| 1. |
- Bolmgren, Kjell, 1966-
(author)
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Adaptation and Constraint in the Plant Reproductive Phase
- 2004
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Doctoral thesis (other academic/artistic)abstract
- Conservatism is a central theme of organismic evolution. Related species share characteristics due to their common ancestry. Some concern have been raised among evolutionary biologists, whether such conservatism is an expression of natural selection or of a constrained ability to adapt.This thesis explores adaptations and constraints within the plant reproductive phase, particularly in relation to the evolution of fleshy fruit types (berries, drupes, etc.) and the seasonal timing of flowering and fruiting. The different studies were arranged along a hierarchy of scale, with general data sets sampled among seed plants at the global scale, through more specific analyses of character evolution within the genus Rhamnus s.l. L. (Rhamnaceae), to descriptive and experimental field studies in a local population of Frangula alnus (Rhamnaceae). Apart from the field study, this thesis is mainly based on comparative methods explicitly incorporating phylogenetic relationships. The comparative study of Rhamnus s.l. species included the reconstruction of phylogenetic hypotheses based on DNA sequences.Among geographically overlapping sister clades, biotic pollination was not correlated with higher species richness when compared to wind pollinated plants. Among woody plants, clades characterized by fleshy fruit types were more species rich than their dry-fruited sister clades, suggesting that the fleshy fruit is a key innovation in woody habitats. Moreover, evolution of fleshy fruits was correlated with a change to more closed (darker) habitats.An independent contrast study within Rhamnus s.l. documented allometric relations between plant and fruit size. As a phylogenetic constraint, allometric effects must be considered weak or non-existent, though, as they did not prevail among different subclades within Rhamnus s.l. Fruit size was correlated with seed size and seed number in F. alnus. This thesis suggests that frugivore selection on fleshy fruit may be important by constraining the upper limits of fruit size, when a plant lineage is colonizing (darker) habitats where larger seed size is adaptive.Phenological correlations with fruit set, dispersal, and seed size in F. alnus, suggested that the evolution of reproductive phenology is constrained by trade-offs and partial interdependences between flowering, fruiting, dispersal, and recruitment phases. Phylogenetic constraints on the evolution of phenology were indicated by a lack of correlation between flowering time and seasonal length within Rhamnus cathartica and F. alnus, respectively. On the other hand, flowering time was correlated with seasonal length among Rhamnus s.l. species. Phenological differences between biotically and wind pollinated angiosperms also suggested adaptive change in reproductive phenology.
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| 2. |
- Bolmgren, Kjell, et al.
(author)
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Are mismatches the norm? Timing of flowering, fruiting, dispersal and germination and their fitness effects in Frangula alnus (Rhamnaceae)
- 2015
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In: Oikos. - : Wiley. - 0030-1299 .- 1600-0706. ; 124, s. 639-648
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Journal article (peer-reviewed)abstract
- The close morphological and temporal links between phases of plant growth and reproduction call for integrated studies incorporating several reproductive phases from flowering to recruitment, and associated plant-animal interactions. Phenological strategies, as well as plastic phenological response to climate change, incorporate complex interactions between developmental constraints, pollination and seed dispersal. Relationships between reproductive phenology and components of fitness were studied for two years in the north-temperate, self-incompatible, insect-pollinated, and bird-dispersed shrub Frangula alnus (Rhamnaceae). Fruit set, dispersal, germination and juvenile survival, as well as seed mass and juvenile size were measured in relation to flowering, fruiting and germination time. The results suggest that effects of flowering and fruiting time prevailed in subsequent phases, to some extent as far as to the juvenile phase, but effects of timing were complex and had partly opposing effects on different fitness components. Early flowers had higher fruit-set and experiments indicated that synchronous peak flowering increased fruit-set, but later flowers had higher seed mass. Peak fruiting was not associated with peak dispersal. Late fruits derived from late flowers promoted dispersal. Juvenile recruitment was enhanced by increasing seed size. We conclude that the phenology of flowering and fruiting in F. alnus comprises several features, each with different and sometimes counteracting effects on fitness components. From a general perspective, this result implies that we should not expect to find finely tuned matches in timing specifically between flowering and pollinators, and fruiting and seed dispersing birds.
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| 3. |
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| 4. |
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| 5. |
- Bolmgren, Kjell
(author)
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Digitization protocol for scoring reproductive phenology from herbarium specimens of seed plants
- 2018
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In: Applications in plant sciences. - : Wiley. - 2168-0450. ; 6
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Journal article (peer-reviewed)abstract
- PREMISE OF THE STUDY: Herbarium specimens provide a robust record of historical plant phenology (the timing of seasonal events such as flowering or fruiting). However, the difficulty of aggregating phenological data from specimens arises from a lack of standardized scoring methods and definitions for phenological states across the collections community.METHODS AND RESULTS: To address this problem, we report on a consensus reached by an iDigBio working group of curators, researchers, and data standards experts regarding an efficient scoring protocol and a data-sharing protocol for reproductive traits available from herbarium specimens of seed plants. The phenological data sets generated can be shared via Darwin Core Archives using the Extended MeasurementOrFact extension.CONCLUSIONS: Our hope is that curators and others interested in collecting phenological trait data from specimens will use the recommendations presented here in current and future scoring efforts. New tools for scoring specimens are reviewed.
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| 6. |
- Bolmgren, Kjell, et al.
(author)
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Fleshy fruits – origins, niche shifts, and diversification.
