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Several larger vertebrate species have recovered from dramatic bottlenecks caused by overhunting and habitat destruction. One of the most notable comebacks concerns the Eurasian beaver (Castor fiber L.), which has increased its range by natural dispersal from both relict populations and populations established through translocations. Genetic methods have recently been used to study beavers at several locations. However, owing to a lack of reference samples from relict populations and alternative names of mitochondrial DNA haplotypes, the ancestry of re-established beaver populations remains obscure. Here, we focus on the genetic characterization of several newly established populations. Unlike previous studies, we also used microsatellite genotypes of reference samples from all relict populations. Our analysis was fully capable of tracing the origin of the nuclear and mitochondrial genome to relict populations. Although we confirmed an extraordinarily low genetic diversity in relict populations, our analysis showed restored diversity in newly established populations resulting from translocations. Recent expansions and stochastic effects have created a strong but complicated population structure, with neighbouring populations differing significantly in genetic composition. We conclude that this restored genetic diversity very likely contributes to the viability and ongoing expansion of the newly established populations.

Plants must continuously respond to environmental changes, and a timely question is whether and how populations respond to ongoing global warming and increased drought frequencies and intensities. Plants can either respond through migration or through phenotypic plasticity or their populations can adapt evolutionarily, which encompasses the evolution of trait means and of trait plasticity. One way to detect such evolutionary changes within plant populations is through historical comparisons where plants grown from seeds collected in the past (“ancestors”) are compared to freshly collected seeds from the same populations (“descendants”) in common garden experiments. We used 21- to 26-year-old seeds stored in seed banks for two multi-species experiments that investigated changes in phenotypic traits and their plasticity conferring drought tolerance in early life stages of European plant species. In the first experiment, we used seedlings of four Mediterranean species, ceased watering and recorded their day of mortality. In the second experiment, we studied phenotypic responses to drought in juvenile plants of nine species originating from temperate regions in Europe. In one of four species in the first experiment, descendants survived significantly longer without watering and were smaller than their ancestors. In the second experiment, descendant plants were generally taller under well-watered conditions but smaller under drought than their ancestors, thus showing stronger plasticity. Our historical comparisons suggest that some populations have likely evolved through changes in trait means and plasticity in ways consistent with adaptation to increased drought. Using seed bank material for historical comparisons has several weaknesses, such as unknown sampling protocols or invisible fractions. However, we show how accurately sampled and stored seed bank collections can be used similar to the resurrection approach for investigating rapid evolutionary processes in early life stages of plants under climate change.

Ensuring ecosystem resilience is an intuitive approach to safeguard the functioning of ecosystems and hence the future provisioning of ecosystem services (ES). However, resilience is a multi-faceted concept that is difficult to operationalize. Focusing on resilience mechanisms, such as diversity, network architectures or adaptive capacity, has recently been suggested as means to operationalize resilience. Still, the focus on mechanisms is not specific enough. We suggest a conceptual framework, resilience trinity, to facilitate management based on resilience mechanisms in three distinctive decision contexts and time-horizons: i) reactive, when there is an imminent threat to ES resilience and a high pressure to act, ii) adjustive, when the threat is known in general but there is still time to adapt management, and iii) provident, when time horizons are very long and the nature of the threats is uncertain, leading to a low willingness to act. Resilience has different interpretations and implications at these different time horizons, which also prevail in different disciplines. Social ecology, ecology, and engineering are often implicitly focussing on provident, adjustive, or reactive resilience, respectively, but these different notions and of resilience and their corresponding social, ecological, and economic trade-offs need to be reconciled. Otherwise, we keep risking unintended consequences of reactive actions, or shying away from provident action because of uncertainties that cannot be reduced. The suggested trinity of time horizons and their decision contexts could help ensuring that longer-term management actions are not missed while urgent threats to ES are given priority.

Plant diversity loss can alter higher trophic -level communities via non -random species interactions, which in turn may cascade to affect key ecosystem func-tions. These non -random linkages might be best captured by patterns of phyloge-netic diversity, which take into account co -evolutionary dependencies. However,lack of adequate phylogenetic data of higher trophic levels hampers our mecha-nistic understanding of biodiversity relationships in species-rich ecosystems.2. We used DNA barcoding to generate data on the phylogenetic diversity of lepi-dopteran caterpillars in a large- scale forest biodiversity experiment in subtropicalChina. We analysed how different metrics of lepidopteran phylogenetic diversity(Faith's PD, MPD, MNTD) and taxonomic diversity were influenced by multiple components of tree diversity (taxonomic, functional, phylogenetic).3. Our data from six sampling periods represent 7,204 mitochondrial cytochrome c oxidase subunit I (COI) sequences of lepidopteran larvae, clustered into 461 mo-lecular operational taxonomic units. Lepidopteran abundance, the effective num-ber of species (irrespective of the focus on rare or common species) and Faith's PD and MPD (reflecting basal evolutionary splits), but not MNTD (reflecting re-cent evolutionary splits), significantly increased with experimentally manipulated ree species richness. Lepidopteran MNTD decreased with increasing tree MNTD. Path analyses showed that tree phylogenetic and functional diversity explained part, but not all of the effects of tree species richness on lepidopteran diversity. Importantly, tree diversity effects on lepidopteran diversity were to a large extent indirect, operating via changes in lepidopteran abundance. 4. Synthesis. Our study shows that evolutionary dependencies determine the response of herbivore communities to changes in host plant diversity. Incorporating a wider range of diversity metrics both at the level of producers and consumers can thus help to develop a more comprehensive understanding of the functional consequences of biodiversity change across trophic levels. Moreover, the dependence of trophic linkages on herbivore abundances underlines the need to address the consequences of current declines in insect abundances for ecosystem structure and functioning. peerReviewed

Plant diversity begets diversity at other trophic levels. While species richness is the most commonly used measure for plant diversity, the number of evolutionary lineages (i.e. phylogenetic diversity) could theoretically have a stronger influence on the community structure of co-occurring organisms. However, this prediction has only rarely been tested in complex real-world ecosystems. Using a comprehensive multitrophic dataset of arthropods and fungi from a species-rich subtropical forest, we tested whether tree species richness or tree phylogenetic diversity relates to the diversity and composition of organisms. We show that tree phylogenetic diversity but not tree species richness determines arthropod and fungi community composition across trophic levels and increases the diversity of predatory arthropods but decreases herbivorous arthropod diversity. The effect of tree phylogenetic diversity was not mediated by changed abundances of associated organisms, indicating that evolutionarily more diverse plant communities increase niche opportunities (resource diversity) but not necessarily niche amplitudes (resource amount). Our findings suggest that plant evolutionary relatedness structures multitrophic communities in the studied species-rich forests and possibly other ecosystems at large. As global change non-randomly threatens phylogenetically distinct plant species, far-reaching consequences on associated communities are expected. A free Plain Language Summary can be found within the Supporting Information of this article.

International audience; Urbanization is one of the most intensive and rapid human-driven factors that threat biodiversity. Finding an indicator of species community responses to urbanization is crucial for predicting the consequences of anthropogenic land cover changes. Here, we develop a framework that relies on functional originality. A species is original or equivalently distinct, regarding its traits, if it possesses rare trait values in a community of species. The most original species have the greatest contributions to the trait diversity of that community. We studied plant species originality, in light of observed changes in the level of species richness, along an urbanization gradient in the region of Paris, France. To evaluate potential impacts of urbanization on species assemblages, we simultaneously considered the local community and regional pool as reference scales where to calculate the originality of each species. Then, for each community, we calculated the mean and skewness of local and regional originalities and the ratio of local to regional originality, providing indication on how functionally diverse a community is, how original it is compared to other communities of the region, how evenly distributed species were in the local and regional functional space, and whether regionally-redundant species become original locally due to limiting similarity. The mean functional originality increased with urbanization at both local and regional scales, although this increase vanished in communities with high species richness. The skewness of originalities increased from zero to positive values with species richness in built-up areas and the ratio of local-to-regional originality increasing along the urbanization gradient, except in species-rich communities. Here our results suggest that urban plant communities are composed of both locally and regionally unique urbanophile species, suggesting processes that limit niche overlap to allow species coexistence. In richer communities, these unique species coexist with regionally-redundant species the occurrence of which could be stochastic. Our conceptual framework shows that species originality can inform on environmental processes that influence biodiversity during community assembly. It is flexible enough to be extended to other regions and other contexts complementing diversity metrics in the research of the mechanisms by which human activities impact species assemblages.

