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Ferns and lycophytes are unique among land plants in having sporophyte (diploid) and gametophyte (haploid) generations that can grow independently of each other. While most studies of fern ecology focus on the more visible sporophytic stage, the gametophyte is critically important, as it is the sexual phase of the life cycle. Yet, fern gametophytes have long been neglected in field studies due to their small size and cryptic morphology. DNA barcoding is a powerful method that can be used to identify field-collected gametophytes to species and allow for detailed study of their ecology. Here, we review the state of DNA barcoding as applied to fern gametophytes. First, we trace the history of DNA barcoding and how it has come to be applied to fern gametophytes. Next, we summarize case studies that show how DNA barcoding has been used to better understand fern species distributions, gametophyte ecology, and community ecology. Finally, we propose avenues for future research using this powerful tool, including next-generation DNA sequencing for in-field identification of cryptic gametophytes.

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All green plants alternate between the gametophyte and sporophyte life stages, but only seed-free vascular plants (ferns and lycophytes) have independent, free-living gametophytes. Fern and lycophyte gametophytes are significantly reduced in size and morphological complexity relative to their sporophytic counterparts and have often been overlooked in ecological and physiological studies. Understanding the ecological and physiological factors that directly impact this life stage is of critical importance because the ultimate existence of a sporophyte is dependent upon successful fertilization in the gametophyte generation. Furthermore, previous research has shown that the dual nature of the life cycle and the high dispersibility of spores can result in different geographic patterns between gametophytes and their respective sporophytes. This variation in distribution patterns likely exacerbates the separation of selective pressures acting on gametophyte and sporophyte generations, and can uniquely impact a species' ecology and physiology. Here, we provide a review of historical and contemporary methodologies used to examine ecological and physiological aspects of fern gametophytes, as well as those that allow for comparisons between the two generations. We conclude by suggesting methodological approaches to answer currently outstanding questions. We hope that the information covered herein will serve as a guide to current researchers and stimulate future discoveries in fern gametophyte ecology and physiology.

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The archived web provides an important footprint of the past, documenting online social behaviour through social media, and news through media outlets websites and government sites. Consequently, web archiving is increasingly gaining attention of heritage institutions, academics and policy makers. The importance of web archives as data resources for (digital) scholars has been acknowledged for investigating the past. Still, heritage institutions and academics struggle to 'keep up to pace' with the fast evolving changes of the World Wide Web and with the changing habits and practices of internet users. While a number of national institutions have set up a national framework to archive 'regular' web pages, social media archiving (SMA) is still in its infancy with various countries starting up pilot archiving projects. SMA is not without challenges; the sheer volume of social media content, the lack of technical standards for capturing or storing social media data and social media's ephemeral character can be impeding factors. The goal of this article is three-fold. First, we aim to extend the most recent descriptive state-of-the-art of national web archiving, published in the first issue of International Journal of Digital Humanities (March 2019) with information on SMA. Secondly, we outline the current legal, technical and operational (such as the selection and preservation policy) aspects of archiving social media content. This is complemented with results from an online survey to which 15 institutions responded. Finally, we discuss and reflect on important challenges in SMA that should be considered in future archiving projects.

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Species-level responses to environmental change depend on the collective responses of their constituent populations and the degree to which populations are specialized to local conditions. Manipulative experiments in common-garden settings make it possible to test for population variation in species' responses to specific climate variables, including those projected to shift as the climate changes in the future. While this approach is being applied to a variety of plant taxa to evaluate their responses to climate change, these studies are heavily biased towards seed-bearing plant species. Given several unique morphological and physiological traits, fern species may exhibit very different responses from angiosperms and gymnosperms. Here, we tested the hypothesis that previously detected population differentiation in a fern species is due to differentiation in thermal performance curves among populations. We collected explants from six populations spanning the species' geographic range and exposed them to 10 temperature treatments. Explant survival, lifespan and the change in photosynthetic area were analysed as a function of temperature, source population and their interaction. Overall results indicated that explants performed better at the lowest temperature examined, and the threshold for explant performance reflects maximum temperatures likely to be experienced in the field. Surprisingly, explant fitness did not differ among source populations, suggesting that temperature is not the driver behind previously detected patterns of population differentiation. These results highlight the importance of other environmental axes in driving population differentiation across a species range, and suggest that the perennial life history strategy, asexual mating system and limited dispersal potential of Vittaria appalachiana may restrict the rise and differentiation of adaptive genetic variation in thermal performance traits among populations.

