Climate change, land-use change, pollution and exploitation are among the main drivers of species' population trends; however, their relative importance is much debated. We used a unique collection of over 1,000 local population time series in 22 communities across terrestrial, freshwater and marine realms within central Europe to compare the impacts of long-term temperature change and other environmental drivers from 1980 onwards. To disentangle different drivers, we related species' population trends to species-and driver-specific attributes, such as temperature and habitat preference or pollution tolerance. We found a consistent impact of temperature change on the local abundances of terrestrial species. Populations of warm-dwelling species increased more than those of cold-dwelling species. In contrast, impacts of temperature change on aquatic species' abundances were variable. Effects of temperature preference were more consistent in terrestrial communities than effects of habitat preference, suggesting that the impacts of temperature change have become widespread for recent changes in abundance within many terrestrial communities of central Europe.

The phenology of seed ripening and release are important for dispersal, reproductive success and survival of plants. Most phenological studies, however, consider early phenological phases. Here, we examined the ecological and evolutionary basis of ripening and seed release phenology. We monitored single flower phenology for 104 plant species from 30 families and three life forms from central Europe. Further, we undertook an associate monitoring study along an elevational gradient over two years. We calculated temperature demands (as growing degree days) for ripening and seed release and examined them with respect to the species' seed mass, life form, dispersal mode and phylogeny. We found a strong correlation between species' seed mass and temperature demands for ripening. For both variables seed mass and temperature demands for seed ripening, we found a strong effect of the species phylogeny. These phylogenetic signals indicate that the evolutionary history of the species' lineage affects its seed mass and the temperature demands for seed ripening. Among the studied life forms, shrub species showed the most efficient ripening process. Anemochorous species showed lower relative humidity during seed release than epizoochorous species. For anemochorous species, the synchronisation of release timing with periods that show favourable environmental conditions for wind dispersal could be interpreted as a phenological adaptation to increase dispersal distances. According to the monitoring along the elevational gradient, individuals from higher altitudes showed lower temperature demands for ripening than individuals from lower altitudes. This might tentatively indicate physiological adaptations to lower temperature demands for locations with a shorter growing season. Our study provides basic insights into the ecological, environmental and evolutionary constraints that shape the ripening and seed release phenology of plants. We introduce data that can be used to advance existing models of ripening phenology, seed release and plant spread.

AimCommon ragweed (Ambrosia artemisiifolia L.) is a medically relevant invasive species of great public interest due to its highly allergenic pollen. We aimed at modelling its potential range, its net primary production (NPP) and important phenological stages.LocationEurope and North America.MethodsWe developed a new physiological model for common ragweed and applied it to simulate the species potential distribution (calibrated with the native range), NPP and phenology in North America and Europe. Based on this model, we investigated which regions are suitable for ragweed growth in Europe and simulated the timing of phenological stages that determine pollen release.ResultsThe model predicted the observed distribution of ragweed in North America well. The application to Europe suggests that large parts of Europe are climatically suitable for ragweed growth and reproduction. The highest potential NPP was predicted in southern-central and south-eastern Europe and southern France, roughly corresponding with hotspots of atmospheric pollen load, but also indicating a higher potential than currently achieved in western Europe and along parts of the northern edge of its distribution. The predicted time of pollen releases in Europe corresponded well with measurements from pollen traps.Main conclusionsThe results suggest that our mechanistic model adequately represents physiological and ecological characteristics that determine the potential distribution, productivity and phenology of common ragweed. The model could be used for predicting the potential distribution and performance of ragweed in the future under climate change and might thus contribute to improved longer term predictions of exposure to allergenic pollen.

