Low levels of regional differentiation and little evidence for local adaptation in rare arable plants

A better understanding of regional differentiation and local adaptation of rare arable plants is essential for the development of suitable methods for the reintroduction of these species. We set up F1 and F2 greenhouse experiments with 4–12 source populations of five rare arable plant species to test for genetically based differentiation in biomass production and phenology in South Germany. For three species, i.e. Arnoseris minima, Consolida regalis and Teesdalia nudicaulis, reciprocal transplant experiments were performed in arable fields to investigate local adaptation in plant establishment as well as biomass production to the northern or southern regions of three seed transfer zones. We found low regional differentiation, but provenance-specific responses to drought stress in Legousia speculum-veneris biomass and A. minima phenology. Moreover, little evidence was identified for local adaptation, while significant differences were seen in the performance between the transplant sites and study years, indicating a high phenotypic variability. Our results suggest that the current seed zones are suitable for the seed transfer of rare arable plants in the study region. Thus, there is a low risk of maladaptation when using autochthonous seed sources within the seed zones, but a high extinction risk of these species and their respective ecosystem functions if no active restoration is done, including transplant measures.     

Low genetic variability and strong differentiation among isolated populations of the rare steppe grass Stipa capillata L. in Central Europe

Stipa capillata L. (Poaceae) is a rare grassland species in Central Europe that is thought to have once been widespread in post‐glacial times. Such relict species are expected to show low genetic diversity within populations and high genetic differentiation between populations due to bottlenecks, long‐term isolation and ongoing habitat fragmentation. These patterns should be particularly pronounced in selfing species. We analysed patterns of random amplified polymorphic DNA (RAPD) variation in the facultatively cleistogamous S. capillata to examine whether genetic diversity is associated with population size, and to draw initial conclusions on the migration history of this species in Central Europe. We analysed 31 S. capillata populations distributed in northeastern, central and western Germany, Switzerland and Slovakia. Estimates of genetic diversity at the population level were low and not related to population size. Among all populations, extraordinarily high levels of genetic differentiation (amova : φ_ST = 0.86; Bayesian analysis: θ^B = 0.758) and isolation‐by‐distance were detected. Hierarchical amova indicated that most of the variability was partitioned among geographic regions (59%), or among populations between regions when the genetically distinct Slovakian populations were excluded. These findings are supported by results of a multivariate ordination analysis. We also found two different groups in an UPGMA cluster analysis: one that contained the populations from Slovakia, and the other that combined the populations from Germany and Switzerland. Our findings imply that S. capillata is indeed a relict species that experienced strong bottlenecks in Central Europe, enhanced by isolation and selfing. Most likely, populations in Slovakia were not the main genetic source for the post‐glacial colonization of Central Europe.     

Isolation and characterization of first microsatellite markers for the noble crayfish, <Emphasis Type="Italic">Astacus astacus</Emphasis>

Noble crayfish (Astacus astacus) is listed as vulnerable by the IUCN Red List of Threatened Species in Europe. However, very little is known about genetic diversity and structuring of noble crayfish populations, mainly because of the lack of informative genetic markers. We describe the isolation and characterization of the first microsatellite markers for this species, which were obtained by screening 4,000 recombinant clones. Eight loci revealed polymorphisms in a panel of 172 individuals from seven populations in Northern Europe. Number of alleles per locus ranged from two to 10 (average 4.4) and heterozygosity levels among populations varied from 0 to 0.80 for H _o and from 0 to 0.72 for H _e.     

First record of the genus Schizothorax in rivers of the Central Himalayas in China

A total of 40 specimens of the genus Schizothorax (Cyprinidae: Schizothoracinae), including 10 matured males, 19 matured females and 11 juveniles, were captured from the Kirong Tsangpo River in China, which is located in the southern slope of the Central Himalayas. These specimens are identified as Schizothorax richardsonii (Grey, 1832) based on morphological characters and molecular analyses using mitochondrial Cyt b gene sequences. The Kirong population of S. richardsonii is relatively isolated from other populations in the Himalayas and has low genetic diversity. This is the first record of the genus Schizothorax fish in rivers of the Central Himalayas in China. As S. richardsonii is a vulnerable species on the IUCN Red List, a protection plan should be conducted to reduce the impact of anthropogenic disturbance by monitoring the natural population dynamics and assessing the ecological determinants of its distribution.     

