Seed weight increases with altitude in the Swiss Alps between related species but not among populations of individual species

Seed weight is a crucial plant life history trait, determining establishment success and dispersal ability. Especially in stressful environments, larger seeds may be selected at the expense of seed number, because larger seeds have a better chance of giving rise to an established offspring. We tested the hypotheses that between related species-pairs and among populations of single species a similar trend for increasing seed weight with increasing altitude should be present. Firstly, we measured seed weights from 29 species-pairs, with one species occurring in lowland areas and a congeneric species from high altitudes. Seeds of the alpine species were 28+/-8% larger than seeds from lowland species (P > 0.01). Compared to the related lowland species, 55% of the alpine species had heavier seeds, 3% (one species) had lighter, and 41% had seeds of approximately equal weight. Secondly, we compared seed weights among populations of four species from different habitats and with different life histories. Seeds from between 11 and 34 populations per species were sampled along altitudinal gradients of 800-1,500 m (ca. 800 m in Scabiosa lucida, ca. 1,000 m in Saxifraga oppositifolia, ca. 1,000 m in Epilobium fleischeri, and ca. 1,500 m in Carex flacca). In all the four species, we found no indication for heavier seeds at higher altitudes. Our results indicate a selection pressure for species with heavier seeds at higher altitude, but the trend does not seem to operate across all cases. Phylogenetic constraints may limit the correlation among altitude and seed weight, operating particularly against selection for larger seed size, the closer populations and species are related to each other

Extensive contemporary pollen-mediated gene flow in two herb species, Ranunculus bulbosus and Trifolium montanum, along an altitudinal gradient in a meadow landscape

Background and Aims Genetic connectivity between plant populations allows for exchange and dispersal of adaptive genes, which can facilitate plant population persistence particularly in rapidly changing environments. Methods Patterns of historic gene flow, flowering phenology and contemporary pollen flow were investigated in two common herbs, Ranunculus bulbosus and Trifolium montanum, along an altitudinal gradient of 1200-1800 m a.s.l. over a distance of 1 km among five alpine meadows in Switzerland. Key Results Historic gene flow was extensive, as revealed by Fst values of 0·01 and 0·007 in R. bulbosus and T. montanum, respectively, by similar levels of allelic richness among meadows and by the grouping of all individuals into one genetic cluster. Our data suggest contemporary pollen flow is not limited across altitudes in either species but is more pronounced in T. montanum, as indicated by the differential decay of among-sibships correlated paternity with increasing spatial distance. Flowering phenology among meadows was not a barrier to pollen flow in T. montanum, as the large overlap between meadow pairs was consistent with the extensive pollen flow. The smaller flowering overlap among R. bulbosus meadows might explain the slightly more limited pollen flow detected. Conclusions High levels of pollen flow among altitudes in both R. bulbosus and T. montanum should facilitate exchange of genes which may enhance adaptive responses to rapid climate chang

Landscape Composition Has Limited Impact on Local Genetic Structure in Mountain Clover, Trifolium montanum L

Semi-dry grasslands in the European Alps have been increasingly fragmented over the last 150 years. Few studies have investigated the implications of landscape configuration for genetic structure and gene flow among remnant habitat patches. Conservation management of semi-dry grassland plants rarely accounts for possible effects of major landscape elements, such as forest patches, as barriers to gene flow and dispersal via seed and pollen, despite their potential importance for biodiversity conservation. Using 1416 individuals from 61 sampling sites across 2 valleys in South-Eastern Switzerland and Amplified fragment length polymorphism (AFLP) fingerprints, we applied a spatial strip and a circle approach to determine the impact of different landscape elements on genetic differentiation in the semi-dry grassland herb Trifolium montanum (mountain clover). Overall genetic differentiation among sampling sites was low (overall F ST = 0.044). Forest area had no effect on gene flow at the landscape scale, but area of semi-dry grassland, the potential habitat of T. montanum, road area, and altitude influenced genetic differentiation among sampling sites. The observed pattern of genetic differentiation suggests that a future increase in forest area, due to land use abandonment, at least in the short term, are unlikely to directly impact patterns of genetic variation in T. montanu

Drought-Adaptation Potential in Fagus sylvatica: Linking Moisture Availability with Genetic Diversity and Dendrochronology

