10 results on '"von Euler, Tove"'
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2. Environmental context influences both the intensity of seed predation and plant demographic sensitivity to attack
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von Euler, Tove, Ågren, Jon, and Ehrlén, Johan
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- 2014
Catalog
3. Floral display and habitat quality affect cost of reproduction in Primula farinosa
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von Euler, Tove, Ågren, Jon, and Ehrlén, Johan
- Published
- 2012
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4. Advancing environmentally explicit structured population models of plants
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Ehrlen, Johan, Morris, William F., von Euler, Tove, Dahlgren, Johan P., Ehrlen, Johan, Morris, William F., von Euler, Tove, and Dahlgren, Johan P.
- Abstract
The relationship between the performance of individuals and the surrounding environment is fundamental in ecology and evolutionary biology. Assessing how abiotic and biotic environmental factors influence demographic processes is necessary to understand and predict population dynamics, as well as species distributions and abundances. We searched the literature for studies that have linked abiotic and biotic environmental factors to vital rates and, using structured demographic models, population growth rates of plants. We found 136 studies that had examined the environmental drivers of plant demography. The number of studies has been increasing rapidly in recent years. Based on the reviewed studies, we identify and discuss several major gaps in our knowledge of environmentally driven demography of plants. We argue that some drivers may have been underexplored and that the full potential of spatially and temporally replicated studies may not have been realized. We also stress the need to employ relevant statistical methods and experiments to correctly identify drivers. Moreover, assessments of the relationship between drivers and vital rates need to consider interactive, nonlinear and indirect effects, as well as effects of intraspecific density dependence.Synthesis. Much progress has already been made by using structured population models to link the performance of individuals to the surrounding environment. However, by improving the design and analyses of future studies, we can substantially increase our ability to predict changes in plant population dynamics, abundances and distributions in response to changes in specific environmental drivers. Future environmentally explicit demographic models should also address how genetic changes prompted by selection imposed by environmental changes will alter population trajectories in the face of continued environmental change and investigate the reciprocal feedback between plants and their biotic drivers. more...
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- 2016
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5. Environmental heterogeneity, population dynamics and life-history differentiation in Primula farinosa
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von Euler, Tove
- Subjects
Ekologi ,Ecology ,Botany ,Botanik - Abstract
Allocation to reproduction is a key life-history trait. Optimal allocation to reproduction depends on environmental conditions because of their effects both on costs and benefits of reproduction and on patterns of growth, fecundity, and mortality. In this thesis, I studied 24 populations of the perennial herb Primula farinosa in the northern part of the Great Alvar on Öland, SE Sweden, and in an experimental garden at Stockholm University to investigate how plant allocation patterns and population dynamics vary along environmental gradients. In the first study, I performed experimental manipulations of reproduction to study costs of reproduction in relation to water availability. In the second study, I performed a demographic survey to investigate the effects of pre-dispersal seed predation on host-plant population dynamics in relation to environmental context. In the third study, I used a common garden experiment to investigate whether environmental variation among natural populations was correlated with genetic differentiation in reproductive effort, and in the fourth study, I performed reciprocal transplantations among four populations to investigate whether genetically based adaptive differentiation among local populations could be detected. The results showed that under natural conditions, plant reproductive costs, intensity of pre-dispersal seed predation, population growth rate and reproductive effort varied with water availability and vegetation height. Costs of reproduction were detected at high and low water availability but not under intermediate soil moisture conditions (paper I). Population dynamics of P. farinosa were affected by environmental conditions both directly, through effects on potential population growth rate (in the absence of seed predation) and indirectly, through effects on seed predation intensity and sensitivity to seed predation (paper II). Among-population genetic differentiation in reproductive allocation was documented in the common-garden experiment (paper III). However, reciprocal transplantations among populations separated by up to 6.2 km provided no evidence of local adaptation to current environmental conditions. Moreover, large differences in the performance of individuals transplanted to different study sites suggest that the study populations display considerable phenotypic plasticity (paper IV). Taken together, the results of these studies suggest that environmental variation has important direct and indirect effects on population dynamics and life history trade-offs in P. farinosa, and that differences in reproductive effort partly reflect genetic differentiation, but that phenotypic variation observed among natural populations does not reflect adaptations to current environmental conditions. At the time of the doctoral defense, the following papers were unpublished and had a status as follows: Paper 2: Manuscript. Paper 3: Manuscript. Paper 4: Manuscript. more...
