| 1. |
- Silva, Willian T.A.F., et al.
(författare)
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Phenological evolution in annual plants under light competition, changes in the growth season and mass loss
- 2024
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Ingår i: Ecology and Evolution. - 2045-7758. ; 14:4
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Tidskriftsartikel (refereegranskat)abstract
- Flowering time is an important phenological trait in plants and a critical determinant of the success of pollination and fruit or seed development, with immense significance for agriculture as it directly affects crop yield and overall food production. Shifts in the growth season, changes in the growth season duration and changes in the production rate are environmental processes (potentially linked to climate change) that can lead to changes in flowering time in the long-term due to selection. In contrast, biomass loss (due to, for example, herbivory or diseases) can have profound consequences for plant mass production and food security. We model the effects of these environmental processes on the flowering time evolutionarily stable strategy (ESS) of annual plants and the potential consequences for reproductive output. Our model recapitulates previous theoretical results linked to climate change and light competition and makes novel predictions about the effects of biomass loss on the evolution of flowering time. Our analysis elucidates how both the magnitude and direction of the evolutionary response can depend on whether biomass loss occurs during the earlier vegetative phase or during the later reproductive phase and on whether or not plants are adapted to grow in dense, competitive environments. Specifically, light competition generates an asymetric effect of mass loss on flowering time even when loss is indiscriminate (equal rates), with vegetative mass loss having a stronger effect on flowering time (resulting in greater ESS change) and final reproductive output.
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| 2. |
- Cantwell-Jones, Aoife, et al.
(författare)
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Mapping trait versus species turnover reveals spatiotemporal variation in functional redundancy and network robustness in a plant-pollinator community
- 2023
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Ingår i: Functional Ecology. - : John Wiley & Sons. - 0269-8463 .- 1365-2435. ; 37:3, s. 748-762
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Tidskriftsartikel (refereegranskat)abstract
- Functional overlap among species (redundancy) is considered important in shaping competitive and mutualistic interactions that determine how communities respond to environmental change. Most studies view functional redundancy as static, yet traits within species—which ultimately shape functional redundancy—can vary over seasonal or spatial gradients. We therefore have limited understanding of how trait turnover within and between species could lead to changes in functional redundancy or how loss of traits could differentially impact mutualistic interactions depending on where and when the interactions occur in space and time. Using an Arctic bumblebee community as a case study, and 1277 individual measures from 14 species over three annual seasons, we quantified how inter- and intraspecific body-size turnover compared to species turnover with elevation and over the season. Coupling every individual and their trait with a plant visitation, we investigated how grouping individuals by a morphological trait or by species identity altered our assessment of network structure and how this differed in space and time. Finally, we tested how the sensitivity of the network in space and time differed when simulating extinction of nodes representing either morphological trait similarity or traditional species groups. This allowed us to explore the degree to which trait-based groups increase or decrease interaction redundancy relative to species-based nodes. We found that (i) groups of taxonomically and morphologically similar bees turn over in space and time independently from each other, with trait turnover being larger over the season; (ii) networks composed of nodes representing species versus morphologically similar bees were structured differently; and (iii) simulated loss of bee trait groups caused faster coextinction of bumblebee species and flowering plants than when bee taxonomic groups were lost. Crucially, the magnitude of these effects varied in space and time, highlighting the importance of considering spatiotemporal context when studying the relative importance of taxonomic and trait contributions to interaction network architecture. Our finding that functional redundancy varies spatiotemporally demonstrates how considering the traits of individuals within networks is needed to understand the impacts of environmental variation and extinction on ecosystem functioning and resilience. Read the free Plain Language Summary for this article on the Journal blog.
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| 3. |
- Johansson, Jacob, et al.
(författare)
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How competition between overlapping generations can influence optimal egg-laying strategies in annual social insects
- 2023
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Ingår i: Oecologia. - 0029-8549. ; 202:3, s. 535-547
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Tidskriftsartikel (refereegranskat)abstract
- Annual social insects are an integral functional group of organisms, particularly in temperate environments. An emblematic part of their annual cycle is the social phase, during which the colony-founding queen rears workers that later assist her in rearing sexual progeny (gynes and drones). In many annual social insects, such as species of bees, wasps, and other groups, developing larvae are provisioned gradually as they develop (progressive provisioning) leading to multiple larval generations being reared simultaneously. We present a model for how the queen in such cases should optimize her egg-laying rate throughout the social phase depending on number-size trade-offs, colony age-structure, and energy balance. Complementing previous theory on optimal allocation between workers vs. sexuals in annual social insects and on temporal egg-laying patterns in solitary insects, we elucidate how resource competition among overlapping larval generations can influence optimal egg-laying strategies. With model parameters informed by knowledge of a common bumblebee species, the optimal egg-laying schedule consists of two temporally separated early broods followed by a more continuous rearing phase, matching empirical observations. However, eggs should initially be laid continuously at a gradually increasing rate when resources are scarce or mortality risks high and in cases where larvae are fully supplied with resources at the egg-laying stage (mass-provisioning). These factors, alongside sexual:worker body size ratios, further determine the overall trend in egg-laying rates over the colony cycle. Our analysis provides an inroad to study and mechanistically understand variation in colony development strategies within and across species of annual social insects.