- 2005
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In: Oikos. - : Wiley. - 0030-1299 .- 1600-0706. ; 109:2, s. 255-272
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Journal article (peer-reviewed)abstract
- We examined shifts in fruit type, fleshy vs non-fleshy, in relation to habitat-related niche shifts, species richness, and historical distribution, in 50 phylogenetically independent plant lineages. Each lineage consisted of a sister-group pair of fleshy vs non-fleshy taxa and their outgroup. Niche shifts were assessed based on plant community characteristics. Two niche dimensions assumed to reflect community dynamics were derived: spatial predictability of disturbances and canopy closure. Phylogenetically independent origins of fleshy fruit types (1) were correlated with changes to habitats characterized by more shaded and spatially more unpredictable disturbances, (2) had an opposite effect on species richness in woody and herbaceous clades, enhancing species richness in woody clades, and (3) were continuously distributed over a period covering the last 70 million years. These results support the hypothesis that fleshy fruit evolution is driven by vegetation dynamics, and suggest that the strength of frugivore mediated selection on fleshy fruits increases when recruitment sites are spatially unpredictable and/or characterized by low light conditions.
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| 7. |
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| 8. |
- Bolmgren, Kjell, et al.
(author)
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Generic limits in Rhamnus s.l. L. (Rhamnaceae) inferred from nuclear and chloroplast DNA sequence phylogenies.
- 2004
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In: Taxon. - : International Association for Plant Taxonomy. - 0040-0262 .- 1996-8175. ; 53:2, s. 383-390
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Journal article (peer-reviewed)abstract
- This study tested the monophyly of the previously proposed genera Alaternus, Frangula, Oreoherzogia, and Rhamnus s.str., and the phylogenetic relations suggested by Grubov (1949), within the Rhamnus s.l. clade.Based on a global sample of 22 species, we derived phylogenetic hypotheses using parsimony analysis of variation in trnL-F (chloroplast) and ITS (nuclear) DNA regions. Both Alaternus, Frangula, and Oreoherzogia gained strong support, and our results further support recognition of Frangula as a monophyletic genus. The resolution between Alaternus, Oreoherzogia, and the rest of Rhamnus s.str. was less clear, and the mainly Mediterranean Oreoherzogia was strongly grouped with the American R. crocea. Therefore, we consider it as unjustified to split the rest of Rhamnus into smaller genera. Regarding Grubov's phylogenetic hypothesis, our study could only support the dichotomy between Frangula and the rest of Rhamnus.
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| 9. |
- Bolmgren, Kjell, et al.
(author)
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One man, 73 years, and 25 species. Evaluating phenological responses using a lifelong study of first flowering dates
- 2013
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In: International journal of biometeorology. - : Springer Science and Business Media LLC. - 0020-7128 .- 1432-1254. ; 57:3, s. 367-375
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Journal article (peer-reviewed)abstract
- Phenological shifts linked to global warming reflect the ability of organisms to track changing climatic conditions. However, different organisms track global warming differently and there is an increasing interest in the link between phenological traits and plant abundance and distribution. Long-term data sets are often used to estimate phenological traits to climate change, but so far little has been done to evaluate the quality of these estimates. Here, we use a 73-year long data series of first flowering dates for 25 species from north-temperate Sweden to evaluate (i) correlations between first flowering dates and year for different time periods and (ii) linear regression models between first flowering date and mean monthly temperatures in preceding months. Furthermore, we evaluate the potential of this kind of data to estimate the phenological temperature sensitivities (i.e. number of days phenological change per degree temperature change, beta(60)) in such models. The sign of the correlations between first flowering dates and year were highly inconsistent among different time periods, highlighting that estimates of phenological change are sensitive to the specific time period used. The first flowering dates of all species were correlated with temperature, but with large differences in both the strength of the response and the period(s) of the year that were most strongly associated with phenological variation. Finally, our analyses indicated that legacy data sets need to be relatively long-term to be useful for estimating phenological temperature sensitivities (beta(60)) for inter-specific comparisons. In 10-year long observation series only one out of 24 species reached a parts per thousand yen80 % probability of estimating temperature sensitivity (beta(60)) within a +/- 1 range, and 17 out of 24 species reached a parts per thousand yen80 % probability when observation series were 20 years or shorter. The standard error for beta(60) ranged from 0.6 to 2.0 for 10-year long observation series, and 19 out of 24 species reached SE < 1 after 15 years. In general, late flowering species will require longer time series than early flowering species.
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| 10. |
- Bolmgren, Kjell
(author)
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Pan European Phenological database (PEP725): a single point of access for European data
- 2018
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In: International Journal of Biometeorology. - : Springer Science and Business Media LLC. - 0020-7128 .- 1432-1254. ; 62, s. 1109-1113
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Journal article (peer-reviewed)abstract
- The Pan European Phenology (PEP) project is a European infrastructure to promote and facilitate phenological research, education, and environmental monitoring. The main objective is to maintain and develop a Pan European Phenological database (PEP725) with an open, unrestricted data access for science and education. PEP725 is the successor of the database developed through the COST action 725 "Establishing a European phenological data platform for climatological applications" working as a single access point for European-wide plant phenological data. So far, 32 European meteorological services and project partners from across Europe have joined and supplied data collected by volunteers from 1868 to the present for the PEP725 database. Most of the partners actively provide data on a regular basis. The database presently holds almost 12 million records, about 46 growing stages and 265 plant species (including cultivars), and can be accessed via . Users of the PEP725 database have studied a diversity of topics ranging from climate change impact, plant physiological question, phenological modeling, and remote sensing of vegetation to ecosystem productivity.
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| 11. |
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| 12. |
- Bolmgren, Kjell, et al.
