| 141. |
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| 142. |
- Posledovich, Diana, 1984-
(author)
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Effects of climate on phenological synchrony between butterflies and their host plants
- 2015
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Doctoral thesis (other academic/artistic)abstract
- Shifts in species’ phenologies and phenological asynchronies between the interacting organisms have received a lot of attention in the context of climate change. Changes in temporal overlap between species, caused by phenological asynchrony, make species depending on one another become so separated in time that they can no longer interact. This may have important consequences both for single species, like fluctuations in abundances, and for the functioning of whole communities by creating mismatches between trophic levels and rearrangements of community structure. This thesis focuses on the impact of temperatures on spring timing and phenological synchrony in a herbivorous insect – host plant system, consisting of the orange tipbutterfly Anthocharis cardamines and five of its Brassicaceae host plant species. Paper I demonstrates that diapause duration and winter thermal conditions can determine the timing of spring emergence in the herbivore, and these traits may differ between species with different feeding strategies. In paper II we show that thermal reaction norms of post-winterdevelopment of A. cardamines display cogradient latitudinal variation.Paper III shows that temperature-mediated phenological plasticity of A. cardamines butterflies and a majority of the most used host plant species is similar within populations originating from different latitudes. Thus, the species’ timing appeared well conserved in response to thermal variation. In paper IV we explored the importance of the butterfly’s adult emergence and thermal conditions on the succeeding part of the butterfly’s life-cycle – larval development. The outcome from the interaction was examined for both the insect and the plant side. The degree in phenological overlap between the female butterflies and host plants as well as temperatures during larval development were found to influence larval development but had no effect on plant reproductive fitness. The four papers of the presented thesis demonstrate that developmental preadaptations, evolvedin a herbivore to maintain phenological synchrony with host plants across yearly variation of spring conditions, can prevent disruption of the interaction under a wide range of temperatures. This indicates that temporary constrained interactions are not always vulnerable to decoupling, particularly if they involve generalist strategy.
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| 143. |
- Posledovich, Diana, et al.
(author)
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Latitudinal variation in diapause duration and post-winter development in two pierid butterflies in relation to phenological specialization
- 2015
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In: Oecologia. - : Springer Science and Business Media LLC. - 0029-8549 .- 1432-1939. ; 177:1, s. 181-190
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Journal article (peer-reviewed)abstract
- Diapause plays a central role in insect life cycles by allowing survival during adverse seasonal conditions as well as synchronizing life cycles with the period of mate and food availability. Seasonal timing is expected to be particularly important for species that are dependent on resources available during a short time window-so-called phenological specialists-and latitudinal clines in seasonality are expected to favor local adaptation in phenological timing. However, to what degree latitudinal variation in diapause dynamics and post-winter development due to such local adaptation is influenced by the degree of phenological specialization is not well known. We experimentally studied two pierid butterfly species and found that the phenological specialist Anthocharis cardamines had shorter diapause duration than the phenological generalist Pieris napi along a latitudinal gradient in Sweden. Moreover, diapause duration increased with latitude in P. napi but not in A. cardamines. Sensitivity of the two species to winter thermal conditions also differed; additional cold temperature during the winter period shortened diapause duration for P. napi pupae but not for A. cardamines pupae. In both species, post-winter pupal development was faster after longer periods of cold conditions, and more southern populations developed faster than northern populations. Post-winter development was also invariably faster at higher temperatures in both species. We argue that the observed differences in diapause dynamics between the two species might be explained by the difference in phenological specialization that influences the costs of breaking diapause too early in the season.
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| 144. |
- Posledovich, Diana, et al.
