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The succulent syndrome is one of the most iconic life strategies in angiosperms, maximising water storage through a suite of adaptations to water-scarcity. Though succulence is considered a classic case of convergent evolution driven by shared environmental drivers, we lack a full understanding of whether the timing and drivers of the diversification of succulent lineages are, in fact, concordant. Here we analyse time-calibrated phylogenetic reconstructions of the seven richest lineages of succulents, and study diversification dynamics in relation to abiotic variables. Our analyses reveal different levels of synchronicity and relation with aridity. The impact of atmospheric CO2on succulent macroevolution is varied. While transitions and radiations are especially concentrated in recent time, following a collapse of atmospheric CO2∼15 million years ago, CO2-dependent diversification is not supported in most lineages. With the exception ofEuphorbia, we find that succulence elevates net diversification, though the effects on underlying speciation and extinction disagree. The phylogenetic distribution of transitions to succulence and rate shift increases suggest these phenomena are decoupled, indicating that succulence might not adhere to a classic key innovation model. We discuss that these evolutionary patterns reveal the ecological complexity of the succulent strategy, beyond simplistic interpretations as adaptations towards aridity.

The composition and diversity of animal-associated microbial communities are shaped by multiple ecological and evolutionary processes acting at different spatial and temporal scales. Skin microbiomes are thought to be strongly influenced by the environment due to the direct interaction of the host’s skin with the external media. As expected, the diversity of amphibian skin microbiomes is shaped by climate and host habitats, whereas phylogenetic effects appear to be weak. However, the relative strength of phylogenetic and environmental effects on amphibian skin microbiomes remains poorly understood. Here, we analysed sequence data from 1,091 adult salamanders in 41 species to characterise and compare the diversity and composition of skin bacteria. We assessed the relative contribution of climate, host habitat, and host phylogeny to the observed patterns of bacterial diversity. We found that microbial alpha was mainly associated with host habitat and climate, but that microbial beta diversity was more strongly associated with host taxonomy and phylogeny. This phylogeny effect predominantly occurred at intermediate levels of host divergence (0–50 Mya). Our results support the importance of environmental factors shaping the diversity of amphibian skin microbiomes, but also support host phylogenetic history as a major factor shaping these microbial communities.

Climate change is a threat to biodiversity. One way that this threat manifests is through pronounced shifts in the geographical range of species over time. To predict these shifts, researchers have primarily used species distribution models. However, these models are based on assumptions of niche conservatism and do not consider evolutionary processes, potentially limiting their accuracy and value. To incorporate evolution into the prediction of species' responses to climate change, researchers have turned to landscape genomic data and examined information about local genetic adaptation using climate models. Although this is an important advancement, this approach currently does not include other evolutionary processes-such as gene flow, population dispersal and genomic load-that are critical for predicting the fate of species across the landscape. Here, we briefly review the current practices for the use of species distribution models and for incorporating local adaptation. We next discuss the rationale and theory for considering additional processes, reviewing how they can be incorporated into studies of species' responses to climate change. We summarize with a conceptual framework of how manifold layers of information can be combined to predict the potential response of specific populations to climate change. We illustrate all of the topics using an exemplar dataset and provide the source code as potential tutorials. This Perspective is intended to be a step towards a more comprehensive integration of population genomics with climate change science.

The Early Cretaceous (145–100 million years ago (Ma)) witnessed the rise of flowering plants (angiosperms), which ultimately lead to profound changes in terrestrial plant communities. However, palaeobotanical evidence shows that the transition to widespread angiosperm-dominated biomes was delayed until the Palaeocene (66–56 Ma). Important aspects of the timing and geographical setting of angiosperm diversification during this period, and the groups involved, remain uncertain. Here we address these aspects by constructing and dating a new and complete family-level phylogeny, which we integrate with 16 million geographic occurrence records for angiosperms on a global scale. We show substantial time lags (mean, 37–56 Myr) between the origin of families (stem age) and the diversification leading to extant species (crown ages) across the entire angiosperm tree of life. In turn, our results show that families with the shortest lags are overrepresented in temperate and arid biomes compared with tropical biomes. Our results imply that the diversification and ecological expansion of extant angiosperms was geographically heterogeneous and occurred long after most of their phylogenetic diversity originated during the Cretaceous Terrestrial Revolution. A new study of the divergence time of angiosperm families shows that although most angiosperm families originated during the middle Cretaceous (~100–90 million years ago), the diversification of families into extant diversity was delayed until the Palaeocene (~66–56 million years ago), this time lag being geographically heterogeneous, and longer in tropical than in temperate and arid biomes.