(author)
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Seed mass and the evolution of fleshy fruits in angiosperms
- 2010
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In: Oikos. - : Wiley. - 0030-1299 .- 1600-0706. ; 119:4, s. 707-718
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Research review (peer-reviewed)abstract
- Fleshy fruits, like drupes and berries, have evolved many times through angiosperm history. Two hypotheses suggest that fleshy fruit evolution is related to changes in the seed mass fitness landscape. The reduced dispersal capability following from an increase in seed mass may be counterbalanced by evolution of traits mediating seed dispersal by animals, such as fleshy fruits. Alternatively, increasing availability and capabilities of frugivores promote evolution of fleshy fruits and allow an increase in seed size. Both these hypotheses predict an association between evolution of fleshy fruits and increasing seed size. We investigated patterns of fruit and seed evolution by contrasting seed mass between fleshy and non-fleshy fruited sister clades. We found a consistent association between possession of fleshy fruits and heavier seeds. The direction of fruit type change did not alter this pattern; seed mass was higher in clades where fleshy fruits evolved and lower in clades where non-fleshy fruits evolved, as compared to their sister clades. These patterns are congruent with the predictions from the two hypotheses, but other evidence is needed to distinguish between them. We emphasize the need to integrate studies of seed disperser effectiveness, seed morphology, and plant recruitment success to better understand the frugivores' role in fleshy fruit evolution.
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| 13. |
- Bolmgren, Kjell
(author)
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The Plant Phenology Ontology: A New Informatics Resource for Large-Scale Integration of Plant Phenology Data
- 2018
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In: Frontiers in Plant Science. - : Frontiers Media SA. - 1664-462X. ; 9
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Journal article (peer-reviewed)abstract
- Plant phenology - the timing of plant life-cycle events, such as flowering or leafing out - plays a fundamental role in the functioning of terrestrial ecosystems, including human agricultural systems. Because plant phenology is often linked with climatic variables, there is widespread interest in developing a deeper understanding of global plant phenology patterns and trends. Although phenology data from around the world are currently available, truly global analyses of plant phenology have so far been difficult because the organizations producing large-scale phenology data are using non-standardized terminologies and metrics during data collection and data processing. To address this problem, we have developed the Plant Phenology Ontology (PPO). The PPO provides the standardized vocabulary and semantic framework that is needed for large-scale integration of heterogeneous plant phenology data. Here, we describe the PPO, and we also report preliminary results of using the PPO and a new data processing pipeline to build a large dataset of phenology information from North America and Europe.
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| 14. |
- Bolmgren, Kjell, et al.
(author)
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Time – size tradeoffs: a phylogenetic comparative study of flowering time, plant height and seed mass in a north-temperate flora
- 2008
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In: Oikos. - : Wiley. - 0030-1299 .- 1600-0706. ; 117:3, s. 424-429
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Journal article (peer-reviewed)abstract
- Parents face a timing problem as to when they should begin devoting resources from their own growth and survival to mating and offspring development. Seed mass and number, as well as maternal survival via plant size, are dependent on time for development. The time available in the favorable season will also affect the size of the developing juveniles and their survival through the unfavorable season. Flowering time may thus represent the outcome of such a time partitioning problem. We analyzed correlations between flowering onset time, seed mass, and plant height in a north-temperate flora, using both cross-species comparisons and phylogenetic comparative methods. Among perennial herbs, flowering onset time was negatively correlated with seed mass (i.e. plants with larger seeds started flowering earlier) while flowering onset time was positively correlated with plant height. Neither of these correlations was found among woody plants. Among annual plants, flowering onset time was positively correlated with seed mass. Cross-species and phylogenetically informed analyses largely agreed, except that flowering onset time was also positively correlated with plant height among annuals in the cross-species analysis. The different signs of the correlations between flowering onset time and seed mass (compar. gee regression coefficient=−7.8) and flowering onset time and plant height (compar. gee regression coefficient=+30.5) for perennial herbs, indicate that the duration of the growth season may underlie a tradeoff between maternal size and offspring size in perennial herbs, and we discuss how the partitioning of the season between parents and offspring may explain the association between early flowering and larger seed mass among these plants.
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| 15. |
- Bolmgren, Kjell, et al.
(author)
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Vårtecken i samhällets tjänst.
- 2010
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In: Svensk Botanisk Tidskrift. ; 104, s. 45-51
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Journal article (other academic/artistic)
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| 16. |
- Cook, Benjamin I., et al.
(author)
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Sensitivity of Spring Phenology to Warming Across Temporal and Spatial Climate Gradients in Two Independent Databases
- 2012
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In: Ecosystems. - : Springer Science and Business Media LLC. - 1432-9840 .- 1435-0629. ; 15:8, s. 1283-1294
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Journal article (peer-reviewed)abstract
- Disparate ecological datasets are often organized into databases post hoc and then analyzed and interpreted in ways that may diverge from the purposes of the original data collections. Few studies, however, have attempted to quantify how biases inherent in these data (for example, species richness, replication, climate) affect their suitability for addressing broad scientific questions, especially in under-represented systems (for example, deserts, tropical forests) and wild communities. Here, we quantitatively compare the sensitivity of species first flowering and leafing dates to spring warmth in two phenological databases from the Northern Hemisphere. One-PEP725-has high replication within and across sites, but has low species diversity and spans a limited climate gradient. The other-NECTAR-includes many more species and a wider range of climates, but has fewer sites and low replication of species across sites. PEP725, despite low species diversity and relatively low seasonality, accurately captures the magnitude and seasonality of warming responses at climatically similar NECTAR sites, with most species showing earlier phenological events in response to warming. In NECTAR, the prevalence of temperature responders significantly declines with increasing mean annual temperature, a pattern that cannot be detected across the limited climate gradient spanned by the PEP725 flowering and leafing data. Our results showcase broad areas of agreement between the two databases, despite significant differences in species richness and geographic coverage, while also noting areas where including data across broader climate gradients may provide added value. Such comparisons help to identify gaps in our observations and knowledge base that can be addressed by ongoing monitoring and research efforts. Resolving these issues will be critical for improving predictions in understudied and under-sampled systems outside of the temperature seasonal mid-latitudes.