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[This corrects the article DOI: 10.1093/aobpla/plx013.][This corrects the article DOI: 10.1093/aobpla/plx013.].

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PREMISE OF THE STUDY: Many ecological and evolutionary processes shape the assembly of organisms into local communities from a regional pool of species. We analyzed phylogenetic and functional diversity to understand community assembly of the ferns of Florida at two spatial scales. METHODS: We built a phylogeny for 125 of the 141 species of ferns in Florida using five chloroplast markers. We calculated mean pairwise dissimilarity (MPD) and mean nearest taxon distance (MNTD) from phylogenetic distances and functional trait data for both spatial scales and compared the results to null models to assess significance. KEY RESULTS: Our results for over vs. underdispersion in functional and phylogenetic diversity differed depending on spatial scale and metric considered. At the county scale, MPD revealed evidence for phylogenetic overdispersion, while MNTD revealed phylogenetic and functional underdispersion, and at the conservation area scale, MPD revealed phylogenetic and functional underdispersion while MNTD revealed evidence only of functional underdispersion. CONCLUSIONS: Our results are consistent with environmental filtering playing a larger role at the smaller, conservation area scale. The smaller spatial units are likely composed of fewer local habitat types that are selecting for closely related species, with the larger-scale units more likely to be composed of multiple habitat types that bring together a larger pool of species from across the phylogeny. Several aspects of fern biology, including their unique physiology and water relations and the importance of the independent gametophyte stage of the life cycle, make ferns highly sensitive to local, microhabitat conditions.

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Selective pressures acting on plant life histories can drive extreme specialization. One example of such specialization is the evolution of dioecious breeding systems. Evolutionary and ecological theory posits that dioecy may subject male and female individuals to different selective pressures and result in unique sex-mediated adaptive traits related to resource allocation and ecophysiology. Cycads are the earliest diverging lineage of seed plants with strict dioecy, yet we know almost nothing about the ecology and physiology of this group. Especially limited is our understanding of potential sex-specific differences and how such differences may influence species ecology. Here we examine the ecophysiology of male and female cycads to understand better, the role that dioecy plays in this group. We evaluated sex-specific differences in ecophysiological traits and resource acquisition in five species. Specifically, we compared photosynthetic physiology, nitrogen and carbon content, isotope discrimination (δ15N and δ13C), and stomatal density. In some cycads, (i) males and females have similar investments in leaf nitrogen but females exhibit greater incorporation of nitrogen from nitrogen-fixing soil bacteria, (ii) males display higher photosynthetic capacity but females show decreased [corrected] water-use efficiency, and (iii) males have higher stomatal conductance but similar stomatal density to females. This study is the first to examine the ecophysiological differences that have evolved in the oldest dioecious lineage of seed-bearing plants. Our results show unexpected differences in photosynthetic physiology and highlight the co-evolution with nitrogen fixing soil bacteria as a potential new key player in an old lineage.

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PREMISE OF THE STUDY: For many plant species, historical climatic conditions may have left lasting imprints that are detectable in contemporary populations. Additionally, if these historical conditions also prevented gene flow among populations, these populations may be differentiated with respect to one another and their contemporary environmental conditions. For the fern, Vittaria appalachiana, one theory is that historical conditions during the Pleistocene largely shaped both the distribution and lack of sporophyte production. Our goals-based on this theory-were to examine physiological differences among and within populations spanning the species' geographic range, and the contribution of historical climatic conditions to this differentiation. METHODS: We exposed explants from five populations to four drying treatments and examined differences in physiological response. Additionally, we examined the role of historical and current climatic conditions in driving the observed population differentiation. KEY RESULTS: Populations differ in their ability to tolerate varying levels of dehydration, displaying a pattern of countergradient selection. Exposure to historical and contemporary climatic conditions, specifically variation in temperature and precipitation regimes, resulted in population divergence observed among contemporary populations. CONCLUSIONS: Historical conditions have shaped not only the distribution of V. appalachiana, but also its current physiological limitations. Results from this study support the hypothesis that climatic conditions during the Pleistocene are responsible for the distribution of this species, and may be responsible for the observed differences in dehydration tolerance. Additionally, dehydration tolerance may be the driving factor for previously reported patterns of countergradient selection in this species.

