| 1. |
- Moore, C. Douglas, et al.
(författare)
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Floral scent changes in response to pollen removal are rare in buzz-pollinated Solanum
- 2024
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Ingår i: Planta. - : Springer. - 0032-0935 .- 1432-2048. ; 260:1
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Tidskriftsartikel (refereegranskat)abstract
- Floral scent influences the recruitment, learning, and behaviour of floral visitors. Variation in floral scent can provide information on the amount of reward available or whether a flower has been visited recently and may be particularly important in species with visually concealed rewards. In many buzz-pollinated flowers, tubular anthers opening via small apical pores (poricidal anthers) visually conceal pollen and appear similar regardless of pollen quantity within the anther. We investigated whether pollen removal changes floral scent composition and emission rate in seven taxa of buzz-pollinated Solanum (Solanaceae). We found that pollen removal reduced both the overall emission of floral scent and the emission of specific compounds (linalool and farnesol) in S. lumholtzianum. Our findings suggest that in six out of seven buzz-pollinated taxa studied here, floral scent could not be used as a signal by visitors as it does not contain information on pollen availability.
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| 2. |
- Hederström, Veronica, et al.
(författare)
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Pollinator-mediated effects of landscape-scale land use on grassland plant community composition and ecosystem functioning – seven hypotheses
- 2024
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Ingår i: Biological Reviews. - 1464-7931. ; 99:3, s. 675-698
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Tidskriftsartikel (refereegranskat)abstract
- Environmental change is disrupting mutualisms between organisms worldwide. Reported declines in insect populations and changes in pollinator community compositions in response to land use and other environmental drivers have put the spotlight on the need to conserve pollinators. While this is often motivated by their role in supporting crop yields, the role of pollinators for reproduction and resulting taxonomic and functional assembly in wild plant communities has received less attention. Recent findings suggest that observed and experimental gradients in pollinator availability can affect plant community composition, but we know little about when such shifts are to be expected, or the impact they have on ecosystem functioning. Correlations between plant traits related to pollination and plant traits related to other important ecosystem functions, such as productivity, nitrogen uptake or palatability to herbivores, lead us to expect non-random shifts in ecosystem functioning in response to changes in pollinator communities. At the same time, ecological and evolutionary processes may counteract these effects of pollinator declines, limiting changes in plant community composition, and in ecosystem functioning. Despite calls to investigate community- and ecosystem-level impacts of reduced pollination, the study of pollinator effects on plants has largely been confined to impacts on plant individuals or single-species populations. With this review we aim to break new ground by bringing together aspects of landscape ecology, ecological and evolutionary plant–insect interactions, and biodiversity–ecosystem functioning research, to generate new ideas and hypotheses about the ecosystem-level consequences of pollinator declines in response to land-use change, using grasslands as a focal system. Based on an integrated set of seven hypotheses, we call for more research investigating the putative pollinator-mediated links between landscape-scale land use and ecosystem functioning. In particular, future research should use combinations of experimental and observational approaches to assess the effects of changes in pollinator communities over multiple years and across species on plant communities and on trait distributions both within and among species.
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| 3. |
- Kemppinen, Julia, et al.
(författare)
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Microclimate, an important part of ecology and biogeography
- 2024
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Ingår i: GLOBAL ECOLOGY AND BIOGEOGRAPHY. - 1466-822X .- 1466-8238. ; 33:6
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Tidskriftsartikel (refereegranskat)abstract
- Brief introduction: What are microclimates and why are they important?Microclimate science has developed into a global discipline. Microclimate science is increasingly used to understand and mitigate climate and biodiversity shifts. Here, we provide an overview of the current status of microclimate ecology and biogeography in terrestrial ecosystems, and where this field is heading next.Microclimate investigations in ecology and biogeographyWe highlight the latest research on interactions between microclimates and organisms, including how microclimates influence individuals, and through them populations, communities and entire ecosystems and their processes. We also briefly discuss recent research on how organisms shape microclimates from the tropics to the poles.Microclimate applications in ecosystem managementMicroclimates are also important in ecosystem management under climate change. We showcase new research in microclimate management with examples from biodiversity conservation, forestry and urban ecology. We discuss the importance of microrefugia in conservation and how to promote microclimate heterogeneity.Methods for microclimate scienceWe showcase the recent advances in data acquisition, such as novel field sensors and remote sensing methods. We discuss microclimate modelling, mapping and data processing, including accessibility of modelling tools, advantages of mechanistic and statistical modelling and solutions for computational challenges that have pushed the state-of-the-art of the field.What's next?We identify major knowledge gaps that need to be filled for further advancing microclimate investigations, applications and methods. These gaps include spatiotemporal scaling of microclimate data, mismatches between macroclimate and microclimate in predicting responses of organisms to climate change, and the need for more evidence on the outcomes of microclimate management.