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| 17. |
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| 18. |
- Davies, T. Jonathan, et al.
(author)
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Phylogenetic conservatism in plant phenology
- 2013
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In: Journal of Ecology. - : Wiley. - 1365-2745 .- 0022-0477. ; 101:6, s. 1520-1530
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Journal article (peer-reviewed)abstract
- Phenological events - defined points in the life cycle of a plant or animal - have been regarded as highly plastic traits, reflecting flexible responses to various environmental cues. The ability of a species to track, via shifts in phenological events, the abiotic environment through time might dictate its vulnerability to future climate change. Understanding the predictors and drivers of phenological change is therefore critical. Here, we evaluated evidence for phylogenetic conservatism - the tendency for closely related species to share similar ecological and biological attributes - in phenological traits across flowering plants. We aggregated published and unpublished data on timing of first flower and first leaf, encompassing 4000 species at 23 sites across the Northern Hemisphere. We reconstructed the phylogeny for the set of included species, first, using the software program Phylomatic, and second, from DNA data. We then quantified phylogenetic conservatism in plant phenology within and across sites. We show that more closely related species tend to flower and leaf at similar times. By contrasting mean flowering times within and across sites, however, we illustrate that it is not the time of year that is conserved, but rather the phenological responses to a common set of abiotic cues. Our findings suggest that species cannot be treated as statistically independent when modelling phenological responses.Synthesis. Closely related species tend to resemble each other in the timing of their life-history events, a likely product of evolutionarily conserved responses to environmental cues. The search for the underlying drivers of phenology must therefore account for species' shared evolutionary histories.
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| 19. |
- Ekholm, Adam, et al.
(author)
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The forgotten season : the impact of autumn phenology on a specialist insect herbivore community on oak
- 2019
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In: Ecological Entomology. - : Wiley. - 0307-6946 .- 1365-2311. ; 44:3, s. 425-435
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Journal article (peer-reviewed)abstract
- 1. Variation in spring phenology - like tree budburst - affects the structure of insect communities, but impacts of autumn phenology have been neglected. Many plant species have recently delayed their autumn phenology, and the timing of leaf senescence may be important for herbivorous insects.2. This study explored how an insect herbivore community associated with Quercus robur is influenced by variation in autumn phenology. For this, schools were asked to record, across the range of oak in Sweden, the autumn phenology of oaks and to conduct a survey of the insect community.3. To tease apart the relative impacts of climate from that of tree phenology, regional tree phenology was first modelled as a function of regional climate, and the tree-specific deviation from this relationship was then used as the metric of relative tree-specific phenology.4. At the regional scale, a warmer climate postponed oak leaf senescence. This was also reflected in the insect herbivore community: six out of 15 taxa occurred at a higher incidence and five out of 18 taxa were more abundant, in locations with a warmerclimate. Similarly, taxonomic richness and herbivory were higher in warmer locations.5. Trees with a relatively late autumn phenology had higher abundances of leaf miners (Phyllonorycter spp.). This caused lower community diversity and evenness on trees with later autumn phenology.6. The findings of the present study illustrate that both regional climate-driven patterns and local variation in oak autumn phenology contribute to shaping the insect herbivore community. Community patterns may thus shift with a changing climate.
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| 20. |
- Eriksson, Ove, et al.
(author)
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Historic hay cutting dates from Sweden 1873-1951 and their implications for conservation management of species-rich meadows
- 2015
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In: Biological Conservation. - : Elsevier BV. - 0006-3207 .- 1873-2917. ; 184, s. 100-107
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Journal article (peer-reviewed)abstract
- Semi-natural hay meadows are species rich habitats, formed by a long history of management and they have experienced a drastic decline all over Europe. There is a vast literature on conservation and species diversity of semi-natural hay-meadows, but very limited information on historic timing of hay cutting. We analyzed data collected between 1873 and 1951 on hay cutting dates and phenology of six plant species from farms distributed across Sweden. The data set comprised 16,015 observations from 175 sites. Results show that date of start and end of hay cutting varied across Sweden. The start of hay cutting was generally delayed by 2.2 days per latitudinal degree and 1.5 days per 100 m altitude, while the end of hay cutting was generally delayed by 2.9 days per latitudinal degree and 2.5 days per 100 m altitude. The average hay cutting period was 18.5 +/- 6.6 days, and became slightly shorter northwards. Site-specific factors had a great impact on when hay cutting was performed, as indicated by a significant correlation between flowering (and leafing) phenology in other species and start date of hay cutting. Today, management for conservation is usually related to a calendar date (e.g. regulated in eligibility criteria and requirements for payment in agri-environment programs in EU). In order to mimic historic management that formed this habitat, management should instead account for latitude and altitude, between-year variation in timing of hay cutting, variation in both start and end dates of hay cutting and if possible local phenological conditions.
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| 21. |
- Freitas, Leandro, et al.
(author)
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Synchrony is more than overlap: measuring phenological synchronization considering time length and intensity
- 2008
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In: Revista Brasileira de Botânica. - 0100-8404. ; 31, s. 721-724
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Journal article (peer-reviewed)abstract
- Synchrony is more than overlap: measuring phenological synchronization considering time length andintensity). The degree of flowering and fruiting synchronization is believed to have ecological and evolutionary relevance atseveral scales. Here we discuss some measures that have been used to estimate synchrony and propose an index that incorporatesboth the entire length of an individual phenophase and variation in the number of flowers or fruits over that time period.This new index describes more accurately the phenological synchrony among individuals and populations.