<div><h3>Background</h3><p>Microevolution is essential for species persistence especially under anticipated climate change scenarios. Species distribution projection models suggested that the dominant tree species of lowland forests in Switzerland, European beech (<em>Fagus sylvatica</em> L.), might disappear from most areas due to expected longer dry periods. However, if genotypes at the moisture boundary of the species climatic envelope are adapted to lower moisture availability, they can serve as seed source for the continuation of beech forests under changing climates.</p> <h3>Methodology/Principal Findings</h3><p>With an AFLP genome scan approach, we studied neutral and potentially adaptive genetic variation in <em>Fagus sylvatica</em> in three regions containing a dry and a mesic site each (<em>n</em>_ind. = 241, <em>n</em>_markers = 517). We linked this dataset with dendrochronological growth measures and local moisture availabilities based on precipitation and soil characteristics. Genetic diversity decreased slightly at dry sites. Overall genetic differentiation was low (<em>F</em>_st = 0.028) and Bayesian cluster analysis grouped all populations together suggesting high (historical) gene flow. The Bayesian outlier analyses indicated 13 markers with three markers differing between all dry and mesic sites and the others between the contrasting sites within individual regions. A total of 41 markers, including seven outlier loci, changed their frequency with local moisture availability. Tree height and median basal growth increments were reduced at dry sites, but marker presence/absence was not related to dendrochronological characteristics.</p> <h3>Conclusion and Their Significance</h3><p>The outlier alleles and the makers with changing frequencies in relation to moisture availability indicate microevolutionary processes occurring within short geographic distances. The general genetic similarity among sites suggests that ‘preadaptive’ genes can easily spread across the landscape. Yet, due to the long live span of trees, fostering saplings originating from dry sites and grown within mesic sites might increase resistance of beech forests during the anticipated longer dry periods.</p> </div

How Much Does Malaria Vector Control Quality Matter: The Epidemiological Impact of Holed Nets and Inadequate Indoor Residual Spraying

BACKGROUND: Insecticide treated nets (ITN) and indoor residual spraying (IRS) are the two pillars of malaria vector control in Africa, but both interventions are beset by quality and coverage concerns. Data from three control programs were used to investigate the impact of: 1) the physical deterioration of ITNs, and 2) inadequate IRS spray coverage, on their respective protective effectiveness. METHODS: Malaria indicator surveys were carried out in 2009 and 2010 in Bioko Island, mainland Equatorial Guinea and Malawi to monitor infection with P. falciparum in children, mosquito net use, net condition and spray status of houses. Nets were classified by their condition. The association between infection and quality and coverage of interventions was investigated. RESULTS: There was reduced odds of infection with P. falciparum in children sleeping under ITNs that were intact (Odds ratio (OR): 0.65, 95% CI: 0.55-0.77 and OR: 0.81, 95% CI: 0.56-1.18 in Equatorial Guinea and in Malawi respectively), but the protective effect became less with increasingly worse condition of the net. There was evidence for a linear trend in infection per category increase in deterioration of nets. In Equatorial Guinea IRS offered protection to those in sprayed and unsprayed houses alike when neighbourhood spray coverage was high (≥80%) compared to those living in areas of low IRS coverage (<20%), regardless of whether the house they lived in was sprayed or not (adjusted OR = 0.54, 95% CI 0.33-0.89). ITNs provided only personal protection, offering no protection to non users. Although similar effects were seen in Malawi, the evidence was much weaker than in Equatorial Guinea. CONCLUSIONS: Universal coverage strategies should consider policies for repair and replacement of holed nets and promote the care of nets by their owners. IRS programs should ensure high spray coverage since inadequate coverage gives little or no protection at all

Foraging patterns of acorn woodpeckers (Melanerpes formicivorus) on valley oak (Quercus lobata Née) in two California oak savanna-woodlands

Landscape characteristics and social behavior can affect the foraging patterns of seed-dependent animals. We examine the movement of acorns from valley oak (Quercus lobata) trees to granaries maintained by acorn woodpeckers (Melanerpes formicivorus) in two California oak savanna-woodlands differing in the distribution of Q. lobata within each site. In 2004, we sampled Q. lobata acorns from 16 granaries at Sedgwick Reserve in Santa Barbara County and 18 granaries at Hastings Reserve in Monterey County. Sedgwick has lower site-wide density of Q. lobata than Hastings as well as different frequencies of other Quercus species common to both sites. We found acorn woodpeckers foraged from fewer Q. lobata seed source trees (Kg = 4.1 ± 0.5) at Sedgwick than at Hastings (Kg = 7.6 ± 0.6) and from fewer effective seed sources (Nem* = 2.00 and 5.78, respectively). The differences between sites are due to a greater number of incidental seed sources used per granary at Hastings than at Sedgwick. We also found very low levels of seed source sharing between adjacent granaries, indicating that territoriality is strong at both sites and that each social group forages on its own subset of trees. We discovered an interesting spatial pattern in the location of granaries. At Sedgwick, acorn woodpeckers situated their granaries within areas of higher-than-average tree density, while at Hastings, they placed them within areas of lower-than-average tree density, with the outcome that granaries at the two sites were located in areas of similar valley oak density. Our results illustrate that landscape characteristics might influence the number of trees visited by acorn woodpeckers and the locations of territories, while woodpecker social behavior, such as territoriality, shapes which trees are visited and whether they are shared with other social groups