Climate change and land‐use changes are among the major threats to biodiversity as they alter global and local environmental conditions in unprecedented dimensions. Therefore, the investigation of the ability of species and communities to cope with rapidly changing environments as well as the comprehensive understanding of possible evolutionary adaptation processes is urgently needed for their sustainable management and the maintenance of associated ecosystem processes. Here, seminatural grasslands receive special attention, because they are among the most species‐rich ecosystems in Central Europe, which are threatened by global change and land‐use intensification already since the beginning of the twentieth century. Hence, understanding their potential to respond to rapidly changing environments is important for future management. Here, the Global Change Experimental Facility (GCEF) is an opportunity to investigate the role of microevolution in response to climate change. Two of the land‐use regimes in the GCEF are seminatural, extensively used species‐rich meadow and pasture grasslands established by sowing common, native, and regionally typical grassland species in 2014. In view of ecological restoration, for each species a seed mixture of up to seven source populations was sown aiming to establish high levels of intraspecific variation from the regional gene pool. Here, we present the first evaluation of genetic and trait variation of source populations and of their establishment in the GCEF two years after sowing for six grassland species. Using AFLP markers, we assessed genetic variation of source populations and tested whether the source gene pools have established in the experiment. Additionally, we investigated phenotypic variation of source populations and performed PST‐FST comparisons to test whether trait differentiation is adaptive. Our study revealed that genetic and phenotypic differentiation of source populations is widespread in the grassland species studied, even on small geographic scales. The GCEF populations are highly diverse due to the mixture of the different, often genetically and phenotypically differentiated source populations. They represent a genetically diverse source for both selection among existing and evolution of new genotypes. Thus, the GCEF can be used as experiment to study evolutionary processes in response to the climate change and land‐use scenarios.

The growing number of restoration projects worldwide increases the demand for seed material of native species. To meet this demand, seeds are often produced through large-scale cultivation on specialised farms, using wild-collected seeds as the original sources. However, during cultivation, plants experience novel environmental conditions compared to those in natural populations, and there is a danger that the plants in cultivation are subject to unintended selection and lose their adaptation to natural habitats. Although the propagation methods are usually designed to maintain as much natural genetic diversity as possible, the effectiveness of these measures have never been tested. We obtained seed of five common grassland species from one of the largest native seed producers in Germany. For each species, the seeds were from multiple generations of seed production. We used AFLP markers and a common garden experiment to test for genetic and phenotypic changes during cultivation of these plants. The molecular markers detected significant evolutionary changes in three out of the five species and we found significant phenotypic changes in two species. The only species that showed substantial genetic and phenotypic changes was the short-lived and predominantly selfing Medicago lupulina, while in the other, mostly perennial and outcrossing species, the observed changes were mostly minor. Agricultural propagation of native seed material for restoration can cause evolutionary changes, at least in some species. We recommend caution, particularly in selfing and short-lived species, where evolution may be more rapid and effects may thus be more severe.

Interactions between species of different trophic levels have long been recognized as fundamental processes in ecology. Although mounting evidence indicates that plant species diversity (PSD) or plant genetic diversity (PGD) can influence the plant-associated arthropod community, these two fundamental levels of biodiversity are not often manipulated simultaneously to assess their effects on species interactions. We used a large tree diversity experiment (BEF-China), which manipulates PSD and PGD in a crossed design to test individual and combined effects of PSD and PGD on multitrophic interaction networks and interaction partner species richness and occurrence. We focused on two tree species, on which sap-sucking Hemiptera and interacting ant species commonly occur. This tri-trophic interaction can be divided into the antagonistic plant–Hemiptera interaction and the mutualistic Hemiptera–ant interaction, known as trophobioses. Qualitative evaluation of tri-trophic interaction networks at different PSD and PGD combinations showed increased interaction partner redundancy at high PSD and PGD. This was supported by increased Hemiptera species richness at high PSD and PGD. Furthermore, the data indicate higher occurrence of Hemiptera and trophobioses and higher trophobiotic ant species richness with increasing PSD and PGD. As no plant diversity component alone caused an effect we conclude that the combined effect of high PGD and high PSD might be additive. In summary, as plant genetic diversity, especially at low species richness, seems to increase the interaction partner redundancy in interaction networks and the diversity of interacting communities, we suggest that genetic diversity should be considered in forest conservation and restoration programs.

One of the main questions in ecosystem restoration is where to obtain the seeds to re-establish plant communities. While the most commonly advocated approach is to use seeds from local sources, some experts argue against this because local populations may harbour little genetic variability for the restored populations to be able to adapt to and survive global change. Instead, they propose alternative strategies such as mixing seeds from various sources to increase genetic variability and adaptive potential, or using seeds from populations that have a similar climate as predicted for the target locality in the future. All these alternative seed-sourcing strategies have in common that they involve a transplanting of plant ecotypes, sometimes over large spatial scales. This is risky because plants from distant origins may be maladapted to the current local abiotic and biotic environment. In addition, introduction of non-local provenances will disrupt natural patterns of within-species biodiversity and will affect ecological networks, with unpredictable consequences. To balance the value of local adaptation with the need for future adaptation potential, we propose ‘regional admixture provenancing’ as a compromise strategy. Here seeds are sourced from multiple populations within the same region as the target locality and mixed prior to use. The mixing of seeds will increase the genetic diversity necessary for future adaptation, while restricting seed origins to a regional scale will maintain regional adaptation and reduce the risk of unintended effects on other biota. This approach is feasible in practice and has recently been implemented in Germany. We believe that it represents a compromise to reconcile opposing views on ecological restoration.

Aims Genetic variation in plant traits represents the raw material for future adaptive evolution. Its extent can be estimated as heritability based on the performance of experimental plants of known relatedness, such as maternal half-sib seed families. While there is considerable heritability information for herbaceous plants and commercially important trees, little is known for woody species of natural subtropical forest. Moreover, it is open whether heritability is higher for species with r- or K-strategies, for more common species with larger distribution ranges than for rarer ones, or for populations closer to the centres of distributional ranges. Methods For 14 woody species in Chinese subtropical forest, we collected 13–38 maternal seed families, assessed seed size, grew replicates of each seed family in one more and one less benign nursery environment and measured stem diameter and plant height after 7 months. Important findings For the different species, plants grew 1.8–8.1 times taller in the more benign environment. For all 14 species, variation between seed families (and thus heritability) was significant (with very few exceptions at the P < 0.001 level) for seed size and for stem diameter and plant height in both nurseries. Moreover, significant seed family by nursery interactions for stem diameter and plant height for all species (P < 0.001) indicated significant heritability for plasticity in these traits. Multiple regression analysis suggests that heritabilities were higher for species with higher age at reproduction and higher wood density (traits indicating a K strategy) but also for species with higher specific leaf area (a trait rather indicating an r strategy). Furthermore, heritabilities were higher for species with larger range sizes, while there was no significant relationship between heritabilities and the distance of the study area to the range margins of our study species. In conclusion, the detected large heritability estimates suggest considerable potential for the evolution of plant performance and its plasticity for trees of subtropical forest. Moreover, our study shows that the simple method of comparing plants of different maternal seed families is valuable to address evolutionary ecological questions for so far understudied species.