New PhytologistVolume 210, Issue 1 p. 13-17 LettersFree Access Herbs are different: clonal and bud bank traits can matter more than leaf–height–seed traits Jitka Klimešová, Jitka Klimešová Institute of Botany, Academy of Sciences of the Czech Republic, CZ-379 82 Třeboň, Czech RepublicSearch for more papers by this authorOliver Tackenberg, Oliver Tackenberg Institute of Ecology, Evolution and Diversity, Goethe-University Frankfurt, Max-von-Laue-Straße 13, D-60438 Frankfurt, GermanySearch for more papers by this authorTomáš Herben, Corresponding Author Tomáš Herben Institute of Botany, Academy of Science of the Czech Republic, CZ-252 43 Průhonice, Czech Republic Department of Botany, Faculty of Science, Charles University, Benátská 2, CZ-128 01 Praha 2, Czech RepublicAuthor for correspondence: tel +420 221951653; email herben@site.cas.czSearch for more papers by this author Jitka Klimešová, Jitka Klimešová Institute of Botany, Academy of Sciences of the Czech Republic, CZ-379 82 Třeboň, Czech RepublicSearch for more papers by this authorOliver Tackenberg, Oliver Tackenberg Institute of Ecology, Evolution and Diversity, Goethe-University Frankfurt, Max-von-Laue-Straße 13, D-60438 Frankfurt, GermanySearch for more papers by this authorTomáš Herben, Corresponding Author Tomáš Herben Institute of Botany, Academy of Science of the Czech Republic, CZ-252 43 Průhonice, Czech Republic Department of Botany, Faculty of Science, Charles University, Benátská 2, CZ-128 01 Praha 2, Czech RepublicAuthor for correspondence: tel +420 221951653; email herben@site.cas.czSearch for more papers by this author First published: 09 December 2015 https://doi.org/10.1111/nph.13788Citations: 59AboutSectionsPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL Share a linkShare onFacebookTwitterLinkedInRedditWechat Introduction Current understanding of functional differences among plant species is based on several key axes of specialization in response to environmental gradients, namely of productivity and disturbance. These axes include leaf economy spectrum, plant size and dispersal ability (Westoby, 1998; Westoby et al., 2002; Wright et al., 2004). These axes are typically proxied by easily measurable traits, namely specific leaf area, height at maturity and seed mass (leaf–height–seed (LHS) traits of Westoby, 1998) which capture well variation in a number of correlated plant characteristics (Westoby & Wright, 2006; Laughlin et al., 2010). While the first comprehensive trait-based analysis was dealing primarily with herbs (Grime, 1977), LHS-based analyses turned out to be particularly powerful to describe ecological differentiation of woody plants. In spite of the fact that woody species constitute less than a half of existing plant species (FitzJohn et al., 2014), much current understanding of plant functional tradeoffs is based on species sets that contain primarily woody species (Verdu, 2002; Kerkhoff et al., 2014; Lamanna et al., 2014). However, differentiation of herbaceous plants is likely to be shaped by factors different from woody species. They do not possess permanent aboveground structures which permits entirely different response to disturbance (Aarssen et al., 2006; Aarssen, 2008; Zanne et al., 2014), but also to other factors, such as drought (Bennett et al., 2015). While strong and infrequent disturbance kills whole plants and generates a long gradient of time-since-disturbance which favours woody species (Meiners et al., 2015), weaker and regular disturbance events leave belowground regenerative organs intact, favouring plants which can resprout from them (Bellingham & Sparrow, 2000; Mackey & Currie, 2001; Buoro & Carlson, 2014). Such disturbances preclude plants from developing long-lived structures aboveground found in trees and favour resprouting from permanent belowground structures (Bellingham & Sparrow, 2000; Vesk et al., 2004; Dietze & Clark, 2008) as found in shrubs (Bond & Midgley, 2001; Vesk et al., 2004; Dietze & Clark, 2008; Clarke et al., 2013) and herbs (Klimešová & Klimeš, 2007; Meiners et al., 2015). Further, short disturbance intervals (such as winter frost in temperate climates, regular drought or grazing) require rapid resprouting and therefore cheap aboveground tissues that are non-woody (Vesk, 2006; Zanne et al., 2014) and thus largely eliminate selective advantage provided by vertical growth and favour expansion in a horizontal dimension by clonal spread. Selective forces operating on resprouting plants are thus fairly different from those operating on trees. As a result, tradeoffs and correlations of their traits should be different from those known from woody species (Meiners et al., 2015). Still we do not know to what extent the key role of the LHS-differentiation applies to herbs as it does to woody species, and trees in particular. We also do not know whether and how traits that determine ability to resprout and spread horizontally in space (namely traits of belowground bud banks and traits of clonal growth) fit into this differentiation or whether they constitute an axis of specialization independent of the LHS traits. Clonal and belowground bud bank traits and their relationship to the LHS scheme We examined relationships between LHS traits and traits of bud bank (size and depth) and of clonal growth (extension of lateral spread, multiplication rate and persistence of clonal connections; for an illustration see Fig. 1) of Central European species (c. 2000 species). Analysis of this data set shows that almost all relationships between LHS traits, bud bank and clonal traits are very weak (Table 1; for methodological details see Supporting Information Methods S1 and Tables S1 and S2). With the exception of bud bank depth and connection persistence, LHS traits explain < 5% of the variation in clonal and bud bank traits (and often much less). This means that the variation on traits that determine resprouting and clonal spread do not fit well into the syndromes of the LHS traits. Figure 1Open in figure viewerPowerPoint A schematic representation of clonal and bud bank traits. Each trait is illustrated by a pair of species that differ in the value of that trait. Red dots, buds. Full horizontal line, living spacer (rhizome or stolon); dashed horizontal line, dead spacer. For further details see Supporting Information Table S1. Table 1. Prediction of clonal and bud bank traits with leaf–height–seed (LHS) traits in a set of herbs of the Central European flora Predictor Bud bank size Mean bud bank depth Multiplication ratea Lateral spreada Persistence of connectionsa Height phylogenetic adjusted R2 0.017*** (+) 0.047*** (+) 0.007* (−) 0.008** (+) −0.001 adjusted R2 0.010*** (+) 0.030*** (+) 0.021*** (−) 0.018*** (+) 0.024*** (+) n 1359 1316 718 715 711 SLA phylogenetic adjusted R2 0.009*** (−) 0.009** (−) 0 −0.001 0.028*** (−) adjusted R2 0.017*** (−) 0.018*** (−) 0.001 0.008* (+) 0.101*** (−) n 1078 1039 577 572 568 Seed mass phylogenetic adjusted R2 0.003* (+) 0.009** (+) 0.008* (−) 0.004 0.007* (+) adjusted R2 −0.001 0.022*** (+) 0.022*** (−) 0.004 0.001 n 990 957 519 517 513 All three phylogenetic adjusted R2 0.032*** 0.065*** 0.003 0.007 0.026*** adjusted R2 0.030*** 0.062*** 0.009 0.016** 0.071*** n 877 848 462 460 457 Phylogenetic adjusted R2 is based on the value of Pagel's λ estimated by maximum likelihood; adjusted R2, adjusted R2 assuming independence of phylogenetic histories of species; n, number of cases; SLA, specific leaf area. R2 values > 0.05 are indicated in bold. Sign of the relationship (if significant) is in parentheses. Asterisks indicate uncorrected significance values: * , P < 0.05; ** , P < 0.01; *** , P < 0.001. a Defined for clonal plants only. For further details see Supporting Information Methods S1 and Table S1. For further information on individual clonal and bud bank traits, see Fig. 1. The few significant cases of correlation of clonal and bud bank traits with the LHS traits (see Table S3; Fig. S1) are likely to be due to two different reasons. First, bud bank depth, and to a much lesser extent bud bank size and lateral spread, are positively correlated with plant height at maturity. These relationships are likely to be due to allometric effects of plant size (Enquist & Niklas, 2001; Schenk & Jackson, 2002). Tall plants are likely to have more extensive root and rhizome systems, bear more buds than short roots and rhizomes (VanderWeide & Hartnett, 2015) and are more likely to spread farther away from the mother plants. Second, negative correlation of specific leaf area with connection persistence implies that clonal plants are also differentiated in terms of leaf economics, and faster growing plants of more productive conditions tend to have short-lived connections between ramets and longer rhizome increments relative to plants that grow slower (see also Jónsdóttir & Watson, 1997; Craine et al., 2001). Clonal and belowground bud bank traits as predictors of herb distribution along ecological gradients An independent axis of plant specialization is not characterized only by a trait which is not correlated with LHS traits, but, at the same time, it must improve substantially the predictive power of LHS traits