| 1. |
- Kemppinen, Julia, et al.
(author)
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Microclimate, an important part of ecology and biogeography
- 2024
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In: GLOBAL ECOLOGY AND BIOGEOGRAPHY. - 1466-822X .- 1466-8238. ; 33:6
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Journal article (peer-reviewed)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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| 2. |
- Greiser, Caroline, 1987-, et al.
(author)
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Microclimatic variation affects developmental phenology, synchrony and voltinism in an insect population
- 2022
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In: Functional Ecology. - : Wiley. - 0269-8463 .- 1365-2435. ; 36:12, s. 3036-3048
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Journal article (peer-reviewed)abstract
- Temperature influences the rate of most biological processes. Nonlinearities in the thermal reaction norms of such processes complicate intuitive predictions of how ectothermic organisms respond to naturally fluctuating temperatures, and by extension, to climate warming. Additionally, organisms developing close to the ground experience a highly variable microclimate landscape that often is poorly captured by coarse standard climate data.Using a butterfly population in central Sweden as a model, we quantified the consequences of small-scale temperature variation on phenology, emergence synchrony and number of annual reproductive cycles (voltinism). By combining empirical microclimate and thermal performance data, we project development of individual green-veined white butterflies (Pieris napi) across 110 sites in an exceptionally high-resolved natural microclimate landscape.We demonstrate that differences among microclimates just meters apart can have large impacts on the rate of development and emergence synchrony of neighbouring butterflies. However, when considering the full development from egg to adult, these temporal differences were reduced in some scenarios, due to negative correlations in development times among life stages. The negative correlations were caused by temperatures at some sites beginning to exceed the optimum for development as the season progressed. Indeed, which sites were optimal for fast development could change across the lifetimes of individual butterflies, that is, ‘fast’ sites could become ‘slow’ sites. Thus, from a thermal point of view, there seem to be no consistently optimal microsites. Importantly, the fast sites were not always the warmest sites. We showed that such unintuitive effects could play an important role in the regulation of phenological synchrony and voltinism in insects, as most sites consistently favoured two generations. The results were generally robust across years and three different egg-laying dates.Using high-resolved empirical climate data on organism-relevant temporal and spatial scales and considering nonlinear responses to temperature, we demonstrated the large and unintuitive population-level consequences of locally and temporarily high temperatures. We suggest to—whenever possible—incorporate species- and life stage-specific nonlinear responses to temperature when studying the effects of natural microclimate variation and climate change on organisms.
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| 3. |
- Isabelle, Siemers, et al.
(author)
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Predictable local adaptation in butterfly photoperiodism but not thermal performance along a latitudinal cline
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Other publication (other academic/artistic)abstract
- In seasonal environments, organisms must synchronize their life cycles to conditions favorable for growth and reproduction. Because season length varies geographically, local adaptation should arise in traits that regulate phenological responses. Geographic photoperiodism clines are well-known, but comparable studies on thermal performance are equivocal and often overlook non-linear responses. Therefore, we examined local adaptation in plastic responses to both photoperiod and temperature along a 752 km latitudinal cline, by comparing four Swedish populations of the butterfly Pieris napi. Using a common garden design, we estimated (1) photoperiod response curves for diapause induction and (2) thermal performance curves for development and growth rates. We show that differences in photoperiodism follow the expected geographical pattern, where diapause is induced at longer daylengths in northern populations (where growth seasons are short and summer days long). However, population differences in thermal performance curves were small and seemingly idiosyncratic, without clear clinal patterns. Photoperiodic responses appear to evolve more readily than thermal responses, indicating that photoperiodism is the key driver of local life cycle synchronization.
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| 4. |
- Kemppinen, Julia, et al.
(author)
-
Microclimate, an important part of ecology and biogeography
- 2024
-
In: Global Ecology and Biogeography. - 1466-822X .- 1466-8238.
-
Journal article (peer-reviewed)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 biogeography: We 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 management: Microclimates 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 science: We 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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| 5. |
- Lindestad, Olle, et al.