Aims Positive plant diversity–ecosystem function relations are ultimately driven by variation in functional traits among individuals that form a community. To date, research has largely focused on the role of species diversity for ecosystem functioning. However, substantial intraspecific trait variation is common and a significant part of this variation caused by genetic differences among individuals. Here, we studied the relative importance of species diversity and seed family (SF) diversity within species for growth and herbivory in experimental subtropical tree assemblages. Methods In 2010, we set up a field experiment in subtropical China, using four species from the local species pool. Trees were raised from seeds, with seeds from the same mother tree forming an SF. We established 23 plots containing one or four species (species diversity treatment) and one or four SFs per species (SF diversity treatment). Tree growth (stem diameter, plant height and crown expansion) and herbivory (percentage leaf loss due to leaf chewers) were monitored annually from 2011 to 2013. Important findings Tree species richness promoted growth but had no effect on herbivory. In contrast, SF diversity reduced growth and increased herbivory but only so in species mixtures. Most of the observed effects were time dependent, with the largest effect found in 2013. Our results suggest that biodiversity can affect plant performance directly via tree species–species interactions, or context dependent, via potential effects on inter-trophic interactions. Two important conclusions should be drawn from our findings. Firstly, in future studies regarding biodiversity and ecosystem functioning (BEF) relationships, intraspecific genetic diversity should be given similar weight as species diversity as it has often been neglected and its effects are not well understood. Secondly, we demonstrate opposite effects of biodiversity among and within species, stressing the importance to consider the effects of multiple levels of biodiversity simultaneously.

Aims Changing biodiversity can affect ecosystem functioning. However, the role of genetic diversity within species, relative to the one of species diversity, has hardly been addressed. Methods To address the effects of both genetic diversity and species diversity during the important stage of early tree life, we used eight seed families (SF) taken from each of 12 evergreen and deciduous tree species of subtropical forest to perform a factorial experiment. We established 264 communities of 16 trees each. Each community had a species diversity of either one or four species and a genetic diversity of either one, two or four SF per species. We measured plant survival, growth rate, final biomass and herbivory 20 months after sowing. Important Findings Species differed from each other in biomass, growth rate, herbivory and survival (P < 0.001). Deciduous species tended to have much higher biomass (P < 0.1) and experienced higher herbivory (P < 0.05) than evergreen species. Species diversity affected the performance of different species differently (species diversity by species interaction, P

In Central Europe, the genus Platanthera traditionally comprised two species, P. chlorantha Cust. ex Rchb. (Pc) and P. bifolia (L.) Rich. (Pb). They are morphologically characterized by a wide and narrow separation of anthers, respectively. However, a third form with intermediate anther distance has repeatedly been hypothesized but only hesitantly accepted. In addition, intermediate morphology has been also used as the main character of P. × hybrida. However, the status of some purported hybrid populations is challenged by the local lack of parental species, their successful reproduction and non-intermediate traits. Despite this unclear situation, detailed genetic and morphological analyses are lacking. Here, we studied morphology and molecular markers within the P. chlorantha/bifolia group in Central Europe. Three morphological groups emerged representing Pc, Pb and a third form, here informally referred to as non-hybrid intermediates (Pn). The latter is characterized, among other trait differences, by intermediate distance between anthers [(0.7)–1–2.2 mm] and long spurs (28–40 mm). Three gene pools were identified, which largely corresponded to the three morphological groups. The Pn gene pool had several high-frequency private alleles substantiating its genetic independence. Some of the Pn populations were previously interpreted as P. × hybrida suggesting that Pn was overlooked hitherto and mistaken to represent hybrids. The non-perfect fit between morphological and genetic groups highlights the potential for fast morphological evolution. Overall, the finding of three distinct lineages within the bifolia/chlorantha group necessitates a thorough reanalysis of reported taxa and a reevaluation of our understanding of their distribution, ecology and evolution.

Vegetative reproduction and spread through clonal growth plays an important role in arctic-alpine ecosystems with short cool growing seasons. Local variation in winter snow accumulation leads to discrete habitat types that may provide divergent conditions for sexual and vegetative reproduction. Therefore, we studied variation in clonal structure of a dominant, evergreen, dwarf shrub (Empetrum nigrum s.l. with the two taxa E. nigrum L. s.s. and E. hermaphroditum Hagerup) along a snow cover gradient and compared clonal diversity and spatial genetic structure between habitats.We studied 374 individual shoots using 105 polymorphic AFLP markers and analyses based on hierarchical clustering, clonal diversity indices, and small-scale spatial genetic structure with pairwise kinship coefficient. We used two approaches to define a threshold of genotypic distance between two samples that are considered the same clone. Clonality was examined among three habitats (exposed ridges, sheltered depressions, birch forest) differing in snow conditions replicated in four study regions in Norway and Sweden.Clonality of E. hermaphroditum differed between habitats with an increase in clonal diversity with decreasing snow depth. Small-scale spatial genetic structure increased with decreasing clonal diversity and increasing clone size. In three study regions, E. hermaphroditum was the only species, whereas in one region E. nigrum also occurred, largely confined to exposed ridges.Our results demonstrated that snow cover in conjunction with associated habitat conditions plays an important role for the mode of propagation of the dwarf shrub E. hermaphroditum.

In plant conservation and ecosystem restoration, plants are often translocated to ensure or enhance plant survival and performance. While the effects of ecotype origin on the performance of translocated plants are increasingly acknowledged among researchers and practitioners, ecotype effects on associated communities and ecosystems have hardly been studied. This is critical because plants also constitute the habitat for a large number of interacting organisms, and many of them might be influenced by plant ecotype characteristics. Here, we studied different ecotypes of Centaurea jacea L., a plant species commonly used in grassland restoration, and their effects on seed herbivores and their parasitoids. We grew eight C. jacea ecotypes originating from different regions in Germany in a common garden and found that the ecotypes differed up to three-fold in the frequencies of seed herbivores. These differences appeared to be mainly driven by ecotype differences in flowering phenology. We also found that there were up to four-fold differences in the frequencies of parasitoids, and even up to nine-fold differences in the abundances of parasitoids among ecotypes. In summary, plants from different origins substantially differed in their effects on interacting organisms, potentially reflecting coevolutionary relationships across trophic levels. The introduction of foreign ecotypes in restoration projects may thus not only affect the plants themselves, but it may also disrupt the balance of their biotic interactions.

Both species and genetic diversity of plant communities can affect insect herbivores, but a few studies have compared the effects of both diversity levels within the same experimental context. We compared the effects of tree species and genetic diversity on abundance, species richness, and β-diversity of leaf-miner communities associated with silver birch using two long-term forest diversity experiments in Finland where birch trees were planted in monocultures and mixtures of birch genotypes or other trees species. Although both abundance and species richness of leaf miners differed among birch genotypes at the tree level, birch genetic diversity had no significant effect on miner abundance and species richness at the plot level. Instead, birch genetic diversity affected leaf-miner β-diversity with species turnover being higher among trees within genotypic mixtures than among trees within monoclonal plots. In contrast, tree species diversity had a significant negative effect on both leaf-miner abundance and species richness at plot level, but no effect on miner β-diversity. Significant tree species diversity effects on leaf-miner abundance and species richness were found only in plots with high tree density. We have demonstrated that plant species and genetic diversity play important but contrasting roles in structuring associated herbivore communities. Tree species diversity largely affects miner abundance and species richness, whereas tree genetic diversity affects miner β-diversity. These results have important implications for conservation and management of woodlands. Electronic supplementary material The online version of this article (10.1007/s00442-019-04351-x) contains supplementary material, which is available to authorized users.

Mating system and gene dispersal distances are two important characteristics that govern the distribution of genetic variation within species. Genetic variation is an important resource for adaptation, but also allows insight into a species reproductive biology. As the reproductive biology is species specific, general inferences across species may be inaccurate and for many species not much is known about the details of gene flow and mating, especially in species-rich ecosystems such as the subtropics. We characterised the mating system and determined historical and current gene flow distances in Rhododendron simsii using microsatellite markers. Adult individuals and seeds were sampled in a near-natural nature reserve in southeast China. We examined the fine-scale spatial genetic structure (SGS), kinship coefficients, outcrossing rates and biparental inbreeding coefficients. Furthermore, we estimated pollen dispersal distances using paternity analysis. We found high outcrossing rates and significant biparental inbreeding. Population differentiation was low while observed heterozygosity and allelic richness were high. Estimates of historical and current gene flow were similar, indicating that genes are on average dispersed over distances of between 10 and 20 m. Paternity analyses suggest frequent mating among neighbouring individuals. We conclude that R. simsii is predominantly, but not obligately outcrossing. Moderate amounts of biparental inbreeding and overall low fine-scale SGS indicate that mating among related individuals is common, but does neither lead to pronounced population differentiation nor to strong aggregation of related individuals. Most likely, gene flow distances in this species are affected by its flowering phenology. Mass-flowering, pollen/pollinator limitation and gravity/wind dispersal of seeds in concert cause short gene dispersal distances. Lastly, population genetic descriptors suggest that R. simsii in the study area represents a large, well connected population in which large amounts of genetic variability are maintained.