Fossil flowers are essential to infer past angiosperm evolutionary processes. The assignment of fossil flowers to extant clades has traditionally relied on morphological similarity and on apomorphies shared with extant taxa. The use of explicit phylogenetic analyses to establish their affinity has so far remained limited. In this study, we built a comprehensive framework to investigate the phylogenetic placement of 24 exceptionally preserved fossil flowers. For this, we assembled a new species-level dataset of 30 floral traits for 1201 extant species that were sampled to represent the stem and crown nodes of all angiosperm families. We explored multiple analytical approaches to integrate the fossils into the phylogeny, including different phylogenetic estimation methods, topological-constrained analyses, and a total evidence approach combining molecular and morphological data of extant and fossil species. Our results were widely consistent across approaches, with minor differences in the support of fossils at different phylogenetic positions. The placement of some fossils is in agreement with previously suggested relationships, but for others, a new placement is indicated. We also identified fossils that are well constrained within particular extant families, whereas others showed high phylogenetic uncertainty. Finally, we present recommendations for future total evidence analyses, regarding the selection of fossils and appropriate methodologies, and provide some perspectives on how to integrate fossils into the investigation of divergence times and the temporal evolution of morphological traits.

Global climate change and habitat loss are displacing tropical montane forests along mountain slopes1–4. Cloud forests are one of the most diverse and fragile of these montane ecosystems5–8, yet little is known about the historical and ongoing impacts of anthropogenic disturbances on these forests. Here we assess historical (1901–2016) changes in the altitudinal range of vascular plant species in Mesoamerican cloud forests and evaluate the relative impacts of climate change and land-use alterations. By analysing thousands of occurrence records from public biological collections, we uncovered common altitudinal shifts across species and suggest an overall contraction of cloud forests starting in the late 1970s. We infered a pervasive and interrelated impact of rising temperatures, changing precipitation patterns, and deforestation on the distribution of cloud forest species across Mesoamerica. Over the last fifty years, cloud forests have declined due to deforestation and warmer and more (seasonally) arid climates9–11. This is pushing species’ to contract their altitudinal ranges and may lead to an increasing probability of abrupt and devastating declines of population sizes, local adaptation, and migration.

The origin of flowering plants (angiosperms) was one of the most transformative events in the history of our planet. Despite considerable interest from multiple research fields, numerous questions remain, including the age of the group as a whole. Recent studies have reported a perplexing range of estimates for the crown-group age of angiosperms, from ca. 140 Ma (Early Cretaceous) to 270 Ma (Permian). Both ends of the spectrum are now supported by both quantitative analyses of the fossil record and fossil-calibrated molecular dating analyses. Here, we first clarify and distinguish among the three ages of angiosperms: the age of their divergence with acrogymnosperms (stem age), the age(s) of emergence of their unique, distinctive features including flowers (morphological age), and the age of the most recent common ancestor of all their living species (crown age). We then demonstrate, based on recent studies, that fossil-calibrated molecular dating estimates of the crown-group age of angiosperms have little to do with either the amount of molecular data or the number of internal fossil calibrations included. Instead, we argue that this age is almost entirely conditioned by its own prior. Lastly, we discuss which future discoveries or novel types of analyses are most likely to bring more definitive answers. In the meantime, we propose that the age of angiosperms is best described as unknown (140–270 Ma) and that future work that depends on the time scale of flowering plant diversification be designed to integrate over this vexing uncertainty.

Anthropogenic greenhouse gas emissions have led to sustained global warming over the last decades1. This is already reshaping the distribution of biodiversity across the world and can lead to the occurrence of large-scale singular events, such as the melting of polar ice sheets2,3. The potential impacts of such a melting event on species persistence across taxonomic groups – in terms of magnitude and geographic extent – remain unexplored. Here we assess impacts on biodiversity of global warming and melting of Greenland’s ice sheet on the distribution of 21,146 species of vascular plants and tetrapods across twelve megadiverse countries. We show that high global warming would lead to widespread reductions in species’ geographic ranges (median range loss, 35–78%), which are magnified (median range loss, 95–99%) with the added contribution of Greenland’s melting and its potentially large impact on oceanic circulation and regional climate changes. Our models project a decline in the geographical extent of species hotspots across countries (median reduction, 48–95%) and a substantial alteration of species composition in the near future (mean temporal dissimilarity, 0.26–0.89). These results imply that, in addition to global warming, the influence of Greenland’s melting can lead to the collapse of biodiversity across the globe, providing an added domino in its cascading effects.