Genetic variation of Sherardia arvensis L. – How land use and fragmentation affect an arable weed

The distribution of arable weeds extends over regions, where the species occur naturally in different kinds of habitats and regions, where they are mainly limited to arable fields.Here, we present a comparative study on the genetic structure of the arable weed Sherardia arvensis L. comprising populations from Mediterranean grasslands in Southern France and populations from arable fields in Germany. Enhanced by intensified land use since the 1960th, overall population density in Germany is very low compared to the density of populations in Southern France. We tested whether genetic variation within and among populations differ between France and Germany due to different patterns of distribution and land use. Therefore, we analysed 231 individuals of S. arvensis from 24 populations using AFLPs. Based on fragment analysis data we compared spatial genetic structure and genetic variation of populations from the two regions.Genetic variation within populations from the two regions (Shannon Index = 0.13 for both) and genetic variation among populations (26.8% and 30.0% in an analysis of molecular variance) were comparable. In both regions a drift-migration model supported the assumption of gene flow between populations. However, a clear correlation of geographical and genetic distances could only be reported for the indigenous populations from France (r = 0.46; P = 0.02), whereas in Germany a spatial genetic relationship between populations was missing (r = 0.16; P = 0.21).Our study revealed that neither French nor German populations are genetically impoverished. For French populations further the spatial genetic structure suggests that there is current gene flow between populations through pollinators and seed dispersal by cattle. For German populations comparable levels of genetic diversity and gene flow were detected, but gene flow was random. This can be traced back in all likelihood to diffuse dispersal by agriculture and the mechanical reshuffling of the individuals from the soil seed bank.     

Managing plant species diversity under fluctuating wetland conditions: the case of temporarily flooded depressions

Temporarily flooded depressions in arable fields support populations of specialised plant species that are affected by flooding and agricultural management. Depending on the degree of flooding, different proportions of wetland and arable species contribute to the seed bank. This is reflected by high inter-annual variations in plant communities with a high conservation value. Due to ongoing agricultural intensification, the biodiversity of temporarily flooded depressions has declined, and several plant species have become regionally extinct. Because seed banks harbour persistent seeds over long periods, they play a crucial role in the conservation and restoration of temporary wetland vegetation. This study focuses on the effects of different flooding regimes on plant species emerging from seed banks of temporarily flooded depressions in arable fields in northeast Germany. We cultivated soil samples from upper and lower wetland zones under short, intermediate and long-term flooding (5, 15 and 40 cm above soil surface) in a common garden experiment over 2 years. We observed significant changes in species composition depending on the flooding duration. Species richness declined and evenness increased with increasing flooding duration. Upper and lower zones showed similar species richness and evenness, but species compositions differed. Red List species emerged from all treatments although the species differed, indicating that all communities emerging under different flooding regimes have a high conservation value. Seed banks under fluctuating site conditions can constitute a series of alternating plant communities. This could be used to develop management strategies that benefit different communities with high conservation values.     

Relationships between Population Size, Genetic Diversity and Fitness Components in the Rare Plant Dictamnus albus in Central Germany

An increasing number of studies support the hypothesis that smaller populations face a higher risk of extinction, and declining population sizes are therefore one of the focal points in plant conservation. In small populations, loss of genetic diversity is often related to reduced reproductive fitness. For the rare Dictamnus albus in Central Germany, an earlier study had already confirmed a significant correlation between population size and genetic diversity. In order to assess whether these variables correlate with fitness components, plant height; flower, fruit and seed production; and germination were studied in a total of 11 populations of different size. In the seven populations that were sampled over two consecutive years, differences among populations and among years were tested using a Two-Way ANOVA. Co-linearity among variables was assessed using principal component analysis (PCA), followed by calculating correlations between ordination axes and both population size and genetic diversity. Plant height and flower number were uncorrelated to the other variables and, together with germination, did not show any correlation to either population size or genetic diversity. However, both size and genetic diversity of populations correlated significantly with other PCA axes that reflected reproductive components such as fruit number, seed number, seed fruit ratio, and seed mass. Our results support the idea that reproduction is hampered in small populations and raise concerns over the loss of genetic diversity in D. albus.     