Polyploids are overrepresented in invasive species. Yet, the role of genetic diversity and drift in colonization success of polyploids remains unclear. Here, we investigate genetic diversity, genetic differentiation and small-scale genetic structure in our model system, the three geo-cytotypes of Centaurea stoebe: monocarpic diploids and polycarpic (allo)tetraploids coexist in the native range (Eurasia), but only tetraploids are reported from the invasive range (North America). For each geo-cytotype, we investigated 18–20 populations varying in size and habitat type (natural vs. ruderal). Population genetic analyses were conducted at eight microsatellite loci. Compared to diploids, tetraploids revealed higher genetic diversity and lower genetic differentiation, whereas both were comparable in tetraploids between both ranges. Within spatial distances of a few meters, diploid individuals were more strongly related to one another than tetraploids. In addition, expected heterozygosity in diploids increased with population size and was higher in natural than in ruderal habitats. However, neither relationship was found for tetraploids. The higher genetic diversity of tetraploid C. stoebe may have enhanced its colonization abilities, if genetic diversity is correlated with fitness and adaptive capabilities. Furthermore, the inheritance of a duplicated chromosome set as well as longevity and frequent gene flow reduces drift in tetraploids. This counteracts genetic depletion during initial introductions and in subsequent phases of small or fluctuating population sizes in ruderal habitats. Our findings advocate the importance of studying colonization genetic processes to gain a more mechanistic understanding of the role of polyploidy in invasion dynamics.

Habitat fragmentation and small population size can lead to genetic erosion in threatened plant populations. Classical theory implies that dioecy can counteract genetic erosion as it decreases the magnitude of inbreeding and genetic drift due to obligate outcrossing. However, in small populations, sex ratios may be strongly male- or female-biased, leading to substantial reductions in effective population size. This may theoretically result in a unimodal relationship between sex ratios and genetic diversity; yet, empirical studies on this relationship are scarce. Using AFLP markers, we studied genetic diversity, structure and differentiation in 14 highly fragmented Antennaria dioica populations from the Central European lowlands. Our analyses focused on the relationship between sex ratio, population size and genetic diversity. Although most populations were small (mean: 35.5 patches), genetic diversity was moderately high. We found evidence for isolation-by-distance, but overall differentiation of the populations was rather weak. Females dominated 11 populations, which overall resulted in a slightly female-biased sex ratio (61.5%). There was no significant relationship between population size and genetic diversity. The proportion of females was not unimodally but positively linearly related to genetic diversity. The high genetic diversity and low genetic differentiation suggest that A. dioica has been widely distributed in the Central European lowlands in the past, while fragmentation occurred only in the last decades. Sex ratio has more immediate consequences on genetic diversity than population size. An increasing proportion of females can increase genetic diversity in dioecious plants, probably due to a higher amount of sexual reproduction.

Biodiversity-ecosystem functioning (BEF) research has extended its scope from communities that are short-lived or reshape their structure annually to structurally complex forest ecosystems. The establishment of tree diversity experiments poses specific methodological challenges for assessing the multiple functions provided by forest ecosystems. In particular, methodological inconsistencies and nonstandardized protocols impede the analysis of multifunctionality within, and comparability across the increasing number of tree diversity experiments. By providing an overview on key methods currently applied in one of the largest forest biodiversity experiments, we show how methods differing in scale and simplicity can be combined to retrieve consistent data allowing novel insights into forest ecosystem functioning. Furthermore, we discuss and develop recommendations for the integration and transferability of diverse methodical approaches to present and future forest biodiversity experiments. We identified four principles that should guide basic decisions concerning method selection for tree diversity experiments and forest BEF research: (1) method selection should be directed toward maximizing data density to increase the number of measured variables in each plot. (2) Methods should cover all relevant scales of the experiment to consider scale dependencies of biodiversity effects. (3) The same variable should be evaluated with the same method across space and time for adequate larger-scale and longer-time data analysis and to reduce errors due to changing measurement protocols. (4) Standardized, practical and rapid methods for assessing biodiversity and ecosystem functions should be promoted to increase comparability among forest BEF experiments. We demonstrate that currently available methods provide us with a sophisticated toolbox to improve a synergistic understanding of forest multifunctionality. However, these methods require further adjustment to the specific requirements of structurally complex and long-lived forest ecosystems. By applying methods connecting relevant scales, trophic levels, and above- and belowground ecosystem compartments, knowledge gain from large tree diversity experiments can be optimized. Biodiversity–ecosystem functioning (BEF) research has extended its scope from communities that are short‐lived or reshape their structure annually to structurally complex forest ecosystems. The establishment of tree diversity experiments poses specific methodological challenges for assessing the multiple functions provided by forest ecosystems. In particular, methodological inconsistencies and nonstandardized protocols impede the analysis of multifunctionality within, and comparability across the increasing number of tree diversity experiments. By providing an overview on key methods currently applied in one of the largest forest biodiversity experiments, we show how methods differing in scale and simplicity can be combined to retrieve consistent data allowing novel insights into forest ecosystem functioning. Furthermore, we discuss and develop recommendations for the integration and transferability of diverse methodical approaches to present and future forest biodiversity experiments. We identified four principles that should guide basic decisions concerning method selection for tree diversity experiments and forest BEF research: (1) method selection should be directed toward maximizing data density to increase the number of measured variables in each plot. (2) Methods should cover all relevant scales of the experiment to consider scale dependencies of biodiversity effects. (3) The same variable should be evaluated with the same method across space and time for adequate larger‐scale and longer‐time data analysis and to reduce errors due to changing measurement protocols. (4) Standardized, practical and rapid methods for assessing biodiversity and ecosystem functions should be promoted to increase comparability among forest BEF experiments. We demonstrate that currently available methods provide us with a sophisticated toolbox to improve a synergistic understanding of forest multifunctionality. However, these methods require further adjustment to the specific requirements of structurally complex and long‐lived forest ecosystems. By applying methods connecting relevant scales, trophic levels, and above‐ and belowground ecosystem compartments, knowledge gain from large tree diversity experiments can be optimized.

Sympatric cryptic lineages are a challenge for the understanding of species coexistence and lineage diversification as well as for management, conservation, and utilization of plant genetic resources. In higher plants studies providing insights into the mechanisms creating and maintaining sympatric cryptic lineages are rare. Here, using microsatellites and chloroplast sequence data, morphometric analyses, and phenological observations, we ask whether sympatrically coexisting lineages in the common wetland plant Juncus effusus are ecologically differentiated and reproductively isolated. Our results show two genetically highly differentiated, homoploid lineages within J. effusus that are morphologically cryptic and have similar preference for soil moisture content. However, flowering time differed significantly between the lineages contributing to reproductive isolation and the maintenance of these lineages. Furthermore, the later flowering lineage suffered less from predispersal seed predation by a Coleophora moth species. Still, we detected viable and reproducing hybrids between both lineages and the earlier flowering lineage and J. conglomeratus, a coexisting close relative. Flowering time differentiation between the lineages can be explained by neutral divergence alone and together with a lack of postzygotic isolation mechanisms; the sympatric coexistence of these lineages is most likely the result of an allopatric origin with secondary contact.