Rising temperatures can lead to the occurrence of a large-scale climatic event, such as the melting of Greenland ice sheet, weakening the AMOC and further increasing dissimilarities between current and future climate. The impacts of such an event are still poorly assessed. Here, we evaluate those impacts across megadiverse countries on 21,146 species of tetrapods and vascular plants using the pessimistic climate change scenario (RCP 8.5) and four different scenarios of Greenland's ice sheet melting. We show that RCP 8.5 emission scenario would lead to a widespread reduction in species' geographic ranges (28-48%), which is projected to be magnified (58-99%) with any added contribution from the melting of Greenland. Also, declines in the potential geographical extent of species hotspots (12-89%) and alterations of species composition (19-91%) will be intensified. These results imply that the influence of a strong and rapid Greenland ice sheet melting, resulting in a large AMOC weakening, can lead to a faster collapse of biodiversity across the globe.

Existing global regionalisation schemes for plants consider the compositional affinities among biotas, but these have not considered phylogenetic information explicitly. Incorporating phylogenetic information may substantially advance our understanding of the relationships among regions and the synopsis of biogeographical schemes, because phylogeny captures information on the evolutionary history of taxa. Here, we present the first phytogeographical delineation of the global vascular flora based on the evolutionary relationships of species.We analysed 8,738,520 geographical occurrence records for vascular plant species together with a time-calibrated phylogenetic tree including 67,420 species. We estimated species composition within 200 × 200 km grid cells across the world, and used a metric of phylogenetic beta diversity to generate a phylogenetic delineation of floristic regions. We contrasted these results with a regionalisation generated using a taxonomic beta diversity metric.We identified 16 phylogenetically distinct phytogeographical units, deeply split into two main clusters that broadly correspond to the Laurasia-Gondwana separation. Our regionalisation broadly matches currently recognized phytogeographical classifications, but also highlights that the Gondwanan area is split into a large Holotropical cluster and an Australian-NeoZelandic-Patagonian cluster. In turn, we found that the northernmost and southernmost units have the most evolutionarily distinct vascular plant assemblages. In contrast, taxonomic dissimilarity returned a regionalisation composed of 23 units with a high degree of shared taxa between Laurasian and Gondwanan areas, with no clear split among their biotas.The integration of phylogenetic information provided new insights into the historical relationships among phytogeographical units, enabling the identification of three large, clearly differentiated biotas, here referred to as kingdoms: Holarctic, Holotropical, and Austral. Our regionalization scheme provides further evidence for delineating transition zones between the Holarctic and Holotropical kingdoms. The latitudinal patterns of evolutionary distinctiveness of vascular plant assemblages are consistent with recent evidence of higher and more recent diversification of flowering plants outside tropical regions.

Anthropogenic greenhouse gas emissions have led to sustained global warming over the last decades1. This is already reshaping the distribution of biodiversity across the world and can lead to the occurrence of large-scale singular events, such as the melting of polar ice sheets2,3. The potential impacts of such a melting event on species persistence across taxonomic groups – in terms of magnitude and geographic extent – remain unexplored. Here we assess impacts on biodiversity of global warming and melting of Greenland’s ice sheet on the distribution of 21,146 species of vascular plants and tetrapods across twelve megadiverse countries. We show that high global warming would lead to widespread reductions in species’ geographic ranges (median range loss, 35–78%), which are magnified (median range loss, 95–99%) with the added contribution of Greenland’s melting and its potentially large impact on oceanic circulation and regional climate changes. Our models project a decline in the geographical extent of species hotspots across countries (median reduction, 48–95%) and a substantial alteration of species composition in the near future (mean temporal dissimilarity, 0.26–0.89). These results imply that, in addition to global warming, the influence of Greenland’s melting can lead to the collapse of biodiversity across the globe, providing an added domino in its cascading effects.

