, but local interactions are thought to have minor effects at larger scales. However, quantitative comparisons of the importance of biotic interactions relative to other drivers are rarely made at larger scales. Using a data set spanning 78 sites and five continents, we assessed the relative importance of biotic interactions and climate in determining plant diversity in alpine ecosystems dominated by nurse-plant cushion species. Climate variables related with water balance showed the highest correlation with richness at the global scale. Strikingly, although the effect of cushion species on diversity was lower than that of climate, its contribution was still substantial. In particular, cushion species enhanced species richness more in systems with inherently impoverished local diversity. Nurse species appear to act as a ‘safety net’ sustaining diversity under harsh conditions, demonstrating that climate and species interactions should be integrated when predicting future biodiversity effects of climate change.
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| 3. |
- Dawes, Melissa A., et al.
(författare)
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An alpine treeline in a carbon dioxide-rich world : synthesis of a nine-year free-air carbon dioxide enrichment study
- 2013
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Ingår i: Oecologia. - : Springer Science and Business Media LLC. - 0029-8549 .- 1432-1939. ; 171:3, s. 623-637
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Tidskriftsartikel (refereegranskat)abstract
- We evaluated the impacts of elevated CO2 in a treeline ecosystem in the Swiss Alps in a 9-year free-air CO2 enrichment (FACE) study. We present new data and synthesize plant and soil results from the entire experimental period. Light-saturated photosynthesis (A max) of ca. 35-year-old Larix decidua and Pinus uncinata was stimulated by elevated CO2 throughout the experiment. Slight down-regulation of photosynthesis in Pinus was consistent with starch accumulation in needle tissue. Above-ground growth responses differed between tree species, with a 33 % mean annual stimulation in Larix but no response in Pinus. Species-specific CO2 responses also occurred for abundant dwarf shrub species in the understorey, where Vaccinium myrtillus showed a sustained shoot growth enhancement (+11 %) that was not apparent for Vaccinium gaultherioides or Empetrum hermaphroditum. Below ground, CO2 enrichment did not stimulate fine root or mycorrhizal mycelium growth, but increased CO2 effluxes from the soil (+24 %) indicated that enhanced C assimilation was partially offset by greater respiratory losses. The dissolved organic C (DOC) concentration in soil solutions was consistently higher under elevated CO2 (+14 %), suggesting accelerated soil organic matter turnover. CO2 enrichment hardly affected the C–N balance in plants and soil, with unaltered soil total or mineral N concentrations and little impact on plant leaf N concentration or the stable N isotope ratio. Sustained differences in plant species growth responses suggest future shifts in species composition with atmospheric change. Consistently increased C fixation, soil respiration and DOC production over 9 years of CO2 enrichment provide clear evidence for accelerated C cycling with no apparent consequences on the N cycle in this treeline ecosystem.
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| 4. |
- Kikvidze, Zaal, et al.
(författare)
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The effects of foundation species on community assembly: a global study on alpine cushion plant communities
- 2015
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Ingår i: Ecology. - : Ecological Society of America. - 0012-9658. ; 96:8, s. 2064-2069
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Tidskriftsartikel (refereegranskat)abstract
- Foundation species can change plant community structure by modulating important ecological processes such as community assembly, yet this topic is poorly understood. In alpine systems, cushion plants commonly act as foundation species by ameliorating local conditions. Here, we analyze diversity patterns of species' assembly within cushions and in adjacent surrounding open substrates (83 sites across five continents) calculating floristic dissimilarity between replicate plots, and using linear models to analyze relationships between microhabitats and species diversity. Floristic dissimilarity did not change across biogeographic regions, but was consistently lower in the cushions than in the open microhabitat. Cushion plants appear to enable recruitment of many relatively stress-intolerant species that otherwise would not establish in these communities, yet the niche space constructed by cushion plants supports a more homogeneous composition of species than the niche space beyond the cushion's influence. As a result, cushion plants support higher α-diversity and a larger species pool, but harbor assemblies with lower ?-diversity than open microhabitats. We conclude that habitats with and without dominant foundation species can strongly differ in the processes that drive species recruitment, and thus the relationship between local and regional species diversity.
