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  • 1.
    Andersson, Petter
    et al.
    Stockholm University, Faculty of Science, Department of Ecology, Environment and Plant Sciences.
    Ehrlén, Johan
    Stockholm University, Faculty of Science, Department of Ecology, Environment and Plant Sciences.
    Hambäck, Peter A.
    Stockholm University, Faculty of Science, Department of Ecology, Environment and Plant Sciences.
    Plant patch structure influences plant fitness via antagonistic and mutualistic interactions but in different directions2016In: Oecologia, ISSN 0029-8549, E-ISSN 1432-1939, Vol. 180, no 4, p. 1175-1182Article in journal (Refereed)
    Abstract [en]

    Plant patch structure and environmental context can influence the outcome of antagonistic and mutualistic plant-insect interactions, leading to spatially variable fitness effects for plants. We investigated the effects of herbivory and pollen limitation on plant reproductive performance in 28 patches of the self-compatible perennial herb Scrophularia nodosa and assessed how such effects varied with plant patch size, plant density and tree cover. Both antagonistic and mutualistic interactions had strong effects on plant reproductive performance. Leaf feeding from herbivores reduced both fruit production and seed germination, and leaf herbivory increased with plant patch size. Experimentally hand-pollinated flowers produced more seeds than open-pollinated flowers, and pollen limitation was more severe in patches with fewer plants. Our study on S. nodosa is one of few which documents that plant patch structure influences the outcome of both antagonistic and mutualistic plant-insect interactions. The results thus provide an example of how variation in plant patch structure and environmental factors can lead to spatially variable fitness effects from mutualistic and antagonistic interactions.

  • 2.
    Arvanitis, Leena
    et al.
    Stockholm University, Faculty of Science, Department of Botany. Växtekologi.
    Wiklund, Christer
    Department of Zoology. Ekologi.
    Ehrlén, Johan
    Stockholm University, Faculty of Science, Department of Botany. Växtekologi.
    Plant ploidy level influences selection by butterfly seed predators2008In: Oikos, Vol. 117, p. 1020-1025Article in journal (Refereed)
    Abstract [en]

    Polyploidization is a common route to plant diversification. Polyploids often differ from their progenitors in size, flower number, flower size and flowering phenology. Such differences may translate into differences in the intensity of interactions with animals. Here we investigated the impact of the ploidy-related differences in tetraploids and octoploids of the perennial herb Cardamine pratensis on pre-dispersal seed predation by the butterfly Anthocharis cardamines. The probability of escaping attack was lower for octoploids than for tetraploids, even after accounting for the fact that octoploids were larger and had fewer flowers than tetraploids. Flower shoot size was correlated with probability of attack in tetraploids but not in octoploids. Differences in plant traits associated with polyploidization can alter interactions with animals, and animal-mediated differences in trait selection between ploidy types can contribute to their further divergence.

  • 3. Bisang,
    et al.
    Ehrlén,
    Stockholm University, Faculty of Science, Department of Botany.
    Hedenäs,
    Are annual growth intervals independent units in the moss Pseudocalligeron trifarium (Amblystegiaceae)2008In: BryologistArticle in journal (Refereed)
  • 4. Bisang, Irene
    et al.
    Ehrlén, Johan
    Stockholm University, Faculty of Science, Department of Ecology, Environment and Plant Sciences.
    Korpelainen, Helena
    Hedenas, Lars
    No evidence of sexual niche partitioning in a dioecious moss with rare sexual reproduction2015In: Annals of Botany, ISSN 0305-7364, E-ISSN 1095-8290, Vol. 116, no 5, p. 771-779Article in journal (Refereed)
    Abstract [en]

    Background and Aims Roughly half of the species of bryophytes have separate sexes (dioecious) and half are hermaphroditic (monoecious). This variation has major consequences for the ecology and evolution of the different species. In some sexually reproducing dioecious bryophytes, sex ratio has been shown to vary with environmental conditions. This study focuses on the dioecious wetland moss Drepanocladus trifarius, which rarely produces sexual branches or sporophytes and lacks apparent secondary sex characteristics, and examines whether genetic sexes exhibit different habitat preferences, i.e. whether sexual niche partitioning occurs. Methods A total of 277 shoots of D. trifarius were randomly sampled at 214 locations and 12 environmental factors were quantified at each site. Sex was assigned to the individual shoots collected in the natural environments, regardless of their reproductive status, using a specifically designed molecular marker associated with female sex. Key Results Male and female shoots did not differ in shoot biomass, the sexes were randomly distributed with respect to each other, and environmental conditions at male and female sampling locations did not differ. Collectively, this demonstrates a lack of sexual niche segregation. Adult genetic sex ratio was female-biased, with 2.8 females for every male individual. Conclusions The results show that although the sexes of D. trifarius did not differ with regard to annual growth, spatial distribution or habitat requirements, the genetic sex ratio was nevertheless significantly female-biased. This supports the notion that factors other than sex-related differences in reproductive costs and sexual dimorphism can also drive the evolution of biased sex ratios in plants.

  • 5. Bisang, Irene
    et al.
    Ehrlén, Johan
    Stockholm University, Faculty of Science, Department of Ecology, Environment and Plant Sciences.
    Persson, Christin
    Hedenas, Lars
    Family affiliation, sex ratio and sporophyte frequency in unisexual mosses2014In: Botanical journal of the Linnean Society, ISSN 0024-4074, E-ISSN 1095-8339, Vol. 174, no 2, p. 163-172Article in journal (Refereed)
    Abstract [en]

    Patterns of sex expression and sex ratios are key features of the life histories of organisms. Bryophytes are the only haploid-dominant land plants. In contrast with seed plants, more than half of bryophyte species are dioecious, with rare sexual expression and sporophyte formation and a commonly female-biased sex ratio. We asked whether variation in sex expression, sex ratio and sporophyte frequency in ten dioecious pleurocarpous wetland mosses of two different families was best explained by assuming that character states evolved: (1) in ancestors within the respective families or (2) at the species level as a response to recent habitat conditions. Lasso regression shrinkage identified relationships between family membership and sex ratio and sporophyte frequency, whereas environmental conditions were not correlated with any investigated reproductive trait. Sex ratio and sporophyte frequency were correlated with each other. Our results suggest that ancestry is more important than the current environment in explaining reproductive patterns at and above the species level in the studied wetland mosses, and that mechanisms controlling sex ratio and sporophyte frequency are phylogenetically conserved. Obviously, ancestry should be considered in the study of reproductive character state variation in plants.(c) 2013 The Linnean Society of London, Botanical Journal of the Linnean Society, 2014, 174, 163-172.

  • 6. Boalt, Elin
    et al.
    Arvanitis, Leena
    Stockholm University, Faculty of Science, Department of Botany.
    Lehtila, Kari
    Ehrlén, Johan
    Stockholm University, Faculty of Science, Department of Botany.
    The association among herbivory tolerance, ploidy level, and herbivory pressure in cardamine pratensis2010In: Evolutionary Ecology, ISSN 0269-7653, E-ISSN 1573-8477, Vol. 24, no 5, p. 1101-1113Article in journal (Refereed)
    Abstract [en]

    We tested whether differences in ploidy level and previous exposure to herbivory can affect plant tolerance to herbivory. We conducted a common garden experiment with 12 populations of two ploidy levels of the perennial herb Cardamine pratensis (five populations of tetraploid ssp. pratensis and seven populations of octoploid ssp. paludosa). Earlier studies have shown that attack rates by the main herbivore, the orange tip butterfly Anthocharis cardamines, are lower in populations of octoploids than in populations of tetraploids, and vary among populations. In the common garden experiment, a combination of natural and artificial damage significantly reduced seed and flower production. We measured tolerance based on four plant-performance metrics: survival, growth, seed production and clonal reproduction. For three of these measurements, tolerance of damage did not differ between ploidy levels. For clonal reproduction, the octoploids had a higher tolerance than the tetraploids, although they experience lower herbivore attack rates in natural populations. Populations from sites with high levels of herbivory had higher tolerance, measured by seed production, than populations with low levels of herbivory. We did not detect any significant costs of tolerance. We conclude that high intensity of herbivory has selected for high tolerance measured by seed production in C. pratensis.

  • 7.
    Bolinder, Kristina
    et al.
    Stockholm University, Faculty of Science, Department of Ecology, Environment and Plant Sciences.
    Humphreys, Aelys M.
    Stockholm University, Faculty of Science, Department of Ecology, Environment and Plant Sciences. Royal Botanic Gardens, UK.
    Ehrlén, Johan
    Stockholm University, Faculty of Science, Department of Ecology, Environment and Plant Sciences.
    Alexandersson, Ronny
    Ickert-Bond, Stefanie M.
    Rydin, Catarina
    Stockholm University, Faculty of Science, Department of Ecology, Environment and Plant Sciences.
    From near extinction to diversification by means of ashift in pollination mechanism in the gymnosperm relict Ephedra (Ephedraceae, Gnetales)2016In: Botanical journal of the Linnean Society, ISSN 0024-4074, E-ISSN 1095-8339, Vol. 180, no 4, p. 461-477Article in journal (Refereed)
    Abstract [en]

    Pollination in gymnosperms is usually accomplished by means of wind, but some groups are insect-pollinated. We show that wind and insect pollination occur in the morphologically uniform genus Ephedra (Gnetales). Based on field experiments over several years, we demonstrate distinct differences between two Ephedra species that grow in sympatry in Greece in pollen dispersal and clump formation, insect visitations and embryo formation when insects are denied access to cones. Ephedra distachya, nested in the core clade of Ephedra, is anemophilous, which is probably the prevailing state in Ephedra. Ephedra foeminea, sister to the remaining species of the genus, is entomophilous and pollinated by a range of diurnal and nocturnal insects. The generalist entomophilous system of E.foeminea, with distinct but infrequent insect visitations, is in many respects similar to that reported for Gnetum and Welwitschia and appears ancestral in Gnetales. The Ephedra lineage is well documented already from the Early Cretaceous, but the diversity declined dramatically during the Late Cretaceous, possibly to near extinction around the Cretaceous-Palaeogene boundary. The clade imbalance between insect- and wind-pollinated lineages is larger than expected by chance and the shift in pollination mode may explain why Ephedra escaped extinction and began to diversify again.