Climate change is a threat to biodiversity. One way that this threat manifests is through pronounced shifts in the geographical range of species over time. To predict these shifts, researchers have primarily used species distribution models. However, these models are based on assumptions of niche conservatism and do not consider evolutionary processes, potentially limiting their accuracy and value. To incorporate evolution into the prediction of species' responses to climate change, researchers have turned to landscape genomic data and examined information about local genetic adaptation using climate models. Although this is an important advancement, this approach currently does not include other evolutionary processes-such as gene flow, population dispersal and genomic load-that are critical for predicting the fate of species across the landscape. Here, we briefly review the current practices for the use of species distribution models and for incorporating local adaptation. We next discuss the rationale and theory for considering additional processes, reviewing how they can be incorporated into studies of species' responses to climate change. We summarize with a conceptual framework of how manifold layers of information can be combined to predict the potential response of specific populations to climate change. We illustrate all of the topics using an exemplar dataset and provide the source code as potential tutorials. This Perspective is intended to be a step towards a more comprehensive integration of population genomics with climate change science.

The gut microbiota is critical for host function. Among mammals, host phylogenetic relatedness and diet are strong drivers of gut microbiota structure, but one factor may be more influential than the other. Here, we used 16S rRNA gene sequencing to determine the relative contributions of host phylogeny and host dietary guild in structuring the gut microbiotas of 11 herbivore species from 5 families living sympatrically in southwest Kenya. Herbivore species were classified as grazers, browsers, or mixed-feeders. We found that gut microbiotas were highly species-specific, and that host taxonomy accounted for more variation in the gut microbiota (30%) than did host dietary guild (10%) or sample month (8%). Overall, similarity among gut microbiotas increased with host phylogenetic relatedness (r=0.73), yet this relationship was not consistent among seven closely related Bovid host species (r=0.21 NS). Within bovids, host dietary guild explained more of the variation in the gut microbiota than did host species. Lastly, while we found that the gut microbiotas of herbivores residing in southwest Kenya converge with those of distinct populations of conspecifics from central Kenya, fine-scale differences in the abundances of bacterial amplicon sequence variants (ASVs) between individuals from the two regions were also observed. Overall, our findings suggest that host phylogeny and taxonomy strongly structure the gut microbiota, but these gut microbial communities could be furthered modified by host ecology, especially among closely related host species.

The Tehuacan-Cuicatlan Valley, located at the southeast of the state of Puebla and the northeast of the state of Oaxaca in Central Mexico, south of the Trans-Mexican Volcanic Belt (TMVB), is of particular interest for understanding the evolutionary dynamics of arid and semi-arid environments, being one of the main reservoirs of biological diversity for the arid zones of North America, including the highest diversity of Agavaceae worldwide and high levels of endemism. Studying in detail the phylogeography, environmental history and population genetics of representative species will hopefully shed light on the evolutionary and ecological dynamics that generated the tremendous biodiversity and endemism of this important region in Mexico. We sequenced three non-coding regions of chloroplast genome of Agave kerchovei, a representative species of the Tehuacan Valley, generating 2,188 bp from 128 individuals sampled from eight populations throughout the species range. We used this data set to (i) characterize the levels of genetic diversity and genetic structure in A. kerchovei; (ii) predict the distribution of A. kerchovei for the present day, and to reconstruct the past geographical history of the species by constructing ecological niche models (ENM); and (iii) compare the levels of diversity in this species with those estimated for the widely distributed Agave lechuguilla. Agave kerchovei has high levels of total chloroplast genetic variation (Hd = 0.718), especially considering that it is a species with a very restricted distribution. However, intrapopulation diversity is low (zero in some populations), and genetic structure is high (F ST = 0.928, G ST = 0.824), which can be expected for endemic species with isolated populations. Our data suggest that Pleistocene glacial cycles have played an important role in the distribution of A. kerchovei, where the climatic variability of the region - likely associated with its topographic complexity - had a significant effect on the levels of genetic diversity and population dynamics, while the potential distribution of the species seems to be stable since the middle Holocene (6 kya). We conclude that in A. kerchovei there is a core group of populations in the Tehuacan Valley, and peripheric populations that appear to be evolving independently and thus the species is fundamentally an endemic species from the Tehuacan Valley while the populations outside the Valley appear to be in the process of incipient speciation.