for plant distribution in the field. Existing data show that traits of clonal growth and belowground bud bank (namely bud bank size and connection persistence) predict species distribution along ecological gradients in Central European vegetation at least as well as the LHS traits. Their net predictive power is similar to that of the LHS traits combined (Fig. 2; Table 2) and is not due to the (small but existing) covariation of these traits with the LHS traits. This leads to a conclusion that clonal and bud bank traits, that is, traits that determine resprouting and clonal multiplication, indeed form axes of specialization of temperate herbs fairly independent of the LHS traits. However, it should be noted that the combined predictive power of both groups of traits reaches only c. 10% of the total variation in the species habitat distribution in the field. Figure 2Open in figure viewerPowerPoint Predictive power of bud bank and clonal traits as a group for species distribution across habitat types compared with the predictive power of leaf–height–seed (LHS) traits. Models for all herbs use bud bank traits only, while models for clonal plants use all clonal traits. For further details see Table 2 and Supporting Information Table S1. Table 2. Predictive power of individual clonal and bud bank traits for occurrence of herb species in habitat types of Central European vegetation Adjusted R2 LHS Adjusted R2 LHS+trait Partial adjusted R2 trait n Bud bank size 0.061*** 0.113*** 0.055*** 757 Mean bud bank depth 0.066*** 0.115*** 0.052*** 730 Multiplication ratea 0.087*** 0.094*** 0.007** 413 Lateral spreada 0.088*** 0.099*** 0.012*** 411 Persistence of connectionsa 0.088*** 0.122*** 0.037*** 409 Relative number of occurrences in major habitat types are taken as dependent variables, and their prediction by leaf–height–seed (LHS) traits (first column) and individual clonal and bud bank traits (second and third columns) is examined by multivariate extension of multiple regression (redundancy analysis). Phylogenetic non-independence of traits is removed using phylogenetic eigenvectors (Diniz-Filho et al., 1998). Differences among rows in the first column (the model with LHS traits only) is due to different number of cases included. Significances are based on randomization tests. ** , P < 0.01; *** , P < 0.001. a Defined for clonal plants only. For further details see Supporting Information Methods S1 and Table S1. First, the distribution along ecological gradients is best predicted by bud bank size and connection persistence. In contrast to the LHS traits, which (namely leaf traits) capture the role of physiological performance and the pace of life, the bud bank size and clonality per se expresses primarily morphological/developmental constraints on the potential to resprout. Although the herbaceous habit probably did not evolve in temperate regions (Zanne et al., 2014), prevalence of resprouting and/or clonally growing herbs is the determining feature of temperate vegetation, both in (semi-)natural habitats and in communities regularly disturbed by human activities such as arable fields, mown and pastured grasslands, and ruderal places (Klimešová & Herben, 2015). The resprouting ability in herbs is likely to have evolved under a number of disturbance regimes, such as large ungulate grazing, fire, flooding and avalanches (Klimeš et al., 1997; Bellingham & Sparrow, 2000; Klimešová & Klimeš, 2007). Second, the differences due to connection persistence and correlated clonal traits are likely to reflect the gradient of stress/productivity as clonal plants with persistent connections are known to occur in stressed and unproductive conditions (Jónsdóttir & Watson, 1997; Klimešová & Herben, 2015). Slow growing clonal plants tend to have long-lived connections between ramets and shorter rhizome increments relative to plants that grow faster (see definition of different clonal growth strategies in de Kroon & Schieving, 1990; Jónsdóttir & Watson, 1997; Craine et al., 2001). This parallels development of costly, but long-lived leaf tissues in slowly growing plants in stressed conditions and cheap short-lived tissues in fast growing species under productive conditions (Reich et al., 1992; Westoby & Wright, 2006). Implications Our analyses support the hypothesis that functional differentiation within herbaceous plants thus is based, to an important extent, on dimensions different from those that are used in large-scale studies that include primarily woody species. This is due to the two fundamentally different strategies that plants use to cope with disturbance: tolerance (resprouting) and avoidance (by dispersing to disturbed habitats by seeds, either in time or in space). The LHS system captures seed and growth-related traits that are primarily important for disturbance avoidance, whereas milder and more frequent disturbances select for the second strategy, which is associated with clonal and bud bank traits that supply reserve meristems for survival. Further, it should be noted here that while the predictive power of clonal and bud bank traits relative to that of the LHS trait is high, neither of them is a very strong predictor of species habitat distribution. This may be partly due to the restricted range of plants studied here, as traits of temperate herbs have smaller ranges relative to what is found across the plant kingdom, namely in height, but also in seed size (see e.g. Thompson & Rabinowitz, 1989; Moles et al., 2007). However, we would like to point out here the low predictive power of all commonly collected traits for species distribution along ecological gradients which is often not paid sufficient attention (but see e.g. Coyle et al., 2014; Moles et al., 2014). Finally, we would like to point out that clonal and bud bank traits should be given more prominence in trait-based analyses of species habitat distribution and coexistence. Clonality is a key potential of plant bodies (Mogie & Hutchings, 1990; Klimešová et al., 2015) with deep interspecific differences in the way in which it is expressed (Klimeš et al., 1997), but we are only beginning to appreciate its full ecological implications. Temperate herbs show rather a broad range of clonal growth types (J. Klimešová, 2015, unpublished data), but clonal growth is also found in trees and woody species, albeit in lower proportions (Aarssen, 2008). While collecting data on its traits is often more difficult than collecting data on LHS traits, it is feasible and has been done both for herbs and woody species (Bond & Midgley, 2001; Klimešová & de Bello, 2009; Clarke et al., 2013; VanderWeide & Hartnett, 2015). Comparative analyses of their role relative to other traits, and their mutual relationships across different biomes and different floras would provide better understanding about how plants respond to a number of factors, namely disturbance. Comparison of the role of clonal growth and bud banks in herbs and woody species would also shed more light on differences between these two fundamental ecological strategies in the plant kingdom. Acknowledgements The authors thank Irena Šímová, Robin Pakeman, Benjamin Blonder and three anonymous referees for thoughtful comments on earlier versions of this paper. The research was partly supported by the Grant Agency of the Czech Republic (projects GA P505/12/1007, P505/13-17118S, Centre of Excellence 14-36079G, PLADIAS). Author contributions J.K. and T.H. planned and designed the research, J.K. and O.T. assembled data, T.H. analysed data, T.H. wrote the manuscript with contributions of J.K. and O.T. Supporting Information Please note: Wiley Blackwell are not responsible for the content or functionality of any supporting information supplied by the authors. Any queries (other than missing material) should be directed to the New Phytologist Central Office. Filename Description nph13788-sup-0001-SupInfo.pdfPDF document, 556.7 KB Fig. S1 Pairwise plots of leaf–height–seed (LHS) traits and clonal traits.Table S1 Bud bank and clonal growth traits used in the analysesMethods S1 Data sources and data analysis. nph13788-sup-0002-TableS2.txtplain text document, 166.2 KB Table S2 Values of individual species traits, and their distribution in the EUNIS habitat types nph13788-sup-0003-TableS3.pdfPDF document, 99.7 KB Table S3 Pearson correlation coefficients of leaf–height–seed (LHS) traits and clonal traits Please note: The publisher is not responsible for the content or functionality of any supporting information supplied by the authors. Any queries (other than missing content) should be directed to the corresponding author for the article. References Aarssen LW. 2008. Death without sex - the 'problem of the small' and selection for reproductive economy in flowering plants. Evolutionary Ecology 22: 279– 298. 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Nature 428: 821– 827. Zanne AE, Tank DC, Cornwell WK, Eastman JM, Smith SA, FitzJohn RG, McGlinn DJ, O'Meara BC, Moles AT, Reich PB et al. 2014. Three keys to the radiation of angiosperms into freezing environments. Nature 514: 394. Citing Literature Volume210, Issue1April 2016Pages 13-17 FiguresReferencesRelatedInformation