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| 5. |
- Sedlacek, Janosch, et al.
(författare)
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Evolutionary potential in the Alpine: trait heritabilities and performance variation of the dwarf willow Salix herbacea from different elevations and microhabitats
- 2016
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Ingår i: Ecology and Evolution. - : Wiley. - 2045-7758. ; 6:12, s. 3940-3952
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Tidskriftsartikel (refereegranskat)abstract
- Alpine ecosystems are seriously threatened by climate change. One of the key mechanisms by which plants can adapt to changing environmental conditions is through evolutionary change. However, we still know little about the evolutionary potential in wild populations of long-lived alpine plants. Here, we investigated heritabilities of phenological traits, leaf size, and performance traits in natural populations of the long-lived alpine dwarf shrub Salix herbacea using relatedness estimates inferred from SSR (Simple Sequence Repeat) markers. Salix herbacea occurs in early-and late-snowmelt microhabitats (ridges and snowbeds), and we assessed how performance consequences of phenological traits and leaf size differ between these microhabitats in order to infer potential for evolutionary responses. Salix herbacea showed low, but significant, heritabilities of leaf size, clonal and sexual reproduction, and moderate heritabilities of phenological traits. In both microhabitats, we found that larger leaves, longer intervals between snowmelt and leaf expansion, and longer GDD (growing-degree days) until leaf expansion resulted in a stronger increase in the number of stems (clonal reproduction). In snowbeds, clonal reproduction increased with a shorter GDD until flowering, while the opposite was found on ridges. Furthermore, the proportion of flowering stems increased with GDD until flowering in both microhabitats. Our results suggest that the presence of significant heritable variation in morphology and phenology might help S. herbacea to adapt to changing environmental conditions. However, it remains to be seen if the rate of such an evolutionary response can keep pace with the rapid rate of climate change.
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| 6. |
- Sedlacek, Janosch, et al.
(författare)
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The Response of the Alpine Dwarf Shrub Salix herbacea to Altered Snowmelt Timing : Lessons from a Multi-Site Transplant Experiment
- 2015
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Ingår i: PLOS ONE. - : Public Library of Science (PLoS). - 1932-6203. ; 10:4
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Tidskriftsartikel (refereegranskat)abstract
- Climate change is altering spring snowmelt patterns in alpine and arctic ecosystems, and these changes may alter plant phenology, growth and reproduction. To predict how alpine plants respond to shifts in snowmelt timing, we need to understand trait plasticity, its effects on growth and reproduction, and the degree to which plants experience a home-site advantage. We tested how the common, long-lived dwarf shrub Salix herbacea responded to changing spring snowmelt time by reciprocally transplanting turfs of S. herbacea between early-exposure ridge and late-exposure snowbed microhabitats. After the transplant, we monitored phenological, morphological and fitness traits, as well as leaf damage, during two growing seasons. Salix herbacea leafed out earlier, but had a longer development time and produced smaller leaves on ridges relative to snowbeds. Longer phenological development times and smaller leaves were associated with reduced sexual reproduction on ridges. On snowbeds, larger leaves and intermediate development times were associated with increased clonal reproduction. Clonal and sexual reproduction showed no response to altered snowmelt time. We found no home-site advantage in terms of sexual and clonal reproduction. Leaf damage probability depended on snowmelt and thus exposure period, but had no short-term effect on fitness traits. We conclude that the studied populations of S. herbacea can respond to shifts in snowmelt by plastic changes in phenology and leaf size, while maintaining levels of clonal and sexual reproduction. The lack of a home-site advantage suggests that S. herbacea may not be adapted to different microhabitats. The studied populations are thus unlikely to react to climate change by rapid adaptation, but their responses will also not be constrained by small-scale local adaptation. In the short term, snowbed plants may persist due to high stem densities. However, in the long term, reduction in leaf size and flowering, a longer phenological development time and increased exposure to damage may decrease overall performance of S. herbacea under earlier snowmelt.