Variation in leaf morphology is correlated with environmental variables, such as precipitation, temperature and soil composition. Several studies have pointed out that individual plasticity can largely explain the foliar phenotypic differences observed in populations due to climatic change and have suggested that the environment plays an important role in the evolution of plant species by selecting for phenotypic variation. Thus, the study of foliar morphology in plant populations can help us identify the environmental factors that have potentially influenced the process of species diversification. In this study, we analyzed morphological variation in the leaf traits of theTernstroemia lineataspecies complex (Penthaphylacaceae) and its relation to climatic variables across the species distribution area to identify the patterns of morphological differentiation within this species complex. Based on the collected leaves of 270 individuals from 32 populations, we analyzed nine foliar traits using spatial interpolation models and multivariate statistics. A principal component analysis identified three main morphological traits (leaf length and two leaf shape variables) that were used to generate interpolated surface maps to detect discrete areas delimited by zones of rapid change in the values of the morphological traits. We identified a mosaic coarse-grain pattern of geographical distribution in the variation of foliar traits. According to the interpolation maps, we could define nine morphological groups and their geographic distributions. Longer leaves, spatulate leaves and the largest foliar area were located in sites with lower precipitation and higher seasonality of precipitation following a northwest–southeast direction and following significant latitudinal and longitudinal gradients. According to the phenogram of the relationships of the nine morphological groups based on morphological similarity, the putative species and subspecies of theT. lineataspecies complex did not show a clear pattern of differentiation. In this study, we found a complex pattern of differentiation with some isolated populations and some other contiguous populations differentiated by different traits. Further genetic and systematic studies are needed to clarify the evolutionary relationships in this species complex.

Variation in rates of molecular evolution (heterotachy) is a common phenomenon among plants. Although multiple theoretical models have been proposed, fundamental questions remain regarding the combined effects of ecological and morphological traits on rate heterogeneity. Here, we used tree ferns to explore the correlation between rates of molecular evolution in chloroplast DNA sequences and several morphological and environmental factors within a Bayesian framework. We revealed direct and indirect effects of body size, biological productivity, and temperature on substitution rates, where smaller tree ferns living in warmer and less productive environments tend to have faster rates of molecular evolution. In addition, we found that variation in the ratio of nonsynonymous to synonymous substitution rates (dN/dS) in the chloroplast rbcL gene was significantly correlated with ecological and morphological variables. Heterotachy in tree ferns may be influenced by effective population size associated with variation in body size and productivity. Macroevolutionary hypotheses should go beyond explaining heterotachy in terms of mutation rates and instead, should integrate population-level factors to better understand the processes affecting the tempo of evolution at the molecular level.

Aim The formation of the Trans-Mexican Volcanic Belt (TMVB) played an important role in driving inter- and intraspecific diversification at high elevations. However, Pleistocene climate changes and ecological factors might also contribute to plant genetic structuring along the volcanic belt. Here, we analysed phylogeographical patterns of the parrot-mistletoe Psittacanthus calyculatus to determine the relative contribution of these different factors. Location Trans-Mexican Volcanic Belt. Methods Using nuclear and chloroplast DNA sequence data for 370 individuals, we investigate the genetic differentiation of 35 populations across the species range. We conducted phylogenetic, population and spatial genetic analyses of P. calyculatus sequences along with ecological niche modelling and Bayesian inference methods to gain insight into the structuring of genetic variation of these populations. Results Our analyses revealed population structure with three genetic groups corresponding to individuals from Oaxaca and those from the central-eastern and western TMVB regions. A significant genetic signal of demographic expansion, an east-to-west expansion predicted by species distribution modelling, and approximate Bayesian computation analyses strongly supported a scenario of habitat isolation and invasion of TMVB by P. calyculatus during the late-Pleistocene. Main conclusions The genetic differentiation of P. calyculatus may be explained by the combined effects of (1) geographical isolation linked to the effects of the glacial/interglacial cycles and environmental factors, driving genetic differentiation from congeners into more xeric vegetation and (2) the invasion of TMVB from east to west, suggesting a role for both colonization and glacial/interglacial cycles models.