We examine the relationships of traits of seed reproduction to traits of clonal growth and bud banks. Although there are a number of functional differences between these sets of traits underlying two different modes of reproduction, they both constitute a response to ecological gradients, which makes them potentially interdependent. We performed phylogenetic regressions of seed traits and traits of bud banks and clonal growth across the Central European flora. We took Ellenberg indicator values and indices of responses to disturbance as information on the positions of species optima along important ecological gradients. The analyses show that there are almost no relationships between these two groups of traits. This contrasts with the existence of strong correlations within these groups of traits which indicate specific syndromes of seed reproduction and of clonality. Both seed traits and traits of bud banks and clonal growth show fairly strong phylogenetic conservatism. The absence of correlations between individual groups of traits is at least partly due to the fact that each trait group shows relationships to different parameters of species' niches. Bud bank traits are determined by the disturbance niche of the species, clonal traits by soil and climatic factors, while seed traits show only weak correlations with the examined environmental factors if phylogeny is taken into account.Synthesis. The absence of integrated syndromes that would cover both seed reproduction and clonality across the flora implies that there are no selective forces that would affect both trait groups simultaneously. Clonal and bud bank traits are more tightly linked to species' niches, presumably because they are selected by local population processes only, in contrast to seed traits, which play a role also in dispersal. As the phylogenetic conservatism of clonal traits is almost as strong as the phylogenetic conservatism of seed traits, these traits do not serve as an evolutionarily more flexible alternative to seed reproduction.