  • 8. Buckley, Yvonne M.
    et al.
    Ramula, Satu
    Blomberg, Simon P.
    Burns, Jean H.
    Crone, Elizabeth E.
    Ehrlén, Johan
    Stockholm University, Faculty of Science, Department of Botany.
    Knight, Tiffany M.
    Pichancourt, Jean-Baptiste
    Quested, Helen
    Stockholm University, Faculty of Science, Department of Botany.
    Wardle, Glenda M.
    Causes and consequences of variation in plant population growth rate: a synthesis of matrix population models in a phylogenetic context2010In: Ecology Letters, ISSN 1461-023X, E-ISSN 1461-0248, Vol. 13, no 9, p. 1182-1197Article, review/survey (Refereed)
    Abstract [en]

    Explaining variation in population growth rates is fundamental to predicting population dynamics and population responses to environmental change. In this study, we used matrix population models, which link birth, growth and survival to population growth rate, to examine how and why population growth rates vary within and among 50 terrestrial plant species. Population growth rates were more similar within species than among species; with phylogeny having a minimal influence on among-species variation. Most population growth rates decreased over the observation period and were negatively autocorrelated between years; that is, higher than average population growth rates tended to be followed by lower than average population growth rates. Population growth rates varied more through time than space; this temporal variation was due mostly to variation in post-seedling survival and for a subset of species was partly explained by response to environmental factors, such as fire and herbivory. Stochastic population growth rates departed from mean matrix population growth rate for temporally autocorrelated environments. Our findings indicate that demographic data and models of closely related plant species cannot necessarily be used to make recommendations for conservation or control, and that post-seedling survival and the sequence of environmental conditions are critical for determining plant population growth rate.

  • 9. Burns, Jean H.
    et al.
    Blomberg, Simon P.
    Crone, Elizabeth E.
    Ehrlén, Johan
    Stockholm University, Faculty of Science, Department of Botany.
    Knight, Tiffany M.
    Pichancourt, Jean-Baptiste
    Ramula, Satu
    Wardle, Glenda M.
    Buckley, Yvonne M.
    Empirical tests of life-history evolution theory using phylogenetic analysis of plant demography2010In: Journal of Ecology, ISSN 0022-0477, E-ISSN 1365-2745, Vol. 98, no 2, p. 334-344Article in journal (Refereed)
    Abstract [en]

    1. A primary goal of evolutionary ecology is to understand factors selecting for the diversity of life histories. Life-history components, such as time-to-reproduction, adult survivorship and fecundity, might differ among species because of variation in direct and indirect benefits of these life histories in different environments or might have lower-than-expected variability because of phylogenetic constraints. Here, we present a phylogenetic examination of demography and life histories using a data base of 204 terrestrial plant species. 2. Overall, statistical models without phylogeny were preferred to models with phylogeny for vital rates and elasticities, suggesting that they lacked phylogenetic signal and are evolutionarily labile. However, the effect of phylogeny was significant in models including sensitivities, suggesting that sensitivities exhibit greater phylogenetic signal than vital rates or elasticities. 3. Species with a greater age at first reproduction had lower fecundity, consistent with a cost of delayed reproduction, but only in some habitats (e.g. grassland). We found no evidence for an indirect benefit of delayed reproduction via a decrease in variation in fecundity with age to first reproduction. 4. The greater sensitivity and lower variation in survival than in fecundity was consistent with buffering of more important vital rates, as others have also found. This suggests that studies of life-history evolution should include survival, rather than only fecundity, for the majority of species. 5. Synthesis. Demographic matrix models can provide informative tests of life-history theory because of their shared construction and outputs and their widespread use among plant ecologists. Our comparative analysis suggested that there is a cost of delayed reproduction and that more important vital rates exhibit lower variability. The absolute importance of vital rates to population growth rates (sensitivities) exhibited phylogenetic signal, suggesting that a thorough understanding of life-history evolution might require an understanding of the importance of vital rates, not just their means, and the role of phylogenetic history.

  • 10. Crone, Elizabeth E.
    et al.
    Ellis, Martha M.
    Morris, William F.
    Stanley, Amanda
    Bell, Timothy
    Bierzychudek, Paulette
    Ehrlén, Johan
    Stockholm University, Faculty of Science, Department of Botany.
    Kaye, Thomas N.
    Knight, Tiffany M.
    Lesica, Peter
    Oostermeijer, Gerard
    Quintana-Ascencio, Pedro F.
    Ticktin, Tamara
    Valverde, Teresa
    Williams, Jennifer L.
    Doak, Daniel F.
    Ganesan, Rengaian
    Mceachern, Kathyrn
    Thorpe, Andrea S.
    Menges, Eric S.
    Ability of Matrix Models to Explain the Past and Predict the Future of Plant Populations2013In: Conservation Biology, ISSN 0888-8892, E-ISSN 1523-1739, Vol. 27, no 5, p. 968-978Article in journal (Refereed)
    Abstract [en]

    Uncertainty associated with ecological forecasts has long been recognized, but forecast accuracy is rarely quantified. We evaluated how well data on 82 populations of 20 species of plants spanning 3 continents explained and predicted plant population dynamics. We parameterized stage-based matrix models with demographic data from individually marked plants and determined how well these models forecast population sizes observed at least 5 years into the future. Simple demographic models forecasted population dynamics poorly; only 40% of observed population sizes fell within our forecasts' 95% confidence limits. However, these models explained population dynamics during the years in which data were collected; observed changes in population size during the data-collection period were strongly positively correlated with population growth rate. Thus, these models are at least a sound way to quantify population status. Poor forecasts were not associated with the number of individual plants or years of data. We tested whether vital rates were density dependent and found both positive and negative density dependence. However, density dependence was not associated with forecast error. Forecast error was significantly associated with environmental differences between the data collection and forecast periods. To forecast population fates, more detailed models, such as those that project how environments are likely to change and how these changes will affect population dynamics, may be needed. Such detailed models are not always feasible. Thus, it may be wiser to make risk-averse decisions than to expect precise forecasts from models. Habilidad de los Modelos Matriciales para Explicar el Pasado y Predecir el Futuro de las Poblaciones de Plantas Resumen La incertidumbre asociada con el pronostico ecologico ha sido reconocida durante un largo tiempo pero rara vez se cuantifica su seguridad. Evaluamos que tan bien la informacion de 82 poblaciones de 20 especies de plantas a lo largo de 3 continentes explica y predice la dinamica de poblacion de las plantas. Realizamos parametros con modelos matriciales con base en estadios con datos demograficos a partir de plantas marcadas individualmente y determinamos que tan bien estos modelos pronostican el tamano de las poblaciones al menos 5 anos en el futuro. Los modelos demograficos simples pronosticaron pobremente las dinamicas de poblacion; solamente el 40% de las poblaciones observadas cayo dentro de los limites de confianza de 85% de nuestros pronosticos. Estos modelos sin embargo explicaron la dinamica de poblacion a lo largo de los anos en los que se colectaron datos; los cambios observados en el tamano de la poblacion durante el periodo de colecta de datos estuvieron positivamente correlacionados con la tasa de crecimiento de la poblacion. Asi, estos modelos son por lo menos una manera segura de cuantificar el estado de la poblacion. Los pronosticos debiles no estuvieron asociados con el numero de plantas individuales o con los anos de datos. Probamos si las tasas vitales dependian de la densidad y encontramos que existe dependencia hacia la densidad tanto positiva como negativa, sin embargo la dependencia de densidad no se asocio con el error de pronostico. El error de pronostico estuvo significativamente asociado con diferencias ambientales entre la recoleccion de datos y los periodos de pronostico. Para predecir el destino de las poblaciones se necesitan modelos mas detallados, como aquellos que proyectan los cambios probables en el ambiente y como estos cambios afectaran a la dinamica de las poblaciones. Tales modelos tan detallados no siempre son factibles. Por ello puede ser mejor tomar decisiones aversas a riesgos que esperar pronosticos precisos de los modelos.