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| 22. |
- Hassel, Linda, et al.
(author)
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Naturens kalender : Förslag till ny miljöövervakning och nya miljömålsindikatorer
- 2013
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Reports (other academic/artistic)abstract
- ”Naturens kalender” är ett projekt som syftar till att följa hur klimatförändringen påverkar grundläggande ekosystemegenskaper och ekosystemtjänster. Genom att bygga upp ett regionalt nätverk av frivilliga fenologiväktare, som gör observationer av utvalda växtarter lövsprickning, blomning, fruktmognad och höstlöv, kan förändringar i naturen följas på regional skala, förändringar som i första hand kan härledas till ett allt varmare klimat.Projektet är en fortsättning av ett projekt som ursprungligen startades i Jönköpings län 2009. Redan i urspungsprojektet fanns tankar kring hur verksamheten skulle kunna växa vidare. Ett viktigt steg var då att skapa en miljömålsindikator för miljömålen ”Begränsad klimatpåverkan”, ”Ett rikt växt- och djurliv” och ”Frisk luft”.För att kunna få regional upplösning av miljömålsindikatorerna krävs regionala nätverk av fenologiväktare. Projektet har tagit fram förslag på hur dessa kan byggas upp och integreras i miljöövervakning. Totalt sett behöver en länskoordinator ca 80 arbetstimmar för att bygga upp verksamheten och 40 timmar för att driva den årligen. I förslaget ingår också en årlig kostnad om ca 40 arbetstimmar för den nationella koordinatorn, för att denna ska kunna bistå i det regionala rekryterings- och utvecklingsarbetet.De befintliga regionala nätverken är baserade på samverkan mellan enstaka professionella observatörer (så som naturum, forskningsstationer eller botaniska trädgårdar) och en större grupp frivilliga så kallade fenologiväktare. Frivilliginsatserna ger fördelar i och med ett större engagemang för ämnet och en större geografisk spridning av inrapporterade data än vad som hade varit möjligt om enbart professionella stationer används. Nackdelen med ett frivilligbaserat nätverk är osäkerheten kring hur långsiktig verksamheten kan bli. En förutsättning för frivilligbaserade system är en aktiv rekryteringsverksamhet och effektiv återkoppling, samt att den statistiska analysen av insamlade data utgår från osäkerhetsfaktorerna. Naturvårdsverket har uttalat sitt stöd för uppbyggnaden av detta system där frivilliga och professionella samverkar, och lämnat återkommande bidrag till utveckling- och rekryteringsverksamheten. SLU:s fortlöpande miljöanalys har å sin sida finansierat den nationella samordnaren sedan 2010 och uttryckt en långsiktig ambition att fortsätta med detta. En länskoordinator, som samverkar med den nationella samordnaren, är viktig för att upprätthålla nätverken även på sikt. Länskoordinatorn har möjlighet att hålla god personlig kontakt med de frivilliga och ordna möten som inspirerar dem att fortsätta över längre perioder. Att fenologidata kommer att ligga till grund för en miljömålsindikator är i sig en motiverande faktor som borgar för en långsiktighet i verksamheten från statligt håll och som bidrar till de frivilligas motivation.När det nationella nätverket, kompletterat med de förtätade regionala, finns på plats finns möjlighet att gå vidare med arbetet att ta fram miljömålsindikatorer baserat på fenologiverksamheten. I projektet har vi tagit fram förslag på sammanlagt sju olika indikatorer till de ovan nämnda miljömålen. Indikatorerna baseras på arter med en stor biologisk eller symbolisk betydelse och har valts för att de förekommer i större delen av landet och är utspridda över vegetationsperioden. Data föreslås att hämtas dels från Svenska fenologinätverket, dels från Pollenlaboratorierna.Projektet är ett samarbetsprojekt mellan länsstyrelserna i Jönköping, Skåne, Örebro och Västerbottens län, samt Svenska fenologinätverket. Svenska fenologinätverket (SWE-NPN) är ett samarbete mellan universitet (GU, LU, SLU, SU), myndigheter (NV, SMHI, Lst), muséer (NRM) och frivilliga. Sveriges lantbruksuniversitet är huvudman för (SWE-NPN).
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| 23. |
- Jin, Hongxiao, et al.
(author)
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Disentangling remotely-sensed plant phenology and snow seasonality at northern Europe using MODIS and the plant phenology index
- 2017
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In: Remote Sensing of Environment. - : Elsevier BV. - 0034-4257 .- 1879-0704. ; 198, s. 203-212
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Journal article (peer-reviewed)abstract
- Land surface phenology is frequently derived from remotely sensed data. However, over regions with seasonal snow cover, remotely-sensed land surface phenology may be dominated by snow seasonality, rather than showing true plant phenology. Overlooking snow influences may lead to inaccurate plant phenology estimation, and consequently to misinterpretation of climate-vegetation interactions. To address the problem we apply the recently developed plant phenology index (PPI) to Moderate Resolution Imaging Spectroradiometer (MODIS) data for estimating plant phenology metrics over northern Europe. We compare PPI-derived start and end of the growing season with ground observations by professionals (6 sites) and nonprofessional citizens (378 sites), with phenology metrics derived from gross primary productivity (GPP, 18 sites), and with data on the timing of snow cover. These data are also compared with land surface phenology metrics derived from the normalized difference vegetation index (NDVI) using the same MODIS data. We find that the PPI-retrieved plant phenology agrees with ground observations and GPP-derived phenology, and that the NDVI-derived phenology to a large extent agrees with the end-of-snowmelt for the start-of-season and the start-of-snowing for the end-of-season. PPI is thereby useful for more accurate estimation of plant phenology from remotely sensed data over northern Europe and other regions with seasonal snow cover.