Vegetation succession on glacier forelands has been well-studied. However, most of the studies investigated only one or few glacier forelands. We studied regional variations in vegetation succession on 16 glacier forelands in the European Alps. To improve our understanding of how vegetation succession is regulated by environmental conditions, we took edaphic and climatic factors into account. We collected vegetation data in three stages (early; middle; late) along a successional gradient on glacier forelands in the Eastern and Western European Alps. The progressions of species richness, vegetation cover and composition during primary succession were compared between these two regions. In addition, the effects of climatic and edaphic factors and grazing were tested. Our results reveal that the vegetation from the early stage did not differ between the regions and different elevations. With progressing time, and especially in the late successional stage, several vegetation differences emerged. The forelands of the Western Alps already developed to open shrubland, while the forelands of the Eastern Alps so far only developed toward grassland. Surprisingly, these differences cannot be explained by different precipitation amounts, but possibly by different regional species pools and elevations of the treelines. We conclude that a complex of edaphic factors closely related to terrain age, regional differences in the species pool, and the different elevation of the treeline in the eastern and western Alps mostly influenced later stages of primary succession on glacier forelands.

Questions: How does the seasonal variability of wind affect the seed release phenology of plant species from different vegetation types? Do wind-dispersed species show a seasonal synchronization of seed release timing with meteorological conditions that promote long-distance dispersal (LDD) by wind?Location: Germany, Central Europe.Methods: We combined empirical observations of seed release phenology with simulations of LDD by wind. We simulated LDD by wind for species differing in seed terminal velocity for open and forested habitats using a broad set of measured meteorological conditions. In order to investigate the extent of seasonal synchronization of seed release with LDD, we compared species' LDD throughout the year with phenological data on timing of seed release for herbaceous species from open and tree species from forested habitats.Results: For tree species with winged seeds and medium seed terminal velocity (e.g. Acer platanoides, Tilia cordata) we found a pronounced seasonal synchronization of seed release timing with high LDD by wind. These species showed an extended ripening duration together with both the highest rate of seed release and high LDD in winter. Species with low seed terminal velocity (i.e. high wind dispersal potential) from open habitats (mainly species from the Asteraceae with plumed seeds) and forested habitats (e.g. tree species of the genera Populus, Salix) both showed high LDD but lacked seasonal synchronization of seed release timing with LDD.Conclusions: For forest species with medium seed terminal velocity, the seasonal timing of seed release during winter and strong winds could be evidence for phenological adaptations to timing of wind dispersal within periods with favourable conditions. Our finding that species with low seed terminal velocity and high LDD throughout the year did not show seasonal seed release synchronization tentatively suggests that selection for other mechanisms such as synchronization with short-term weather events might promote LDD of these species. Our results provide insights into how seasonal seed release timing of plant species from different vegetation types affects LDD by wind and shows that seed release phenology should be considered while assessing species' wind dispersal potential.

