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.

Premise of research. Ferns (monilophytes) and lycophytes are unique among land plants in having two independent life stages: the gametophyte generation, which is generally small, cordiform, and short-lived, senescing after fertilization, and the sporophyte generation, which is considered the dominant, long-lived portion of the life cycle produced following fertilization. In many species of epiphytic ferns, however, the gametophyte generation is capable of sustained vegetative growth, and some are able to reproduce asexually via gemmae. These two characteristics have increased the independence of these gametophytes, so much so that some species never produce sporophytes at all, while other species produce sporophytes only in parts of their geographic range, a trend we term here the "separation of generations." Pivotal results. Long-lived fern gametophytes have evolved independently in several families and can be found around the world. We present a comprehensive review of the long-lived fern gametophytes that are able to forgo the production of a sporophyte, including accounts of their discovery, taxonomy, biology, ecology, and biogeography. We also present several hypotheses concerning why these species do not produce sporophytes, identify gaps in our knowledge about these organisms, and suggest areas of future study. Conclusions. While several populations of independent gametophytes have been identified and characterized in temperate regions, it is likely that the bulk of species with spatially separated generations occur in the tropics, where little work has been done. Additionally, virtually no studies have been undertaken that attempt to determine the underlying factors inhibiting sporophyte production in ferns. As 2017 marks the fiftieth anniversary of the first comprehensive study published on independent fern gametophytes, we can think of no better time for a review on their biology and an assessment of the work that still needs to be done.

The Mesozoic is often referred to as the “age of Cycads.” During this period, dinosaurs roamed vast Cycad forests, yet modern Cycads are a vestige of their Mesozoic glory. Extant species represent the oldest lineage of dioecious seed-bearing plants. This curious phylogenic position is matched by their unusual ecology: most species are extremely rare while others form dense colonies that may play important roles in forest function. In spite of this and quite remarkably, Cycads are the most poorly studied lineage of seed plants and almost nothing is known of their ecophysiology. The study by Krieg et al. is the first of its kind to examine sex-mediated ecophysiology in Cycads. Their results show unexpended differences in photosynthetic physiology and highlight the role that nitrogen fixing soil bacteria may play in Cycad reproduction and ecology. They found that species can vary markedly in nitrogen relations and that plant sex can drive unique leaf physiology. Their study is a cycadological call to arms for plant scientists to refocus efforts on this enigmatic group.

Recent ecological studies have revealed that rapid evolution within populations can have significant impacts on the ecological dynamics of communities and ecosystems. These eco-evolutionary dynamics (EED) are likely to have substantial and quantifiable effects in restored habitats over timescales that are relevant for the conservation and restoration of small populations and threatened communities. Restored habitats may serve as "hotspots" for EED due to mismatches between transplanted genotypes and the restored environment, and novel interactions among lineages that do not share a coevolutionary history, both of which can generate strong selection for rapid evolutionary change that has immediate demographic consequences. Rapid evolution that influences population dynamics and community processes is likely to have particularly large effects during the establishment phase of restoration efforts. Finally, restoration activities and their associated long-term monitoring programs provide outstanding opportunities for using eco-evolutionary experimental approaches. Results from such studies will address questions about the effects of rapid evolutionary change on the ecological dynamics of populations and interacting species, while simultaneously providing critical, but currently overlooked, information for conservation practices. Implications for Practice• The success of restorations can be improved by understanding how feedbacks between ecological dynamics and rapid evolutionary change of translocated populations unfold in the restored environment, and the effects of these interactions on the establishment, development, and persistence of restored ecological communities. • Practitioners and scientists should integrate long-term ecological monitoring data with measurements of phenotypic traits over time to quantify eco-evolutionary dynamics in restored communities. • Results from these studies will provide practitioners with improved guidelines for how to choose genetic sources of propagules to increase the success of restored populations and communities.

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.

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.

Historical conditions have shaped not only the distribution of , 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.

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.