Trait differentiation and adaptation of plants along elevation gradients

Studies of genetic adaptation in plant populations along elevation gradients in mountains have a long history, but there has until now been neither a synthesis of how frequently plant populations exhibit adaptation to elevation nor an evaluation of how consistent underlying trait differences across species are. We reviewed studies of adaptation along elevation gradients (i) from a meta‐analysis of phenotypic differentiation of three traits (height, biomass and phenology) from plants growing in 70 common garden experiments; (ii) by testing elevation adaptation using three fitness proxies (survival, reproductive output and biomass) from 14 reciprocal transplant experiments; (iii) by qualitatively assessing information at the molecular level, from 10 genomewide surveys and candidate gene approaches. We found that plants originating from high elevations were generally shorter and produced less biomass, but phenology did not vary consistently. We found significant evidence for elevation adaptation in terms of survival and biomass, but not for reproductive output. Variation in phenotypic and fitness responses to elevation across species was not related to life history traits or to environmental conditions. Molecular studies, which have focussed mainly on loci related to plant physiology and phenology, also provide evidence for adaptation along elevation gradients. Together, these studies indicate that genetically based trait differentiation and adaptation to elevation are widespread in plants. We conclude that a better understanding of the mechanisms underlying adaptation, not only to elevation but also to environmental change, will require more studies combining the ecological and molecular approaches.     

Temperature effects on forest herbs assessed by warming and transplant experiments along a latitudinal gradient

Slow‐colonizing forest understorey plants are probably not able to rapidly adjust their distribution range following large‐scale climate change. Therefore, the acclimation potential to climate change within their actual occupied habitats will likely be key for their short‐ and long‐term persistence. We combined transplant experiments along a latitudinal gradient with open‐top chambers to assess the effects of temperature on phenology, growth and reproductive performance of multiple populations of slow‐colonizing understorey plants, using the spring flowering geophytic forb Anemone nemorosa and the early summer flowering grass Milium effusum as study species. In both species, emergence time and start of flowering clearly advanced with increasing temperatures. Vegetative growth (plant height, aboveground biomass) and reproductive success (seed mass, seed germination and germinable seed output) of A. nemorosa benefited from higher temperatures. Climate warming may thus increase future competitive ability and colonization rates of this species. Apart from the effects on phenology, growth and reproductive performance of M. effusum generally decreased when transplanted southwards (e.g., plant size and number of individuals decreased towards the south) and was probably more limited by light availability in the south. Specific leaf area of both species increased when transplanted southwards, but decreased with open‐top chamber installation in A. nemorosa. In general, individuals of both species transplanted at the home site performed best, suggesting local adaptation. We conclude that contrasting understorey plants may display divergent plasticity in response to changing temperatures which may alter future understorey community dynamics.     

Differentiation and adaptation in <Emphasis Type="Italic">Brassica nigra</Emphasis> populations: interactions with related herbivores

Local adaptation and population differentiation of plants are well documented, but studies on interactions with natural enemies are rare. In particular, evidence for plant adaptation to the local biotic environment, such as herbivores remains poor. We used the black mustard Brassica nigra, an annual species of river valley and coastal habitats to (1) analyse population differentiation in plant traits and herbivory in a common garden experiment, (2) examine home versus away differences in a reciprocal transplant experiment and (3) test whether plants are adapted to local herbivores or vice versa under standard greenhouse conditions. In the common garden experiment, we found significant differentiation in plant traits, leaf damage and herbivore number among seven populations of B. nigra from France and Germany (distance 15–1,000 km). Differences were particularly strong among coastal and river valley populations and did not necessarily increase with geographical distance. A herbivore removal treatment did not change population differentiation when compared with the control allowing natural colonisation. The reciprocal transplant experiment at a scale of 15–30 km did not reveal local plant adaptation, whilst one dominant herbivore species (Meligethes aeneus) occurred in significantly higher numbers on local plants. A greenhouse experiment combining three aphid (Brevicoryne brassicae) and plant populations of the same provenance indicated herbivore adaptation to their local plants rather than plant adaptation, but overall contrasts between local and non-local combinations were not significant. The results suggest that herbivores may counteract local plant adaptation to other environmental factors. Our study has important implications for plant translocations in ecological restoration projects.     