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| 24. |
- Johansson, Jacob, et al.
(author)
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Climate change and the optimal flowering time of annual plants in seasonal environments
- 2013
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In: Global Change Biology. - : Wiley. - 1354-1013 .- 1365-2486. ; 19:1, s. 197-207
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Journal article (peer-reviewed)abstract
- Long-term phenology monitoring has documented numerous examples of changing flowering dates during the last century. A pivotal question is whether these phenological responses are adaptive or not under directionally changing climatic conditions. We use a classic dynamic growth model for annual plants, based on optimal control theory, to find the fitness-maximizing flowering time, defined as the switching time from vegetative to reproductive growth. In a typical scenario of global warming, with advanced growing season and increased productivity, optimal flowering time advances less than the start of the growing season. Interestingly, increased temporal spread in production over the season may either advance or delay the optimal flowering time depending on overall productivity or season length. We identify situations where large phenological changes are necessary for flowering time to remain optimal. Such changes also indicate changed selection pressures. In other situations, the model predicts advanced phenology on a calendar scale, but no selection for early flowering in relation to the start of the season. We also show that the optimum is more sensitive to increased productivity when productivity is low than when productivity is high. All our results are derived using a general, graphical method to calculate the optimal flowering time applicable for a large range of shapes of the seasonal production curve. The model can thus explain apparent maladaptation in phenological responses in a multitude of scenarios of climate change. We conclude that taking energy allocation trade-offs and appropriate time scales into account is critical when interpreting phenological patterns.
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| 25. |
- Johansson, Jacob, et al.
(author)
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Is timing of reproduction according to temperature sums an optimal strategy?
- 2019
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In: Ecology and Evolution. - : Wiley. - 2045-7758. ; 9:20, s. 11598-11605
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Journal article (peer-reviewed)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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| 26. |
- Kharouba, Heather M., et al.
(author)
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Global shifts in the phenological synchrony of species interactions over recent decades
- 2018
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In: Proceedings of the National Academy of Sciences of the United States of America. - : Proceedings of the National Academy of Sciences. - 0027-8424 .- 1091-6490. ; 115:20, s. 5211-5216
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Journal article (peer-reviewed)abstract
- Phenological responses to climate change (e.g., earlier leaf-out or egg hatch date) are now well documented and clearly linked to rising temperatures in recent decades. Such shifts in the phenologies of interacting species may lead to shifts in their synchrony, with cascading community and ecosystem consequences. To date, single-system studies have provided no clear picture, either finding synchrony shifts may be extremely prevalent [Mayor SJ, et al. (2017) Sci Rep 7:1902] or relatively uncommon [Iler AM, et al. (2013) Glob Chang Biol 19:2348-2359], suggesting that shifts toward asynchrony may be infrequent. A meta-analytic approach would provide insights into global trends and how they are linked to climate change. We compared phenological shifts among pairwise species interactions (e.g., predator-prey) using published long-term time-series data of phenological events from aquatic and terrestrial ecosystems across four continents since 1951 to determine whether recent climate change has led to overall shifts in synchrony. We show that the relative timing of key life cycle events of interacting species has changed significantly over the past 35 years. Further, by comparing the period before major climate change (pre-1980s) and after, we show that estimated changes in phenology and synchrony are greater in recent decades. However, there has been no consistent trend in the direction of these changes. Our findings show that there have been shifts in the timing of interacting species in recent decades; the next challenges are to improve our ability to predict the direction of change and understand the full consequences for communities and ecosystems.
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| 27. |
- Kullberg, Cecilia, et al.
(author)
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Change in spring arrival of migratory birds under an era of climate change, Swedish data from the last 140 years
- 2015
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In: Ambio. - : Springer Science and Business Media LLC. - 0044-7447 .- 1654-7209. ; 44, s. S69-S77
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Journal article (peer-reviewed)abstract
- Many migratory bird species have advanced their spring arrival during the latest decades, most probably due to climate change. However, studies on migratory phenology in the period before recent global warming are scarce. We have analyzed a historical dataset (1873-1917) of spring arrival to southern and central Sweden of 14 migratory bird species. In addition, we have used relative differences between historical and present-day observations (1984-2013) to evaluate the effect of latitude and migratory strategy on day of arrival over time. There was a larger change in spring phenology in short-distance migrants than in long-distance migrants. Interestingly, the results further suggest that climate change has affected the phenology of short-distance migrants more in southern than in central Sweden. The results suggest that the much earlier calculated arrival to southern Sweden among short-distance migrants mirrors a change in location of wintering areas, hence, connecting migration phenology and wintering range shifts.
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| 28. |
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| 29. |
- Lessard-Therrien, Malie, et al.
