The written history of plant phenology: shaping primary sources for secondary publications.

Phenological research establishes the science of nature's natural calendar. This research, the monitoring and analysis of seasonal rhythms of plants and animals, is commonly based on citizen science data. Such data may be digitized from primary sources provided by the citizen scientist's original phenological diaries. Secondary data sources are formed by historical publications (for example, yearbooks and climate bulletins). While primary data has the advantage of first-hand notetaking, its digitization may, in practice, be time-consuming. Contrastingly, secondary data can contain well-organized typesetting, making digitization less labour-intensive. However, secondary data can be reshaped by the motivations of the historical actors who were collating the data. This study compared data from 1876-1894 gathered originally by citizen scientists (primary data) and the secondary data founded upon the previous primary data, later published by the Finnish Society of Sciences and Letters as a series of phenological yearbooks. In the secondary data, the recorded numbers of taxa and their phenological stages appeared to be fewer and phenological events standardized, with an increased prevalence of agricultural phenology (at the cost of autumn phenology). Moreover, it seems the secondary data had been screened for potential outliers. While secondary sources may provide current phenologists with coherent sets of relevant data, future users must be aware of potential data reshaping resulting from the preferences of historical actors. These actors may weigh and limit the original observations according to their own criteria and preferences.

Plant phenological dataset collated by the Finnish Society of Sciences and Letters.

Long records of phenological observations constitute data for ecological, climate, and global change studies. Here we provide a unique dataset of plant phenological observations made in boreal Europe between 1750 and 1965 from locations situated across historical and modern Finland, mostly between 70° and 60° N and 30° and 20° E. This dataset was generated initially by the efforts of several generations of volunteers representing naturalists whose field observations and notes had initially made the continuous collection of the data possible. In addition, the data were collated by the Finnish Economic Society and the Finnish Society of Sciences and Letters and published irregularly in the form of several monographs and periodicals by contemporary academic enthusiasts. Each phenological observation contains 11 features including: site name, site latitude, site longitude, scientific species name, phenological stage, and (if any) its substage, year, date (month and day) and the day since the summer solstice, the original literature source, and outlier estimate. Species names given originally either in Latin, Finnish, German, and/or Swedish were transformed into scientific species names. Moreover, outdated taxonomic names were updated as appropriate. Phenological stages that had been given originally either in German, Finnish, and/or Swedish were transformed into English and standardized by excluding synonyms. Site names were adopted at the county level, with corresponding latitude and longitude generated herein. The digitized dataset represents 265,478 observations of 985 taxa (assigned to variety/subspecies/species/hybrid/genus) for their 16 different phenological stages made in 371 locations across the region. We provide this dataset to support comparative studies and modeling projects, seeking to improve the understanding of terrestrial ecosystem dynamics and its responses to a changing environment from a local to a global scale. Use of this dataset for academic or educational purposes is encouraged as long as the data source is correctly cited with attribution given to this presentation of the data. Users are free to use and analyze the data; additionally, we would like to hear from other researchers who use this dataset in teaching or for their own research.

Non-native vascular flora of the Arctic: Taxonomic richness, distribution and pathways.

We present a comprehensive list of non-native vascular plants known from the Arctic, explore their geographic distribution, analyze the extent of naturalization and invasion among 23 subregions of the Arctic, and examine pathways of introductions. The presence of 341 non-native taxa in the Arctic was confirmed, of which 188 are naturalized in at least one of the 23 regions. A small number of taxa (11) are considered invasive; these plants are known from just three regions. In several Arctic regions there are no naturalized non-native taxa recorded and the majority of Arctic regions have a low number of naturalized taxa. Analyses of the non-native vascular plant flora identified two main biogeographic clusters within the Arctic: American and Asiatic. Among all pathways, seed contamination and transport by vehicles have contributed the most to non-native plant introduction in the Arctic.

Postglacial colonization history reflects in the genetic structure of natural populations of Festuca rubra in Europe.

We conducted a large-scale population genetic survey of genetic diversity of the host grass Festuca rubra s.l., which fitness can be highly dependent on its symbiotic fungus Epichloë festucae, to evaluate genetic variation and population structure across the European range. The 27 studied populations have previously been found to differ in frequencies of occurrence of the symbiotic fungus E. festucae and ploidy levels. As predicted, we found decreased genetic diversity in previously glaciated areas in comparison with nonglaciated regions and discovered three major maternal genetic groups: southern, northeastern, and northwestern Europe. Interestingly, host populations from Greenland were genetically similar to those from the Faroe Islands and Iceland, suggesting gene flow also between those areas. The level of variation among populations within regions is evidently highly dependent on the postglacial colonization history, in particular on the number of independent long-distance seed colonization events. Yet, also anthropogenic effects may have affected the population structure in F. rubra. We did not observe higher fungal infection rates in grass populations with lower levels of genetic variability. In fact, the fungal infection rates of E. festucae in relation to genetic variability of the host populations varied widely among geographical areas, which indicate differences in population histories due to colonization events and possible costs of systemic fungi in harsh environmental conditions. We found that the plants of different ploidy levels are genetically closely related within geographic areas indicating independent formation of polyploids in different maternal lineages.