Glacial History Affected Phenotypic Differentiation in the Alpine Plant,Campanula thyrsoides

Numerous widespread Alpine plant species show molecular differentiation among populations from distinct regions. This has been explained as the result of genetic drift during glacial survival in isolated refugia along the border of the European Alps. Since genetic drift may affect molecular markers and phenotypic traits alike, we asked whether phenotypic differentiation mirrors molecular patterns among Alpine plant populations from different regions. Phenotypic traits can be under selection, so we additionally investigated whether part of the phenotypic differentiation can be explained by past selection and/or current adaptation. Using the monocarpic Campanula thyrsoides as our study species, a common garden experiment with plants from 21 populations from four phylogeographic groups located in regions across the Alps and the Jura Mountains was performed to test for differentiation in morphological and phenological traits. Past selection was investigated by comparing phenotypic differentiation among and within regions with molecular differentiation among and within regions. The common garden results indicated regional differentiation among populations for all investigated phenotypic traits, particularly in phenology. Delayed flowering in plants from the South-eastern Alps suggested adaptation to long sub-mediterranean summers and contrasted with earlier flowering of plants experiencing shorter growing seasons in regions with higher elevation to the West. Comparisons between molecular and phenotypic differentiation revealed diversifying selection among regions in height and biomass, which is consistent with adaptation to environmental conditions in glacial refugia. Within regions, past selection acted against strong diversification for most phenotypic traits, causing restricted postglacial adaptation. Evidence consistent with post-glacial adaptation was also given by negative correlation coefficients between several phenotypic traits and elevation of the population''s origin. In conclusion, our study suggests that, irrespective of adaptation of plants to their current environment, glacial history can have a strong and long-lasting influence on the phenotypic evolution of Alpine plants.     

Natural hybridisation between two coastal endemic species of Armeria (Plumbaginaceae) from Portugal. 2. Ecological investigations on a hybrid zone

A clinal range of morphological variation between two coastal endemic species of the Genus Armeria in Portugal (A. pseudoarmeria and A. welwitschii) was investigated to test the hypothesis of hybrid advantage in contact zones between species. The putative F1 hybrids morphotypes could be submitted to endogenous selection as most of them show deficiencies in pollen fertility and seed setting in comparison with the parental species. Reciprocal transplant experiments in three sectors along the cline revealed that the intermediate F1 morphotypes are less productive in biomass than the parents even in their sector of origin. These data do not show evidence for the Hybrid Bound Superiority Model. Rather they are in favour of the Tension Zone Model where a dynamic balance is obtained between the continuous production of hybrids and the selection against them. Nevertheless the Tension Zone Model postulates similar fitness for the parents along the cline, which is not the case as the parents are clearly differentiated for nutrient uptake. Soil and plant leaf elemental analysis revealed that, in transplantation, some of the hybrids correspond to a geochemical specialisation diverging from that of the parents suggesting a local adaptation. Owing the high frequency and the healthy developmental aspect of the intermediate morphs in central and northern sector selection must be weak against hybrids. It is concluded that in natural situations the two models could not be strictly exclusive.     

Geographic and Habitat Origin Influence Biomass Production and Storage Translocation in the Clonal Plant Aegopodium podagraria

Through physiological integration, clonal plants can support ramets in unfavourable patches, exploit heterogeneously distributed resources and distribute resources that are taken up over large areas. Physiological integration generally increases in adverse conditions, but it is not well known which factors determine the evolution of physiological integration. The aim of this study was to investigate if clonal plants from Southern and Northern populations of the clonal herb Aegopodium podagraria differed in physiological integration in terms of translocation of carbon to the rhizomes, and in biomass production using a reciprocal transplant experiment. Aegopodium podagraria from shaded conditions have been suggested to share more resources than clones from open conditions and therefore, plants from forest and open populations within the Southern and Northern regions were included. The regional growing conditions greatly affected biomass production. Plants grown in North Sweden produced more biomass and allocated more biomass to shoots, while plants grown in South Sweden allocated more biomass to rhizomes. There was a regional origin effect as plants originating from North Sweden produced more biomass in both regions. Within the Northern region, plants from shaded habitats translocated more ¹⁴C to the rhizomes, suggesting more storage there than in plants from open habitats. In addition to genetic differentiation in biomass production between Northern and Southern populations, probably as a response to a shorter growing season in the North, there appeared to be genetic differentiation in physiological integration within the Northern region. This shows that both regional and local conditions need to be taken into account in future studies of genetic differentiation of physiological integration in clonal plants.     