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- 2012
6. Local adaptation and life history differentiation in plant populations
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von Euler, Tove and von Euler, Tove
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- 2009
7. A demographic assessment of local adaptation in a grassland perennial herb
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von Euler, Tove, Madec, Camille, Ågren, Jon, Ehrlén, Johan, von Euler, Tove, Madec, Camille, Ågren, Jon, and Ehrlén, Johan
- Abstract
Habitat heterogeneity in abiotic and biotic factors drives the evolution of adaptive population differentiation. Assessments of local adaptation among populations of perennial plants are commonly based on estimates of one or a few fitness components in reciprocal transplant experiments. However, natural selection does not act on fitness components but on life-time fitness, and local adaptation should therefore ideally be assessed based on integrated measures of the performance during the entire life cycle. We transplanted seedlings and adult plants reciprocally among four populations of the perennial herb Primula farinosa differing in abiotic and biotic conditions on the island of Öland, SE Sweden. We recorded survival, growth, flowering and fruit production during three consecutive years (2010-2012) and used integral projection models to quantify variation in total fitness, estimated as population growth rate. Transplant site had large effects on most aspects of plant performance, and the effects of population of origin on survival, growth, flowering propensity and fruit production varied among sites for several year × cohort combinations. However, no evidence of local adaptation, expressed through single fitness components or total fitness, was found. The results suggest that populations of P. farinosa differ genetically in traits influencing fitness, but these differences do not match current selection regimes. This study provides a template for how reciprocal transplant experiments can be combined with long-term demographic studies and population models to assess local adaptation in long-lived species based on estimates of total fitness. more...
8. A demographic assessment of local adaptation in a grassland perennial herb
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von Euler, Tove, Madec, Camille, Ehrlén, Johan, Ågren, Jon, von Euler, Tove, Madec, Camille, Ehrlén, Johan, and Ågren, Jon
- Abstract
The importance of local adaptation to the distribution and performance of plants is well recognized. Several studies have documented local adaptation among populations of perennial plant species based on assessments of one or a few fitness components. However, natural selection does not act on fitness components but on life-time fitness. Assessments of local adaptation should therefore ideally be based on integrated measures of the performance during the entire life cycle. We transplanted seedlings and adult plants reciprocally among four populations of the perennial herb Primula farinosa separated by up to 6.2 km in alvar grasslands in SE Sweden, and recorded survival, growth, flowering and fruit production during two-three consecutive years (2009-2011). We used integral projection models to quantify variation in total fitness, estimated as population growth rate. Transplant site had large effects on most aspects of plant performance, and there were also significant effects of population of origin on survival, growth, flowering propensity and fruit production. However, no evidence of local adaptation expressed through single fitness components or total fitness was detected. The results suggest that at the spatial scale examined genetic differentiation among alvar populations of P. farinosa is not related to current selection regimes. Furthermore, this study illustrates how total fitness can be estimated to assess local adaptation in long-lived species. more...
9. Genetic differentation in reproductive effort in the perennial herb Primula farinosa is related to vegetation height
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von Euler, Tove, Ågren, Jon, Ehrlén, Johan, von Euler, Tove, Ågren, Jon, and Ehrlén, Johan
- Abstract
Spatial variation in abiotic and biotic environmental factors influences vital rates and selection on reproductive strategies. Environmental factors that increase plant mortality, reduce competition and create gaps favorable for seedling recruitment should favor high reproductive effort in plants. To determine whether reproductive effort was negatively related to vegetation height and water availability, we quantified variation in age at first reproduction and relative allocation to flower production in flowering plants in field surveys and in a common-garden experiment that included twenty populations of Primula farinosa in calcareous alvar grasslands in SE Sweden. Reproductive effort of flowering plants varied significantly among populations both at the sites of origin and in the common-garden experiment, whereas there were no differences in age at first reproduction. Both in the field and in the common garden, reproductive effort decreased with increasing vegetation height at the sites of origin, and in the field it also tended to decrease with increasing soil moisture. The results indicate that observed variation in reproductive effort represent both genetic differentiation and phenotypic plasticity, that genetic differences in reproductive effort may have evolved in response to divergent selection associated with among-population differences in vegetation height, and that water availability is one determinant of plastic variation in reproductive effort. more...
10. Environmental context influences the impact of pre-dispersal seed predation on host plant population dynamics in multiple ways
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von Euler, Tove, Ågren, Jon, Ehrlén, Johan, von Euler, Tove, Ågren, Jon, and Ehrlén, Johan
- Abstract
Environmental heterogeneity influences species distributions as well as population dynamics within species. Effects of the environment can be both direct and indirect, altering the outcome of biotic interactions. Although it is well known that biotic interactions may strongly affect several vital rates, few studies have investigated how the effect of biotic interactions on life-time fitness and population dynamics depends on environmental context. We studied how the effect of pre-dispersal seed predation on host plant population growth rates varied with soil conditions and vegetation height, monitoring 24 populations of the perennial herb Primula farinosa during three consecutive years. First, we investigated how reductions in population growth rate due to seed predators were related to predation intensity and the sensitivity of population growth rate to predation, respectively. Second, we examined how predation intensity and sensitivity were related to environmental context in terms of soil depth, soil moisture, soil nutrient composition and vegetation height. Both seed predation intensity and sensitivity of population growth rate to seed predation varied considerably among populations, and both contributed to variation in the effects of seed predation on population growth rate. Soil moisture influenced population growth rate in three different ways; via direct effects on potential growth rate, via effects on predation intensity and via effects on the sensitivity of population growth rates to seed predation. We conclude that, in our study system, environmental context influences how biotic interactions affect population dynamics, and that a given environmental parameter can influence population growth rate in different directions through effects on potential growth rate, intensity of biotic interactions, and the sensitivity of population growth rate to these biotic interactions. more...
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