(author)
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Latitudinal variation in thermal reaction norms of post-winter pupal development in two butterflies differing in phenological specialization
- 2014
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In: Biological Journal of the Linnean Society. - : Oxford University Press (OUP). - 0024-4066 .- 1095-8312. ; 113:4, s. 981-991
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Journal article (peer-reviewed)abstract
- Latitudinal clines in thermal reaction norms of development are a common phenomenon in temperate insects. Populations from higher latitudes often develop faster throughout the range of relevant temperatures (i.e countergradient variation) because they must be able to complete their life cycle within a shorter seasonal time window compared to populations at lower latitudes. In the present study, we experimentally demonstrate that two species of butterflies Anthocharis cardamines (L.) and Pieris napi (L.) instead show a cogradient variation in thermal reaction norms of post-winter pupal development so that lower latitude populations develop faster than higher latitude populations. The two species share host plants but differ in the degree of phenological specialization, as well as in the patterns of voltinism. We suggest that the pattern in A. cardamines, a univoltine phenological specialist feeding exclusively on flowers and seedpods, is the result of selection for matching to the phenological pattern of its local host plants. The other species, P. napi, is a phenological generalist feeding on the leaves of the hosts and it shows a latitudinal cline in voltinism. Because the latitudinal pattern in P. napi was an effect of slow development in a fraction of the pupae from the most northern population, we hypothesize that this population may include both bivoltine and univoltine genotypes. Consequently, although the two species both showed cogradient patterns in thermal reaction norms, it appears likely that this was for different reasons.
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| 145. |
- Posledovich, Diana, et al.
(author)
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Phenological synchrony between a butterfly and its host plants : Experimental test of effects of spring temperature
- 2018
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In: Journal of Animal Ecology. - : Wiley. - 0021-8790 .- 1365-2656. ; 87:1, s. 150-161
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Journal article (peer-reviewed)abstract
- 1. Climate-driven changes in the relative phenologies of interacting species may potentially alter the outcome of species interactions. 2. Phenotypic plasticity is expected to be important for short-term response to new climate conditions, and differences between species in plasticity are likely to influence their temporal overlap and interaction patterns. As reaction norms of interacting species may be locally adapted, any such climate-induced change in interaction patterns may vary among localities. However, consequences of spatial variation in plastic responses for species interactions are understudied. 3. We experimentally explored how temperature affected synchrony between spring emergence of a butterfly, Anthocharis cardamines, and onset of flowering of five of its host plant species across a latitudinal gradient. We also studied potential effects on synchrony if climate-driven northward expansions would be faster in the butterflies than in host plants. Lastly, to assess how changes in synchrony influence host use we carried out an experiment to examine the importance of the developmental stage of plant reproductive structures for butterfly oviposition preference. 4. In southern locations, the butterflies were well-synchronized with the majority of their local host plant species across temperatures, suggesting that thermal plasticity in butterfly development matches oviposition to host plant development and that thermal reaction norms of insects and plants result in similar advancement of spring phenology in response to warming. In the most northern region, however, relative phenology between the butterfly and two of its host plant species changed with increased temperature. We also show that the developmental stage of plants was important for egg-laying, and conclude that temperature-induced changes in synchrony in the northernmost region are likely to lead to shifts in host use in A.cardamines if spring temperatures become warmer. Northern expansion of butterfly populations might possibly have a positive effect on keeping up with host plant phenology with more northern host plant populations. 5. Considering that the majority of insect herbivores exploit multiple plant species differing in their phenological response to spring temperatures, temperature-induced changes in synchrony might lead to shifts in host use and changes in species interactions in many temperate communities.
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| 146. |
- Posledovich, Diana, et al.
(author)
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The developmental race between maturing host plants and their butterfly herbivore – the influence of phenological matching and temperature
- 2015
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In: Journal of Animal Ecology. - : Wiley. - 0021-8790 .- 1365-2656. ; 84:6, s. 1690-1699
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Journal article (peer-reviewed)abstract
- Interactions between herbivorous insects and their host plants that are limited in time are widespread. Therefore, many insect-plant interactions result in a developmental race, where herbivores need to complete their development before plants become unsuitable, while plants strive to minimize damage from herbivores by outgrowing them. When spring phenologies of interacting species change asymmetrically in response to climate warming, there will be a change in the developmental state of host plants at the time of insect herbivore emergence. In combination with altered temperatures during the subsequent developmental period, this is likely to affect interaction strength as well as fitness of interacting species. Here, we experimentally explore whether the combined effect of phenological matching and thermal conditions influence the outcome of an insect-host interaction. We manipulated both developmental stages of the host plants at the start of the interaction and temperature during the subsequent developmental period in a model system of a herbivorous butterfly, Anthocharis cardamines, and five of its Brassicaceae host plant species. Larval performance characteristics were favoured by earlier stages of host plants at oviposition as well as by higher developmental temperatures on most of the host species. The probability of a larva needing a second host plant covered the full range from no influence of either phenological matching or temperature to strong effects of both factors, and complex interactions between them. The probability of a plant outgrowing a larva was dependent only on the species identity. This study demonstrates that climatic variation can influence the outcome of consumer-resource interactions in multiple ways and that its effects differ among host plant species. Therefore, climate warming is likely to change the temporal match between larval and plant development in some plant species, but not in the others. This is likely to have important implications for host plant use and possibly influence competitive relationships.