Rapid genetic delineation of local provenance seed‐collection zones for effective rehabilitation of an urban bushland remnant

Abstract The rehabilitation of native plant communities in urban bushland remnants is an increasingly important activity requiring the collection of large amounts of seed. Best practice generally identifies that local seed are best, but how far does the local provenance extend? Using the DNA fingerprinting technique amplified fragment length polymorphism, we assessed genetic differentiation between potential seed source populations and the target population, Bold Park, a large and significant bushland remnant in Perth, Western Australia. For each of 15 species, analysis of molecular variance was used to partition genetic variation within and among populations. Genetic differentiation between Bold Park and potential seed source populations was assessed by non‐metric multidimensional scaling ordination, and statistically by Fisher’s exact tests. The partitioning of variation among populations (Φ_ST) varied from 0.66 for Santalum acuminatum to 0.04 for Mesomelaena pseudostygia. For eight of 15 species, Bold Park plants were completely or largely non‐overlapping with other populations in ordinations, suggesting genetic differentiation and a narrow provenance. Five species showed overlap between Bold Park and some other, but not all, populations sampled, with geographically closest populations generally undifferentiated. Only two species, Acanthocarpus preissii and Mesomeleana pseudostygia, showed little genetic differentiation between Bold Park and all other populations, suggesting a regional genetic provenance. These species can be classified into three broad provenance classes – narrow, local and regional – to help guide decisions about appropriate seed‐collection zones for the rehabilitation of urban bushland remnants.     

Response of the two rare arable weed species Lithospermum arvense and Scandix pecten-veneris to climate change conditions

Rare weeds are currently under pressure due to intensifying arable management practices, and as a consequence of climate change, these practices will likely become even more intensive, together with a greater uniformity of land use. As a result, ecological stresses will increase for most species of rare weeds, in some cases leading to their further decline or even extinction. Moreover, climate change will alter the suitability of the environment for many plants, since average temperatures are predicted to increase and precipitation extremes to become more common. For most arable weed species it is unclear, whether the anticipated changes in environmental conditions are disadvantageous or beneficial. Little is known about specific biological responses of rare weeds to climate changes, and this study attempts to close some of these knowledge gaps. Here, the rare arable weed Lithospermum arvense and the endangered arable species Scandix pecten-veneris were investigated with regard to the effects of higher temperature and different crop densities on flowering time, shoot development, plant height, dry mass and seed production. Semi-field experiments were conducted with winter wheat crop for 3 years, involving 48 climate cages, in which every second was a variant of warmer temperature and contrasting crop density. We observed that S. pecten-veneris flowered earlier under warmer conditions and had fewer seeds and less biomass in the dense wheat crop compared to control conditions, while L. arvense grew taller, it produced fewer seeds in the high density crop. We suggest that such data concerning the biological responses of weeds can improve the precision of bioclimatic distribution models. Finally, we discuss strategies, such as relocation or non-intrusive management practices, for preventing further disappearances of rare arable weeds. Our results should be of considerable interest for the fields of plant ecology, biodiversity research and conservation.     

Testing the Home‐Site Advantage in Forest Trees on Disturbed and Undisturbed Sites

Restoration of plant populations is often undertaken using seed or plants from local sources because it is assumed they will be best adapted to the prevailing conditions. However, the effect of site disturbance on local adaptation has rarely been examined. We assessed local adaptation in three southwestern Australian forest tree species (Eucalyptus marginata, Corymbia calophylla, and Allocasuarina fraseriana) using reciprocal transplant trials at disturbed and undisturbed sites. Performance of plants within the trials was assessed over 2 years. Planting location accounted for the majority of the variation in most measures of performance, although significant variation of percent emergence among source populations was also detected. In all species, percent emergence and survival of plants sourced from Darling Range populations was significantly higher than that of plants from the Swan Coastal Plain, regions of contrasting edaphic and climatic environment. Survival of E. marginata over the first 18 months and emergence of C. calophylla were both higher in local plants, providing at least weak evidence for local adaptation. Where a local advantage was observed, the relative performance of local and nonlocal seed did not vary among disturbed and undisturbed sites. Evidence for enhanced establishment from local seed in at least one species leads us to recommend that where sufficient high‐quality seed supplies exist locally, these should be used in restoration. We also recommend longer‐term studies to include the possibility of local adaptation becoming evident at later life history stages.     