Into Africa: Molecular phylogenetics and historical biogeography of sub-Saharan African woodferns (Dryopteris).

PREMISE OF THE STUDY: Our goal was to infer the phylogenetic relationships and historical biogeography of the genus Dryopteris with a focus on taxa in sub-Saharan Africa and neighboring islands. In general, little is known about the relationships between African fern species and their congeners in other geographic regions, and our aim was to determine whether the sub-Saharan African species of Dryopteris are monophyletic and evolved within Africa or arrived there via repeated dispersals into Africa from other regions. METHODS: We obtained sequence data for five chloroplast markers from 214 species of Dryopteris and 18 outgroups. We performed phylogenetic and molecular dating analyses using a Bayesian relaxed clock method in BEAST with fossil and secondary calibration points and estimated ancestral ranges for the genus globally by comparing multiple models in BioGeoBEARS. KEY RESULTS: We found that 22 of 27 accessions of sub-Saharan African Dryopteris belong to a large clade of 31 accessions that also includes taxa from Indian and Atlantic Ocean islands. Additional accessions of taxa from our regions of interest have Asian, Hawaiian, European, or North American species as their closest relatives. CONCLUSIONS: The majority of sub-Saharan African Dryopteris species are descended from a shared common ancestor that dispersed to Africa from Asia approximately 10 Ma. There have been subsequent dispersal events from the African mainland to islands in the Atlantic and Indian Oceans, including Madagascar. Several additional species are estimated to have descended from ancestors that reached Africa via separate events over the last roughly 20 million years.

Geographic Variation in Festuca rubra L. Ploidy Levels and Systemic Fungal Endophyte Frequencies.

Polyploidy and symbiotic Epichloë fungal endophytes are common and heritable characteristics that can facilitate environmental range expansion in grasses. Here we examined geographic patterns of polyploidy and the frequency of fungal endophyte colonized plants in 29 Festuca rubra L. populations from eight geographic sites across latitudes from Spain to northernmost Finland and Greenland. Ploidy seemed to be positively and negatively correlated with latitude and productivity, respectively. However, the correlations were nonlinear; 84% of the plants were hexaploids (2n = 6x = 42), and the positive correlation between ploidy level and latitude is the result of only four populations skewing the data. In the southernmost end of the gradient 86% of the plants were tetraploids (2n = 4x = 28), whereas in the northernmost end of the gradient one population had only octoploid plants (2n = 8x = 56). Endophytes were detected in 22 out of the 29 populations. Endophyte frequencies varied among geographic sites, and populations and habitats within geographic sites irrespective of ploidy, latitude or productivity. The highest overall endophyte frequencies were found in the southernmost end of the gradient, Spain, where 69% of plants harbored endophytes. In northern Finland, endophytes were detected in 30% of grasses but endophyte frequencies varied among populations from 0% to 75%, being higher in meadows compared to riverbanks. The endophytes were detected in 36%, 30% and 27% of the plants in Faroe Islands, Iceland and Switzerland, respectively. Practically all examined plants collected from southern Finland and Greenland were endophyte-free, whereas in other geographic sites endophyte frequencies were highly variable among populations. Common to all populations with high endophyte frequencies is heavy vertebrate grazing. We propose that the detected endophyte frequencies and ploidy levels mirror past distribution history of F. rubra after the last glaciation period, and local adaptations to past or prevailing selection forces such as vertebrate grazing.

Development and characterization of chloroplast microsatellite markers in a fine-leaved fescue, Festuca rubra (Poaceae).

PREMISE OF THE STUDY: Chloroplast microsatellite markers were developed for Festuca rubra to examine its population genetic characteristics, taxonomy, and coevolution with its endophyte Epichloë festucae. • METHODS AND RESULTS: Thirteen polymorphic markers were identified from the chloroplast genome of a F. ovina accession and intergenic chloroplast sequences of F. rubra accessions. They amplified a total of 65 alleles in a sample of 93 individuals of F. rubra originating from six different populations located in the Faroe Islands, Finland, Greenland, Norway, and Spain. • CONCLUSIONS: The developed microsatellite primer pairs can be used by researchers in population genetic and taxonomic studies, and by plant breeders in breeding programs on grasses.