  • 11. Crone, Elizabeth E.
    et al.
    Menges, Eric S.
    Ellis, Martha M.
    Bell, Timothy
    Bierzychudek, Paulette
    Ehrlen, Johan
    Stockholm University, Faculty of Science, Department of Botany.
    Kaye, Thomas N.
    Knight, Tiffany M.
    Lesica, Peter
    Morris, William F.
    Oostermeijer, Gerard
    Quintana-Ascencio, Pedro F.
    Stanley, Amanda
    Ticktin, Tamara
    Valverde, Teresa
    Williams, Jennifer L.
    How do plant ecologists use matrix population models?2011In: Ecology Letters, ISSN 1461-023X, E-ISSN 1461-0248, Vol. 14, no 1, p. 1-8Article in journal (Refereed)
    Abstract [en]

    P>Matrix projection models are among the most widely used tools in plant ecology. However, the way in which plant ecologists use and interpret these models differs from the way in which they are presented in the broader academic literature. In contrast to calls from earlier reviews, most studies of plant populations are based on < 5 matrices and present simple metrics such as deterministic population growth rates. However, plant ecologists also cautioned against literal interpretation of model predictions. Although academic studies have emphasized testing quantitative model predictions, such forecasts are not the way in which plant ecologists find matrix models to be most useful. Improving forecasting ability would necessitate increased model complexity and longer studies. Therefore, in addition to longer term studies with better links to environmental drivers, priorities for research include critically evaluating relative/comparative uses of matrix models and asking how we can use many short-term studies to understand long-term population dynamics.

  • 12.
    Dahlberg, C. Johan
    et al.
    Stockholm University, Faculty of Science, Department of Ecology, Environment and Plant Sciences.
    Ehrlén, Johan
    Stockholm University, Faculty of Science, Department of Ecology, Environment and Plant Sciences.
    Hylander, Kristoffer
    Stockholm University, Faculty of Science, Department of Ecology, Environment and Plant Sciences.
    Performance of Forest Bryophytes with Different Geographical Distributions Transplanted across a Topographically Heterogeneous Landscape2014In: PLoS ONE, ISSN 1932-6203, E-ISSN 1932-6203, Vol. 9, no 11, article id e112943Article in journal (Refereed)
    Abstract [en]

    Most species distribution models assume a close link between climatic conditions and species distributions. Yet, we know little about the link between species’ geographical distributions and the sensitivity of performance to local environmental factors. We studied the performance of three bryophyte species transplanted at south- and north-facing slopes in a boreal forest landscape in Sweden. At the same sites, we measured both air and ground temperature. We hypothesized that the two southerly distributed species Eurhynchium angustirete and Herzogiella seligeri perform better on south-facing slopes and in warm conditions, and that the northerly distributed species Barbilophozia lycopodioides perform better on north-facing slopes and in relatively cool conditions. The northern, but not the two southern species, showed the predicted relationship with slope aspect. However, the performance of one of the two southern species was still enhanced by warm temperatures. An important reason for the inconsistent results can be that microclimatic gradients across landscapes are complex and influenced by many climate-forcing factors. Therefore, comparing only north- and south-facing slopes might not capture the complexity of microclimatic gradients. Population growth rates and potential distributions are the integrated results of all vital rates. Still, the study of selected vital rates constitutes an important first step to understand the relationship between population growth rates and geographical distributions and is essential to better predict how climate change influences species distributions.

  • 13.
    Dahlberg, C. Johan
    et al.
    Stockholm University, Faculty of Science, Department of Ecology, Environment and Plant Sciences.
    Ehrlén, Johan
    Stockholm University, Faculty of Science, Department of Ecology, Environment and Plant Sciences.
    Hylander, Kristoffer
    Stockholm University, Faculty of Science, Department of Ecology, Environment and Plant Sciences.
    Population dynamics of moss transplants across microclimatic gradientsManuscript (preprint) (Other academic)
    Abstract [en]

    In order to determine the response of a species to climatic change it is important to study how climatic factors influence its vital rates and population growth rate across climatic gradients. We investigated how microclimate influence the population dynamics of transplants from northern and more southern populations of the forest bryophyte Hylocomiastrum umbratum. We predicted that its population growth rate is favored by moist microclimates with colder maximum temperatures, longer snow cover duration and less evaporation, and that annual shoots (segments) will be shorter under drier conditions. We also predicted that northern populations will have higher population growth rate and larger segments than southern populations when transplanted to the northern range. We placed transplants from three northern and three southern populations of H. umbratum at 30 forested sites in central Sweden differing in microclimate. We marked and followed the growth of individual shoots during two years, and calculated population growth rates and stable stage distributions of segment size classes using transition matrix models for northern and southern transplants, respectively, at each locality. Population growth rate was lower and shorter segments developed at sites with higher evaporation, corresponding to our hypothesis. There were no significant difference in population growth rate and stable stage segment length between southern and northern populations. Higher evaporation during the summer result in lower population growth rates of H. umbratum by affecting vital rates, in terms of less segment growth. Both climate change and forestry may alter evaporation conditions across the landscape and, thus, the future distribution of the species.

  • 14.
    Dahlberg, C. Johan
    et al.
    Stockholm University, Faculty of Science, Department of Ecology, Environment and Plant Sciences.
    Ehrlén, Johan
    Stockholm University, Faculty of Science, Department of Ecology, Environment and Plant Sciences.
    Meineri, Eric
    Stockholm University, Faculty of Science, Department of Ecology, Environment and Plant Sciences.
    Plant landscape climatic optima correlate with their continental range optimaManuscript (preprint) (Other academic)
    Abstract [en]

    Aim

    Factors determining species’ distributions at smaller scales may inform us about larger scale distributions, and vice versa. We predicted that landscape and continental climatic optima for plants are positively correlated, and that species that have their optima outside a given focal landscape will cluster at the warmest or coldest landscape patches. Also, we predicted that the correlations of temperature optima are stronger for vascular plants than for bryophytes, since bryophytes may be regulated also by air moisture.

    Location

    Ångermanland, Sweden (landscape scale); Europe (continental scale).

    Methods

    We derived landscape optima from fine-grained temperature models (50 m) and species inventories, and continental optima from MaxEnt niche modelling based on GBIF occurrences and Worldclim temperatures (c. 1000 m), for 96 bryophytes and 50 vascular plants. Optima were derived for growing degree days, and maximum and minimum temperature.

    Results

    The landscape and continental optima of all species were positively correlated for growing degree days and maximum temperature (r = 0.19 and r = 0.44), but not for minimum temperature (r = -0.010). Species with their continental optima outside the focal landscape did not clearly cluster in the most extreme parts of the landscape. For vascular plants the correlation was positive for both growing degree days and maximum temperature (r = 0.50 and r = 0.64), but for bryophytes only for maximum temperature (r = 0.34).

    Main conclusions

    The optima correlations for maximum temperature and growing degree days indicate that we can infer large scale distribution patterns of plants from their local scale distributions, and suggest in which environments species occur if we only know their continental scale optima. The lack of clustering of southern and northern species limits the possibility for conservation actions targeting microrefugia. Lastly, the correlations indicate that the distributions of vascular plants were more influenced by temperature than bryophytes.

  • 15.
    Dahlgren, Johan
    et al.
    Stockholm University, Faculty of Science, Department of Botany.
    Ehrlen, Johan
    Stockholm University, Faculty of Science, Department of Botany.
    Incorporating environmental change over succession in an integral projection model of population dynamics of a forest herb2011In: Oikos, ISSN 0030-1299, E-ISSN 1600-0706, Vol. 120, no 8, p. 1183-1190Article in journal (Refereed)
    Abstract [en]

    Despite seemingly obvious effects of environmental drivers, mechanisms behind long-term changes in plant population sizes over time are often poorly known. We investigated how soil potassium concentration and seed predation are likely to change over time as a result of succession from deciduous forest to spruce forest, and how this affects population trajectories of Actaea spicata. Observations and addition experiments showed that high soil potassium concentration increased individual growth rates. Among-site comparisons showed that soil potassium concentration was lower where proportion spruce was higher. Incorporation of a gradual increase in spruce over time in an integral projection model where individual growth depended on potassium suggested a net decrease in A. spicata population sizes over forest succession. This result suggests that small changes in factors with small effects on individual performance can influence patterns of species occupancy along successional gradients. We incorporated also density independent and density dependent effects of pre-dispersal seed predation over succession into the same model. Seed predation influenced the tree composition at which A. spicata population growth was positive. However, significant effects of A. spicata population size on seed predation intensity did not translate into important feedback effects on population growth trajectories over succession. Our results illustrate how demographic models can be used to gain understanding of the mechanisms behind effects of environmental change on species abundances and distributions by the simultaneous inclusion of changing abiotic and biotic factors.

  • 16.
    Dahlgren, Johan
    et al.
    Stockholm University, Faculty of Science, Department of Botany.
    Ehrlén, Johan
    Stockholm University, Faculty of Science, Department of Botany.
    Linking environmental variation to population dynamics of a forest herb2009In: Journal of Ecology, ISSN 0022-0477, E-ISSN 1365-2745, Vol. 97, no 4, p. 666-674Article in journal (Refereed)
    Abstract [en]

    . Although necessary for understanding and predicting population dynamics, abiotic and biotic interactions have only rarely been coupled to demography and population dynamics.

    2. We estimated effects of 11 environmental factors on survival, growth and fertility of the perennial herb Actaea spicata and incorporated significant factors into integral projection models to assess their effect on population dynamics.

    3. Statistical models suggested that high soil potassium concentration increased individual growth and that seed predation and, to a lesser extent, canopy cover reduced seed production.