Co-occurring patterns of endophyte infection and genetic structure in the alpine grass, <Emphasis Type="Italic">Festuca eskia</Emphasis>: implications for seed sourcing in ecological restoration

Choosing the provenance of seed used in ecological restoration could entail its success. An alternative approach to examine local adaptation in seed sourcing is the assessment of genetic structure and diversity based on molecular markers. These types of analyses focus on the genetics of the target plant itself and eliminate the genetic influence of associated organisms, such as Epichloë/Neotyphodium endophytes in grasses. By impacting the fitness of their host, such symbionts may influence population genetic structure and diversity. Therefore, seed sourcing for grasses must consider the influence of their endophytes to increase seed translocation success and minimize the risks associated with this practice. To delineate seed zones for restoration of the alpine fescue Festuca eskia Ramond ex. DC. (Poaceae), we assessed population genetic differentiation and diversity patterns in the species including endophyte occurrence along altitudinal and longitudinal gradients in the Pyrenees Mountains. Twenty-three populations were analysed for endophyte status, and three STS and one SSR marker were used to examine genetic differentiation and diversity patterns. Results showed that F. eskia hosts an asexual form of Epichloë and infection frequency within populations decreased from East to West (100 vs. 8–25%). Molecular markers separated F. eskia into two East and West groups, and endophyte infection and genetic patterns were congruent with molecular data. Little evidence for genetic differentiation or difference in endophyte occurrence associated with altitude was detected. Little variation was found in within population diversity, regardless of provenance altitude and site, and/or endophyte infection frequency. The results of this study suggested the establishment of two distinct management units for F. eskia seed sourcing restoration.     

Plant population differentiation and climate change: responses of grassland species along an elevational gradient

Mountain ecosystems are particularly susceptible to climate change. Characterizing intraspecific variation of alpine plants along elevational gradients is crucial for estimating their vulnerability to predicted changes. Environmental conditions vary with elevation, which might influence plastic responses and affect selection pressures that lead to local adaptation. Thus, local adaptation and phenotypic plasticity among low and high elevation plant populations in response to climate, soil and other factors associated with elevational gradients might underlie different responses of these populations to climate warming. Using a transplant experiment along an elevational gradient, we investigated reproductive phenology, growth and reproduction of the nutrient‐poor grassland species Ranunculus bulbosus, Trifolium montanum and Briza media. Seeds were collected from low and high elevation source populations across the Swiss Alps and grown in nine common gardens at three different elevations with two different soil depths. Despite genetic differentiation in some traits, the results revealed no indication of local adaptation to the elevation of population origin. Reproductive phenology was advanced at lower elevation in low and high elevation populations of all three species. Growth and reproduction of T. montanum and B. media were hardly affected by garden elevation and soil depth. In R. bulbosus, however, growth decreased and reproductive investment increased at higher elevation. Furthermore, soil depth influenced growth and reproduction of low elevation R. bulbosus populations. We found no evidence for local adaptation to elevation of origin and hardly any differences in the responses of low and high elevation populations. However, the consistent advanced reproductive phenology observed in all three species shows that they have the potential to plastically respond to environmental variation. We conclude that populations might not be forced to migrate to higher elevations as a consequence of climate warming, as plasticity will buffer the detrimental effects of climate change in the three investigated nutrient‐poor grassland species.     