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| 7. |
- Björkman, Anne, 1981, et al.
(författare)
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Plant functional trait change across a warming tundra biome
- 2018
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Ingår i: Nature. - : Springer Science and Business Media LLC. - 0028-0836 .- 1476-4687. ; 562:7725, s. 57-62
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Tidskriftsartikel (refereegranskat)abstract
- The tundra is warming more rapidly than any other biome on Earth, and the potential ramifications are far-reaching because of global feedback effects between vegetation and climate. A better understanding of how environmental factors shape plant structure and function is crucial for predicting the consequences of environmental change for ecosystem functioning. Here we explore the biome-wide relationships between temperature, moisture and seven key plant functional traits both across space and over three decades of warming at 117 tundra locations. Spatial temperature–trait relationships were generally strong but soil moisture had a marked influence on the strength and direction of these relationships, highlighting the potentially important influence of changes in water availability on future trait shifts in tundra plant communities. Community height increased with warming across all sites over the past three decades, but other traits lagged far behind predicted rates of change. Our findings highlight the challenge of using space-for-time substitution to predict the functional consequences of future warming and suggest that functions that are tied closely to plant height will experience the most rapid change. They also reveal the strength with which environmental factors shape biotic communities at the coldest extremes of the planet and will help to improve projections of functional changes in tundra ecosystems with climate warming.
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| 8. |
- Björkman, Anne, 1981, et al.
(författare)
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Tundra Trait Team: A database of plant traits spanning the tundra biome
- 2018
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Ingår i: Global Ecology and Biogeography. - : Wiley. - 1466-822X .- 1466-8238. ; 27:12, s. 1402-1411
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Tidskriftsartikel (refereegranskat)abstract
- © 2018 The Authors Global Ecology and Biogeography Published by John Wiley & Sons Ltd Motivation: The Tundra Trait Team (TTT) database includes field-based measurements of key traits related to plant form and function at multiple sites across the tundra biome. This dataset can be used to address theoretical questions about plant strategy and trade-offs, trait–environment relationships and environmental filtering, and trait variation across spatial scales, to validate satellite data, and to inform Earth system model parameters. Main types of variable contained: The database contains 91,970 measurements of 18 plant traits. The most frequently measured traits (>1,000 observations each) include plant height, leaf area, specific leaf area, leaf fresh and dry mass, leaf dry matter content, leaf nitrogen, carbon and phosphorus content, leaf C:N and N:P, seed mass, and stem specific density. Spatial location and grain: Measurements were collected in tundra habitats in both the Northern and Southern Hemispheres, including Arctic sites in Alaska, Canada, Greenland, Fennoscandia and Siberia, alpine sites in the European Alps, Colorado Rockies, Caucasus, Ural Mountains, Pyrenees, Australian Alps, and Central Otago Mountains (New Zealand), and sub-Antarctic Marion Island. More than 99% of observations are georeferenced. Time period and grain: All data were collected between 1964 and 2018. A small number of sites have repeated trait measurements at two or more time periods. Major taxa and level of measurement: Trait measurements were made on 978 terrestrial vascular plant species growing in tundra habitats. Most observations are on individuals (86%), while the remainder represent plot or site means or maximums per species. Software format: csv file and GitHub repository with data cleaning scripts in R; contribution to TRY plant trait database (www.try-db.org) to be included in the next version release.
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| 9. |
- Elmendorf, Sarah C., et al.