    4. Demographic models showed that both soil potassium concentration and pre-dispersal seed predation could reverse population growth from positive to negative. The observed range of soil potassium concentration corresponded to growth rates (lambda) between 0.96 and 1.07, at mean observed seed predation intensity. At observed mean potassium concentration, growth rate ranged from 0.99 to 1.02 over observed seed predation intensities.

    5. Sensitivity of population growth rate to different vital rates strongly influenced the relative effects of the two factors. Elasticity analysis suggested that proportional changes in soil potassium concentration result in seven times larger effects on population growth rate than changes in seed predation.

    6. Synthesis. We conclude that relatively weak associations between environmental factors and vital rates can have substantial long-term effects on population growth. Approaches based on detailed demographic models, that simultaneously assess abiotic and biotic effects on population growth rate, constitute important tools for establishing the links between the environment and dynamics of populations and communities.

  • 17. Dahlgren, Johan P.
    et al.
    Bengtsson, Karin
    Ehrlén, Johan
    Stockholm University, Faculty of Science, Department of Ecology, Environment and Plant Sciences.
    The demography of climate-driven and density-regulated population dynamics in a perennial plant2016In: Ecology, ISSN 0012-9658, E-ISSN 1939-9170, Vol. 97, no 4, p. 899-907Article in journal (Refereed)
    Abstract [en]

    Identifying the internal and external drivers of population dynamics is a key objective in ecology, currently accentuated by the need to forecast the effects of climate change on species distributions and abundances. The interplay between environmental and density effects is one particularly important aspect of such forecasts. We examined the simultaneous impact of climate and intraspecific density on vital rates of the dwarf shrub Fumana procumbens over 20 yr, using generalized additive mixed models. We then analyzed effects on population dynamics using integral projection models. The population projection models accurately captured observed fluctuations in population size. Our analyses suggested the population was intrinsically regulated but with annual fluctuations in response to variation in weather. Simulations showed that implicitly assuming variation in demographic rates to be driven solely by the environment can overestimate extinction risks if there is density dependence. We conclude that density regulation can dampen effects of climate change on Fumana population size, and discuss the need to quantify density dependence in predictions of population responses to environmental changes.

  • 18.
    Dahlgren, Johan P.
    et al.
    Stockholm University, Faculty of Science, Department of Botany.
    Garcia, Maria B.
    Ehrlén, Johan
    Stockholm University, Faculty of Science, Department of Botany.
    Nonlinear relationships between vital rates and state variables in demographic models2011In: Ecology, ISSN 0012-9658, E-ISSN 1939-9170, Vol. 92, no 5, p. 1181-1187Article in journal (Refereed)
    Abstract [en]

    To accurately estimate population dynamics and viability, structured population models account for among-individual differences in demographic parameters that are related to individual state. In the widely used matrix models, such differences are incorporated in terms of discrete state categories, whereas integral projection models (IPMs) use continuous state variables to avoid artificial classes. In IPMs, and sometimes also in matrix models, parameterization is based on regressions that do not always model nonlinear relationships between demographic parameters and state variables. We stress the importance of testing for nonlinearity and propose using restricted cubic splines in order to allow for a wide variety of relationships in regressions and demographic models. For the plant Borderea pyrenaica, we found that vital rate relationships with size and age were nonlinear and that the parameterization method had large effects on predicted population growth rates, lambda (linear IPM, 0.95; nonlinear IPMs, 1.00; matrix model, 0.96). Our results suggest that restricted cubic spline models are more reliable than linear or polynomial models. Because even weak nonlinearity in relationships between vital rates and state variables can have large effects on model predictions, we suggest that restricted cubic regression splines should be considered for parameterizing models of population dynamics whenever linearity cannot be assumed.

  • 19.
    Dahlgren, Johan
    et al.
    Stockholm University, Faculty of Science, Department of Botany.
    von Zeipel, Hugo
    Stockholm University, Faculty of Science, Department of Botany.
    Ehrlén, Johan
    Stockholm University, Faculty of Science, Department of Botany. växtekologi.
    Variation in vegetative and flowering phenology in a forest herb caused by environmental heterogeneity2007In: AMERICAN JOURNAL OF BOTANY, Vol. 94, no 9, p. 1570-1576Article in journal (Refereed)
  • 20.
    Ehrlén, Johan
    Stockholm University, Faculty of Science, Department of Ecology, Environment and Plant Sciences.
    Selection on flowering time in a life-cycle context2015In: Oikos, ISSN 0030-1299, E-ISSN 1600-0706, Vol. 124, no 1, p. 92-101Article in journal (Refereed)
    Abstract [en]

    The main way in which plants can exert control over their local environment is by the timing of different events within their life cycles. Regarding timing of flowering as an integrated part of both the annual cycle and of the whole life cycle, rather than as an isolated event, has important implications for how we assess selection on timing of reproduction and interpret existing phenological patterns in perennial plants. I argue that: 1) we have little unequivocal evidence of pollinator-mediated selection on flowering time, but perhaps more evidence of antagonist-mediated selection; 2) much of selection on flowering time might occur before flowers have developed and after reproduction; 3) vital rates of non-flowering individuals can influence the strength and direction of selection on flowering time, and 4) differences in the direction of selection on flowering date between years might well correspond to consistent selection on the mechanisms determining flowering time. Overall, a life cycle perspective on timing of flowering is likely to facilitate the identification of selective agents and the understanding of the complex mechanisms underlying spatial and temporal variation in selection as well as to enable more accurate predictions of responses to environmental change.

  • 21.
    Ehrlén, Johan
    et al.
    Stockholm University, Faculty of Science, Department of Botany.
    Borg-Karlson, Anna-Karin
    Kolb, Annette
    Selection on plant optical traits and floral scent: Effects via seed development and antagonistic interactions2012In: Basic and Applied Ecology, ISSN 1439-1791, E-ISSN 1618-0089, Vol. 13, no 6, p. 509-515Article in journal (Refereed)
    Abstract [en]

    Evolutionary explanations of plant reproductive traits have usually emphasized optical characteristics of plants and selection mediated by pollinators. In recent years, studies have been broadened by incorporating also interactions with antagonists and by studying plant fragrant cues. Here, we examined if optical and fragrance traits of the perennial herb Primula veris correlated with reproductive success, in terms of fruit and seed set, and with avoidance of seed predators. Selection path analysis showed that both optical and fragrance traits influenced total seed production, and effects occurred both via fruit and seed set and via predator avoidance. In one case the same trait, inflorescence height, influenced total seed production both positively and negatively through effects on different components of fitness. Our results lend support to the notion that selection by mutualists and antagonists simultaneously acts on optical and fragrance traits.

  • 22.
    Ehrlén, Johan
    et al.
    Stockholm University, Faculty of Science, Department of Ecology, Environment and Plant Sciences.
    Morris, William F.
    Predicting changes in the distribution and abundance of species under environmental change2015In: Ecology Letters, ISSN 1461-023X, E-ISSN 1461-0248, Vol. 18, no 3, p. 303-314Article, review/survey (Refereed)
    Abstract [en]

    Environmental changes are expected to alter both the distribution and the abundance of organisms. A disproportionate amount of past work has focused on distribution only, either documenting historical range shifts or predicting future occurrence patterns. However, simultaneous predictions of abundance and distribution across landscapes would be far more useful. To critically assess which approaches represent advances towards the goal of joint predictions of abundance and distribution, we review recent work on changing distributions and on effects of environmental drivers on single populations. Several methods have been used to predict changing distributions. Some of these can be easily modified to also predict abundance, but others cannot. In parallel, demographers have developed a much better understanding of how changing abiotic and biotic drivers will influence growth rate and abundance in single populations. However, this demographic work has rarely taken a landscape perspective and has largely ignored the effects of intraspecific density. We advocate a synthetic approach in which population models accounting for both density dependence and effects of environmental drivers are used to make integrated predictions of equilibrium abundance and distribution across entire landscapes. Such predictions would constitute an important step forward in assessing the ecological consequences of environmental changes.

  • 23.
    Ehrlén, Johan
    et al.
    Stockholm University, Faculty of Science, Department of Ecology, Environment and Plant Sciences.
    Morris, William F.
    von Euler, Tove
    Stockholm University, Faculty of Science, Department of Ecology, Environment and Plant Sciences.
    Dahlgren, Johan P.
    Advancing environmentally explicit structured population models of plants2016In: Journal of Ecology, ISSN 0022-0477, E-ISSN 1365-2745, Vol. 104, no 2, p. 292-305Article in journal (Refereed)
    Abstract [en]

    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.