Some algorithms used to model species' distributions are often only considered as black boxes; coefficients of the underlying niche functions are often not interpreted ecologically. Here, we focus on the maximum entropy approach that is commonly and successfully applied in order to model species' distribution. By means of an eigenanalysis, we decompose the niche function into independent factors that can be interpreted separately. In addition, we derive parameters that can be used to characterize the species' niche, especially considering the steepness of the modelled niche function and the sensitivity of the considered species against changes in certain environmental conditions. On the example of three well-studied Taiga forest tree species we illustrate the capability and scope of our approach. Given the easy availability of environmental data and species occurrences, the presented approach seems to be a feasible way to gain deeper insights into the factors that are related to species' distributions.

Advances in phenology and pole- and up-ward shifts in geographic ranges are well-documented signs that species are responding to climate change. A deeper understanding of such responses across ecologically different species groups will help to assess future consequences for entire ecosystems. A less well-studied pattern linked with climate change is increases in abundances of warm-adapted species compared with cold-adapted species. To compare how recent climate change has affected the abundances of species across different taxonomic groups, we analyzed long-term local population trends and related them to the species temperature niche, as inferred from geographic distributions. We used population data sets collected in different regions of Central Europe, primarily Germany, for bats, birds, butterflies, ground beetles, springtails and dry grassland plants. We found that temperature niche was positively associated with long-term population trends in some of the taxonomic groups (birds, butterflies, ground beetles) but was less important in others (bats, springtails, and grassland plants). This variation in the importance of temperature niche suggested that some populations have been affected more than others by climate change, which may be explained by differences in species attributes, such as generation time and microhabitat preference. Our findings indicate that relating temperature niches of species to population trends is a useful method to quantify the impact of climate change on local population abundances. We show that this widely applicable approach is particularly suited for comparative cross-system analyses to identify which types of organisms, in which habitats, are responding the most to climate change. (C) 2015 Elsevier Ltd. All rights reserved.

Today, international travel and global freight transportation are increasing and have a direct influence on the introduction and establishment of non-native mosquito species as well as on the spread of arthropod (mosquito)-borne diseases inside Europe. One of the mosquito species that has become invasive in many areas is the Asian rock pool or bush mosquito Ochlerotatus japonicus japonicus (synonyms: Aedes japonicus japonicus or Hulecoeteomyia japonica japonica). This species was detected in Germany in 2008 for the first time. Until today, three different Oc. j. japonicus populations have been documented. Laboratory studies have shown that Oc. j. japonicus can act as a vector for a variety of disease agents. Thus, the knowledge on its current distribution is essential for different measurements. In the present study, ecological niche models were used to estimate the potential distribution of Oc. j. japonicus in Germany. The aim was to detect areas within Germany that could potentially function as habitats for this species. According to our model, areas in western, southern, and central Germany offer suitable conditions for the mosquito and may therefore be at risk for an invasion of the species. We strongly suggest that those areas should be monitored more intensively in the future. For this purpose, it would also be essential to search for possible dispersal routes as well as for natural barriers.