Lack of local adaptation of invasive crofton weed (Ageratina adenophora) in different climatic areas of Yunnan Province,China

Aims Crofton weed, with a subtropical origin, has successfully invaded in diverse habitats that belong to different climate zones in Southwest China. We tested whether local adaptation plays an important role in the successful invasion of crofton weed in heterogeneous environments.Methods Five populations from different habitats with an altitude ranging from 678 to 2356 m were selected. Plant height, biomass, seed yield and seed germination capability of these populations were investigated in the field. Greenhouse and reciprocal transplant experiments with the five populations were conducted, and all the above characters were measured and compared among these populations.Important findings Plant height, biomass, seed yield and seed germination rate were each significantly different among the five populations in field. However, there was no difference among these populations in the greenhouse experiment. In the reciprocal transplant experiment, plants from the five populations responded similarly to different habitats in the field, indicating lack of local adaptation. Instead, phenotypic plasticity likely plays a key role in the invasion success of crofton weed in different habitats.     

Phenological Adaptations in Ficus tikoua Exhibit Convergence with Unrelated Extra-Tropical Fig Trees

Flowering phenology is central to the ecology and evolution of most flowering plants. In highly-specific nursery pollination systems, such as that involving fig trees (Ficus species) and fig wasps (Agaonidae), any mismatch in timing has serious consequences because the plants must balance seed production with maintenance of their pollinator populations. Most fig trees are found in tropical or subtropical habitats, but the dioecious Chinese Ficus tikoua has a more northerly distribution. We monitored how its fruiting phenology has adapted in response to a highly seasonal environment. Male trees (where fig wasps reproduce) had one to three crops annually, whereas many seed-producing female trees produced only one fig crop. The timing of release of Ceratosolen fig wasps from male figs in late May and June was synchronized with the presence of receptive figs on female trees, at a time when there were few receptive figs on male trees, thereby ensuring seed set while allowing remnant pollinator populations to persist. F. tikoua phenology has converged with those of other (unrelated) northern Ficus species, but there are differences. Unlike F. carica in Europe, all F. tikoua male figs contain male flowers, and unlike F. pumila in China, but like F. carica, it is the second annual generation of adult wasps that pollinate female figs. The phenologies of all three temperate fig trees generate annual bottlenecks in the size of pollinator populations and for female F. tikoua also a shortage of fig wasps that results in many figs failing to be pollinated.     

Local adaptation,genetic divergence,and experimental selection in a foundation grass across the US Great Plains’ climate gradient

Many prior studies have uncovered evidence for local adaptation using reciprocal transplant experiments. However, these studies are rarely conducted for a long enough time to observe succession and competitive dynamics in a community context, limiting inferences for long‐lived species. Furthermore, the genetic basis of local adaptation and genetic associations with climate has rarely been identified. Here, we report on a long‐term (6‐year) experiment conducted under natural conditions focused on Andropogon gerardii, the dominant grass of the North American Great Plains tallgrass ecosystem. We focus on this foundation grass that comprises 80% of tallgrass prairie biomass and is widely used in 20,000 km² of restoration. Specifically, we asked the following questions: (a) Whether ecotypes are locally adapted to regional climate in realistic ecological communities. (b) Does adaptive genetic variation underpin divergent phenotypes across the climate gradient? (c) Is there evidence of local adaptation if the plants are exposed to competition among ecotypes in mixed ecotype plots? Finally, (d) are local adaptation and genetic divergence related to climate? Reciprocal gardens were planted with 3 regional ecotypes (originating from dry, mesic, wet climate sources) of Andropogon gerardii across a precipitation gradient (500–1,200 mm/year) in the US Great Plains. We demonstrate local adaptation and differentiation of ecotypes in wet and dry environments. Surprisingly, the apparent generalist mesic ecotype performed comparably under all rainfall conditions. Ecotype performance was underpinned by differences in neutral diversity and candidate genes corroborating strong differences among ecotypes. Ecotype differentiation was related to climate, primarily rainfall. Without long‐term studies, wrong conclusions would have been reached based on the first two years. Further, restoring prairies with climate‐matched ecotypes is critical to future ecology, conservation, and sustainability under climate change.     