Mongolia's salmonids are suffering extensive population declines; thus, more comprehensive fisheries management and conservation strategies are required. To assist with their development, a better understanding of the genetic structure and diversity of these threatened species would allow a more targeted approach for preserving genetic variation and ultimately improve long‐term species recoveries. It is hypothesized that the unfragmented river basins that have persisted across Mongolia provide unobstructed connectivity for resident salmonid species. Thus, genetic structure is expected to be primarily segregated between major river basins. We tested this hypothesis by investigating the population structure for three salmonid genera (Hucho, Brachymystax and Thymallus) using different genetic markers to identify evolutionarily significant units (ESUs) and priority rivers to focus conservation efforts. Fish were assigned to separate ESUs when the combined evidence of mitochondrial and nuclear data indicated genetic isolation. Hucho taimen exhibited a dichotomous population structure forming two ESUs, with five priority rivers. Within the Brachymystax genus, there were three B. lenokESUs and one B. tumensisESU, along with six priority rivers. While B. tumensiswas confirmed to display divergent mtDNA haplotypes, haplotype sharing between these two congeneric species was also identified. For T. baicalensis,only a single ESU was assigned, with five priority rivers identified plus Lake Hovsgol. Additionally, we confirmed that T. nigrescens from Lake Hovsgol is a synonym of T. baicalensis. Across all species, the most prominent pattern was strong differentiation among major river basins with low differentiation and weak patterns of isolation by distance within river basins, which corroborated our hypothesis of high within‐basin connectivity across Mongolia. This new genetic information provides authorities the opportunity to distribute resources for management between ESUs while assigning additional protection for the more genetically valuable salmonid rivers so that the greatest adaptive potential within each species can be preserved.

SummaryAlthough spatial and temporal patterns of phylogenetic community structure during succession are inherently interlinked and assembly processes vary with environmental and phylogenetic scale, successional studies of community assembly have yet to integrate spatial and temporal components of community structure, while accounting for scaling issues. To gain insight into the processes that generate biodiversity after disturbance, we combine analyses of spatial and temporal phylogenetic turnover across phylogenetic scales, accounting for covariation with environmental differences.We compared phylogenetic turnover, at the species-and individual-level, within and between five successional stages, representing woody plant communities in a subtropical forest chronosequence. We decomposed turnover at different phylogenetic depths and assessed its covariation with between-plot abiotic differences.Phylogenetic turnover between stages was low relative to species turnover and was not explained by abiotic differences. However, within the late successional stages, there was high presence/absence-based turnover (clustering) that occurred deep in the phylogeny and covaried with environmental differentiation.Our results support a deterministic model of community assembly where (i) phylogenetic composition is constrained through successional time, but (ii) towards late succession, species sorting into preferred habitats according to niche traits that are conserved deep in phylogeny, becomes increasingly important.

Growing evidence shows that epigenetic mechanisms contribute to complex traits, with implications across many fields of biology. In plant ecology, recent studies have attempted to merge ecological experiments with epigenetic analyses to elucidate the contribution of epigenetics to plant phenotypes, stress responses, adaptation to habitat, and range distributions. While there has been some progress in revealing the role of epigenetics in ecological processes, studies with non-model species have so far been limited to describing broad patterns based on anonymous markers of DNA methylation. In contrast, studies with model species have benefited from powerful genomic resources, which contribute to a more mechanistic understanding but have limited ecological realism. Understanding the significance of epigenetics for plant ecology requires increased transfer of knowledge and methods from model species research to genomes of evolutionarily divergent species, and examination of responses to complex natural environments at a more mechanistic level. This requires transforming genomics tools specifically for studying non-model species, which is challenging given the large and often polyploid genomes of plants. Collaboration among molecular geneticists, ecologists and bioinformaticians promises to enhance our understanding of the mutual links between genome function and ecological processes.

One of the key questions in ecosystem restoration is the choice of the seed material for restoring plant communities. The most common strategy is to use local seed sources, based on the argument that many plants are locally adapted and thus local seed sources should provide the best restoration success. However, the evidence for local adaptation is inconsistent, and some of these inconsistencies may be due to dif- ferent experimental approaches that have been used to test for local adaptation. We illustrate how conclusions about local adaptation depend on the experimental design and in particular on the method of data analysis. We used data from a multispecies reciprocal transplant experiment and analyzed them in three different ways: (1) com- paring local vs. foreign plants within species and sites, corresponding to tests of the “local is best” paradigm in ecological restoration, (2) comparing sympatric vs. allopatric populations across sites but within species, and (3) comparing sympatric and allopatric populations across multiple species. These approaches reflect different experimental designs: While a local vs. foreign comparison can be done even in small experiments with a single species and site, the other two approaches require a reciprocal transplant experiment with one or multiple species, respectively. The three different analyses led to contrasting results. While the local/foreign approach indicated lack of local adapta - tion or even maladaptation, the more general sympatric/allopatric approach rather suggested local adaptation, and the most general cross- species sympatric/allopatric test provided significant evidence for local adaptation. The analyses demonstrate how the design of experiments and methods of data analysis impact conclusions on the presence or absence of local adaptation. While small- scale, single- species experiments may be useful for identifying the appropriate seed material for a specific restoration project, general patterns can only be detected in reciprocal transplant experiments with multiple species and sites.

Arctic ecosystems face strong changes in snow conditions due to global warming. In contrast to habitat specialists, species occupying a wide range of microhabitats under different snow conditions may better cope with such changes. We studied how growth and reproduction of the dominant dwarf shrub Empetrum hermaphroditum varied among three habitat types differing in winter snow depth and summer irradiation, and whether the observed patterns were consistent along a local climatic gradient (sub-continental vs. sub-oceanic climates) and along a latitudinal gradient (northern Sweden vs. central Norway). Habitat type explained most of the variation in growth and reproduction. Shoots from shallow snow cover and high summer irradiation habitats had higher numbers of flowers and fruits, lower ramet heights, shorter shoot segments, lower numbers of lateral shoots and total biomass but higher leaf density and higher relative leaf allocation than shoots from habitats with higher snow depth and lower summer irradiation. In addition, biomass, leaf allocation and leaf life expectancy were strongly affected by latitude, whereas local climate had strong effects on seed number and seed mass. Empetrum showed high phenotypic trait variation, with a consistent match between local habitat conditions and its growth and reproduction. Although study areas varied strongly with respect to latitude and local climatic conditions, response patterns of growth and reproduction to habitats with different environmental conditions were consistent. Large elasticity of traits suggests that Empetrum may have the potential to cope with changing snow conditions expected in the course of climate change.

Polyploidy is a fundamental mechanism in evolution, but is hard to detect in taxa with agmatoploidy or aneuploidy. We tested whether a combination of chromosome counting, microsatellite analyses and flow cytometric measurements represents a suitable approach for the detection of basic chromosome numbers and ploidy in Kobresia (Cyperaceae). Chromosome counting resulted in 2n = 64 for Kobresia pygmaea and K. cercostachys, 2n = 58 and 64 for K. myosuroides, and 2n = 72 for K. simpliciuscula. We characterized eight microsatellite loci for K. pygmaea, which gave a maximum of four alleles per individual. Cross-species amplification was tested in 26 congeneric species and, on average, six of eight loci amplified successfully. Using flow cytometry, we confirmed tetraploidy in K. pygmaea. Basic chromosome numbers and ploidy were inferred from chromosome counts and the maximum number of alleles per locus. We consider the basic numbers as x = 16 and 18, with irregularities derived from agmatoploidy and aneuploidy. Across all Kobresia taxa, ploidy ranged from diploid up to heptaploid. The combination of chromosome counts and microsatellite analyses is an ideal method for the determination of basic chromosome numbers and for inferring ploidy, and flow cytometry is a suitable tool for the identification of deviating cytotypes. (C) 2014 The Linnean Society of London

Aim Fossil-based biome reconstructions predict that during the Last Glacial Maximum (LGM), the subtropical zone of East Asia was reduced to a narrow southern belt. In contrast, previous phylogeographical studies of subtropical plant species, many of which are rare, indicated different glacial refugia north of this predicted area. Here, we aim to elucidate the phylogeographical structure and putative refugia of Castanopsis eyrei, a widely distributed tree of subtropical evergreen broad-leaved forests of China. Location Subtropical China. Methods We compiled distribution data and employed climate envelope model projections to predict potential areas at the LGM. Microsatellite data and chloroplast DNA (cpDNA) sequence data were obtained for 31 populations sampled throughout the species' range. Microsatellites were analysed with Bayesian clustering. Relationships among cpDNA haplotypes were depicted in a statistical parsimony network. We analysed patterns of variation within and among populations and clusters and along latitudinal clines. Results Modelling revealed a potential LGM distribution of C. eyrei in a broad but interrupted belt overlapping the southern part of the present range. Nuclear microsatellites revealed two main clusters, suggesting a split between the western and eastern range, and a south-to-north decline in genetic variation. The eastern cluster harboured significantly higher nuclear genetic diversity. Sixteen closely related cpDNA haplotypes were identified. Populations were strongly differentiated at cpDNA markers, but lacked phylogeographical structure. Both data sets revealed higher genetic differentiation in the western cluster than in the eastern cluster. Main conclusions Our results suggest at least two putative refugia during the LGM, further refugia-within-refugia substructure and a post-glacial northwards recolonization. Topographical differences between the mountainous western and the lowland eastern refugia may have affected the patterns of genetic differentiation between the extant populations. Incongruence between nuclear and chloroplast data might be attributed to ancestral polymorphism of cpDNA and chloroplast capture, but does not contradict the hypothesis of multiple refugia. Our results are likely to represent a template for evolutionary history and phylogeography in this region.