(author)
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Variation in butterfly diapause duration in relation to voltinism suggests adaptation to autumn warmth, not winter cold
- 2020
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In: Functional Ecology. - : Wiley. - 0269-8463 .- 1365-2435. ; 34:5, s. 1029-1040
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Journal article (peer-reviewed)abstract
- The life cycles of animals vary in relation to local climate, as a result of both direct environmental effects and population-level variation in plastic responses. Insects often respond to the approach of winter by entering diapause, a hormonally programmed resting state where development is suspended and metabolism suppressed. Populations often differ in the duration of diapause, but the adaptive reasons for this are unclear. We performed a common-garden overwintering experiment with respirometric measurements in order to investigate the progression of diapause in the butterfly Pararge aegeria. Both the duration of diapause and the depth of metabolic suppression were shown to vary between populations. In contrast to previous results from various insects, diapause duration did not correspond to the local length of winter. Instead, the observed pattern was consistent with a scenario in which diapause duration is primarily a product of selection for suppressed metabolism during warm autumn conditions. The relationship between optimal diapause duration and the length of the warm season is complicated by variation in the number of yearly generations (voltinism). These results shed new light on variation in diapause ecophysiology, and highlight voltinism as an integrated product of selection at multiple points in the seasonal cycle. A free Plain Language Summary can be found within the Supporting Information of this article.
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| 6. |
- Süess, Philip, 1988-, et al.
(author)
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Diapause termination and post-diapause development are predictable successive temperature rate processes allowing for phenological synchronization in the green-veined white butterfly Pieris napi
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Other publication (other academic/artistic)abstract
- Ectothermic animals like insects have long been studied for their dependence on environmental temperatures on life-history trait performance. However, most research in temperate regions has focused on summer growth seasons, when insects develop and reproduce. Yet, periods between growth seasons, such as winters, constitute the major portion of insects’ lives in the temperate zone. During these unfavorable conditions, insects generally enter a dormant physiological state called diapause. Here, we quantify the temperature dependence of diapause termination and couple it with spring development. Using a novel methodology, we estimate diapause termination rates at four constant temperatures and show that diapause termination in the butterfly Pieris napi follows a unimodal thermal reaction norm, with optimal rates at winter temperatures. We model this reaction norm as a mirrored version of a typical thermal performance curve (TPC) and use it to predict diapause termination successfully in multiple fluctuating laboratory temperatures, though predictions in field settings were unsuccessful. Moreover, we convincingly show that P. napi post-diapause development resumes directly after diapause termination in a sequential manner and that the temperature-dependence of this development follows a typical development rate TPC. As diapause termination typically takes place in winter, development is halted until spring since winter temperatures usually reside around or below the minimum temperature for development. We propose that this sequence of two thermally separated TPCs is crucial for synchronizing the spring emergence of adult butterflies. In conclusion, we present a new and unified temperature-based framework linking winter and spring biology in diapausing insects, with great applications for future predictive phenology modeling.
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| 7. |
- von Schmalensee, Loke, 1990-
(author)
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How to generate accurate continuous thermal regimes from sparse but regular temperature measurements
- 2023
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In: Methods in Ecology and Evolution. - 2041-210X. ; 14:5, s. 1208-1216
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Journal article (peer-reviewed)abstract
- In ecology, there is an emerging emphasis on the importance of capturing temperature variation at relevant scales. Temperature fluctuates continuously in nature but is sampled at discrete time points, so how often should ecologists measure temperature to capture its variation? A recent development in thermal ecology is the use of spectral analysis of temperature time series to determine at what frequencies important temperature fluctuations occur. Building on this, I borrow from signal processing theory to show how continuous thermal regimes can be effectively reconstructed from discrete, regular, measurements, and provide a rule of thumb for designing temperature sampling schemes that capture ecologically relevant temporal variation.I introduce sinc interpolation, a method for reconstructing continuous waveforms from discrete samples. Furthermore, I introduce the Nyquist–Shannon sampling theorem, which states that continuous complex waveforms can be perfectly sinc-interpolated from discrete, regular, samples if sampling intervals are sufficiently short. To demonstrate the power of these concepts in an ecological context, I apply them to several published high-resolved (15-min intervals) temperature time series used for ecological predictions of insect development times. First, I use spectral analysis to illuminate the fluctuation frequencies that dominate the temperature data. Second, I employ sinc interpolation over artificially thinned versions of the temperature time serifes. Third, I compare interpolated temperatures with observed temperatures to demonstrate the Nyquist–Shannon sampling theorem and its relation to spectral analysis. Last, I repeat the ecological predictions using sinc-interpolated temperatures.Daily, and less frequent, fluctuations dominated the variation in all the temperature time series. Therefore, in accordance with the Nyquist–Shannon sampling theorem, 11-h measurement intervals consistently retrieved most 15-min temperature variation. Moreover, previous predictions of insect development times were improved by using sinc-interpolated, rather than averaged, temperatures.By identifying the highest frequency at which ecologically (or otherwise) relevant temperature fluctuations occur and applying the Nyquist–Shannon sampling theorem, ecologists (or others doing climate-related research) can use sinc interpolation to produce remarkably accurate continuous thermal regimes from sparse but regular temperature measurements. Surprisingly, these concepts have remained largely unexplored in ecology despite their applicability, not least in thermal ecology.