Large expert-curated database for benchmarking document similarity detection in biomedical literature search

Document recommendation systems for locating relevant literature have mostly relied on methods developed a decade ago. This is largely due to the lack of a large offline gold-standard benchmark of relevant documents that cover a variety of research fields such that newly developed literature search techniques can be compared, improved and translated into practice. To overcome this bottleneck, we have established the RElevant LIterature SearcH consortium consisting of more than 1500 scientists from 84 countries, who have collectively annotated the relevance of over 180 000 PubMed-listed articles with regard to their respective seed (input) article/s. The majority of annotations were contributed by highly experienced, original authors of the seed articles. The collected data cover 76% of all unique PubMed Medical Subject Headings descriptors. No systematic biases were observed across different experience levels, research fields or time spent on annotations. More importantly, annotations of the same document pairs contributed by different scientists were highly concordant. We further show that the three representative baseline methods used to generate recommended articles for evaluation (Okapi Best Matching 25, Term Frequency-Inverse Document Frequency and PubMed Related Articles) had similar overall performances. Additionally, we found that these methods each tend to produce distinct collections of recommended articles, suggesting that a hybrid method may be required to completely capture all relevant articles. The established database server located at https://relishdb.ict.griffith.edu.au is freely available for the downloading of annotation data and the blind testing of new methods. We expect that this benchmark will be useful for stimulating the development of new powerful techniques for title and title/abstract-based search engines for relevant articles in biomedical research.Peer reviewe

Characterization of eighteen novel microsatellite markers and multiplex PCR protocol for Fagus sylvatica

ISSN:1877-7252ISSN:1877-726

Population genetic diversity of the clonal plant Geum reptans (Rosaceae) in the Swiss Alps

In the alpine landscape most plant populations are spatially isolated due to extreme patchiness and strong natural fragmentation. We used RAPD-PCR (randomly amplified polymorphic DNA polymerase chain reaction) for a study of the genetic diversity within and among 20 populations of Geum reptans, ail outcrossing clonal plant species in the Swiss Alps. Populations were sampled at different altitudes, in early-, medmin- and late-successional habitats (Population origin) using a spatially hierarchical design, with distances among populations ranging from 0.2 to 208 kin. Seed and pollen dispersibility was estimated by direct measurements. Seed dispersibility by wind was low with only 0.015 the seeds flying over 100 in. Observed pollen flow was even more restricted. Molecular diversity within populations was irrespective of population origin (H-c = 0.22 +/- 0.004) and similar to the average of other RAPD studies. Contrary to our expectation, Populations were only moderately differentiated (G(st) = 0.14). However, there was a clear spatial genetic structure and a positive relationship between pairwise genetic and geographic distances. Our results indicate considerable gene flow among populations within the same regional area, and we found no indication for genetic depletion during succession or in peripheral habitats. We conclude that, despite the high natural fragmentation and the importance of vegetative reproduction in this alpine plant,gene flow and repeated seedling recruitment during succession might be more frequent than commonly suggested

The importance of population origin and environment on clonal and sexual reproduction in the alpine plant Geum reptans

1. Reproductive behaviour of plants may change in contrasting habitats. In two separate glasshouse experiments, we studied effects of population origin (early vs. late successional and low vs. high altitudinal habitats) and environmental effects (competition and temperature) on plant size and sexual vs. clonal reproduction in Geum reptans L. 2. Plant size and reproduction differed significantly among populations, but only plant size differed between contrasting habitats. 3. If plants grew with competition or at warm temperature, plant size and reproduction were reduced and more plants reproduced only with stolons. Individuals with flowers were larger than those that reproduced only with stolons, indicating a smaller minimum plant size for clonal than for sexual reproduction. 4. Populations of different origin changed little in their response to environmental treatments. Plants from early successional habitats tended to produce more flowers in the competition-free treatment, whereas in plants from late successional habitats the opposite was true. 5. The results indicate limited adaptation in reproductive behaviour to contrasting habitats. Nevertheless, great size-dependent plasticity in the proportion of sexual vs. clonal reproduction ensures population persistence and reproduction in a large range of habitat conditions