(författare)
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Global assessment of experimental climate warming on tundra vegetation : heterogeneity over space and time
- 2012
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Ingår i: Ecology Letters. - : Wiley. - 1461-023X .- 1461-0248. ; 15:2, s. 164-175
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Forskningsöversikt (refereegranskat)abstract
- Understanding the sensitivity of tundra vegetation to climate warming is critical to forecasting future biodiversity and vegetation feedbacks to climate. In situ warming experiments accelerate climate change on a small scale to forecast responses of local plant communities. Limitations of this approach include the apparent site-specificity of results and uncertainty about the power of short-term studies to anticipate longer term change. We address these issues with a synthesis of 61 experimental warming studies, of up to 20 years duration, in tundra sites worldwide. The response of plant groups to warming often differed with ambient summer temperature, soil moisture and experimental duration. Shrubs increased with warming only where ambient temperature was high, whereas graminoids increased primarily in the coldest study sites. Linear increases in effect size over time were frequently observed. There was little indication of saturating or accelerating effects, as would be predicted if negative or positive vegetation feedbacks were common. These results indicate that tundra vegetation exhibits strong regional variation in response to warming, and that in vulnerable regions, cumulative effects of long-term warming on tundra vegetation and associated ecosystem consequences have the potential to be much greater than we have observed to date.
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| 10. |
- Elmendorf, Sarah C., et al.
(författare)
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Plot-scale evidence of tundra vegetation change and links to recent summer warming
- 2012
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Ingår i: Nature Climate Change. - : Nature Publishing Group. - 1758-678X .- 1758-6798. ; 2:6, s. 453-457
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Tidskriftsartikel (refereegranskat)abstract
- Temperature is increasing at unprecedented rates across most of the tundra biome. Remote-sensing data indicate that contemporary climate warming has already resulted in increased productivity over much of the Arctic, but plot-based evidence for vegetation transformation is not widespread. We analysed change in tundra vegetation surveyed between 1980 and 2010 in 158 plant communities spread across 46 locations.We found biome-wide trends of increased height of the plant canopy and maximum observed plant height for most vascular growth forms; increased abundance of litter; increased abundance of evergreen, low-growing and tall shrubs; and decreased abundance of bare ground. Intersite comparisons indicated an association between the degree of summer warming and change in vascular plant abundance, with shrubs, forbs and rushes increasing with warming. However, the association was dependent on the climate zone, the moisture regime and the presence of permafrost. Our data provide plot-scale evidence linking changes in vascular plant abundance to local summer warming in widely dispersed tundra locations across the globe.
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| 11. |
- Fry, Ellen L., et al.
(författare)
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Vegetation type, not the legacy of warming, modifies the response of microbial functional genes and greenhouse gas fluxes to drought in Oro-Arctic and alpine regions
- 2023
-
Ingår i: FEMS microbiology ecology. - 1574-6941. ; 99:12
-
Tidskriftsartikel (refereegranskat)abstract
- Climate warming and summer droughts alter soil microbial activity, affecting greenhouse gas (GHG) emissions in Arctic and alpine regions. However, the long-term effects of warming, and implications for future microbial resilience, are poorly understood. Using one alpine and three Arctic soils subjected to in situ long-term experimental warming, we simulated drought in laboratory incubations to test how microbial functional-gene abundance affects fluxes in three GHGs: carbon dioxide, methane, and nitrous oxide. We found that responses of functional gene abundances to drought and warming are strongly associated with vegetation type and soil carbon. Our sites ranged from a wet, forb dominated, soil carbon-rich systems to a drier, soil carbon-poor alpine site. Resilience of functional gene abundances, and in turn methane and carbon dioxide fluxes, was lower in the wetter, carbon-rich systems. However, we did not detect an effect of drought or warming on nitrous oxide fluxes. All gene-GHG relationships were modified by vegetation type, with stronger effects being observed in wetter, forb-rich soils. These results suggest that impacts of warming and drought on GHG emissions are linked to a complex set of microbial gene abundances and may be habitat-specific.
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| 12. |
- Harrison, Paula A., et al.