(author)
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A phylogenetic comparative study of flowering phenology along an elevational gradient in the Canadian subarctic
- 2014
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In: International journal of biometeorology. - : Springer Science and Business Media LLC. - 0020-7128 .- 1432-1254. ; 58:4, s. 455-462
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Journal article (peer-reviewed)abstract
- Climate change is affecting high-altitude and high-latitude communities in significant ways. In the short growing season of subarctic habitats, it is essential that the timing and duration of phenological phases match favorable environmental conditions. We explored the time of the first appearance of flowers (first flowering day, FFD) and flowering duration across subarctic species composing different communities, from boreal forest to tundra, along an elevational gradient (600-800 m). The study was conducted on Mount Irony (856 m), North-East Canada (54A degrees 90'N, 67A degrees 16'W) during summer 2012. First, we quantified phylogenetic signal in FFD at different spatial scales. Second, we used phylogenetic comparative methods to explore the relationship between FFD, flowering duration, and elevation. We found that the phylogenetic signal for FFD was stronger at finer spatial scales and at lower elevations, indicating that closely related species tend to flower at similar times when the local environment is less harsh. The comparatively weaker phylogenetic signal at higher elevation may be indicative of convergent evolution for FFD. Flowering duration was correlated significantly with mean FFD, with later-flowering species having a longer flowering duration, but only at the lowest elevation. Our results indicate significant evolutionary conservatism in responses to phenological cues, but high phenotypic plasticity in flowering times. We suggest that phylogenetic relationships should be considered in the search for predictions and drivers of flowering time in comparative analyses, because species cannot be considered as statistically independent. Further, phenological drivers should be measured at spatial scales such that variation in flowering matches variation in environment.
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| 30. |
- Lessard-Therrien, Malie, et al.
(author)
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Predicting flowering phenology in a subarctic plant community
- 2014
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In: Botany. - : Canadian Science Publishing. - 1916-2790 .- 1916-2804. ; 92:10, s. 749-756
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Journal article (peer-reviewed)abstract
- Phenological studies are rarely reported from arctic and subarctic regions, but are essential to evaluate species' response to climate change in these rapidly warming ecosystems. Here, we present a phylogenetic analysis of flowering phenology across an elevational gradient in the Canadian subarctic. We found that the timing of first flower was best explained by a combination of snowmelt, elevation, and growing degree-days. We also show that early flowering species have demonstrated lower intraspecific variability in their response to climate cues in comparison with late flowering species, such that individual flowering times of early species are more closely tied to environmental predictors. Previous work has suggested that early flowering species are more variable in their phenology. However, these studies have mostly examined variation in phenology over time, whereas we examined variation in phenology over space. We suggest that both patterns can be explained by the tighter coupling between phenology and climate cues for early flowering species. Thus, early flowering species have low intraspecific variance in flowering times within a single growing season as individuals respond more uniformly to a common set of cues in comparison with late flowering species. However, these same species may show large variance between years reflecting interannual variation in climate.
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| 31. |
- Lindh, Magnus, 1973-, et al.
(author)
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Constrained growth flips the direction of optimal phenological responses among annual plants
- 2016
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In: New Phytologist. - : Wiley-Blackwell. - 0028-646X .- 1469-8137. ; 209:4, s. 1591-1599
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Journal article (peer-reviewed)abstract
- Phenological changes among plants due to climate change are well documented, but often hard to interpret. In order to assess the adaptive value of observed changes, we study how annual plants with and without growth constraints should optimize their flowering time when productivity and season length changes. We consider growth constraints that depend on the plant's vegetative mass: self-shading, costs for nonphotosynthetic structural tissue and sibling competition. We derive the optimal flowering time from a dynamic energy allocation model using optimal control theory. We prove that an immediate switch (bang-bang control) from vegetative to reproductive growth is optimal with constrained growth and constant mortality. Increasing mean productivity, while keeping season length constant and growth unconstrained, delayed the optimal flowering time. When growth was constrained and productivity was relatively high, the optimal flowering time advanced instead. When the growth season was extended equally at both ends, the optimal flowering time was advanced under constrained growth and delayed under unconstrained growth. Our results suggests that growth constraints are key factors to consider when interpreting phenological flowering responses. It can help to explain phenological patterns along productivity gradients, and links empirical observations made on calendar scales with life-history theory.
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| 32. |
- MacDougall, Andrew S., et al.
(author)
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Comparison of the distribution and phenology of Arctic Mountain plants between the early 20th and 21st centuries
- 2021
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In: Global Change Biology. - : John Wiley & Sons. - 1354-1013 .- 1365-2486. ; 27:20, s. 5070-5083
-
Journal article (peer-reviewed)abstract
- Arctic plants are adapted to climatic variability, but their long-term responses to warming remain unclear. Responses may occur by range shifts, phenological adjustments in growth and reproduction, or both. Here, we compare distribution and phenology of 83 arctic and boreal mountain species, sampled identically in the early 20th (1917-1919) and 21st centuries (2017-2018) from a region of northern Sweden that has warmed significantly. We test two compensatory hypotheses to high-latitude warming-upward shifts in distribution, and earlier or extended growth and reproduction. For distribution, we show dramatic upward migration by 69% of species, averaging 6.1 m per decade, especially boreal woodland taxa whose upward expansion has reduced arctic montane habitat by 30%. Twenty percent of summit species showed distributional shifts but downward, especially moisture-associated snowbed flora. For phenology, we detected wide inter-annual variability in the onset of leafing and flowering in both eras. However, there was no detectable change in growing-season length, relating to two mechanisms. First, plot-level snow melt data starting in 1917 demonstrated that melt date, rather than vernal temperatures, better predicts plant emergence, with snow melt influenced by warmer years having greater snowfall-warmer springs did not always result in earlier emergence because snowbeds can persist longer. Second, the onset of reproductive senescence between eras was similar, even when plant emergence was earlier by a month, possibly due to intensified summer heat stress or hard-wired 'canalization' where senescence occurs regardless of summer temperature. Migrations in this system have possibly buffered arctic species against displacement by boreal expansion and warming, but ongoing temperature increases, woody plant invasion, and a potential lack of flexibility in timing of senescence may foreshadow challenges.
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| 33. |
- Mazer, Susan J., et al.
(author)
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Flowering date of taxonomic families predicts phenological sensitivity to temperature: Implications for forecasting the effects of climate change on unstudied taxa.