Summary Plant communities and their ecosystem functions are expected to be more resilient to future habitat fragmentation and deterioration if the species comprising the communities have a wide range of dispersal and persistence strategies. However, the extent to which the diversity of dispersal and persistence traits in plant communities is determined by the current and historical characteristics of sites and their surrounding landscape has yet to be explored. Using quantitative information on long-distance seed dispersal potential by wind and animals (dispersal in space) and on species' persistence/longevity (dispersal in time), we (i) compared levels of dispersal and persistence trait diversity (functional richness, FRic, and functional divergence, FDiv) in seminatural grassland plant communities with those expected by chance, and (ii) quantified the extent to which trait diversity was explained by current and historical landscape structure and local management history – taking into account spatial and phylogenetic autocorrel. Null model analysis revealed that more grassland communities than expected had a level of trait diversity that was lower or higher than predicted, given the level of species richness. Both the range (FRic) and divergence (FDiv) of dispersal and persistence trait values increased with grassland age. FDiv was mainly explained by the interaction between current grazing intensity and the amount of grassland habitat in the surrounding landscape in 1938. Synthesis. The study suggests that the variability of dispersal and persistence traits in grassland plant communities is driven by deterministic assembly processes, with both history and current management (and their interactions), playing a major role as determinants of trait diversity. While a long continuity of grazing management is likely to have promoted the diversity of dispersal and persistence traits in present-day grasslands, communities in sites that are well grazed at the present day, and were also surrounded by large amounts of grassland in the past, showed the highest diversity of dispersal and persistence strategies. Our results indicate that the historical context of a site within a landscape will influence the extent to which current grazing management is able to maintain a diversity of dispersal and persistence strategies and buffer communities (and their associated functions) against continuing habitat fragmentation. (Less)

Fragmentation of tropical forests influences abiotic and biotic processes that affect the genetic structure of plant populations. In forest fragments, edge effects, i.e. changes of abiotic and biotic factors at forest edges, may be prevalent. In two forest fragments (c. 200 ha atc. 2450 m asl) of tropical montane forest in Bolivia, sympatric populations of the dioecious tree speciesClusia sphaerocarpaandC. lechleriwere used as case study species to compare genetic diversity and small-scale genetic structure (SGS) between edge and interior habitats. Eight microsatellite markers were employed to genotype 343 individuals including adults, juveniles and seedlings ofC. sphaerocarpaand 196 ofC. lechleri. Genetic differentiation was found between habitats in both species (ΦRT= 0.071 forC. sphaerocarpaand ΦRT= 0.028 forC. lechleri) and among ages inC. sphaerocarpa(ΦRT= 0.016). Overall, SGS was weak but significant with more pronounced SGS inC. lechleri(Sp= 0.0128) than inC. sphaerocarpa(Sp= 0.0073). However, positive spatial genetic autocorrelation extended only up to 10 m. ForC. sphaerocarpa, SGS was stronger in seedling and juvenile stages than in adults and in the forest interior than at forest edges. Our results show that edge effects can extend to the genetic level by breaking-up local genetic structures, probably due to increased gene flow and enhanced pollination and seed-dispersal interactions at forest edges.

Summary 1. Theory predicts that the processes generating biodiversity after disturbance will change during succession. Comparisons of phylogenetic and functional (alpha and beta) diversity with taxonomic diversity can provide insights into the extent to which community assembly is driven by deterministic or stochastic processes, but comparative approaches have yet to be applied to successional systems. 2. We characterized taxonomic, phylogenetic and functional plant (alpha and beta) diversity within and between four successional stages in a > 270-year-long arable-to-grassland chronosequence. Null models were used to test whether functional and phylogenetic turnover differed from random expectations, given the levels of species diversity. 3. The three facets of diversity showed different patterns of change during succession. Between early and early-mid succession, species richness increased but there was no increase in functional or phylogenetic diversity. Higher than predicted levels of functional similarity between species within the early and early-mid successional stages, indicate that abiotic filters have selected for sets of functionally similar species within sites. Between late-mid and late succession, there was no further increase in species richness, but a significant increase in functional alpha diversity, suggesting that functionally redundant species were replaced by functionally more dissimilar species. Functional turnover between stages was higher than predicted, and higher than within-stage turnover, indicating that different assembly processes act at different successional stages. 4. Synthesis. Analysis of spatial and temporal turnover in different facets of diversity suggests that deterministic processes generate biodiversity during post-disturbance ecosystem development and that the relative importance of assembly processes has changed over time. Trait-mediated abiotic filtering appears to play an important role in community assembly during the early and early-mid stages of arable-to-grassland succession, whereas the relative importance of competitive exclusion appears to have increased towards the later successional stages. Phylogenetic diversity provided a poor reflection of functional diversity and did not contribute to inferences about underlying assembly processes. Functionally deterministic assembly suggests that it may be possible to predict future post-disturbance changes in biodiversity, and associated ecosystem attributes, on the basis of species’ functional traits but not phylogeny.

DNA methylation is an important, heritable epigenetic modification in most eukaryotic organisms that is connected with numerous biological processes. To study the impact of natural epigenetic variation in an ecological or evolutionary context, epigenetic studies are increasingly using methylation-sensitive amplification polymorphism (MSAP) for surveys at the population or species level. However, no consensus exists on how to interpret and score the multistate information obtained from the MSAP banding patterns. Here, we review the previously used scoring approaches for population epigenetic studies and develop new alternatives. To assess effects of the different approaches on parameters of epigenetic diversity and differentiation, we applied eight scoring schemes to a case study of three populations of the plant species Viola elatior. For a total number of 168 detected polymorphic MSAP fragments, the number of ultimately scored polymorphic epiloci ranged between 78 and 286 depending on the particular scoring scheme. Both, estimates of epigenetic diversity and differentiation varied strongly between scoring approaches. However, linear regression and PCoA revealed qualitatively similar patterns, suggesting that the scoring approaches are largely consistent. For single-locus analyses of MSAP data, for example the search for loci under selection, we advocate a new scoring approach that separately takes into account different methylation types and thus seems appropriate for drawing more detailed conclusions in ecological or evolutionary contexts. An R script (MSAP_score.r) for scoring and basic data analysis is provided.

A large threat to biological diversity worldwide is habitat fragmentation, with negative effects on organisms arising as a result of changes in the abiotic or biotic environment and via changes in genetic processes. We examined genetic diversity, population structure and gene flow as well as the importance of genetic diversity for plant and population performance in 17 differently-sized populations of the locally rare, self-incompatible, perennial forest herb Phyteuma spicatum. Genetic variation, characterized by AFLPs, was low (mean gene diversity, He: 0.126) and generally increased with increasing population size. Bayesian analysis of population structure showed that populations located in the same forest patch or in close vicinity formed genetic clusters. Population differentiation conformed to a pattern of isolation by distance (IBD). Gene dispersal distances were higher when estimated within than among populations, suggesting that gene flow is more restricted on a landscape scale. Two seedling vital rates were influenced by population genetic parameters, while most late life-cycle stages and population growth rate were not affected. These results suggest that genetic load is purged early in the life cycle by selective mortality, which may buffer populations against the negative genetic effects of small population size. The overall low levels of genetic diversity, however, imply that populations are poorly equipped to respond to future changes in the environment. This is of special concern as short-distance gene dispersal indicates that colonization of new sites in response to putative changes in the environment is unlikely. 2012 Elsevier Ltd. All rights reserved.