(författare)
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Synthesizing plausible futures for biodiversity and ecosystem services in Europe and Central Asia using scenario archetypes
- 2019
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Ingår i: Ecology and Society. - 1708-3087. ; 24:2
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Tidskriftsartikel (refereegranskat)abstract
- Scenarios are a useful tool to explore possible futures of social-ecological systems. The number of scenarios has increased dramatically over recent decades, with a large diversity in temporal and spatial scales, purposes, themes, development methods, and content. Scenario archetypes generically describe future developments and can be useful in meaningfully classifying scenarios, structuring and summarizing the overwhelming amount of information, and enabling scientific outputs to more effectively interface with decision-making frameworks. The Intergovernmental Platform for Biodiversity and Ecosystem Services (IPBES) faced this challenge and used scenario archetypes in its assessment of future interactions between nature and society. We describe the use of scenario archetypes in the IPBES Regional Assessment of Europe and Central Asia. Six scenario archetypes for the region are described in terms of their driver assumptions and impacts on nature (including biodiversity) and its contributions to people (including ecosystem services): business-as-usual, economic optimism, regional competition, regional sustainability, global sustainable development, and inequality. The analysis shows that trade-offs between nature's contributions to people are projected under different scenario archetypes. However, the means of resolving these trade-offs depend on differing political and societal value judgements within each scenario archetype. Scenarios that include proactive decision making on environmental issues, environmental management approaches that support multifunctionality, and mainstreaming environmental issues across sectors, are generally more successful in mitigating tradeoffs than isolated environmental policies. Furthermore, those scenario archetypes that focus on achieving a balanced supply of nature's contributions to people and that incorporate a diversity of values are estimated to achieve more policy goals and targets, such as the UN Sustainable Development Goals and the Convention on Biological Diversity Aichi targets. The scenario archetypes approach is shown to be helpful in supporting science-policy dialogue for proactive decision making that anticipates change, mitigates undesirable trade-offs, and fosters societal transformation in pursuit of sustainable development.
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| 13. |
- Henry, Greg H.R., et al.
(författare)
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The International Tundra Experiment (ITEX): 30 years of research on tundra ecosystems
- 2022
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Ingår i: Arctic Science. - : Canadian Science Publishing. - 2368-7460. ; 8:3, s. 550-571
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Tidskriftsartikel (refereegranskat)abstract
- The International Tundra Experiment (ITEX) was founded in 1990 as a network of scientists studying responses of tundra ecosystems to ambient and experimental climate change at Arctic and alpine sites across the globe. Common measurement and experimental design protocols have facilitated synthesis of results across sites to gain biome-wide insights of climate change impacts on tundra. This special issue presents results from more than 30 years of ITEX research. The importance of snow regimes, bryophytes, and herbivory are highlighted, with new protocols and studies proposed. The increasing frequency and magnitude of extreme climate events is shown to have strong effects on plant reproduction. The most consistent plant trait response across sites is an increase in vegetation height, especially for shrubs. This will affect surface energy balance, carbon and nutrient dynamics and trophic level interactions. Common garden studies show adaptation responses in tundra species to climate change but they are species and regionally specific. Recommendations are made including establishing sites near northern communities to increase reciprocal engagement with local knowledge holders and establishing multi-factor experiments. The success of ITEX is based on collegial cooperation among researchers and the network remains focused on documenting and understanding impacts of environmental change on tundra ecosystems.
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| 14. |
- Lett, Signe, et al.
(författare)
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Can bryophyte groups increase functional resolution in tundra ecosystems?
- 2022
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Ingår i: Arctic Science. - Ottawa : Canadian Science Publishing. - 2368-7460. ; 8:3, s. 609-637
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Tidskriftsartikel (refereegranskat)abstract
- The relative contribution of bryophytes to plant diversity, primary productivity, and ecosystem functioning increases towards colder climates. Bryophytes respond to environmental changes at the species level, but because bryophyte species are relatively difficult to identify, they are often lumped into one functional group. Consequently, bryophyte function remains poorly resolved. Here, we explore how higher resolution of bryophyte functional diversity can be encouraged and implemented in tundra ecological studies. We briefly review previous bryophyte functional classifications and the roles of bryophytes in tundra ecosystems and their susceptibility to environmental change. Based on shoot morphology and colony organization, we then propose twelve easily distinguishable bryophyte functional groups. To illustrate how bryophyte functional groups can help elucidate variation in bryophyte effects and responses, we compiled existing data on water holding capacity, a key bryophyte trait. Although plant functional groups can mask potentially high interspecific and intraspecific variability, we found better separation of bryophyte functional group means compared with previous grouping systems regarding water holding capacity. This suggests that our bryophyte functional groups truly represent variation in the functional roles of bryophytes in tundra ecosystems. Lastly, we provide recommendations to improve the monitoring of bryophyte community changes in tundra study sites.