- 2013
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In: American Journal of Botany. - : Wiley. - 0002-9122 .- 1537-2197. ; 100:7, s. 1381-1397
-
Journal article (peer-reviewed)abstract
- Premise of the study: Numerous long-term studies in seasonal habitats have tracked interannual variation in first flowering date (FFD) in relation to climate, documenting the effect of warming on the FFD of many species. Despite these efforts, long-term phenological observations are still lacking for many species. If we could forecast responses based on taxonomic affinity, however, then we could leverage existing data to predict the climate-related phenological shifts of many taxa not yet studied. Methods: We examined phenological time series of 1226 species occurrences (1031 unique species in 119 families) across seven sites in North America and England to determine whether family membership (or family mean FFD) predicts the sensitivity of FFD to standardized interannual changes in temperature and precipitation during seasonal periods before flowering and whether families differ significantly in the direction of their phenological shifts. Key results: Patterns observed among species within and across sites are mirrored among family means across sites; early-flowering families advance their FFD in response to warming more than late-flowering families. By contrast, we found no consistent relationships among taxa between mean FFD and sensitivity to precipitation as measured here. Conclusions: Family membership can be used to identify taxa of high and low sensitivity to temperature within the seasonal, temperate zone plant communities analyzed here. The high sensitivity of early-flowering families (and the absence of early-flowering families not sensitive to temperature) may reflect plasticity in flowering time, which may be adaptive in environments where early-season conditions are highly variable among years.
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| 34. |
- Olsson, Cecilia, et al.
(author)
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Performance of tree phenology models along a bioclimatic gradient in Sweden
- 2013
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In: Ecological Modelling. - : Elsevier BV. - 0304-3800 .- 1872-7026. ; 266, s. 103-117
-
Journal article (peer-reviewed)abstract
- Tree phenology has been recognized as an important indicator of climate change, and a wide range of budburst models have been developed. The models differ in temperature sensitivity, and the choice of model can therefore influence the result of climate impact assessments. In this study we compared the ability of 15 models to simulate budburst of the main forest tree species in Sweden. Records on the timing of budburst, available for 1873-1918 and 1966-2011, were used for model evaluation. The predefined models, having different chilling, competence and forcing modules, represented different hypothesis on temperature impact on tree phenology. We extracted the model-specific forcing units accumulated by the observed day of budburst, and tested for covariation with bio-climatic gradients. For all tree species, most models indicated a negative relation between forcing requirement and latitude, which may indicate provenance specific adaptations. The thermal continentality index, which in Sweden is highly correlated with latitude, did provide some additional explanation for the period of 1873-1918 but not for the period of 1966-2011. For most model- and tree species combinations, temperature anomalies explain a significant part of the variability in forcing units accumulated at day of budburst. This indicates that the budburst models were not able to fully track the response to inter-annual variations in temperature conditions, probably due to difficulties in capturing species and provenance specific chilling requirement, day length response and impact of spring backlashes. (C) 2013 Elsevier B.V. All rights reserved.
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| 35. |
- Pau, Stephanie, et al.
(author)
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Predicting phenology by integrating ecology, evolution and climate science
- 2011
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In: Global Change Biology. - : Wiley. - 1354-1013. ; 17:12, s. 3633-3643
-
Research review (peer-reviewed)abstract
- Forecasting how species and ecosystems will respond to climate change has been a major aim of ecology in recent years. Much of this research has focused on phenology - the timing of life-history events. Phenology has well-demonstrated links to climate, from genetic to landscape scales; yet our ability to explain and predict variation in phenology across species, habitats and time remains poor. Here, we outline how merging approaches from ecology, climate science and evolutionary biology can advance research on phenological responses to climate variability. Using insight into seasonal and interannual climate variability combined with niche theory and community phylogenetics, we develop a predictive approach for species' reponses to changing climate. Our approach predicts that species occupying higher latitudes or the early growing season should be most sensitive to climate and have the most phylogenetically conserved phenologies. We further predict that temperate species will respond to climate change by shifting in time, while tropical species will respond by shifting space, or by evolving. Although we focus here on plant phenology, our approach is broadly applicable to ecological research of plant responses to climate variability.
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| 36. |
- Wolkovich, E. M., et al.
(author)
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Warming experiments underpredict plant phenological responses to climate change
- 2012
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In: Nature. - : Springer Science and Business Media LLC. - 0028-0836 .- 1476-4687. ; 485:7399, s. 494-497
-
Journal article (peer-reviewed)abstract
- Warming experiments are increasingly relied on to estimate plant responses to global climate change(1,2). For experiments to provide meaningful predictions of future responses, they should reflect the empirical record of responses to temperature variability and recent warming, including advances in the timing of flowering and leafing(3-5). We compared phenology (the timing of recurring life history events) in observational studies and warming experiments spanning four continents and 1,634 plant species using a common measure of temperature sensitivity (change in days per degree Celsius). We show that warming experiments underpredict advances in the timing of flowering and leafing by 8.5-fold and 4.0-fold, respectively, compared with long-term observations. For species that were common to both study types, the experimental results did not match the observational data in sign or magnitude. The observational data also showed that species that flower earliest in the spring have the highest temperature sensitivities, but this trend was not reflected in the experimental data. These significant mismatches seem to be unrelated to the study length or to the degree of manipulated warming in experiments. The discrepancy between experiments and observations, however, could arise from complex interactions among multiple drivers in the observational data, or it could arise from remediable artefacts in the experiments that result in lower irradiance and drier soils, thus dampening the phenological responses to manipulated warming. Our results introduce uncertainty into ecosystem models that are informed solely by experiments and suggest that responses to climate change that are predicted using such models should be re-evaluated.
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