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| 4. |
- Johansson, Jacob, et al.
(författare)
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Implementation and Evaluation of the ACE DTLS Framework over Internet of Things Devices
- 2022
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Konferensbidrag (refereegranskat)abstract
- Internet of Things (IoT)-devices are becoming more advanced and powerful than ever, and the application potential is increasing rapidly. This paper significantly contributes in three ways. First, it modifies, extends and implements the well-known security-driven authorization in a constrained environment-datagram transport layer security (ACE-DTLS) protocol's framework on resource-constrained IoT devices in a local network. Second, ACE-DTLS framework is compared with the Baseline method by adopting performance indicators for example, power dissipation, PLR, latency, overall network performance and a resource server. Third, radio duty cycles (RDC) are adopted for optimizing the energy efficiency of the constrained IoT devices during CPU processing. Experimental environment was examined with three tests i.e., COAP, COAP+token, and COAP+DTLS by putting router at three main distances (1m, 6m and 12m). It is observed that COAP has less PLR, power drain and latency than COAP+token and COAP+DTLS, while COAp+DTLS shows relatively high latency, power drain and PLR at 6m and 12m distances.
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| 5. |
- Samplonius, Jelmer M., et al.
(författare)
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Strengthening the evidence base for temperature-mediated phenological asynchrony and its impacts
- 2021
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Ingår i: Nature Ecology and Evolution. - : Springer Science and Business Media LLC. - 2397-334X. ; 5:2, s. 155-164
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Forskningsöversikt (refereegranskat)abstract
- Climate warming has caused the seasonal timing of many components of ecological food chains to advance. In the context of trophic interactions, the match–mismatch hypothesis postulates that differential shifts can lead to phenological asynchrony with negative impacts for consumers. However, at present there has been no consistent analysis of the links between temperature change, phenological asynchrony and individual-to-population-level impacts across taxa, trophic levels and biomes at a global scale. Here, we propose five criteria that all need to be met to demonstrate that temperature-mediated trophic asynchrony poses a growing risk to consumers. We conduct a literature review of 109 papers studying 129 taxa, and find that all five criteria are assessed for only two taxa, with the majority of taxa only having one or two criteria assessed. Crucially, nearly every study was conducted in Europe or North America, and most studies were on terrestrial secondary consumers. We thus lack a robust evidence base from which to draw general conclusions about the risk that climate-mediated trophic asynchrony may pose to populations worldwide.
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| 6. |
- Silva, Willian, et al.
(författare)
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Light competition and phenological adaptation of annual plants to a changing climate
- 2021
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Ingår i: Climate Change Ecology. - : Elsevier BV. - 2666-9005. ; 2
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Tidskriftsartikel (refereegranskat)abstract
- Shifting flowering seasons is a global effect of climate change that can have important long-term evolutionary and demographic effects on plant communities. Life history optimization theory can be a valuable tool to assert the adaptive value and fitness effects of observed phenological shifts, but takes plant-plant competition rarely into account. Here we combine energy allocation models with evolutionary game theory to assess how size-asymmetric competition for light can influence phenological adaptations and fitness responses to a changing climate –here represented as changes of the start, end and intensity of the growing season. We focus on annual plants which, due to their short generation times, are particularly likely to exhibit rapid demographic and evolutionary responses to environmental change. We find that while light competition favors late flowering times, it does not affect the direction of selection in the climate changes scenarios considered here. We predict, however, that plants adapted to light competition face more detrimental fitness consequences if the growing season advances, becomes shorter or less intense. We also show that adaptation to changing growing seasons under light competition can favor increased investment in vegetative growth with the counterintuitive side effect that seed production is reduced at the same time. In sum, our study highlights several effects of light competition that may help to interpret phenological trends and idiosyncratic fitness effects of climate change in wild plant communities.
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| 7. |
- Johansson, Jacob, et al.
(författare)
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Is timing of reproduction according to temperature sums an optimal strategy?
- 2019
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Ingår i: Ecology and Evolution. - : Wiley. - 2045-7758. ; 9:20, s. 11598-11605
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Tidskriftsartikel (refereegranskat)abstract
- Temperature sums are widely used to predict the seasonal timing of yearly recurring biological events, such as flowering, budburst, and hatching. We use a classic energy allocation model for annual plants to compare a strategy for reproductive timing that follows a temperature sum rule (TSR) with a strategy that follows an optimal control rule (OCR) maximizing reproductive output. We show that the OCR corresponds to a certain TSR regardless of how temperature is distributed over the growing season as long as the total temperature sum over the whole growing season is constant between years. We discuss such scenarios, thus outlining under which type of variable growth conditions TSR maximizes reproductive output and should be favored by natural selection. By providing an ultimate explanation for a well-documented empirical pattern this finding enhances the credibility of temperature sums as predictors of the timing of biological events. However, TSR and OCR respond in opposite directions when the total yearly temperature sum changes between years, representing, for example, variation in the length of the growing season. Our findings have implications for predicting optimal responses of organisms to climatic changes and suggest under which conditions natural selection should favor photoperiod versus temperature control.