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| 15. |
- Prager, Case M., et al.
(författare)
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Integrating natural gradients, experiments, and statistical modeling in a distributed network experiment : An example from the WaRM Network
- 2022
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Ingår i: Ecology and Evolution. - : John Wiley & Sons. - 2045-7758. ; 12:10
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Tidskriftsartikel (refereegranskat)abstract
- A growing body of work examines the direct and indirect effects of climate change on ecosystems, typically by using manipulative experiments at a single site or performing meta-analyses across many independent experiments. However, results from single-site studies tend to have limited generality. Although meta-analytic approaches can help overcome this by exploring trends across sites, the inherent limitations in combining disparate datasets from independent approaches remain a major challenge. In this paper, we present a globally distributed experimental network that can be used to disentangle the direct and indirect effects of climate change. We discuss how natural gradients, experimental approaches, and statistical techniques can be combined to best inform predictions about responses to climate change, and we present a globally distributed experiment that utilizes natural environmental gradients to better understand long-term community and ecosystem responses to environmental change. The warming and (species) removal in mountains (WaRM) network employs experimental warming and plant species removals at high- and low-elevation sites in a factorial design to examine the combined and relative effects of climatic warming and the loss of dominant species on community structure and ecosystem function, both above- and belowground. The experimental design of the network allows for increasingly common statistical approaches to further elucidate the direct and indirect effects of warming. We argue that combining ecological observations and experiments along gradients is a powerful approach to make stronger predictions of how ecosystems will function in a warming world as species are lost, or gained, in local communities.
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| 16. |
- Prevéy, Janet S., et al.
(författare)
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The tundra phenology database: more than two decades of tundra phenology responses to climate change
- 2022
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Ingår i: Arctic Science. - : Canadian Science Publishing. - 2368-7460. ; 8:3, s. 1026-1039
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Tidskriftsartikel (refereegranskat)abstract
- Observations of changes in phenology have provided some of the strongest signals of the effects of climate change on terrestrial ecosystems. The International Tundra Experiment (ITEX), initiated in the early 1990s, established a common protocol to measure plant phenology in tundra study areas across the globe. Today, this valuable collec-tion of phenology measurements depicts the responses of plants at the colder extremes of our planet to experimental and ambient changes in temperature over the past decades. The database contains 150 434 phenology observations of 278 plant species taken at 28 study areas for periods of 1–26 years. Here we describe the full data set to increase the visibility and use of these data in global analyses and to invite phenology data contributions from underrepresented tundra locations. Portions of this tundra phenology database have been used in three recent syntheses, some data sets are expanded, others are from entirely new study areas, and the entirety of these data are now available at the Polar Data Catalogue (https://doi.org/10.21963/13215).
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| 17. |
- Rasmus, Sirpa, et al.
(författare)
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Policy documents considering biodiversity, land use, and climate in the European Arctic reveal visible, hidden, and imagined nexus approaches
- 2024
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Ingår i: One Earth. - : Cell Press. - 2590-3330 .- 2590-3322.
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Tidskriftsartikel (refereegranskat)abstract
- The Arctic is experiencing rapid and interlinked socio-environmental changes. Therefore, governance approaches that take the complex interactions between climate change, biodiversity loss, increasing land use pressures, and local livelihoods into account are needed: nexus approaches. However, an overview of whether and to what extent Arctic policies address these nexus elements in concert has been missing. Here we analyzed a large sample of publicly available assessment reports and policy documents from the terrestrial European Arctic. Our results show that, although nexus approaches are widely adopted in Arctic policy reporting, the emphasis varies among the governance levels, and documents underestimate certain interactions: local communities and traditional livelihoods are seldom seen as actors with agency and impact. Practical implementations were identified as potential advancements in Arctic governance: ecosystem-specific, technological, and authoritative solutions; co-production of knowledge; and adaptive co-management. Implementation of nexus approaches can promote more holistic environmental governance and guide cross-sectoral policies.