The Early Cretaceous (145-100 million years ago (Ma)) witnessed the rise of flowering plants (angiosperms), which ultimately lead to profound changes in terrestrial plant communities. However, palaeobotanical evidence shows that the transition to widespread angiosperm-dominated biomes was delayed until the Palaeocene (66-56 Ma). Important aspects of the timing and geographical setting of angiosperm diversification during this period, and the groups involved, remain uncertain. Here we address these aspects by constructing and dating a new and complete family-level phylogeny, which we integrate with 16 million geographic occurrence records for angiosperms on a global scale. We show substantial time lags (mean, 37-56 Myr) between the origin of families (stem age) and the diversification leading to extant species (crown ages) across the entire angiosperm tree of life. In turn, our results show that families with the shortest lags are overrepresented in temperate and arid biomes compared with tropical biomes. Our results imply that the diversification and ecological expansion of extant angiosperms was geographically heterogeneous and occurred long after most of their phylogenetic diversity originated during the Cretaceous Terrestrial Revolution.

Climate change is one of the most important threats to biodiversity and crop sustainability. The impact of climate change is often evaluated on the basis of expected changes in species’ geographical distributions. Genomic diversity, local adaptation, and migration are seldom integrated into projections of species’ responses to climate change. Here we predict that climate change will impact populations of two wild relatives of maize, the teosintes Zea mays ssp. mexicana and Z. mays ssp. parviglumis, by altering patterns of local adaptation and decreasing migration probabilities. These alterations appear to be geographically heterogeneous across populations, suggesting that the possible impacts of climate change will vary considerably among populations. This in spite that most populations exhibit high levels of genetic diversity and are predicted to lie within future suitable areas. The heterogeneous patterns of local adaptation uncovered in teosintes are also evident across maize landraces, which suggests that climate change may give way to future maladaptation of several landraces within currently cultivated areas, possibly leading to increased chances of production shocks under increased temperatures. The predicted alterations to habitat distribution, migration potential, and patterns of local adaptation in wild and cultivated maize, raises a red flag for the future of populations. This underscores the need for continued integration of agronomical practices, genomic data, and climate models to better understand the impacts of a rapidly changing climate on cultivated and wild species.

Host specialization after host shifting is traditionally viewed as the pathway to speciation in parasitic plants. However, geographical and environmental changes can also influence parasite speciation, through hybridization processes. Here we investigated the impact of past climatic fluctuations, environment, and host shifts on the genetic structure and patterns of hybridization and gene flow between Psittacanthus calyculatus and P. schiedeanus, a Mesoamerican species complex. Using microsatellites (408 individuals), we document moderate genetic diversity but high genetic differentiation between widespread parental clusters, calyculatus in dry pine-oak forests and schiedeanus in cloud forests. Bayesian analyses identified a third cluster, with admixture between parental clusters in areas of xeric and tropical dry forests and high levels of migration rates following secondary contact. Coincidently host associations in these areas differ from those in areas of parental species, suggesting that past hybridization played a role in environmental and host shifts. Overall, the observed genetic and geographic patterns suggest that these Psittacanthus populations could have entered a distinct evolutionary pathway. The results provide evidence for highlights on the importance of the Pleistocene climate changes, habitat differences, and potential host shifts in the evolutionary history of Neotropical mistletoes.

The patterns of geographic differentiation in fern species have been linked to climatic differences across regions and the distribution of available habitat. In this paper, the association between some climatic features and patterns of geographic differentiation in American tree ferns was evaluated. For this, the occurrence ranges of 190 species were plotted and then analysed using track analysis. Here we identify six generalised tracks that span the main highland regions of tropical America: the Andes, the Guyana Highlands, the Brazilian Atlantic coast, lower Central America, the Greater Antilles, and upper Central America-Mexico. We did not find an association between cloud forest habitat and the differentiation pattern revealed by generalised tracks in Central America. Instead, these patterns are congruent with well-documented geological boundaries in the region. Climatic variables associated with cloud forest habitat were extracted from each generalised track and subjected to ANOVA, showing t...