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| 8. |
- Johansson, Jacob, et al.
(författare)
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Twelve fundamental life histories evolving through allocation-dependent fecundity and survival
- 2018
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Ingår i: Ecology and Evolution. - : John Wiley & Sons. - 2045-7758. ; 8:6, s. 3172-3186
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Tidskriftsartikel (refereegranskat)abstract
- An organism's life history is closely interlinked with its allocation of energy between growth and reproduction at different life stages. Theoretical models have established that diminishing returns from reproductive investment promote strategies with simultaneous investment into growth and reproduction (indeterminate growth) over strategies with distinct phases of growth and reproduction (determinate growth). We extend this traditional, binary classification by showing that allocation-dependent fecundity and mortality rates allow for a large diversity of optimal allocation schedules. By analyzing a model of organisms that allocate energy between growth and reproduction, we find twelve types of optimal allocation schedules, differing qualitatively in how reproductive allocation increases with body mass. These twelve optimal allocation schedules include types with different combinations of continuous and discontinuous increase in reproduction allocation, in which phases of continuous increase can be decelerating or accelerating. We furthermore investigate how this variation influences growth curves and the expected maximum life span and body size. Our study thus reveals new links between eco-physiological constraints and life-history evolution and underscores how allocation-dependent fitness components may underlie biological diversity.
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| 9. |
- Kristensen, Nadiah Pardede, et al.
(författare)
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Carryover effects from natal habitat type upon competitive ability lead to trait divergence or source–sink dynamics
- 2018
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Ingår i: Ecology Letters. - : Wiley. - 1461-023X. ; 21:9, s. 1341-1352
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Tidskriftsartikel (refereegranskat)abstract
- Local adaptation to rare habitats is difficult due to gene flow, but can occur if the habitat has higher productivity. Differences in offspring phenotypes have attracted little attention in this context. We model a scenario where the rarer habitat improves offspring's later competitive ability – a carryover effect that operates on top of local adaptation to one or the other habitat type. Assuming localised dispersal, so the offspring tend to settle in similar habitat to the natal type, the superior competitive ability of offspring remaining in the rarer habitat hampers immigration from the majority habitat. This initiates a positive feedback between local adaptation and trait divergence, which can thereafter be reinforced by coevolution with dispersal traits that match ecotype to habitat type. Rarity strengthens selection on dispersal traits and promotes linkage disequilibrium between locally adapted traits and ecotype-habitat matching dispersal. We propose that carryover effects may initiate isolation by ecology.
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| 10. |
- Kristensen, Nadiah Pardede, et al.
(författare)
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Evolution of resident bird breeding phenology in a landscape with heterogeneous resource phenology and carryover effects
- 2018
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Ingår i: Evolutionary Ecology. - : Springer Science and Business Media LLC. - 0269-7653 .- 1573-8477. ; 32:5, s. 509-528
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Tidskriftsartikel (refereegranskat)abstract
- It is generally expected that, in environments with pronounced seasonal resource peaks, birds’ reproductive success will be maximised when nestlings’ peak food demand coincides with the timing of high food availability. However in certain birds that stay resident over winter, earlier breeding leads juveniles to join the winter flock earlier, which by the prior residence effect increases their success in breeding territory competition. This trade-off between reproduction and competition may explain why, in certain species, breeding phenology is earlier and asynchronous with the resource. This study extends a previous model of the evolution of breeding phenology in a single habitat type to a landscape with two habitat types: ‘early’ and ‘late’ resource phenology. The offspring’s natal habitat type has a carryover effect upon their competitive ability regardless of which habitat type they settle in to potentially breed. We find that, when the difference in resource phenology between habitats is small (weak carryover effect), breeding phenology in the late habitat evolves to occur earlier and more asynchronously than in the early habitat, to compensate for the competitive disadvantage to juveniles raised there. However if the difference is large (strong carryover effect), then the reproductive cost of earlier breeding outweighs the benefit of the compensation, so instead breeding phenology in the late habitat evolves to become more synchronous with the resource. Recruitment is generally asymmetric, from early to late habitat type. However if the early habitat is less frequent in the landscape or produces fewer offspring, then the asymmetry is reduced, and if there is some natal habitat-type fidelity, then recruitment can have an insular pattern, i.e. most recruits to each habitat type come from that same habitat type. We detail the different scenarios in which the different recruitment patterns are predicted, and we propose that they have implications for local adaptation.
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