Strong environmental gradients can affect the genetic structure of plant populations, but little is known as to whether closely related species respond similarly or idiosyncratically to ecogeographic variation. We analysed the extent to which gradients in temperature and rainfall shape the genetic structure of four Stipa species in four bioclimatic regions in Jordan. Genetic diversity, differentiation and structure of Stipa species were investigated using amplified fragment length polymorphism (AFLP) molecular markers. For each of the four study species, we sampled 120 individuals from ten populations situated in distinct bioclimatic regions and assessed the degree of genetic diversity and genetic differentiation within and among populations. The widespread ruderals Stipa capensis and S. parviflora had higher genetic diversity than the geographically restricted semi-desert species S. arabica and S. lagascae. In three of the four species, genetic diversity strongly decreased with precipitation, while genetic diversity increased with temperature in S. capensis. Most genetic diversity resided among populations in the semi-desert species (Φ(ST) = 0.572/0.595 in S. arabica/lagascae) but within populations in the ruderal species (Φ(ST) = 0.355/0.387 S. capensis/parviflora). Principal coordinate analysis (PCoA) and STRUCTURE analysis showed that Stipa populations of all species clustered ecogeographically. A genome scan revealed that divergent selection at particular AFLP loci contributed to genetic differentiation. Irrespective of their different life histories, Stipa species responded similarly to the bioclimatic gradient in Jordan. We conclude that, in addition to predominant random processes, steep climatic gradients might shape the genetic structure of plant populations.

Introductions of alien plant species are often likely to consist of a few individuals. Thus, invasion success may strongly depend on their reproductive biology. A high number of self-compatible plants species are known to be successful colonizers of new habitats, even able to establish populations from single propagules. However, many other invasive species require pollen vectors. Here, we investigated the mating system of Buddleja davidii , a fast growing shrub native to China that colonizes quickly in disturbed habitats such as quarries, river banks, along railways and roads, both in its native and invasive regions. It was intentionally introduced to Europe as an ornamental plant because of its fragrant and showy flowers. We additionally studied its vulnerability to biparental inbreeding depression by performing a controlled crossing experiment using pollen from the same population or from geographically close and distant populations, respectively. As a measure for pollination success, we used capsule weight, seed number per capsule and seed weight for each treatment. The self-incompatibility index for B. davidii was found to be 96% suggesting that successful reproduction strongly depends on cross-pollination and the presence of appropriate pollen vectors. Since cross-pollination did not reveal significant differences in measured traits, it is assumed that invasive B. davidii -populations do not suffer from biparental inbreeding depression. B. davidii has fragrant and rewarding flowers that mainly attract butterflies. We conclude that the long distance pollen transfer performed by these insects may have prevented inbreeding so far and thus contributes to the invasive spread of B. davidii in Europe.

A highly selfing breeding system affects gene flow, which may have consequences for patterns of genetic variation and differentiation on both the population and species level. Feather grasses (Stipa spp.) are dominant elements of Eurasian steppes that persist in Central Europe in scattered isolated populations that are of great conservation interest. Cleistogamy is common in the Stipa pennata group, the phylogeny of which is largely unresolved. Intraspecific patterns of genetic variation can be characterised by lack of gene flow due to selfing, but also by large-scale historical migrations and long-term isolation. We analysed both 5 species within the S. pennata group and 33 populations of Stipa pulcherrima sampled across a large part of its range. Using AFLP markers we assessed phylogenetic relationships of the S. pennata group and patterns of genetic variation within and among populations. The S. pennata group formed a consistent clade separated from S. capillata. Stipa pulcherrima was sister to S. eriocaulis, but the relationships among S. pennata s. str., S. borysthenica., and S. tirsa remained unresolved. Within-population genetic variation was extremely low in all species of the S. pennata group (H e = 0.0–0.013). In S. pulcherrima, genetic variation was consistently relatively high in the east (Romania, Russia) and declined toward western populations, with many populations at the western range edge lacking genetic variation entirely. Populations were strongly differentiated (F ST = 0.762), and this differentiation did not follow a classical pattern of isolation by distance. Bayesian cluster analysis revealed nine gene pools in S. pulcherrima, which were mostly geographically clustered. Overall the results suggest that S. pulcherrima and species of the S. pennata group are characterised by a cleistogamous breeding system leading to extremely low levels of genetic variation and high levels of population differentiation at both the population and species level. Postglacial colonisation, current population isolation, and population bottlenecks at the western range periphery have further reduced genetic variation and obviated gene exchange. Thus, genetic variation can only be preserved by the conservation of multiple populations.

In plant populations a positive correlation between population size, genetic variation and fitness components is often found, due to increased pollen limitation or reduced genetic variation and inbreeding depression in smaller populations. However, components of fitness also depend on environmental factors which can vary strongly between years. The dry grassland species Muscari tenuiflorum experiences long term habitat isolation and small population sizes. We analyzed seed production of M. tenuiflorum in four years and its dependence on population size and genetic variation. Genetic diversity within populations was high (AFLP: He = 0.245; allozymes: He = 0.348). An analysis of molecular variance revealed considerable population differentiation (AFLP: 26%; allozyme: 17%). An overall pattern of isolation by distance was found, which, however was not present at distances below 20 km, indicating stronger effects of genetic drift. Genetic diversity was positively correlated to population size. Self pollination reduced seed set by 24%, indicating inbreeding depression. Reproductive fitness was not correlated to genetic diversity and a positive correlation with population size was present in two of four study years. The absence of a general pattern stresses the importance for multi-year studies. Overall, the results show that despite long term habitat isolation M. tenuiflorum maintains seed production in many years independent of population size. The long term persistence of populations is thus expected to depend less on intrinsic genetic or demographic properties affecting seed production but on successful plant establishment and persistence, which latter are based on conservation and protection of suitable habitats.

Aims The dispersal of pollen and seeds is spatially restricted and may vary among plant populations because of varying biotic interactions, population histories or abiotic conditions. Because gene dispersal is spatially restricted, it will eventually result in the development of spatial genetic structure (SGS), which in turn can allow insights into gene dispersal processes. Here, we assessed the effect of habitat characteristics like population density and community structure on small-scale SGS and estimate historical gene dispersal at different spatial scales. Methods In a set of 12 populations of the subtropical understory shrub Ardisia crenata, we assessed genetic variation at 7 microsatellite loci within and among populations. We investigated small-scale genetic structure with spatial genetic autocorrelation statistics and heterogeneity tests and estimated gene dispersal distances based on population differentiation and on within-population SGS. SGS was related to habitat characteristics by multiple regression.

Differences in herbivory among woody species can greatly affect the functioning of forest ecosystems, particularly in species-rich (sub)tropical regions. However, the relative importance of the different plant traits which determine herbivore damage remains unclear. Defence traits can have strong effects on herbivory, but rarely studied geographical range characteristics could complement these effects through evolutionary associations with herbivores. Herein, we use a large number of morphological, chemical, phylogenetic and biogeographical characteristics to analyse interspecific differences in herbivory on tree saplings in subtropical China. Unexpectedly, we found no significant effects of chemical defence traits. Rather, herbivory was related to the plants' leaf morphology, local abundance and climatic niche characteristics, which together explained 70% of the interspecific variation in herbivory in phylogenetic regression. Our study indicates that besides defence traits and apparency to herbivores, previously neglected measures of large-scale geographical host distribution are important factors influencing local herbivory patterns among plant species. Differences in herbivory among woody species can greatly affect the functioning of forest ecosystems, particularly in species-rich (sub)tropical regions. However, the relative importance of the different plant traits which determine herbivore damage remains unclear. Defence traits can have strong effects on herbivory, but rarely studied geographical range characteristics could complement these effects through evolutionary associations with herbivores. Herein, we use a large number of morphological, chemical, phylogenetic and biogeographical characteristics to analyse interspecific differences in herbivory on tree saplings in subtropical China. Unexpectedly, we found no significant effects of chemical defence traits. Rather, herbivory was related to the plants' leaf morphology, local abundance and climatic niche characteristics, which together explained 70% of the interspecific variation in herbivory in phylogenetic regression. Our study indicates that besides defence traits and apparency to herbivores, previously neglected measures of large-scale geographical host distribution are important factors influencing local herbivory patterns among plant species.