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| 8. |
- von Schmalensee, Loke, 1990-, et al.
(author)
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Methodological artefacts cause counter-intuitive evolutionary conclusions in a simulation study
- 2024
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In: Ecology Letters. - 1461-023X .- 1461-0248. ; 27:6
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Journal article (peer-reviewed)abstract
- In their simulation study, Garcia-Costoya et al. (2023) conclude that evolutionary constraints might aid populations facing climate change. However, we are concerned that this conclusion is largely a consequence of the simulated temperature variation being too small, and, most importantly, that uneven limitations to standing variation disadvantage unconstrained populations. In their simulation study, Garcia-Costoya et al. (2023) conclude that evolutionary constraints might aid populations facing climate change. However, we are concerned that this conclusion is largely a consequence of the simulated temperature variation being too small, and, most importantly, that uneven limitations to standing variation disadvantage unconstrained populations.image
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| 9. |
- von Schmalensee, Loke, 1990-, et al.
(author)
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Seasonal specialization drives divergent population dynamics in two closely related butterflies
- 2023
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In: Nature Communications. - 2041-1723. ; 14
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Journal article (peer-reviewed)abstract
- Seasons impose different selection pressures on organisms through contrasting environmental conditions. How such seasonal evolutionary conflict is resolved in organisms whose lives span across seasons remains underexplored. Through field experiments, laboratory work, and citizen science data analyses, we investigate this question using two closely related butterflies (Pieris rapae and P. napi). Superficially, the two butterflies appear highly ecologically similar. Yet, the citizen science data reveal that their fitness is partitioned differently across seasons. Pieris rapae have higher population growth during the summer season but lower overwintering success than do P. napi. We show that these differences correspond to the physiology and behavior of the butterflies. Pieris rapae outperform P. napi at high temperatures in several growth season traits, reflected in microclimate choice by ovipositing wild females. Instead, P. rapae have higher winter mortality than do P. napi. We conclude that the difference in population dynamics between the two butterflies is driven by seasonal specialization, manifested as strategies that maximize gains during growth seasons and minimize harm during adverse seasons, respectively.
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| 10. |
- von Schmalensee, Loke, 1990-
(author)
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Temperature variation in time and space, and its effects on insects
- 2023
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Doctoral thesis (other academic/artistic)abstract
- Nature is variable. Unfortunately, compressed representations of this variable world, like averages, are often lossy and insufficient for ecological purposes. This is particularly true for temperature variation, which organisms typically respond to in a nonlinear way. As biologists, we must therefore be careful to study temperature variation at the appropriate scales, and assess its consequences in the right biological contexts.In this dissertation, I tackle the interplay between temperature variation, seasonality, and life histories of insects, primarily focusing on Pieris butterflies. In Chapter I, I demonstrate that insect development times in naturally fluctuating settings can be accurately predicted using thermal performance curves established under constant settings. However, this accuracy is contingent upon the incorporation of environmental temperature data high-resolved in both time and space. My work in Chapter II investigates the divergent seasonal population dynamics exhibited by Pieris rapae and P. napi, two closely related and ecologically similar butterflies. The species’ differences in season-specific success correlate with distinct thermal adaptations, and delineate P. rapae and P. napi into the roles of summer and winter specialists, respectively. We hypothesize that warm-adapted summer specialists will be favored by climate warming, but that cold-tolerant winter specialists will find refuge in places with very short growth seasons. In Chapter III, a comprehensive examination spanning a 750 km latitudinal cline unveils discernible latitude-specific photoperiodic reaction norms in P. napi, yet an absence of parallel trends in their thermal responses. We argue that, in seasonal environments, the reliability of photoperiodic cues and the clear link between photoperiodism and fitness make photoperiodic responses evolve more readily than temperature responses. In Chapter IV, I integrate principles from signal processing into thermal ecology. I show that relatively sparse temperature time-series can be effectively interpolated using well-known signal processing techniques, improving the accuracy of ecological predictions.The Earth is warmer now than it was just a century ago, and will likely keep facing drastic temperature changes in the near future. This will have complex downstream effects on living organisms all over the world. As a concluding remark, I would therefore like to emphasize the importance of a nuanced perspective on the consequences of temperature variation in nature.
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