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| 18. |
- Stöckli, Veronika, et al.
(författare)
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Using historical plant surveys to track biodiversity on mountain summits
- 2011
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Ingår i: Plant Ecology & Diversity. - : Taylor & Francis. - 1755-0874 .- 1755-1668. ; 4:4, Special Issue, s. 415-425
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Tidskriftsartikel (refereegranskat)abstract
- Background: Botanical records have been collected from mountain summits worldwide since the sixteenth century. Such records are of particular interest following the end of the Little Ice Age, when alpine climate changed. Aims: To review the evolution of alpine summit flora research and define appropriate re-surveys for documenting floristic changes since the mid-nineteenth century. Methods: The history of botanical observations of mountain summits worldwide conducted between the mid-sixteenth and mid-twentieth century is outlined. Secondly, we review evidence for floristic change on mountain summits from studies made between 1980 and 2010. Thirdly, we examine the methods used in earlier summit surveys and suggest appropriate approaches for reconducting such surveys. Results: We found ca. 300 summit flora studies up to 200 years old that are potentially suitable for re-surveying; most of them are in the Alps. Recent studies showed an increase in species numbers and an upward range extension of some species from lower elevations. For re-surveying it is judged best to carry out data collection by individual surveyors for sound comparisons with earlier studies. Conclusions: Data collected in historical summit flora studies allow their exploitation for long-term observation provided contemporary methods are replicated and the detection rate is estimated in the re-surveys.
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| 19. |
- Wheeler, Julia A., et al.
(författare)
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The snow and the willows : earlier spring snowmelt reduces performance in the low-lying alpine shrub Salix herbacea
- 2016
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Ingår i: Journal of Ecology. - : Wiley. - 0022-0477 .- 1365-2745. ; 104:4, s. 1041-1050
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Tidskriftsartikel (refereegranskat)abstract
- Current changes in shrub abundance in alpine and arctic tundra ecosystems are primarily driven by climate change. However, while taller shrub communities are expanding, dwarf shrub communities show reductions under climate warming, and the mechanisms driving the latter (such as warming temperatures or accelerated spring snowmelt) may be complex. To determine and disentangle the response of a widespread arctic-alpine prostrate dwarf shrub to both climate warming and changes in snowmelt time, we investigated phenology, clonal and sexual reproduction, leaf size, wood tissue carbon balance and leaf damage in 480 patches of Salix herbacea, along its elevational and snowmelt microhabitat range over 3years in a space-for-time substitution. Earlier snowmelt was associated with longer phenological development periods, an increased likelihood of herbivory and fungal damage, lower stem density, smaller leaves and lower end-of-season wood reserve carbohydrates. Furthermore, while early snowmelt was associated with an increased proportion of flowering stems, the proportion of fruiting stems was not, as fruit set decreased significantly with earlier snowmelt. Warmer temperatures at lower elevations were associated with lower stem numbers and larger leaves.Synthesis. Our study indicates that phenology, fitness proxies and fungal/insect damage of the dwarf shrub S.herbacea are strongly influenced by snowmelt timing, and that earlier spring snowmelt reduced performance in S.herbacea. The likely mechanisms for many of the observed patterns are related to adverse temperature conditions in the early growing season. Reductions in clonal (stem number) and sexual reproduction (reduced fruit set) under earlier snowmelt, in addition to increasing damage probability, will likely lead to lower fitness and poorer performance, particularly in shrubs growing in early-exposure microhabitats. Further, we saw few concurrent benefits of higher temperatures for S.herbacea, particularly as warming was associated with lower clonal growth. As growing seasons become warmer and longer in arctic and alpine tundra ecosystems, early snowmelt is a critical mechanism reducing fitness and performance in a widespread dwarf shrub and may ultimately reduce dwarf shrub communities in tundra biomes.
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