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| 4. |
- Johansson, Victor, et al.
(författare)
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Oviposition preferences and larval survival of the marsh fritillary butterfly : The adverse impact of grazing
- 2024
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Ingår i: Insect Conservation and Diversity. - : John Wiley & Sons. - 1752-458X .- 1752-4598. ; 17:4, s. 642-650
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Tidskriftsartikel (refereegranskat)abstract
- Species-rich semi-natural grasslands have been lost during the last century due to agricultural intensification. This has had large negative consequences for many specialised species, including grassland butterflies. To prevent further loss, management regimes in the remaining grasslands must maintain habitat quality over time, and we therefore need to understand the habitat preferences of specialised species and how different management regimes affect their survival. We studied the egg-laying preferences of the threatened marsh fritillary butterfly in relation to host plant properties, microclimate and management (grazing) on Gotland, Sweden. Moreover, we followed the survival of eggs and larvae from 27 egg batches during a period of 8 months (from June 2020 to March 2021) in grazed and ungrazed areas. We found 92 egg batches in total and the average number of eggs was 184.5. Egg-laying probability increased with increasing host plant size and abundance, and environmental variables associated with a warm microclimate (low grass cover, low vegetation height and south-facing edges). The 27 egg batches that were followed over time had on average 203 eggs in June. Roughly 28% of the eggs developed into larvae, and about 17% of these survived over the entire study period, resulting in an overall 4.7% survival. Egg survival was higher in ungrazed habitats compared with grazed; in March (post-hibernation), there were almost nine times more eggs in ungrazed habitats. This study highlights the complex habitat ecology of specialised butterflies and underscores the detrimental impact of intense grazing, advocating for rotational grazing or mowing regimes. We study oviposition preferences and survival of both eggs and larvae (post-hibernation) for the marsh fritillary, in relation to host plant availability, microclimate conditions and grazing management Egg-laying probability increased with increasing host plant size and abundance, and environmental variables associated with a warm microclimate (low grass cover, low vegetation height and south-facing edges) Egg survival was clearly higher in ungrazed habitats compared with grazed; in March (post-hibernation), there were almost nine times more eggs in ungrazed habitats. image
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| 5. |
- Monteux, Sylvain, 1989-, et al.
(författare)
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Controlling biases in targeted plant removal experiments
- 2024
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Ingår i: New Phytologist. - : John Wiley & Sons. - 0028-646X .- 1469-8137. ; 242:4, s. 1835-1845
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Tidskriftsartikel (refereegranskat)abstract
- Targeted removal experiments are a powerful tool to assess the effects of plant species or (functional) groups on ecosystem functions. However, removing plant biomass in itself can bias the observed responses. This bias is commonly addressed by waiting until ecosystem recovery, but this is inherently based on unverified proxies or anecdotal evidence. Statistical control methods are efficient, but restricted in scope by underlying assumptions.We propose accounting for such biases within the experimental design, using a gradient of biomass removal controls. We demonstrate the relevance of this design by presenting (1) conceptual examples of suspected biases and (2) how to observe and control for these biases.Using data from a mycorrhizal association-based removal experiment, we show that ignoring biomass removal biases (including by assuming ecosystem recovery) can lead to incorrect, or even contrary conclusions (e.g. false positive and false negative). Our gradient design can prevent such incorrect interpretations, regardless of whether aboveground biomass has fully recovered.Our approach provides more objective and quantitative insights, independently assessed for each variable, than using a proxy to assume ecosystem recovery. Our approach circumvents the strict statistical assumptions of, for example, ANCOVA and thus offers greater flexibility in data analysis.
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| 6. |
- Alatalo, Juha M., et al.