  • 24.
    Ehrlén, Johan
    et al.
    Stockholm University, Faculty of Science, Department of Botany.
    Münzbergova, Zuzana
    Timing of flowering - opposed selection on different fitness components and trait covariation2009In: American Naturalist, ISSN 0003-0147, E-ISSN 1537-5323, Vol. 173, p. 819-830Article in journal (Refereed)
  • 25.
    Ehrlén, Johan
    et al.
    Stockholm University, Faculty of Science, Department of Ecology, Environment and Plant Sciences.
    Raabova, Jana
    Dahlgren, Johan P.
    Flowering schedule in a perennial plant; life-history trade-offs, seed predation, and total offspring fitness2015In: Ecology, ISSN 0012-9658, E-ISSN 1939-9170, Vol. 96, no 8, p. 2280-2288Article in journal (Refereed)
    Abstract [en]

    Optimal timing of reproduction within a season may be influenced by several abiotic and biotic factors. These factors sometimes affect different components of fitness, making assessments of net selection difficult. We used estimates of offspring fitness to examine how pre-dispersal seed predation influences selection on flowering schedule in an herb with a bimodal flowering pattern, Actaea spicata. Within individuals, seeds from flowers on early terminal inflorescences had a higher germination rate and produced larger seedlings than seeds from flowers on late basal inflorescences. Reproductive value, estimated using demographic integral projection models and accounting for size-dependent differences in future performance, was two times higher for intact seeds from early flowers than for seeds from late flowers. Fruits from late flowers were, however, much more likely to escape seed predation than fruits from early flowers. Reproductive values of early and late flowers balanced at a predation intensity of 63%. Across 15 natural populations, the strength of selection for allocation to late flowers was positively correlated with mean seed predation intensity. Our results suggest that the optimal shape of the flowering schedule, in terms of the allocation between early and late flowers, is determined by the trade-off between offspring number and quality, and that variation in antagonistic interactions among populations influences the balancing of this trade-off. At the same time they illustrate that phenotypic selection analyses that fail to account for differences in offspring fitness might be misleading.

  • 26.
    Elmhagen, Bodil
    et al.
    Stockholm University, Faculty of Science, Department of Zoology.
    Destouni, Georgia
    Stockholm University, Faculty of Science, Department of Physical Geography.
    Angerbjörn, Anders
    Stockholm University, Faculty of Science, Department of Zoology.
    Borgström, Sara
    Stockholm University, Faculty of Science, Stockholm Resilience Centre.
    Boyd, Emily
    Stockholm University, Faculty of Science, Stockholm Resilience Centre. University of Reading, England.
    Cousins, Sara A. O.
    Stockholm University, Faculty of Science, Department of Physical Geography.
    Dalen, Love
    Ehrlén, Johan
    Stockholm University, Faculty of Science, Department of Physical Geography. Stockholm University, Faculty of Science, Department of Ecology, Environment and Plant Sciences.
    Ermold, Matti
    Hambäck, Peter A.
    Stockholm University, Faculty of Science, Department of Ecology, Environment and Plant Sciences.
    Hedlund, Johanna
    Stockholm University, Faculty of Science, Department of Zoology.
    Hylander, Kristoffer
    Stockholm University, Faculty of Science, Department of Ecology, Environment and Plant Sciences.
    Jaramillo, Fernando
    Stockholm University, Faculty of Science, Department of Physical Geography.
    Lagerholm, Vendela K.
    Stockholm University, Faculty of Science, Department of Zoology. Swedish Museum of Natural History, Sweden.
    Lyon, Steve W.
    Stockholm University, Faculty of Science, Department of Physical Geography.
    Moor, Helen
    Stockholm University, Faculty of Science, Stockholm Resilience Centre.
    Nykvist, Björn
    Stockholm University, Faculty of Science, Stockholm Resilience Centre. Stockholm University, Stockholm Environment Institute.
    Pasanen-Mortensen, Marianne
    Stockholm University, Faculty of Science, Department of Zoology.
    Plue, Jan
    Stockholm University, Faculty of Science, Department of Physical Geography.
    Prieto, Carmen
    Stockholm University, Faculty of Science, Department of Physical Geography.
    van der Velde, Ype
    Stockholm University, Faculty of Science, Department of Physical Geography. Wageningen University & Research Center, Netherlands.
    Lindborg, Regina
    Stockholm University, Faculty of Science, Department of Physical Geography.
    Interacting effects of change in climate, human population, land use, and water use on biodiversity and ecosystem services2015In: Ecology & society, ISSN 1708-3087, E-ISSN 1708-3087, Vol. 20, no 1, article id UNSP 23Article in journal (Refereed)
    Abstract [en]

    Human population growth and resource use, mediated by changes in climate, land use, and water use, increasingly impact biodiversity and ecosystem services provision. However, impacts of these drivers on biodiversity and ecosystem services are rarely analyzed simultaneously and remain largely unknown. An emerging question is how science can improve the understanding of change in biodiversity and ecosystem service delivery and of potential feedback mechanisms of adaptive governance. We analyzed past and future change in drivers in south-central Sweden. We used the analysis to identify main research challenges and outline important research tasks. Since the 19th century, our study area has experienced substantial and interlinked changes; a 1.6 degrees C temperature increase, rapid population growth, urbanization, and massive changes in land use and water use. Considerable future changes are also projected until the mid-21st century. However, little is known about the impacts on biodiversity and ecosystem services so far, and this in turn hampers future projections of such effects. Therefore, we urge scientists to explore interdisciplinary approaches designed to investigate change in multiple drivers, underlying mechanisms, and interactions over time, including assessment and analysis of matching-scale data from several disciplines. Such a perspective is needed for science to contribute to adaptive governance by constantly improving the understanding of linked change complexities and their impacts.

  • 27.
    Eriksson, Ove
    et al.
    Stockholm University, Faculty of Science, Department of Botany. Växtekologi.
    Ehrlén, Johan
    Stockholm University, Faculty of Science, Department of Botany. Växtekologi.
    Seedling recruitment and population ecology2008In: Seedling Ecology and Evolution, Cambridge University Press, Cambridge , 2008, p. 239-254Chapter in book (Refereed)
  • 28.
    Fogelström, Elsa
    et al.
    Stockholm University, Faculty of Science, Department of Ecology, Environment and Plant Sciences.
    Olofsson, Martin
    Stockholm University, Faculty of Science, Department of Zoology.
    Posledovich, Diana
    Stockholm University, Faculty of Science, Department of Zoology.
    Wiklund, Christer
    Stockholm University, Faculty of Science, Department of Zoology.
    Dahlgren, Johan P.
    Ehrlén, Johan
    Stockholm University, Faculty of Science, Department of Ecology, Environment and Plant Sciences.
    Plant-herbivore synchrony and selection on plant flowering phenology2017In: Ecology, ISSN 0012-9658, E-ISSN 1939-9170, Vol. 98, no 3, p. 703-711Article in journal (Refereed)
    Abstract [en]

    Temporal variation in natural selection has profound effects on the evolutionary trajectories of populations. One potential source of variation in selection is that differences in thermal reaction norms and temperature influence the relative phenology of interacting species. We manipulated the phenology of the butterfly herbivore Anthocharis cardamines relative to genetically identical populations of its host plant, Cardamine pratensis, and examined the effects on butterfly preferences and selection acting on the host plant. We found that butterflies preferred plants at an intermediate flowering stage, regardless of the timing of butterfly flight relative to flowering onset of the population. Consequently, the probability that plant genotypes differing in timing of flowering should experience a butterfly attack depended strongly on relative phenology. These results suggest that differences in spring temperature influence the direction of herbivore-mediated selection on flowering phenology, and that climatic conditions can influence natural selection also when phenotypic preferences remain constant.

  • 29. Garcia,
    et al.
    Pico,
    Ehrlén,
    Stockholm University, Faculty of Science, Department of Botany.
    Life span correlates with population dynamics in perennial herbaceous plants2008In: American Journal of BotanyArticle in journal (Refereed)
  • 30. Garcia, Maria B.
    et al.
    Dahlgren, Johan P.
    Stockholm University, Faculty of Science, Department of Botany.
    Ehrlen, Johan
    Stockholm University, Faculty of Science, Department of Botany.
    No evidence of senescence in a 300-year-old mountain herb2011In: Journal of Ecology, ISSN 0022-0477, E-ISSN 1365-2745, Vol. 99, no 6, p. 1424-1430Article in journal (Refereed)
    Abstract [en]

    1. Understanding how vital rates and reproductive value change with age is fundamental to demography, life history evolution and population genetics. The universality of organism senescence has been questioned on both theoretical and empirical grounds, and the prevalence and strength of senescence remain a controversial issue. Plants are particularly interesting for studies of senescence since individuals of many species have been reported to reach very high ages. 2. In this study, we examined whether the herb Borderea pyrenaica, known to reach ages of more than 300 years, experiences senescence. We collected detailed demographic information from male and female individuals in two populations over 5 years. An unusual morphological feature in this species enabled us to obtain exact age estimates for each of the individuals at the end of the demographic study. 3. We used restricted cubic regression splines and generalized linear models to determine nonlinear effects of age and size on vital rates. We then incorporated the effects of age and size in integral projection models of demography for determining the relationship between age and reproductive value. As the species is dioecious, we performed analyses separately for males and females and examined also the hypothesis that a larger reproductive effort in females comes at a senescence cost. 4. We found no evidence for senescence. Recorded individuals reached 260 years, but growth and fecundity of female and male individuals did not decrease at high ages, and survival and reproductive value increased with age. The results were qualitatively similar also when accounting for size and among-individual vital rate heterogeneity, with the exception that male flowering probability decreased with age when accounting for size increases. 5. Synthesis. Overall, our results show that performance of both male and female plants of B. pyrenaica may increase rather than decrease at ages up to several centuries, and they support the notion that senescence may be negligible in long-lived modular organisms. This highlights the need to explore mechanisms that enable some species to maintain high reproductive values also at very high ages and to identify the evolutionary reasons why some organisms appear to experience no or negligible senescence.