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| 147. |
- Posledovich, Diana, et al.
(author)
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Weak effect of spring temperatures on phenological synchrony between herbivore emergence and host plant suitability
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Other publication (other academic/artistic)abstract
- Many species interactions are maintained by precise timing of life-cycle events across seasonal variation. Ecological implications of changes in phenologies, associated with climate change, with respect to species interactions are to a large extent unexplored. Changes in phenological distance between herbivores and their host plant species under new environmental conditions may potentially lead to shifts in host use patterns, with some plant species becoming more or less available at the time of a herbivore’s emergence. In addition, latitudinal variation in the timing of phenological events can lead to different patterns in host use shifts among populations of a given herbivore. Here we explored latitudinal variation in the effects of temperature on the degree of phenological synchrony between emergence of a butterfly, A. cardamines, and five of its herbaceous host plant species in a set of laboratory experiments to investigate the possibility that there will be shifts in the butterfly’ host utilization due to changes in thermal environment. The results suggest a similar temperature-mediated phenological plasticity between the butterflies and their host plants in three latitudinally divergent populations. In general, butterflies appeared to be well-synchronized with the majority of their host plant species across temperatures. In the most northern region, however, phenological distance between the butterfly and two out of four plant species was affected by temperature and decreased in warmer treatments. We relate this to a lower diversity of plant species and shorter period of host availability in the northern region. This creates a stronger selection pressure on the northern butterflies for a closer matching of their emergence to the plant flowering period. As the butterflies discriminated against non-flowering hosts with respect to oviposition, we conclude that a shift in host use in A. cardamines appears to be a possible scenario under spring warming, especially in the northern region.
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| 148. |
- Pulido, Fernando, et al.
(author)
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Widespread latitudinal asymmetry in the performance of marginal populations : A meta-analysis
- 2023
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In: Global Ecology and Biogeography. - : Wiley. - 1466-822X .- 1466-8238. ; 32:6, s. 842-854
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Journal article (peer-reviewed)abstract
- Aim: Range shifts are expected to occur when populations at one range margin perform better than those at the other margin, yet no global trend in population performances at range margins has been demonstrated empirically across a wide range of taxa and biomes. Here we test the prediction that, if impacts of ongoing climate change on performance in marginal populations are widespread, then populations from the high-latitude margin (HLM) should perform as well as or better than central populations, whereas low-latitude margin (LLM) populations should perform worse.Location: Global.Time period: 1995–2019.Major taxa studied: Plants and animals.Methods: To test our prediction, we used a meta-analysis to quantify empirical support for asymmetry in the performance of high- and low-latitude margin populations compared to central populations. Performance estimates (survival, reproduction, or lifetime fitness) for populations occurring in their natural environment were derived from 51 papers involving 113 margin-centre comparisons from 54 species and 705 populations from the Americas, Europe, Africa and Australia. We then related these performance differences to climatic differences among populations. We also tested whether patterns are consistent across taxonomic kingdoms (plants vs animals) and across realms (marine vs terrestrial).Results: Populations at margins performed significantly worse than central populations, and this trend was primarily driven by the low-latitude margin. Although the difference was of small magnitude, it was largely consistent across biological kingdoms and realms. Differences in performance were weakly (p = .08) related to the difference in average temperatures between central and marginal populations.Main conclusions: The observed asymmetry in performance in marginal populations is consistent with predictions about the effects of global climate change, though further research is needed to confirm the effect of climate. It indicates that changes in demographic rates in marginal populations can serve as early-warning signals of impending range shifts.
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| 149. |
- Ryberg, Eleonor E., et al.