No obvious genetic erosion,but evident relict status at the westernmost range edge of the Pontic‐Pannonian steppe plant Linum flavum L. (Linaceae) in Central Europe

We investigate patterns of genetic variation along an east–west transect of Central European populations of Linum flavum and interpret the Quaternary history of its peripheral populations, especially those at the westernmost isolated range edge, discussing their migrations and possible relict status. We defined our peripheral transect across three study regions from Central Hungary, eastern Austria to southwestern Germany. Using AFLP fingerprinting and cpDNA sequence variation (rpL16 intron, atpI‐H), we analyzed 267 and 95 individuals, respectively, representing each study region by four populations. Hierarchical AMOVA (AFLPs) indicated significant variation among study regions (12% of total variance) and moderate differentiation between populations (10%). Population differentiation was high at the westernmost range edge (11.5%, Germany), but also in the east (13.4%, Hungary), compared to the Austrian study region (8.6%). Correspondingly, AFLP diversity was highest in the center of the study transect in eastern Austria. CpDNA haplotypes support a pattern of regional structuring with the strongest separation of the westernmost range edge, and some haplotype sharing among Austrian and Hungarian individuals. Equilibrating nucleotide versus haplotype diversity patterns, the highly diverse populations at the Pannonian range edge (Austria) indicate long‐term persistence, while Central Pannonian populations are obviously effected by recent bottlenecks. Intermediate nucleotide, but high haplotype diversity within the westernmost exclave (Swabian Alb), is indicative of a founder bottleneck during its pre‐LGM or early postglacial migration history, followed by sufficient time to accumulate cpDNA variation. The not obviously reduced genetic diversity and distinctiveness of L. flavum at the westernmost range edge suggest a long‐term persistence (relict status) of populations in this region, where the species has survived probably even the Würm glaciation in extra‐Mediterranean refugia. This genetic relict variation represents an important part of the overall genetic diversity found in the western periphery of this steppe plant and highlights the high conservation priority of respective gene pools.     

Clonal diversity,spatial dynamics,and small genetic population size in the rare sunflower, <Emphasis Type="Italic">Helianthus verticillatus</Emphasis>

Knowledge of population size is an important step for identifying populations of immediate conservation concern. However, this task is difficult in plant species that exhibit clonal growth, since a simple “head count” may not be appropriate. Here, I determine the genetic population size and the extent of clonality in the four known populations of a rare sunflower, Helianthus verticillatus. Previous work in this species revealed high genetic diversity in all populations but significant fitness differences among them. In this study, populations exhibited high clonal diversity but consisted of far fewer genetic individuals than previously reported. Moreover, the clonal structure of populations was clumped, such that genotypes were highly clustered, which may promote selfing among genets. The results of this study are related to previously examined levels of genetic diversity and fitness, and findings are discussed in the context of the ecological and biological dynamics in clonal plant populations. Finally, the results of this study led to an upgrade in the priority status of this species for the Endangered Species List.     