The knowledge of phenotypic variation in the European range of the highly allergenic Ambrosia artemisiifolia L. (common ragweed) is not entirely complete, even though it is an invasive species of utmost concern. We hypothesized the prevalence of phenotypic differentiations between common ragweed populations in the introduced range, and we assumed that those differentiations were related to environmental conditions at the points of origin. Using a common garden experiment, we investigated biomass allocation, growth rates, and flowering phenology of 38 European common ragweed populations originating from a major geographical gradient. We observed considerable phenotypic variation in growth parameters and flowering phenology, e.g. mean aboveground biomass varied from 23.3 to 47.3 g between the populations. We were able to relate most measured traits with environmental parameters prevailing at the points of origin. For example, early growth of ruderal populations was highly correlated with temperature and precipitation at the point of origin. Late growth and flowering phenology were highly correlated with latitude, i.e. individuals from northern populations grew smaller and flowered and dispersed their pollen and seeds up to 5 weeks earlier than individuals from southern populations. We also found a longitudinal gradient in flowering phenology which has not yet been described. The existence of such a high variability in the introduced range may facilitate further range expansion. We suggest that the correlation with environmental variables rests upon genetic variation possibly due to adaptations to the respective environment. To clarify if such adaptation results from multiple events of introduction or as evolutionary response after introduction, genetic investigations are needed.

Germination characteristics and frost tolerance of seedlings are crucial parameters for establishment and invasion success of plants. Within this study, we investigated germination characteristics of Ambrosia artemisiifolia L. populations from native and invasive ranges. We determined germination rates and speed under different temperature conditions. From these parameters we calculated minimal, optimal, and maximal temperature for germination. We also investigated the frost tolerance of seedlings. The European populations were characterized by a higherfitness with higher germination rates and germination speed, increased biomass and higher frost tolerance of seedlings. Furthermore, the temperature niche width for germination was significantly broader for the European populations. The increased frost tolerance of the European populations might allow germination earlier in the year which may subsequently lead to higher biomass allocation due to a longer growing period and result in higher pollen and seed production. The increase in germination rates, germination speed and seedling frost tolerance might result in a higher fitness of the European populations which may facilitate further successful invasion and sharpen the existing problems.

Germination characteristics and frost tolerance of seedlings are crucial parameters for establishment and invasion success of plants. The characterization of differences between populations in native and invasive ranges may improve our understanding of range expansion and adaptation. Here, we investigated germination characteristics of Ambrosia artemisiifolia L., a successful invader in Europe, under a temperature gradient between 5 and 25 °C. Besides rate and speed of germination we determined optimal, minimal and maximal temperature for germination of ten North American and 17 European populations that were sampled along major latitudinal and longitudinal gradients. We furthermore investigated the frost tolerance of seedlings. Germination rate was highest at 15 °C and germination speed was highest at 25 °C. Germination rate, germination speed, frost tolerance of seedlings, and the temperature niche width for germination were significantly higher and broader, respectively, for European populations. This was partly due to a higher seed mass of these populations. Germination traits lacked evidence for adaptation to climatic variables at the point of origin for both provenances. Instead, in the native range, seedling frost tolerance was positively correlated with the risk of frosts which supports the assumption of local adaptation. The increased frost tolerance of European populations may allow germination earlier in the year which may subsequently lead to higher biomass allocation--due to a longer growing period--and result in higher pollen and seed production. The increase in germination rates, germination speed and seedling frost tolerance might result in a higher fitness of the European populations which may facilitate further successful invasion and enhance the existing public health problems associated with this species.

Germination characteristics and frost tolerance of seedlings are crucial parameters for establishment and invasion success of plants. Within this study, we investigated germination characteristics of Ambrosia artemisiifolia L. populations from native and invasive ranges. We determined germination rates and speed under different temperature conditions. From these parameters we calculated minimal, optimal, and maximal temperature for germination. We also investigated the frost tolerance of seedlings. The European populations were characterized by a higher fitness with higher germination rates and germination speed, increased biomass and higher frost tolerance of seedlings. Furthermore, the temperature niche width for germination was significantly broader for the European populations. The increased frost tolerance of the European populations might allow germination earlier in the year which may subsequently lead to higher biomass allocation – due to a longer growing period – and result in higher pollen and seed production. The increase in germination rates, germination speed and seedling frost tolerance might result in a higher fitness of the European populations which may facilitate further successful invasion and sharpen the existing problems.