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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.

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PREMISE OF THE STUDY: Theory predicts that limited gene flow between populations will promote population differentiation, and experimental studies have found that differentiation is often explained by local adaptation in sexually reproducing angiosperms. However, few experiments have examined the drivers of differentiation among populations in asexual land plants with limited dispersal potential. Here, we evaluated the role of temperature in driving population differentiation in an asexual, obligate gametophyte fern species. METHODS: We reciprocally transplanted Vittaria appalachiana gametophytes among six populations that spanned the species' geographic range in the Appalachian Mountains and Plateau. Temperature, survival, and senescence rates were measured for 1 year. KEY RESULTS: Populations had significantly different fitness responses to different sites, consistent with the hypothesis that populations have differentiated across the species' range. There was some evidence for local adaptation in marginal populations and for countergradient selection favoring particularly robust genotypes at the northern range edge. Most populations had relatively high fitness at the site with the most stable temperature conditions and were negatively affected by decreasing minimum temperatures. CONCLUSIONS: Populations of Vittaria appalachiana exhibit highly variable responses to transplantation across the species' range, and only a small subset of these responses are due to local adaptation. Differences in daily minimum temperature explain some variation in fitness, but other site-specific factors also have significant impacts on transplant fitness. These results indicate that asexual, patchily distributed species with limited dispersal may exhibit population-specific responses to global climate change that have not been elucidated by empirical work focused on sexually reproducing angiosperms.

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Reflective practice is an important skill for undergraduate medical students to acquire and nurture as they develop into medical professionals. There has been increasing interest over the past decade into when and how best to introduce reflection into medical curricula. This paper summarises findings from a review of the literature and explores different approaches to the introduction and assessment of reflective practice work, and students' attitudes and understanding of the concept.

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Antidepressants have long been recognized as a contributory factor to falls and many studies show an association between antidepressants and falls. There are extensive data for tricyclic antidepressants (TCAs) and related drugs, and for selective serotonin reuptake inhibitors (SSRIs), but few data for other classes of antidepressants. Sedation, insomnia and impaired sleep, nocturia, impaired postural reflexes and increased reaction times, orthostatic hypotension, cardiac rhythm and conduction disorders, and movement disorders have all been postulated as contributing factors to falls in patients taking antidepressants. Sleep disturbance is a cardinal feature of depression, and all antidepressants have effects on sleep. TCAs and related drugs cause marked sedation with daytime drowsiness. SSRIs and related drugs have an alerting effect, impairing sleep duration and quality and causing insomnia, which may result in nocturia and daytime drowsiness. Daytime drowsiness is a significant risk factor for falls, both in untreated depression and in depression treated with antidepressants. Clinically significant orthostatic hypotension is common with TCAs and related drugs, the older monoamine oxidase inhibitors and serotonin-norepinephrine reuptake inhibitors (SNRIs). It occurs less commonly with SSRIs, and rarely with moclobemide and bupropion, and is not reported as a significant adverse effect of hypericum (St John's wort). Cardiac rhythm and conduction disturbances are well recognized with TCAs, tetracyclics and SNRIs, but have also been reported with SSRIs. The contribution of antidepressant-induced conduction and rhythm disturbances to falls cannot be assessed with current data. There are insufficient data to exonerate any individual antidepressant or class of antidepressants as a potential cause of falls. The magnitude of the increased risk of falling with an antidepressant is about the same as the excess risk found in patients with untreated depression.

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