Regional diversity,population trends and threat assessment of the weeds of traditional agriculture in Greece

On the basis of extensive field studies throughout Greece and of about 19 500 field and literature records extracted from the Flora Hellenica Database, we provide the first survey of wild plant species of traditional agriculture in Greece (hereafter TA species). For each of the 138 taxa, life form, rareness (on national scale), local abundance (habitat occupancy) and regional restrictedness are given. We infer population trends from the record chronology of the taxa in the Flora Hellenica Database, and we assess the Red List status of the arable plants using IUCN criteria. According to current knowledge, two TA species are presumed Extinct in Greece and seven Critically Endangered. Almost half of the species are threatened, including 46 Vulnerable and 15 Endangered taxa. There is a high proportion of locally distributed taxa among Greek TA species. Distribution patterns show a pronounced south–north gradient, and the unique character of the East Aegean arable flora is revealed. Most arable species are annuals (83%). Perennial herbs, mostly bulbous or tuberous plants (geophytes), account for 17%, and a major proportion of the latter must be considered as threatened at different levels. The chronology of decline of certain TA species is reflected by processes of agricultural intensification and regional urbanization. We suggest conservation measures for the unique arable flora of Greece. To reflect the geographical and ecoregional variation, in situ measures should focus on areas with species‐rich arable fields in all phytogeographical regions of Greece. © 2014 The Linnean Society of London, Botanical Journal of the Linnean Society, 2014, 175 , 607–623.     

Redlistr: tools for the IUCN Red Lists of ecosystems and threatened species in R

The International Union for the Conservation of Nature (IUCN) Red List of ecosystems and Red List of threatened species are global standards for assessing risks of ecosystem collapse and species extinction. However, misconceptions of the Red List assessment process, along with its technically demanding nature, can result in the misapplication of their criteria, leading to inconsistent and potentially unreliable assessments. To address this problem, we developed redlistr, an R package aiding in the production of consistent species and ecosystem Red List assessments. Redlistr's features include methods to calculate 1) area from spatial data, 2) range size metrics, 3) rates of change of distributions or populations, and 4) distribution or population at another time from these rates. A key feature of the package is the systematic approach used to eliminate geometric uncertainty when estimating area of occupancy. Here, we develop two case studies to demonstrate the functionalities of redlistr with typical workflows for both species and ecosystems. Redlistr was developed to be accessible to users with a broad range of experience in programming for spatial and temporal data analysis, and sufficiently flexible to allow users to parameterise functions and select equations to fit their purposes. The package specifically aims to assist researchers and conservation practitioners to conduct robust and transparent risk assessments of ecosystems and species under the IUCN Red List criteria but is also useful for other studies requiring analyses of range size, area change and calculations of rates of change.     

Effects of landscape structure on genetic diversity of Geum urbanum L. populations in agricultural landscapes

Plant species in fragmented populations are affected by landscape structure because persistence within and migration among inhabited patches may be influenced by the identity and configuration of surrounding habitat elements. This may also be true for species of the semi-natural vegetation in agricultural landscapes. To determine the effect of landscape elements we analyzed Wood Avens (Geum urbanum L.) populations within three 4×4 km² agricultural landscapes in Germany, Switzerland and Estonia, which differ in levels of land use intensity and habitat fragmentation. Genetic variation was determined in 15 randomly selected populations in each landscape using 10 microsatellite loci. The landscape structure was assessed at two circles around each population, with radii defined by the range limits of spatial genetic autocorrelation. Multiple regression analysis was used to determine the influence of landscape structure variables for inter- and intrapopulation genetic diversity. Gene diversity was equally high in Germany (H_e=0.27) and Switzerland (H_e=0.26) but lower in Estonia (H_e=0.16). A high overall inbreeding coefficient (F_IS=0.89) was found, as expected for a selfing breeding system in G. urbanum. Genetic differentiation among populations was high (overall F_ST=0.43, 0.48, and 0.45 in Estonia, Switzerland and Germany, respectively), and did not differ among the three landscapes. Only a moderate influence of individual land use types on genetic diversity within and among populations was found with some idiosyncratic relationships. Genetic variation within populations was correlated to the amount of hedgerows positively in Estonia but negatively in Switzerland. The study demonstrates that the distribution of individual land use types affects the genetic pattern of a common plant species. However, different variables were identified to influence the genetic structure in three different landscapes. This indicates a major influence of landscape-specific land use history and stochastic processes determining gene flow and plant population structure.     