Evidence for plasticity,but not local adaptation,in invasive Japanese knotweed (<Emphasis Type="Italic">Reynoutria japonica</Emphasis>) in North America

While local adaptation and phenotypic plasticity are commonly observed in species occupying heterogeneous environments, these phenomena are less well understood in invasive species. However, plant invasions offer the opportunity to study these dynamics as they occur in species colonizing new habitats. In this study, we examined local adaptation and phenotypic plasticity in an invasive plant, Reynoutria japonica, across a broad latitudinal range within North America. We performed full-factorial reciprocal transplants using plants from three sites and examined fitness responses in both sexual and clonal reproductive measures, as well as vegetative responses in height, basal stem diameter, and biomass. For all vegetative traits, there was a significant effect of source population, indicating genetic differentiation among populations. There was also a significant effect of transplant site, suggesting phenotypic plasticity. However, there was no evidence of local adaptation at the North American meta-population level for either measure of sexual or clonal fitness. All three comparisons for sexual fitness failed to show any differences between source populations, indicating a lack of local adaptation. For clonal fitness, two of the three comparisons showed local maladaptation, and only one showed greater fitness at the home compared to foreign sites, but this population had greater fitness at all sites, indicating greater fitness overall for this population rather than local adaptation. The fact that we did not detect consistent patterns of local adaptation in these populations across a broad geographic range is somewhat surprising given that local adaptation appears common in many species, including invasives, and that the populations have been established for over a century. However, the lack of local adaptation observed in this species may indicate that phenotypic plasticity within the species is sufficient to allow the persistence of R. japonica in a variety of environments across its invaded range.     

Local adaptation in the monocarpic perennial Carlina vulgaris at different spatial scales across Europe

Spatial variation in environmental conditions can lead to local adaptation of plant populations, particularly if gene flow among populations is low. Many studies have investigated adaptation to contrasting environmental conditions, but little is known about the spatial scale of adaptive evolution. We studied population differentiation and local adaptation at two spatial scales in the monocarpic grassland perennial Carlina vulgaris. We reciprocally transplanted seedlings among five European regions (northwestern Czech Republic, central Germany, Luxembourg, southern Sweden and northwestern Switzerland) and among populations of different sizes within three of the regions. We recorded survival, growth and reproduction over three growing periods. At the regional scale, several performance traits and the individual fitness of C. vulgaris were highest if the plants were grown in their home region and they decreased with increasing transplant distance. The effects are likely due to climatic differences that increased with the geographical distance between regions. At the local scale, there were significant interactions between the effects of the population of origin and the transplant site, but these were not due to an enhanced performance of plants at their home site and they were not related to the geographical or environmental distance between the site of origin and the transplant site. The size of the population of origin did not influence the strength of local adaptation. The results of our study suggest that C. vulgaris consists of regionally adapted genotypes, and that distance is a good predictor of the extent of adaptive differentiation at large scales ( > 200 km) but not at small scales. We conclude that patterns of local adaptation should be taken into account for the efficient preservation of genetic resources, when assessing the status of a plant species and during conservation planning.Electronic supplementary material Supplementary material is available in the online version of this article at and is accessible for authorized users.     

Local Adaptation and the Effects of Grazing on the Performance of Nassella pulchra: Implications for Seed Sourcing in Restoration

The use of local seed sources for revegetation is accepted practice to reduce the potential that propagules will be poorly adapted to site conditions. However, data are often lacking to determine the distance within which seed sources represent local genotypes. Short‐term reciprocal transplant studies represent a class of tools to detect local adaptation of target species. We conducted a reciprocal transplant of Nassella pulchra between two central California locations to test for adaptation to local environmental conditions over a 3‐year period. Experimental plots at one location were split between grazed and ungrazed sites to evaluate the potential influence of livestock grazing on the detection or magnitude of local adaptation. During each year of the study, evidence of a home‐site advantage depended on the location, traits studied, and population. At the end of the 3‐year study period, however, we detected consistent evidence of a home‐site advantage for seedling biomass among grazed sites at one location and ungrazed plots at the other location. In effect, local adaptation was only apparent in the final year of the study. Short‐term reciprocal transplant studies are an effective tool to guide the selection of seed sources most likely to germinate and to become established at a restoration site, but such studies cannot rule out local adaptation, which may not be immediately detectable.     