  • 31. Graae, Bente J.
    et al.
    Vandvik, Vigdis
    Armbruster, W. Scott
    Eiserhardt, Wolf L.
    Svenning, Jens-Christian
    Hylander, Kristoffer
    Stockholm University, Faculty of Science, Department of Ecology, Environment and Plant Sciences.
    Ehrlén, Johan
    Stockholm University, Faculty of Science, Department of Ecology, Environment and Plant Sciences.
    Speed, James D. M.
    Klanderud, Kari
    Brathen, Kari Anne
    Milbau, Ann
    Opedal, Oystein H.
    Alsos, Inger G.
    Ejrnaes, Rasmus
    Bruun, Hans Henrik
    Birks, H. John B.
    Westergaard, Kristine B.
    Birks, Hilary H.
    Lenoir, Jonathan
    Stay or go - how topographic complexity influences alpine plant population and community responses to climate change2018In: Perspectives in plant ecology, evolution and systematics, ISSN 1433-8319, E-ISSN 1618-0437, Vol. 30, p. 41-50Article in journal (Refereed)
    Abstract [en]

    In the face of climate change, populations have two survival options - they can remain in situ and tolerate the new climatic conditions (stay), or they can move to track their climatic niches (go). For sessile and small-stature organisms like alpine plants, staying requires broad climatic tolerances, realized niche shifts due to changing biotic interactions, acclimation through plasticity, or rapid genetic adaptation. Going, in contrast, requires good dispersal and colonization capacities. Neither the magnitude of climate change experienced locally nor the capacities required for staying/going in response to climate change are constant across landscapes, and both aspects may be strongly affected by local microclimatic variation associated with topographic complexity. We combine ideas from population and community ecology to discuss the effects of topographic complexity in the landscape on the immediate stay or go opportunities of local populations and communities, and on the selective pressures that may have shaped the stay or go capacities of the species occupying contrasting landscapes. We demonstrate, using example landscapes of different topographical complexity, how species' thermal niches could be distributed across these landscapes, and how these, in turn, may affect many population and community ecological processes that are related to adaptation or dispersal. Focusing on treeless alpine or Arctic landscapes, where temperature is expected to be a strong determinant, our theorethical framework leads to the hypothesis that populations and communities of topographically complex (rough and patchy) landscapes should be both more resistant and more resilient to climate change than those of topographically simple (flat and homogeneous) landscapes. Our theorethical framework further points to how meta-community dynamics such as mass effects in topographically complex landscapes and extinction lags in simple landscapes, may mask and delay the long-term outcomes of these landscape differences under rapidly changing climates.

  • 32.
    Greiser, Caroline
    et al.
    Stockholm University, Faculty of Science, Department of Ecology, Environment and Plant Sciences.
    Meineri, Eric
    Stockholm University, Faculty of Science, Department of Ecology, Environment and Plant Sciences. Marseille University, France.
    Luoto, Miska
    Ehrlén, Johan
    Stockholm University, Faculty of Science, Department of Ecology, Environment and Plant Sciences.
    Hylander, Kristoffer
    Stockholm University, Faculty of Science, Department of Ecology, Environment and Plant Sciences.
    Monthly microclimate models in a managed boreal forest landscape2018In: Agricultural and Forest Meteorology, ISSN 0168-1923, E-ISSN 1873-2240, Vol. 250-251, p. 147-158Article in journal (Refereed)
    Abstract [en]

    The majority of microclimate studies have been done in topographically complex landscapes to quantify and predict how near-ground temperatures vary as a function of terrain properties. However, in forests understory temperatures can be strongly influenced also by vegetation. We quantified the relative influence of vegetation features and physiography (topography and moisture-related variables) on understory temperatures in managed boreal forests in central Sweden. We used a multivariate regression approach to relate near-ground temperature of 203 loggers over the snow-free seasons in an area of ∼16,000 km2 to remotely sensed and on-site measured variables of forest structure and physiography. We produced climate grids of monthly minimum and maximum temperatures at 25 m resolution by using only remotely sensed and mapped predictors. The quality and predictions of the models containing only remotely sensed predictors (MAP models) were compared with the models containing also on-site measured predictors (OS models). Our data suggest that during the warm season, where landscape microclimate variability is largest, canopy cover and basal area were the most important microclimatic drivers for both minimum and maximum temperatures, while physiographic drivers (mainly elevation) dominated maximum temperatures during autumn and early winter. The MAP models were able to reproduce findings from the OS models but tended to underestimate high and overestimate low temperatures. Including important microclimatic drivers, particularly soil moisture, that are yet lacking in a mapped form should improve the microclimate maps. Because of the dynamic nature of managed forests, continuous updates of mapped forest structure parameters are needed to accurately predict temperatures. Our results suggest that forest management (e.g. stand size, structure and composition) and conservation may play a key role in amplifying or impeding the effects of climate-forcing factors on near-ground temperature and may locally modify the impact of global warming.

  • 33.
    Hambäck, Peter A.
    et al.
    Stockholm University, Faculty of Science, Department of Botany.
    Dahlgren, Johan P.
    Stockholm University, Faculty of Science, Department of Botany.
    Andersson, Petter
    Stockholm University, Faculty of Science, Department of Botany.
    Rabasa, Sonja G.
    Bommarco, Riccardo
    Ehrlén, Johan
    Stockholm University, Faculty of Science, Department of Botany.
    Plant trait-mediated interactions between early and late herbivores on common figwort (Scrophularia nodosa) and effects on plant seed set2011In: Ecoscience, ISSN 1195-6860, Vol. 18, no 4, p. 375-381Article in journal (Refereed)
    Abstract [en]

    This study examined the interactive effects of early and late season herbivory on the growth and reproductive output of figwort (Scrophularia nodosa). The early season herbivore is a pentatomid bug that feeds on and kills the apical meristem, while the late season herbivores are 2 weevil species and a sawfly that all feed on leaves and flowers. The direct effect of early season meristem damage on plant reproduction was quite limited, although meristem damage did cause increased branching. This change in plant morphology may entail that early season herbivores have profound indirect effects on plant reproduction by affecting the abundance of and damage caused by late season herbivores. Comparisons of plants with and without early season meristem damage, natural and artificial, also suggest that plants with meristem damage are significantly shorter throughout most of the summer and receive less damage late in season. However, the reduced damage translated to increased flowering but not to increased fruit production, suggesting that the plants were able to compensate for late season damage. In the end, and despite damage, figwort was well able to tolerate the observed meristem and leaf damage.

  • 34. Herben, T
    et al.
    Münzbergová, Z
    Mildén, Mikael
    Stockholm University, Faculty of Science, Department of Botany.
    Ehrlén, Johan
    Cousins, Sara A O
    Eriksson, Ove
    Stockholm University, Faculty of Science, Department of Botany.
    Longterm spatial dynamics of Succisa pratensis in a changing rural landscape: linking dynamical modelling with historical maps2006In: Journal of Ecology, ISSN 0022-0477, E-ISSN 1365-2745, Vol. 94, no 1, p. 131-143Article in journal (Refereed)
    Abstract [en]

    We attempt to explain the current distribution of a long-lived perennial plant, Succisa pratensis, in a rural landscape in southern Sweden by linking its population biology with documented changes in the landscape, using a dynamical, spatially explicit model incorporating population dynamics and spatial spreading of the plant. Changes in the landscape were inferred from historical maps (1850 and 1900) and aerial photographs (1945 and 2001).

     

    We tested whether predictions for the current species distribution are affected by assumptions about its early 19th century distribution, to determine whether recent history and current processes are dominant, and how past landscape changes determine current distributions.

     

    Initial conditions influence predictions of current distribution, suggesting that the current distribution still partly reflects the distribution of the species in the early 19th century. A period of 150 years is too short for Succisa to have spread extensively if dispersal parameters are given realistic values.

     

    Simulations in which present-day land-use patterns were imposed at earlier dates showed that changes in landscape structure over the past 175 years also had a strong effect on the present-day habitat occupancy and population sizes of Succisa.

     

    The dominant process for Succisanow is extinction from marginal habitats. It is therefore likely that the (relatively) high present-day occupation patterns are still due to much larger areas having been available in the past rather than to successful dispersal. Although the species has responded to landscape changes, there is little evidence of population sizes reaching equilibrium.

     

    Our approach shows that the wealth of landscape information available from historical maps can be linked with data on population biology by means of dynamical models that can make predictions about species dynamics.