(författare)
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Bryophyte cover and richness decline after 18 years of experimental warming in Alpine Sweden
- 2024
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Annan publikation (övrigt vetenskapligt/konstnärligt)abstract
- 1. Bryophytes in the Arctic and Alpine regions are important in terms of biodiversity, cover and biomass. However, climate change and widespread shrubification of alpine and arctic tundra is predicted to increase in the future, with potentially large impacts on bryophyte communities.2. We studies the impact of 18 years of experimental warming with open top chambers (OTCs) on bryophyte cover, richness and diversity in an alpine mesic meadow and a heath plant community in Northern Sweden. In addition we investigated the relationship between deciduous shrubs and bryophytes.3. Cover and richness of bryophytes both declined due to long-term warming, while diversity did not show any significant responses. After 18 years, bryophyte cover had decreased by 71% and 26 in the heath and meadow, while richness declined by 39% and 26%, respectively.4. Synthesis. Decline in total bryophyte cover in both communities in response to long-term warming was driven by a general decline in many species, with only two individual species showing significant declines. Although most of the species included in the individual analyses did not show any detectable changes, the cumulative change in all species was significant. In addition, species loss was slower than the general decline in bryophyte abundance. As hypothesized, we found significant negative relationship between deciduous shrub cover and bryophyte cover, but not bryophyte richness, in both plant communities. This is likely due to a more delayed decline in species richness compared to abundance, similar to what was observed in response to long-term warming.
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| 7. |
- Li, Yonghua, et al.
(författare)
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Density affects plant size in the Gobi Desert
- 2024
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Ingår i: Science of the Total Environment. - 0048-9697. ; 912
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Tidskriftsartikel (refereegranskat)abstract
- Plant size is a crucial functional trait with substantial implications in agronomy and forestry. Understanding the factors influencing plant size is essential for ecosystem management and restoration efforts. Various environmental factors and plant density play significant roles in plant size. However, how plant size responds to mean annual precipitation (MAP), mean annual temperature (MAT), and density in the arid areas remains incomplete. To address this knowledge gap, we conducted comprehensive vegetation surveys in the Gobi Desert in northwestern China with a MAP below 250 mm. We also collected climate data to disentangle the respective influences of climate and density on the community-weighted plant height, crown length, and crown width. Our observations revealed that the community-weighted mean plant height, crown length, and width demonstrated a positive association with MAT but negative relationships with both MAP and density. These patterns can be attributed to the predominance of shrubs over herbs in arid regions, as shrubs tend to be larger in size. The proportion of shrubs increases with MAT, while it decreases with MAP and density, resulting in higher plant height and larger crown dimensions. Although both MAP and MAT affect plant size in the Gobi Desert, our findings highlight the stronger role of plant density in regulating plant size, indicating that the surrounding plant community and competition among individuals are crucial drivers of plant size patterns. Our findings provide valuable guidance for nature-based solutions for vegetation restoration and ecosystem management, highlighting the importance of considering plant density as a key factor when designing and implementing restoration strategies in arid areas.
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| 8. |
- Traveset, Anna, et al.
(författare)
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Effect of green infrastructure on restoration of pollination networks and plant performance in semi-natural dry grasslands across Europe
- 2024
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Ingår i: Journal of Applied Ecology. - 0021-8901 .- 1365-2664. ; 61:5, s. 1015-1028
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Tidskriftsartikel (refereegranskat)abstract
- Agricultural intensification, afforestation and land abandonment are major drivers of biodiversity loss in semi-natural grasslands across Europe. Reversing these losses requires the reinstatement of plant–animal interactions such as pollination. Here we assessed the differences in species composition and patterns of plant-pollinator interactions in ancient and restored grasslands and how these patterns are influenced by landscape connectivity, across three European regions (Belgium, Germany and Sweden).We evaluated the differences in pollinator community assemblage, abundance and interaction network structure between 24 ancient and restored grasslands. We then assessed the effect of surrounding landscape functional connectivity (i.e. green infrastructure, GI) on these variables and tested possible consequences on the reproduction of two model plants, Lotus corniculatus and Salvia pratensis.Neither pollinator richness nor species composition differed between ancient and restored grasslands. A high turnover of interactions across grasslands was detected but was mainly due to replacement of pollinator and plant species. The impact of grassland restoration was consistent across various pollinator functional groups, whereas the surrounding GI had differential effects. Notably, bees, butterflies, beetles, and dipterans (excluding hoverflies) exhibited the most significant responses to GI variations. Interestingly, networks in restored grasslands were more specialised (i.e. less functionally redundant) than in ancient ones and also showed a higher number of insect visits to habitat-generalist plant species. Landscape connectivity had a similar effect, with habitat-specialist plant species receiving fewer visits at higher GI values.Fruit set in S. pratensis and L. corniculatus was unaffected by grassland type or GI. However, the fruit set in the specialist S. pratensis increased with the number of pollinator visits, indicating a positive correlation between pollinator activity and reproductive success in this particular species.Synthesis and applications. Our findings provide evidence of the necessity to enhance ecosystem functions while avoiding biotic homogenisation. Restoration programs should aim at increasing landscape connectivity which influences plant communities, pollinator assemblages and their interaction patterns. To avoid generalist species taking over from specialists in restored grasslands, we suggest reinforcing the presence of specialist species in the latter, for instance by means of introductions, as well as increasing the connectivity to source populations.