Long-distance dispersal (LDD) of plant seeds by wind is affected by functional traits of the species, specifically seed terminal velocity and height of seed release above the vegetation cover (HAC), as well as by the meteorological parameters wind speed and vertical turbulence. The relative importance of these parameters is still under debate and the importance of their variability in vegetation types, sites and years has only rarely been quantified. To address these topics, we performed simulation studies for different vegetation types, sites, years and plant species with PAPPUS, a process based trajectory model. We found that LDD (measured in terms of migration rates) was higher in forests compared to open landscapes. Forests also showed greater between-year variability in LDD. Terminal velocity had an effect on LDD in both vegetation types, while the effect of HAC was significant only in the open landscape. We found considerable differences in how vertical turbulence and wind speed affect LDD between species and vegetation types: In the open landscape the strength of the positive relationship between vertical turbulence and LDD generally decreases with terminal velocity, whereas it increases in forests. The strength of the predominantly positive effect of wind speed on LDD increases with terminal velocity in both vegetation types, while in forests we found even negative relationships for species with low terminal velocity. Our results generally suggest that the effects of vertical turbulence and wind speed on LDD by wind diverge for species with different functional traits as well as in different vegetation types.

The aquatic and terrestrial realms differ in many physical properties that not only require specific physiological adaptations but also cause differences in dispersal options. We thus expect that life-history traits related to dispersal and colonization are under selection pressure because freshwater habitats are more isolated and thus more difficult to reach. We compared traits from European databases of three taxonomic groups along the passive–active dispersal gradient: plants (Plantes), snails (Mollusca: Gastropoda: Prosobranchia et Pulmonata) and hoverflies (Diptera: Syrphidae), all of which have both terrestrial and freshwater species (plants and snails) or early life stages (hoverflies). Aquatic taxa seem to be more successful long-distance dispersers than are terrestrial taxa. Our analysis also revealed lower numbers of seeds or eggs produced in the aquatic habitats. However, aquatic taxa often allocate resources to offspring guarding (vegetative propagules in plants, egg capsules in snails) and breeding-site selection (syrphids). Colonization of the aquatic realm is reinforced by increases in life span (plants), clonal spread (plants), shorter generation times (snails), selfing ability (marginal effect in pulmonate snails) or paedogenesis (two incidences in hoverflies, needs further studies). Probably, the variety of strategies reflects the different evolutionary backgrounds that elicit different combinations of trade-offs, but all traits also might increase invasibility of species.

Future climate change is predicted to advance faster than the postglacial warming. Migration may therefore become a key driver for future development of biodiversity and ecosystem functioning. For 140 European plant species we computed past range shifts since the last glacial maximum and future range shifts for a variety of Intergovernmental Panel on Climate Change (IPCC) scenarios and global circulation models (GCMs). Range shift rates were estimated by means of species distribution modelling (SDM). With process-based seed dispersal models we estimated species-specific migration rates for 27 dispersal modes addressing dispersal by wind (anemochory) for different wind conditions, as well as dispersal by mammals (dispersal on animal's coat - epizoochory and dispersal by animals after feeding and digestion - endozoochory) considering different animal species. Our process-based modelled migration rates generally exceeded the postglacial range shift rates indicating that the process-based models we used are capable of predicting migration rates that are in accordance with realized past migration. For most of the considered species, the modelled migration rates were considerably lower than the expected future climate change induced range shift rates. This implies that most plant species will not entirely be able to follow future climate-change-induced range shifts due to dispersal limitation. Animals with large day- and home-ranges are highly important for achieving high migration rates for many plant species, whereas anemochory is relevant for only few species.

Only a small proportion of introduced plant species become invasive and may eventually create ecological or economic problems. In many species it is still not clear which traits cause biological invasions. As a case study we focussed on the fast-spreading Epilobium brachycarpum in Central Europe to investigate the potential of this species to become a transformer or agricultural weed. We (1) documented the spread of the species in Central Europe, (2) modelled its range and (3) seed dispersal, (4) described its phytosociological alignment, (5) analysed the traits of invaded vegetation types, (6) described seed production, population densities and life cycle, (7) did competition and germination tests, and (8) drafted a risk assessment. Relevant traits and characteristics of E. brachycarpum are (i) formation of dense stands under ruderal conditions, (ii) high seed production, (iii) effective seed dispersal, (iv) high competitiveness on bare soils against other ruderal plants, and (v) ecological niche shift compared to its native range. We expect E. brachycarpum to settle in the Mediterranean, sub-Mediterranean and many parts of temperate Europe within the next decades in habitats strongly altered by human activities, especially open stands of the alliance Sisymbrion. We predict that E. brachycarpum will become a noxious weed in vineyards, and that it will also colonise vegetation of the alliances Bidention and Carici-Epilobion.