  • 35. Horvitz, Carol C.
    et al.
    Ehrlén, Johan
    Stockholm University, Faculty of Science, Department of Botany.
    Matlaga, David
    Context-dependent pollinator limitation in stochastic environments: can increased seed set overpower the cost of reproduction in an understorey herb?2010In: Journal of Ecology, ISSN 0022-0477, E-ISSN 1365-2745, Vol. 98, no 2, p. 268-278Article in journal (Refereed)
    Abstract [en]

    1. In the understorey herb Lathyrus vernus seed production is pollen limited, but increased reproduction results in a lower probability of remaining reproductive. Putting these two results together, previous research reported that population growth rate lambda was negatively impacted by high pollination. 2. Thus, costs and benefits have to be translated into the common currency of their respective effects on population dynamics to determine whether populations are truly pollen limited or whether they are already at an optimal level of pollination. 3. Also, when pollinators and demography vary from year to year we require a framework that examines reproductive benefits and demographic costs in the context of a variable environment. Whether or not additional pollination will increase the stochastic population growth rate lambda(S) depends upon the balance of stochastic elasticities of the costs and benefits. 4. In constant environment models, where seed survival, germination and seedling survival were increased, we found that the high cost of reproduction could be offset by improvements in seed survival and germination, but not by improvements of seedling survival. 5. In variable environment models, where changes in the sequence and frequencies of high- and low-pollination years mixed with occasional high-germination years were modelled, we found that increasing the frequency of high-germination conditions could offset the cost of reproduction, and the offset was even greater if high-germination years occurred after a high-pollination year or if high pollination was accompanied by high-germination conditions in the same year. 6. Both deterministic lambda and stochastic lambda(S) were less sensitive to perturbation of reproduction than to perturbation of the probability for flowering plants to remain reproductive. In other words, a small change in the parameter which is related to the 'cost' of reproduction had a bigger effect than a small change in the parameter which is related to the 'benefit' of increased pollination for Lathyrus. 7.Synthesis. Stochastic environment-specific elasticities for reproduction and stasis of flowering plants differ in their response to environmental context. The cost-benefit relationships, the ultimate fitness consequences of supplemental pollen, are influenced by the frequency and sequence of years differing in pollen availability and recruitment conditions.

  • 36.
    Hylander, Kristoffer
    et al.
    Stockholm University, Faculty of Science, Department of Ecology, Environment and Plant Sciences.
    Ehrlen, Johan
    Stockholm University, Faculty of Science, Department of Ecology, Environment and Plant Sciences.
    The mechanisms causing extinction debts2013In: Trends in Ecology & Evolution, ISSN 0169-5347, E-ISSN 1872-8383, Vol. 28, no 6, p. 341-346Article in journal (Refereed)
    Abstract [en]

    Extinction debts can result from many types of habitat changes involving mechanisms other than metapopulation processes. This is a fact that most recent literature on extinction debts pays little attention to. We argue that extinction debts can arise because (i) individuals survive in resistant life-cycle stages long after habitat quality change, (ii) stochastic extinctions of populations that have become small are not immediate, and (iii) metapopulations survive long after that connectivity has decreased if colonization-extinction dynamics is slow. A failure to distinguish between these different mechanisms and to simultaneously consider both the size of the extinction debt and the relaxation time hampers our understanding of how extinction debts arise and our ability to prevent ultimate extinctions.

  • 37.
    Hylander, Kristoffer
    et al.
    Stockholm University, Faculty of Science, Department of Ecology, Environment and Plant Sciences.
    Ehrlén, Johan
    Stockholm University, Faculty of Science, Department of Ecology, Environment and Plant Sciences.
    Luoto, Miska
    Meineri, Eric
    Stockholm University, Faculty of Science, Department of Ecology, Environment and Plant Sciences.
    Microrefugia: Not for everyone2015In: Ambio, ISSN 0044-7447, E-ISSN 1654-7209, Vol. 44, p. s60-S68Article in journal (Refereed)
    Abstract [en]

    Microrefugia are sites that support populations of species when their ranges contract during unfavorable climate episodes. Here, we review and discuss two aspects relevant for microrefugia. First, distributions of different species are influenced by different climatic variables. Second, climatic variables differ in the degree of local decoupling from the regional climate. Based on this, we suggest that only species limited by climatic conditions decoupled from the regional climate can benefit from microrefugia. We argue that this restriction has received little attention in spite of its importance for microrefugia as a mechanism for species resilience (the survival of unfavorable episodes and subsequent range expansion). Presence of microrefugia will depend on both the responses of individual species to local climatic variation and how climate-forcing factors shape the correlation between local and regional climate across space and time.

  • 38. Jones, Owen R.
    et al.
    Scheuerlein, Alexander
    Salguero-Gomez, Roberto
    Camarda, Carlo Giovanni
    Schaible, Ralf
    Casper, Brenda B.
    Dahlgren, Johan P.
    Ehrlén, Johan
    Stockholm University, Faculty of Science, Department of Ecology, Environment and Plant Sciences.
    Garcia, Maria B.
    Menges, Eric S.
    Quintana-Ascencio, Pedro F.
    Caswell, Hal
    Baudisch, Annette
    Vaupel, James W.
    Diversity of ageing across the tree of life2014In: Nature, ISSN 0028-0836, E-ISSN 1476-4687, Vol. 505, no 7482, p. 169-+Article in journal (Refereed)
    Abstract [en]

    Evolution drives, and is driven by, demography. A genotype moulds its phenotype's age patterns of mortality and fertility in an environment; these two patterns in turn determine the genotype's fitness in that environment. Hence, to understand the evolution of ageing, age patterns of mortality and reproduction need to be compared for species across the tree of life. However, few studies have done so and only for a limited range of taxa. Here we contrast standardized patterns over age for 11 mammals, 12 other vertebrates, 10 invertebrates, 12 vascular plants and a green alga. Although it has been predicted that evolution should inevitably lead to increasing mortality and declining fertility with age after maturity, there is great variation among these species, including increasing, constant, decreasing, humped and bowed trajectories for both long-and short-lived species. This diversity challenges theoreticians to develop broader perspectives on the evolution of ageing and empiricists to study the demography of more species.

  • 39. Jonsson,
    et al.
    Bertilsson,
    Stockholm University, Faculty of Science, Department of Botany.
    Ehrlén,
    Stockholm University, Faculty of Science, Department of Botany.
    Lönn,
    Genetic divergence of climatically marginal populations of Vicia pisiformis on the Scandinavian peninsula2008In: HereditasArticle in journal (Refereed)
  • 40. Kharouba, Heather M.
    et al.
    Ehrlén, Johan
    Stockholm University, Faculty of Science, Department of Ecology, Environment and Plant Sciences.
    Gelman, Andrew
    Bolmgren, Kjell
    Allen, Jenica M.
    Travers, Steve E.
    Wolkovich, Elizabeth M.
    Global shifts in the phenological synchrony of species interactions over recent decades2018In: Proceedings of the National Academy of Sciences of the United States of America, ISSN 0027-8424, E-ISSN 1091-6490, Vol. 115, no 20, p. 5211-5216Article in journal (Refereed)
    Abstract [en]

    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.

  • 41. Kolb, Annette
    et al.
    Dahlgren, Johan P.
    Stockholm University, Faculty of Science, Department of Botany.
    Ehrlén, Johan
    Stockholm University, Faculty of Science, Department of Botany.
    Population size affects vital rates but not population growth rate of a perennial plant2010In: Ecology, ISSN 0012-9658, E-ISSN 1939-9170, Vol. 91, no 11, p. 3210-3217Article in journal (Refereed)
    Abstract [en]

    Negative effects of habitat fragmentation on individual performance have been widely documented, but relatively little is known about how simultaneous effects on multiple vital rates translate into effects on population viability in long-lived species. In this study, we examined relationships between population size, individual growth, survival and reproduction, and population growth rate in the perennial plant Phyteuma spicatum. Population size positively affected the growth of seedlings, the survival of juveniles, the proportion of adults flowering, and potential seed production. Analyses with integral projection models, however, showed no relationship between population size and population growth rate. This was due to the fact that herbivores and pathogens eliminated the relationship between population size and seed production, and that population growth rate was not sensitive to changes in the vital rates that varied with population size. We conclude that effects of population size on vital rates must not translate into effects on population growth rate, and that populations of long-lived organisms may partly be able to buffer negative effects of small population size on vital rates that have a relatively small influence on population growth rate. Our study illustrates that we need to be cautious when assessing the consequences of habitat fragmentation for population viability based on effects on only one or a few vital rates.

  • 42. Kolb, Annette
    et al.
    Ehrlén, Johan
    Stockholm University, Faculty of Science, Department of Botany.
    Environmental context drives seed predator-mediated selection on a floral display trait2010In: Evolutionary Ecology, ISSN 0269-7653, E-ISSN 1573-8477, Vol. 24, no 2, p. 433-445Article in journal (Refereed)
    Abstract [en]

    Linking trait selection to environmental context is necessary to move beyond the simple recognition that selection is spatially variable and to understand what ultimately drives this variation. Natural selection acts through differences among individuals in lifetime fitness and information about effects on fitness components is therefore often not sufficient to gain such an understanding. We investigated how environmental context influenced intensity of seed predation, flower abortion and selection on floral display traits in 44-52 populations of the perennial herb Primula veris over 2 years. Phenotypic selection on both inflorescence height and flower number varied among populations and was mediated partly by pre-dispersal seed predation and flower abortion in one of the years. Among-population variation in selection on inflorescence height, but not flower number, was linked to variation in canopy cover via its effects on seed predation. Lifetime fitness was less sensitive to seed predator damage in shaded environments but estimates of selection based on lifetime fitness agreed qualitatively with those based on seed output. Our results demonstrate that seed predators constitute an important link between environmental conditions and trait evolution in plants, and that selection on plant traits by seed predators can depend on environmental context.