Variation in overall fitness due to seed source: projections for predictive provenancing

Seed sourcing decisions affect short- and long-term restoration outcomes. Seeds sourced closer to restoration sites are likely to be better adapted to local conditions and therefore may perform better than those sourced farther away, following assumptions of local adaptation. However, plants may not be adapted to future conditions under climate change; hence, managers are considering a predictive provenancing approach, where plant materials adapted to predicted conditions are used at a site. Currently, there is little empirical evidence available to inform this approach. To address this, we evaluate predictive provenancing using three species of forbs used in tallgrass prairie restorations (Allium cernuum, Chamaecrista fasciculata, and Rudbeckia hirta) in a common garden experiment in northeastern Illinois, U.S.A. We compared the fitness in plants sourced from three regional zones across a latitudinal gradient that represents different climate projections, relative to the planting site. Data were analyzed using Aster life-history models and generalized linear models. We found that source affected overall fitness in all three species, but no climate proxy had the highest fitness across all species. The performance at each life stage had different effects on overall fitness, which varied by source. We observed later reproductive phenology in southern-sourced plants for all three species, possibly due to adaptation to longer growing seasons. The mixed results of this study suggest that climate proxy alone would not be sufficient to determine an effective and accurate predictive provenancing strategy. Long-term tests are needed to pursue such a strategy for high-priority species.     

Fine-scale genetically based differentiation of life-history traits in the perennial shrub Lupinus arboreus

Across large spatial scales, plants often exhibit genetically based differentiation in traits that allow adaptation to local sites. At smaller spatial scales, sharp boundaries between edaphic conditions also can create strong gradients in selection that counteract gene flow and result in local adaptation. Few studies, however, have examined the degree to which continuous populations of perennial plants exhibit genetically based differentiation in life-history traits over small spatial scales. We quantified the degree of genetically based differentiation in adaptive traits among bush lupine (Lupinus arboreus) from nearby dune and grassland sites (sites separated by < 0.75 km) that formed part of a larger continuous population of L. arboreus. We also investigated the spatial genetic structure of bush lupine by examining how genetic structure differed between seeds and juvenile plants that were less than two years old. We calculated F-statistics from gel electrophoresis of 10 polymorphic loci. We then used these values to infer levels of gene flow. To examine differentiation in adaptive traits, we created full-sibling/half-sibling families of lupine within each area and established reciprocal common gardens at each site. Across two years, we measured canopy volume, flowering time, seed set, and mortality of progeny planted in each garden. Spatial genetic structure among seeds was virtually nonexistent (F(ST) = 0.002), suggesting that gene flow between the three areas could be quite high. However, genetic structure increased 20-fold among juvenile plants (F(ST) = 0.041). We found strong evidence for fine-scale genetically based differentiation and local adaptation in adaptive traits such as plant size, flowering phenology, fecundity, and mortality. Thus, it is likely that strong but differing selection regimes within each area drive spatial differentiation in lupine life-history traits.     

Genetic structure among arable populations of Capsella bursa‐pastoris is linked to functional traits and in‐field conditions

Wild arable plants can be an economic burden but they also support diverse arable food webs and contribute to valuable ecosystem functions. These benefits may have been compromised over recent decades by declining weed diversity. The decline in wild arable plant diversity has been viewed predominantly in terms of species shifts a view that ignores the genetic and functional variation existing within species and the impact on ecological and evolutionary processes which this may have. To examine within‐species diversity, ISSR markers were used in parallel with environmental and phenotypic characterisation, to investigate the population structure and diversity of Capsella bursa‐pastoris (shepherd's purse) from arable fields in the UK. Analysis of 338 ISSR products for 109 individuals from 51 accessions obtained from the seed banks of 33 arable fields showed that in‐field populations of shepherd's purse were genetically differentiated between individuals, and among accessions and fields. In addition, cluster analysis identified three genetically distinct regional‐scale populations. Phenotypic variation was present at all scales of genetic differentiation, including the regional scale where populations differed in their key life‐history traits: flowering time, fecundity and dormancy. Genetic drift is proposed as a contributor to differentiation among genetically isolated but locally co‐occurring accessions. In addition, the genetic and phenotypic variation in shepherd's purse exhibited large scale, spatial trends and showed statistically significant associations with cropping intensity and soil‐pH. These results suggest that adaptation as a result of selection by cropping practise and soil‐pH has played a role in the ability of shepherd's purse to colonise and persist in arable fields.