The development of spatial genetic structure (SGS) in seed plants has been linked to several biological attributes of species, such as breeding system and life form. However, little is known about SGS in ferns, which together with lycopods are unique among land plants in having two free-living life stages. We combined spatial aggregation statistics and spatial genetic autocorrelation analyses using five plastid microsatellites and one nuclear gene to investigate SGS in two populations of the outcrossing tree fern Alsophila firma (Cyatheaceae). We assessed how the observed patterns compare with those estimated for other ferns and seed plants. Populations of A. firma exhibited strong SGS, spatial clustering of individuals, substantial clonal diversity and no inbreeding. SGS in ferns appears to be higher than in most seed plants analysed to date. Contrary to our expectations, an outcrossing breeding system, wind dispersal and an arborescent life form did not translate into weak or no SGS. In ferns, SGS is probably being affected by the life cycle with two free-living life stages. The reproductive biology of ferns appears to be more complex than previously thought. This implies that SGS in ferns is affected by some factors that cannot be inferred from the study of flowering plants. © 2015 The Linnean Society of London, Botanical Journal of the Linnean Society, 2015, 177, 439–449.

Variation in rates of molecular evolution (heterotachy) is a common phenomenon among plants. Although multiple theoretical models have been proposed, fundamental questions remain regarding the combined effects of ecological and morphological traits on rate heterogeneity. Here, we used tree ferns to explore the correlation between rates of molecular evolution in chloroplast DNA sequences and several morphological and environmental factors within a Bayesian framework. We revealed direct and indirect effects of body size, biological productivity, and temperature on substitution rates, where smaller tree ferns living in warmer and less productive environments tend to have faster rates of molecular evolution. In addition, we found that variation in the ratio of nonsynonymous to synonymous substitution rates (dN/dS) in the chloroplast rbcL gene was significantly correlated with ecological and morphological variables. Heterotachy in tree ferns may be influenced by effective population size associated with variation in body size and productivity. Macroevolutionary hypotheses should go beyond explaining heterotachy in terms of mutation rates and instead, should integrate population-level factors to better understand the processes affecting the tempo of evolution at the molecular level.

AIM: We investigated changes in distribution of cloud forests during the last 130 kyr, and tested whether these changes explain the spatial patterns of genetic diversity of the tree fern Alsophila firma (Cyatheaceae), a species restricted to this habitat. LOCATION: Mexican cloud forests. METHODS: We sampled 204 individuals from 16 localities. Genetic data consisted of DNA sequences for five chloroplast microsatellites and one nuclear gene. We used distribution modelling to predict the historical distribution of cloud forests during the last glacial period, using two palaeoclimate models: the Model for Interdisciplinary Research on Climate (MIROC) and the Community Climate System Model (CCSM). We tested the correlation between temporal cloud forest stability and genetic diversity and used an approximate Bayesian computation (ABC) framework to test two plausible demographic scenarios. RESULTS: The range fluctuations observed for cloud forests during the last 130 kyr are key factors affecting the distribution of genetic variation in A. firma. Increased genetic diversity in areas with high temporal environmental suitability is probably the result of increased population sizes and higher interpopulation connectivity. In accordance with the expansion of cloud forests predicted by CCSM, the genetic data supported the scenario of a population expansion occurring c. 110 ka, followed by population divergence c. 20 ka. However, population dynamics involving expansion of suitable microclimates could reconcile the stability of cloud forests predicted by MIROC and the observed genetic patterns. MAIN CONCLUSIONS: The predicted changes in the distribution of cloud forests were congruent with the population genetics of A. firma. However, the choice of palaeoclimate model has a substantial impact on the inferences drawn from the observed genetic and demographic patterns. The use of alternative palaeoclimate hypotheses and biome modelling can provide a common analytical framework for evaluating the historical cohesiveness of forest communities.

Variation in species richness across regions and between different groups of organisms is a major feature of evolution. Several factors have been proposed to explain these differences, including heterogeneity in the rates of species diversification and the age of clades. It has been frequently assumed that rapid rates of diversification are coupled to high rates of ecological and morphological evolution, leading to a prediction that remains poorly explored for most species: the positive association between ecological niche divergence, morphological evolution and species diversification. We combined a time-calibrated phylogeny with distribution, ecological and body size data for scaly tree ferns (Cyatheaceae) to test whether rates of species diversification are predicted by the rates at which clades have evolved distinct ecological niches and body sizes. We found that rates of species diversification are positively correlated with rates of ecological and morphological evolution, with rapidly diversifying clades also showing rapidly evolving ecological niches and body sizes. Our results show that rapid diversification of scaly tree ferns is associated with the evolution of species with comparable morphologies that diversified into similar, yet distinct, environments. This suggests parallel evolutionary pathways opening in different tropical regions whenever ecological and geographical opportunities arise. Accordingly, rates of ecological niche and body size evolution are relevant to explain the current patterns of species richness in this ‘ancient’ fern lineage across the tropics.