Seed preferences by rodents in the agri‐environment and implications for biological weed control

Post‐dispersal seed predation and endozoochorous seed dispersal are two antagonistic processes in relation to plant recruitment, but rely on similar preconditions such as feeding behavior of seed consumers and seed traits. In agricultural landscapes, rodents are considered important seed predators, thereby potentially providing regulating ecosystem services in terms of biological weed control. However, their potential to disperse seeds endozoochorously is largely unknown. We exposed seeds of arable plant species with different seed traits (seed weight, nutrient content) and different Red List status in an experimental rye field and assessed seed removal by rodents. In a complementary laboratory experiment, consumption rates, feeding preferences, and potential endozoochory by two vole species (Microtus arvalis and Myodes glareolus) were tested. Seed consumption by rodents after 24 h was 35% in the field and 90% in the laboratory. Both vole species preferred nutrient‐rich over nutrient‐poor seeds and M. glareolus further preferred light over heavy seeds and seeds of common over those of endangered plants. Endozoochory by voles could be neglected for all tested plant species as no seeds germinated, and only few intact seeds could be retrieved from feces. Synthesis and applications. Our results suggest that voles can provide regulating services in agricultural landscapes by depleting the seed shadow of weeds, rather than facilitating plant recruitment by endozoochory. In the laboratory, endangered arable plants were less preferred by voles than noxious weeds, and thus, our results provide implications for seed choice in restoration approaches. However, other factors such as seed and predator densities need to be taken into account to reliably predict the impact of rodents on the seed fate of arable plants.     

Comparative population genetic structure in a plant-pollinator/seed predator system

Comparative analyses of spatial genetic structure of populations of plants and the insects they interact with provide an indication of how gene flow, natural selection and genetic drift may jointly influence the distribution of genetic variation and potential for local co‐adaptation for interacting species. Here, we analysed the spatial scale of genetic structure within and among nine populations of an interacting species pair, the white campion Silene latifolia and the moth Hadena bicruris, along a latitudinal gradient across Northern/Central Europe. This dioecious, short‐lived perennial plant inhabits patchy, often disturbed environments. The moth H. bicruris acts both as its pollinator and specialist seed predator that reproduces by laying eggs in S. latifolia flowers. We used nine microsatellite markers for S. latifolia and eight newly developed markers for H. bicruris. We found high levels of inbreeding in most populations of both plant and pollinator/seed predator. Among populations, significant genetic structure was observed for S. latifolia but not for its pollinator/seed predator, suggesting that despite migration among populations of H. bicruris, pollen is not, or only rarely, carried over between populations, thus maintaining genetic structure among plant populations. There was a weak positive correlation between genetic distances of S. latifolia and H. bicruris. These results indicate that while significant structure of S. latifolia populations creates the potential for differentiation at traits relevant for the interaction with the pollinator/seed predator, substantial gene flow in H. bicruris may counteract this process in at least some populations.     

Life history variation between species of the relictual genus Borderea (Dioscoreaceae): phylogeography, genetic diversity, and population genetic structure assessed by RAPD markers

The genus Borderea consists of two species, B. pyrenaica and B. chouardii, taxa which have been previously considered as conspecific due to their overall close morphology. These two sole species of the rare genus of Dioscoreaceae are endemic to the Pyrenees (Spain, France). This mountain range likely operated as a refugium for these plants during the last glaciations. B. chouardii is only known from a single population in the Spanish Prepyrenees and has been classified as at risk of extinction in the Red List of Endangered Species (IUCN); B. pyrenaica shows a narrow distribution range in the central Pyrenees and Prepyrenees. We analysed genetic variation, population structure and differentiation in these two taxa using RAPD markers. Our study was conducted on the same seven populations for which very low levels of genetic differentiation were detected previously through allozyme analysis. By contrast, high levels of genetic variability were detected through the RAPD hypervariable markers. Twelve RAPD primers produced 112 distinct bands in the 397 surveyed individuals, totalling 395 different RAPD phenotypes. Only four bands were monomorphic across all samples of Borderea, whereas 21 of the polymorphic bands were species‐specific (20 for B. chouardii, and one for B. pyrenaica). The largest genetic distances were those between the B. chouardii and the B. pyrenaica phenotypes. An analysis of molecular variance showed greater variance between groups (B. chouardii vs. B. pyrenaica, 76.08%) than within groups (3.60%). RAPD band specificity, phenotypic distances, and the partitioning of variance all support the taxonomic separation of the two species. Statistical evaluation of within‐ and among‐population RAPD genetic variability in B. pyrenaica showed that genetic variability was higher within populations (>80%) than among them. No clear pattern of RAPD differentiation could be observed among the six studied populations of this taxon though slight differences in genetic diversity could be observed in the more isolated Prepyrenean populations compared with the more widespread Pyrenean ones. These results suggest a recent postglacial origin of the present B. pyrenaica populations. © 2003 The Linnean Society of London, Biological Journal of the Linnean Society, 2003, 80 , 483–498.     