  • 43.
    Kolb, Annette
    et al.
    Stockholm University, Faculty of Science, Department of Botany. växtekologi.
    Ehrlén, Johan
    Stockholm University, Faculty of Science, Department of Botany. växtekologi.
    Eriksson, Ove
    Stockholm University, Faculty of Science, Department of Botany. växtekologi.
    Ecological and evolutionary consequences of spatial and temporal variation in pre-dispersal seed predation.2007In: Perspectives in Plant Ecology, Evolution and Systematics, Vol. 9, p. 79-100Article in journal (Refereed)
  • 44. Kolb, Annette
    et al.
    Leimu, Roosa
    Ehrlén, Johan
    Stockholm University, Faculty of Science, Department of Botany. Växtekologi.
    Environmental context influences the outcome of a plant-seed predator interaction2007In: OIKOS, Vol. 116, no 5, p. 864-872Article in journal (Other (popular science, discussion, etc.))
  • 45.
    König, Malin A. E.
    et al.
    Stockholm University, Faculty of Science, Department of Ecology, Environment and Plant Sciences.
    Lehtila, Kari
    Wiklund, Christer
    Stockholm University, Faculty of Science, Department of Zoology.
    Ehrlén, Johan
    Stockholm University, Faculty of Science, Department of Ecology, Environment and Plant Sciences.
    Among-Population Variation in Tolerance to Larval Herbivory by Anthocharis cardamines in the Polyploid Herb Cardamine pratensis2014In: PLoS ONE, ISSN 1932-6203, E-ISSN 1932-6203, Vol. 9, no 6, p. e99333-Article in journal (Refereed)
    Abstract [en]

    Plants have two principal defense mechanisms to decrease fitness losses to herbivory: tolerance, the ability to compensate fitness after damage, and resistance, the ability to avoid damage. Variation in intensity of herbivory among populations should result in variation in plant defense levels if tolerance and resistance are associated with costs. Yet little is known about how levels of tolerance are related to resistance and attack intensity in the field, and about the costs of tolerance. In this study, we used information about tolerance and resistance against larval herbivory by the butterfly Anthocharis cardamines under controlled conditions together with information about damage in the field for a large set of populations of the perennial plant Cardamine pratensis. Plant tolerance was estimated in a common garden experiment where plants were subjected to a combination of larval herbivory and clipping. We found no evidence of that the proportion of damage that was caused by larval feeding vs. clipping influenced plant responses. Damage treatments had a negative effect on the three measured fitness components and also resulted in an earlier flowering in the year after the attack. Tolerance was related to attack intensity in the population of origin, i.e. plants from populations with higher attack intensity were more likely to flower in the year following damage. However, we found no evidence of a relationship between tolerance and resistance. These results indicate that herbivory drives the evolution for increased tolerance, and that changes in tolerance are not linked to changes in resistance. We suggest that the simultaneous study of tolerance, attack intensity in the field and resistance constitutes a powerful tool to understand how plant strategies to avoid negative effects of herbivore damage evolve.

  • 46.
    König, Malin A. E.
    et al.
    Stockholm University, Faculty of Science, Department of Ecology, Environment and Plant Sciences.
    Wiklund, Christer
    Stockholm University, Faculty of Science, Department of Zoology.
    Ehrlén, Johan
    Stockholm University, Faculty of Science, Department of Ecology, Environment and Plant Sciences.
    Butterfly oviposition preference is not related to larval performance on a polyploid herb2016In: Ecology and Evolution, ISSN 2045-7758, E-ISSN 2045-7758, Vol. 6, no 9, p. 2781-2789Article in journal (Refereed)
    Abstract [en]

    The preference-performance hypothesis predicts that female insects maximize their fitness by utilizing host plants which are associated with high larval performance. Still, studies with several insect species have failed to find a positive correlation between oviposition preference and larval performance. In the present study, we experimentally investigated the relationship between oviposition preferences and larval performance in the butterfly Anthocharis cardamines. Preferences were assessed using both cage experiments and field data on the proportion of host plant individuals utilized in natural populations. Larval performance was experimentally investigated using larvae descending from 419 oviposition events by 21 females on plants from 51 populations of two ploidy types of the perennial herb Cardamine pratensis. Neither ploidy type nor population identity influenced egg survival or larval development, but increased plant inflorescence size resulted in a larger final larval size. There was no correlation between female oviposition preference and egg survival or larval development under controlled conditions. Moreover, variation in larval performance among populations under controlled conditions was not correlated with the proportion of host plants utilized in the field. Lastly, first instar larvae added to plants rejected for oviposition by butterfly females during the preference experiment performed equally well as larvae growing on plants chosen for oviposition. The lack of a correlation between larval performance and oviposition preference for A. cardamines under both experimental and natural settings suggests that female host choice does not maximize the fitness of the individual offspring.

  • 47.
    König, Malin A. E.
    et al.
    Stockholm University, Faculty of Science, Department of Ecology, Environment and Plant Sciences.
    Wiklund, Christer
    Stockholm University, Faculty of Science, Department of Zoology.
    Ehrlén, Johan
    Stockholm University, Faculty of Science, Department of Ecology, Environment and Plant Sciences.
    Context-dependent resistance against butterfly herbivory in a polyploid herb2014In: Oecologia, ISSN 0029-8549, E-ISSN 1432-1939, Vol. 174, no 4, p. 1265-1272Article in journal (Refereed)
    Abstract [en]

    Spatial variation in biotic interactions and natural selection are fundamental parts of natural systems, and can be driven by differences in both trait distributions and the local environmental context of the interaction. Most studies of plant–animal interactions have been performed only in natural settings, making it difficult to disentangle the effects of traits and context. To assess the relative importance of trait differences and environmental context for among-population variation in plant resistance to herbivory, we compared oviposition by the butterfly Anthocharis cardamines on two ploidy types of the herb Cardamine pratensis under experimentally controlled conditions with oviposition in natural populations. Under controlled conditions, plants from octoploid populations were significantly more preferred than plants from tetraploid populations. This difference was largely mediated by differences in flower size. Among natural populations, there was no difference in oviposition rates between the two ploidy types. Our results suggest that differences in oviposition rates among populations of the two cytotypes in the field are caused mainly by differences in environmental context, and that the higher attractiveness of octoploids to herbivores observed under common environmental conditions is balanced by the fact that they occur in habitats which harbor lower densities of butterflies. This illustrates that spatial variation in biotic interactions is the net result of differences in trait distributions of the interacting organisms and differences in environmental context, and that variation in both traits and context are important in understanding species interactions.

  • 48.
    König, Malin A. E.
    et al.
    Stockholm University, Faculty of Science, Department of Ecology, Environment and Plant Sciences.
    Wiklund, Christer
    Stockholm University, Faculty of Science, Department of Zoology.
    Ehrlén, Johan
    Stockholm University, Faculty of Science, Department of Ecology, Environment and Plant Sciences.
    Timing of flowering and intensity of attack by a butterfly herbivore in a polyploid herb2015In: Ecology and Evolution, ISSN 2045-7758, E-ISSN 2045-7758, Vol. 5, no 9, p. 1863-1872Article in journal (Refereed)
    Abstract [en]

    Timing of plant development both determines the abiotic conditions that the plant experiences and strongly influences the intensity of interactions with other organisms. Plants and herbivores differ in their response to environmental cues, and spatial and temporal variation in environmental conditions might influence the synchrony between host plants and herbivores, and the intensity of their interactions. We investigated whether differences in first day of flowering among and within 21 populations of the polyploid herb Cardamine pratensis influenced the frequency of oviposition by the butterfly Anthocharis cardamines during four study years. The proportion of plants that became oviposited upon differed among populations, but these differences were not related to mean flowering phenology within the population in any of the four study years. Attack rates in the field were also not correlated with resistance to oviposition estimated under controlled conditions. Within populations, the frequency of butterfly attack was higher in early-flowering individuals in two of the four study years, while there was no significant relationship in the other 2years. Larger plants were more likely to become oviposited upon in all 4years. The effects of first flowering day and size on the frequency of butterfly attack did not differ among populations. The results suggest that differences in attack intensities among populations are driven mainly by differences in the environmental context of populations while mean differences in plant traits play a minor role. The fact that within populations timing of flowering influenced the frequency of herbivore attack only in some years and suggests that herbivore-mediated selection on plant phenology differs among years, possibly because plants and herbivores respond differently to environmental cues.

  • 49.
    König, Malin
    et al.
    Stockholm University, Faculty of Science, Department of Ecology, Environment and Plant Sciences.
    Lehtilä, Kari
    Södertörn University.
    Wiklund, Christer
    Stockholm University, Faculty of Science, Department of Zoology.
    Ehrlén, Johan
    Stockholm University, Faculty of Science, Department of Ecology, Environment and Plant Sciences.
    Among-population variation in tolerance to larval herbivory by Anthocharis cardamines in the polyploid herb Cardamine pratensisManuscript (preprint) (Other academic)
  • 50.
    König, Malin
    et al.
    Stockholm University, Faculty of Science, Department of Ecology, Environment and Plant Sciences.
    Wiklund, Christer
    Stockholm University, Faculty of Science, Department of Zoology.
    Ehrlén, Johan
    Stockholm University, Faculty of Science, Department of Ecology, Environment and Plant Sciences.
    Among-population variation in butterfly oviposition preference and larval performance on a polyploid herbManuscript (preprint) (Other academic)
12 1 - 50 of 88
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