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| 9. |
- Camila Pacheco-Riano, L., et al.
(författare)
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Reliability of presence-only data for assessing plant community responses to climate warming
- 2024
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Ingår i: ECOGRAPHY. - 0906-7590 .- 1600-0587. ; 2024:7
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Tidskriftsartikel (refereegranskat)abstract
- Climate warming has triggered shifts in plant distributions, resulting in changes within communities, characterized by an increase in warm-demanding species and a decrease in cold-adapted species - referred to as thermophilization. Researchers conventionally rely on co-occurrence data from vegetation assemblages to examine these community dynamics. Despite the increasing availability of presence-only data in recent decades, their potential has largely remained unexplored due to concerns about their reliability. Our study aimed to determine whether climate-induced changes in community dynamics, as inferred from presence-only data from the Global Biodiversity Information Facility (GBIF), corresponded with those derived from co-occurrence plot data. To assess the differences between these datasets, we computed a community temperature index (CTI) using a transfer function, weighted-averaging partial least squares regression (WA-PLS). We calibrated the transfect function model based on the species-temperature relationship using data before recent climate warming. Then we assessed the differences in CTI and examined the temporal trend in thermophilization. In a preliminary analysis, we assessed the performance of this calibration using three datasets: 1) Norwegian co-occurrence data, 2) presence-only data from a broader European region organized into pseudo-plots (potentially capturing a larger part of the species niches), and 3) a combined dataset merging 1) and 2). The transfer function including the combined dataset performed best. Subsequently, we compared the CTI for the co-occurrence plots paired up spatially and temporally with presence-only pseudo-plots. The results demonstrated that presence-only data can effectively evaluate species assemblage responses to climate warming, with consistent CTI and thermophilization values to what was found for the co-occurrence data. Employing presence-only data for evaluating community responses opens up better spatial and temporal resolution and much more detailed analyses of such responses. Our results therefore outline how a large amount of presence-only data can be used to enhance our understanding of community dynamics in a warmer world.
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| 10. |
- Eckdahl, Johan
(författare)
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Boreal Forest Wildfire in a Changing Climate
- 2024
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- The boreal region contains 40% of the earth’s carbon (C) that is stored in vegetation and soils with its forests accounting for almost 30% of the terrestrial C sink. Boreal forests are experiencing some of the most rapid rates of climatic warming and increases in fire activity, threatening to release large amounts of their dense C reserves to the atmosphere. While climate and wildfire place strong controls on ecosystem function, few observations have been made regarding their potential synergistic effects. This thesis utilized 50 separately occurring summer 2018 wildfires, each paired with an unburnt control and spread across the near-entire climatic range of boreal Fennoscandia, providing the first field campaign targeting regional-scale variation in boreal wildfire activity. It was found that climate determined the prefire quantity and structure of forest fuel, which in turn controlled both the immediate and extended fire-induced removal rates of C and nitrogen (N) to the surrounding land and atmosphere. Reorganization of ecosystem structure through wildfire burning strengthened climatic control over soil microbial community structure and nutrient cycling, with warmer regions experiencing enhanced nutrient mobilization under oligotrophic processing of remaining burnt organic soil. Greater warmth and soil fertility together stimulated growth of broadleaf overstory species under a restricted recovery capacity of previously established coniferous and ericaceous plant communities, though this transition to novel growth patterns was limited by residual, biodiversity inhibiting plant-soil feedbacks. Together these results suggest that continued climate change and wildfire can serve to remove C and nutrients from burnt boreal forests under a limited capacity for their reaccumulation. This postfire resource drain is capable of influencing longer-term patterns of ecosystem regrowth and the boreal forest contribution to the global land-atmosphere C balance that is deserving of further study.
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