Genetic diversity and phylogenetic relationships of the Manchurian zokor <Emphasis Type="Italic">Myospalax psilurus</Emphasis> (Rodentia,Muridae) according to RAPD-PCR analysis

The population structuring and low genetic diversity of the Manchurian zokor Myospalax psilurus Milne-Edwards, 1874, an East Asian endemic included in the Red List of Russia, were demonstrated. Two separate geographical groups differing in the level of their genetic diversity were found on the territory of the Primorskii krai. The subpopulation located closest to the main area of this species was determined as ancestral. A subspecies differentiation of the Primorskii krai and Transbaikal M. psilurus populations was shown, as was the monophyletic origin of M. psilurus and its high divergence from M. aspalax. The animals from northern localities are recommended for reintroduction in nature under species recovery programs in Primorskii krai.     

Reintroduction of rare arable plants by seed transfer. What are the optimal sowing rates?

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Genetic diversity and its effect on fitness in an endangered plant species, <Emphasis Type="Italic">Dracocephalum austriacum</Emphasis> L.

The aim of this study was to estimate genetic diversity and assess its importance for plant fitness in a species belonging to the most endangered species in Europe, Dracocephalum austriacum L., and to select the most valuable populations for conservation of genetic diversity within the species in the studied regions. We analyzed allozyme variation of 12 populations in three distinct regions (Czech Karst, Moravia and Slovak Karst) in Central Europe. The results showed high genetic diversity within populations (80.14%) and relatively low differentiation among populations within regions (9.42%) and between regions (10.45%). Seed production was significantly higher in larger, genetically more diverse and less inbred populations. The results suggest that genetic diversity has important effect on seed production in this species and thus can be expected to have strong direct consequences for plant fitness and vitality of the whole populations. They also show large variation in genetic diversity between populations and indicate which populations should get a priority in attempts to conserve all the genetic diversity within the region.     

Effect of Hay Transfer on Long-Term Establishment of Vegetation and Grasshoppers on Former Arable Fields

The transfer of seed‐containing hay is a restoration measure for the introduction of plant species of local provenance. We investigated the effect of hay transfer on species richness and on long‐term establishment of target plant and grasshopper species on former arable fields with and without topsoil removal in comparison to reference sites in a nature reserve. Plant species richness, the number of target plant species, and Red List plant species were significantly positively affected by hay transfer, both on the scale of whole restoration fields and on permanent plots of 4 m². Eight years after the start of the restoration, only few of the transferred plant species had disappeared and some target species were newly found. Grasshoppers were affected not by hay transfer but by topsoil removal. The proportion of target grasshopper and plant species and Red List grasshopper species was higher on topsoil removal sites with low standing crop and high cover of bare soil than on sites without soil removal. On topsoil removal sites without hay, however, plant species richness was very low because of the slow natural dispersal of the target species. Vegetation and grasshopper communities still differed between restoration fields and the nature reserve. Nevertheless, our results indicate that the transfer of autochthonous seed‐containing hay is a successful method to establish species‐rich grasslands with a high proportion of target species.