The eu-oceanic therophytic woodland herb Ceratocapnos claviculata has been expanding north- and eastwards into north temperate and subcontinental regions during the past decades. The rapid range expansion of the species may be an example of a species which is strongly profiting from global change. Against this background, in the present paper we review the taxonomy, morphology, distribution, habitat requirements, life cycle and biology of the species.

The use of local provenances in restoration, agriculture and forestry has been identified and widely implemented as a measure for species and community conservation. In practice, provenances are often delineated based on climate, geomorphology and correlated spatial descriptors following the boundaries of larger natural regions. They are thought to comprise genetically homogenous plant material. Here we investigate genetic variation at AFLP loci in 26 natural populations of the regionally common grassland species Geranium pratense, which is often used in seed mixtures. Most studied populations are located in one previously delineated provenance in Germany. We assess within- and among provenance differentiation patterns and aspects of gene flow by investigating the mating system, the genetic structure at regional and local scale, gene dispersal and potential selective mechanisms that may have contributed to differentiation patterns found. Compared to other herbaceous, insect-pollinated grassland species and despite being outcrossed (mean t m = 0.88), G. pratense showed low genetic diversity (mean H E = 0.15), considerable genetic differentiation among populations within provenances (mean pairwise F ST = 0.20) and a pronounced within-population spatial genetic structure (mean Sp = 0.064). A genome scan approach identified three potentially adaptive loci. However, their allelic frequencies were only weakly related to climatic parameters thus providing little evidence for adaptive divergence. Nevertheless, the distribution of genetic diversity and derived gene dispersal estimates indicate limited dispersal ability, suggesting that gene flow at distances larger than 10 km is negligible. Our findings may question the approach of delineating provenances by general criteria, and highlight the importance of species-specific studies on differentiation and adaptation patterns.

The most common management practices in European grasslands are grazing by livestock and mowing for silage and hay. Grazing and mowing differ in their potential effects on plant gene flow and resulting population–genetic structure. After assessing its breeding system, we investigated the effect of land use on the population–genetic structure in the common grassland plant Veronica chamaedrys using 63 study populations on meadows, mown pastures and pastures in three regions in Germany, the so-called Biodiversity Exploratories. We determined plant density and analysed the genetic diversity, differentiation and small-scale genetic structure using amplified fragment length polymorphism (AFLP) markers. The breeding system of V. chamaedrys turned out as self-incompatible and outcrossing. Its genetic diversity did not differ among land-use types. This may be attributed to large population sizes and the strong dispersal ability of the species, which maintains genetically diverse populations not prone to genetic drift. Genetic differentiation among populations was low (overall F ST = 0.075) but significant among the three regions. Land use had only weak effects on population differentiation in only one region. However, land use affected small-scale genetic structure suggesting that gene flow within plots was more restricted on meadows than on mown and unmown pastures. Our study shows that land use influences genetic structure mainly at the small scale within populations, despite high gene flow.

The fragrant orchid Gymnadenia conopsea s.l. is a controversial taxon with two commonly distinguished species, G. conopsea s.str. and G. densiflora. Despite morphological similarity, differentiation between the taxa has been reported for several characters; however, character variation within taxa has obviated a clear consensus. We assessed ITS sequences, microsatellite variation and chromosome numbers on the European scale (1,420 samples) and conducted morphological analyses for 626 samples from Germany. ITS analysis revealed a 2% nucleotide divergence between the taxa, similar to the divergence between other Gymnadenia species. The ITS sequences of G. densiflora form a well-supported monophyletic group sharing a most recent common ancestor with G. nigra and G. austriaca. Thus, G. conopsea and G. densiflora are not sister species, and a species rank is supported for G. densiflora (Wahlenb.) Dietrich and G. conopsea (L.) R.Br. s.str. This was confirmed by the microsatellite analysis, which revealed a strong genetic differentiation between the taxa because of largely non-overlapping sets of alleles. Chromosome numbers showed that G. conopsea was either diploid or tetraploid, whereas G. densiflora was diploid throughout. Morphologically, the taxa differed significantly in the mean value of a number of diagnostic characters. However, a discriminant analysis showed that the morphological variability is substantial, and on the individual level an unequivocal assignment is not possible as 96% of G. conopsea, but only 77% of G. densiflora could be assigned correctly. Further studies are needed on character variation within and among species and ploidy levels to allow for a better identification of the genetically differentiated but morphologically similar taxa.

Habitat fragmentation and reduction of population size have been found to nega- tively affect plant reproduction in 'new rare' species that were formerly common. This has been attributed primarily to effects of increased inbreeding but also to pollen limitation. In contrast, little is known about the reproduction of 'old rare' species that are naturally restricted to small and isolated habitats and thus may have developed strategies to cope with long-term isolation and small population size. Here we study the effects of pollen source and quantity on reproduction of the 'old rare' bumblebee-pollinated herb, Astragalus exscapus. In two populations of this species, we tested for pollen autodeposition, inbreeding depression and out- breeding depression. Caged plants were left unpollinated or were pollinated with pollen from the same plant, from the same population or from a distant population (50 km). Additionally, we tested for pollen limitation by pollen supplementation in four populations of different size and density. In the absence of pollinators, plants did not produce seed whereas self-pollinated plants did. This indicates a self-com- patible breeding system dependent on insect pollination. Both self-pollination and, in one of the two populations, cross-pollination with pollen from plants from the distant population resulted in a lower number of seeds per flower than cross-polli- nation with pollen from plants from the resident population, indicating inbreeding and outbreeding depression. Pollen addition enhanced fruit set and number of seeds per flower in three of the four populations, indicating pollen limitation. The degree of pollen limitation was lowest in the smallest but densest population. Our results suggest that, similar to 'new rare' plant species, also 'old rare' species may be at risk of inbreeding depression and pollen limitation.

Euphorbia palustris L. (Euphorbiaceae) is a tall perennial hemicryptophyte, native to Europe and small parts of adjacent Western Asia. It is considered a so-called river corridor plant that is exclusively or predominantly confined to the basins of large rivers. As most natural habitats along European rivers have been destroyed and the remaining habitats fragmented and degraded by the regulation of watercourses, land reclamation, and agricultural intensification, E. palustris is now endangered in most of Central Europe. To enhance its conservation, to give scientific advice for its management and to supplement the scarce information about the species available from the literature, this paper reviews its taxonomy, morphology, distribution, habitat requirements, life cycle, population biology and genetics as well as the conservation status across its distribution range. © 2011 Elsevier GmbH. All rights reserved.

Effects of habitat fragmentation on genetic diversity vary among species. This may be attributed to the interacting effects of species traits and landscape structure. While widely distributed and abundant species are often considered less susceptible to fragmentation, this may be different if they are small sized and show limited dispersal. Under intensive land use, habitat fragmentation may reach thresholds at which gene flow among populations of small-sized and dispersal-limited species becomes disrupted. Here, we studied the genetic diversity of two abundant and widespread bush crickets along a gradient of habitat fragmentation in an agricultural landscape. We applied traditional (GST, θ) and recently developed (, D) estimators of genetic differentiation on microsatellite data from each of twelve populations of the grassland species Metrioptera roeselii and the forest-edge species Pholidoptera griseoaptera to identify thresholds of habitat fragmentation below which genetic population structure is affected. Whereas the grassland species exhibited a uniform genetic structuring (GST = 0.020–0.033; D = 0.085–0.149) along the whole fragmentation gradient, the forest-edge species’ genetic differentiation increased significantly from D