(author)
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Postglacial peatland vegetation succession in Store Mosse bog, south-central Sweden : An exploration of factors driving species change
- 2022
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In: Boreas. - : Wiley. - 0300-9483 .- 1502-3885. ; 51:3, s. 651-666
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Journal article (peer-reviewed)abstract
- Boreal peatlands are facing significant changes in response to a warming climate. Sphagnum mosses are key species in these ecosystems and contribute substantially to carbon sequestration. Understanding the factors driving vegetation changes on longer time scales is therefore of high importance, yet challenging since species changes are typically affected by a range of internal and external processes acting simultaneously within the system. This study presents a high-resolution macrofossil analysis of a peat core from Store Mosse bog (south-central Sweden), dating back to nearly 10 000 cal. a BP. The aim is to identify factors driving species changes on multidecadal to millennial timescales considering internal autogenic, internal biotic and external allogenic processes. A set of independent proxy data was used as a comparison framework to estimate changes in the bog and regional effective humidity, nutrient input and cold periods. We found that Store Mosse largely follows the expected successional pathway for a boreal peatland (i.e. lake -> fen -> bog). However, the system has also been affected by other interlinked factors. Of interest, we note that external nutrient input (originating from dust deposition and climate processes) has had a negative effect on Sphagnum while favouring vascular plants, and increased fire activity (driven by allogenic and autogenic factors) typically caused post-fire, floristic wet shifts. These effects interactively caused a floristic reversal and near disappearance of a once-established Sphagnum community, during which climate acted as an indirect driver. Overall, this study highlights that the factors driving vegetation change within the peatland are multiple and complex. Consideration of the role of interlinked factors on Sphagnum is crucial for an improved understanding of the drivers of species change on short- and long-term scales.
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| 150. |
- Ryberg, Eleonor Eva Stina, 1989-
(author)
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Holocene species distributions in boreal peatlands : An exploration of factors driving change using Temporal Paleo-Species Distribution Models
- 2024
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Doctoral thesis (other academic/artistic)abstract
- Northern peatlands are terrestrial ecosystems that provide specialized habitats in which biomass production exceeds decomposition, resulting in accumulation of organic matter. Understanding what factors drive species changes in future climate conditions in these systems is of high importance since this has the potential to affect ecosystem functioning and biodiversity, and by extension carbon sequestration. In ecology, a common method for investigating species’ relationships with climate variation, linked with spatial information, is species distribution modelling (SDM). This method typically uses information about current climate conditions tied to locations of species occurrences, forecasting the effects of change on future geographic distributions based on the implicit assumption that temporal variation can be substituted by contemporary spatial variation. This assumption might not be met for several reasons, namely (1) species changes often occur over much longer time-scales than the ones involved in contemporary ecology, and therefore (2) responses to climatic changes are time-lagged. Incorporating paleo-records of actual (past) changes in species distributions and climate conditions therefore provides a much more direct way to model species responses to climate change. In this project, a combination of methods from the fields of paleoecology and ecology were employed to create a novel approach to explore species distribution changes over time in boreal peatlands. This was done by first reconstructing the vegetation of two proximal peatlands (Store Mosse and Dala Mosse bogs; Paper I and III) in south-central Sweden, followed by statistical modeling of the species data and climatic parameters over time (obtained from independent paleoclimate data; Paper II and III), creating Temporal Paleo-Species Distribution Models (Temporal Paleo-SDMs). Paper I identifies factors driving species changes in Store Mosse bog based on internal (successional steps and biotic interactions) and external (climatic) processes. This study tests the assumption that climate has been the main driver of species change by producing a high-resolution postglacial vegetation reconstruction using macrofossil analysis, which is assessed against a set of independent proxy records representing changes in local and regional hydrology, nutrient input, and temperature. Paper II uses the same high-resolution plant macrofossil dataset from Store Mosse and pairs this with independent information about local and regional climate conditions, nutrient input and fire incidence during the same period to create the first Temporal Paleo-SDM and thereby assess the relationships between bog species and climate variability over time (reaching ~10 000 cal yr BP). Paper III tests the repeatability of the Temporal Paleo-SDM method by applying it to a new high-resolution species dataset from Dala Mosse, using the same climate parameters as in Paper II. This thesis bridges across paleoecology and ecology and shows the power of interdisciplinary collaborations and demonstrates the useful contributions they can make in future peatland research.
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