Background Ecological adaptation to host taxa is thought to result in mistletoe speciation via race formation. However, historical and ecological factors could also contribute to explain genetic structuring particularly when mistletoe host races are distributed allopatrically. Using sequence data from nuclear (ITS) and chloroplast (trnL-F) DNA, we investigate the genetic differentiation of 31 Psittacanthus schiedeanus (Loranthaceae) populations across the Mesoamerican species range. We conducted phylogenetic, population and spatial genetic analyses on 274 individuals of P. schiedeanus to gain insight of the evolutionary history of these populations. Species distribution modeling, isolation with migration and Bayesian inference methods were used to infer the evolutionary transition of mistletoe invasion, in which evolutionary scenarios were compared through posterior probabilities. Results Our analyses revealed shallow levels of population structure with three genetic groups present across the sample area. Nine haplotypes were identified after sequencing the trnL-F intergenic spacer. These haplotypes showed phylogeographic structure, with three groups with restricted gene flow corresponding to the distribution of individuals/populations separated by habitat (cloud forest localities from San Luis Potosí to northwestern Oaxaca and Chiapas, localities with xeric vegetation in central Oaxaca, and localities with tropical deciduous forests in Chiapas), with post-glacial population expansions and potentially corresponding to post-glacial invasion types. Similarly, 44 ITS ribotypes suggest phylogeographic structure, despite the fact that most frequent ribotypes are widespread indicating effective nuclear gene flow via pollen. Gene flow estimates, a significant genetic signal of demographic expansion, and range shifts under past climatic conditions predicted by species distribution modeling suggest post-glacial invasion of P. schiedeanus mistletoes to cloud forests. However, Approximate Bayesian Computation (ABC) analyses strongly supported a scenario of simultaneous divergence among the three groups isolated recently. Conclusions Our results provide support for the predominant role of isolation and environmental factors in driving genetic differentiation of Mesoamerican parrot-flower mistletoes. The ABC results are consistent with a scenario of post-glacial mistletoe invasion, independent of host identity, and that habitat types recently isolated P. schiedeanus populations, accumulating slight phenotypic differences among genetic groups due to recent migration across habitats. Under this scenario, climatic fluctuations throughout the Pleistocene would have altered the distribution of suitable habitat for mistletoes throughout Mesoamerica leading to variation in population continuity and isolation. Our findings add to an understanding of the role of recent isolation and colonization in shaping cloud forest communities in the region. Electronic supplementary material The online version of this article (doi:10.1186/s12862-016-0648-6) contains supplementary material, which is available to authorized users.

Analyses of richness and endemism of Cyatheales (tree ferns) in tropical America were performed and evidence of a diversity gradient is presented. For this, the occurrence ranges of 239 species were plotted into a 5° × 5° grid-cell map and then analyzed using species richness and endemism indices. Here we show that species richness and endemism are not distributed randomly over the landscape, but do aggregate into defined regions of high diversity in tropical America: the northern Andes, lower Central America, upper Central America and Mexico, the Guyana Highlands, southeastern Brazil, and the Antilles. These distributional patterns are congruent with the geographical distribution of cloud forest, which in turn is determined by topography, high humidity, and persistent cloud immersion. The mountain regions of tropical America, especially the cloud forests, harbour most of the species of American Cyatheales and have high levels of habitat loss and climatic fragility. Conservation policies for Cyatheales are centred on the local use and trade of many tree fern species, but none such policies focus on cloud forest habitat loss. This makes tree ferns a critically endangered group of plants. In the face of the current environmental crisis and global climate change, the presence of Cyatheales in these regions sounds the alarm on their conservation priorities.

Based on known data sets and maximum entropy distribution data of fern and lycopod species registered in the Yucatan Peninsula, track and parsimony analyses were undertaken to evaluate the contribution of these groups to the establishment of biogeographical relationships of the peninsula with other areas. The resulting generalized tracks clearly agree with the geological origin of the peninsula and the previously recognized relationship with the Greater Antilles is not supported for ferns and lycopods. Instead, a Central American generalized track connects the Yucatan Peninsula with south-eastern Mexico and Central America. Floristically, the peninsula harbours 66 species of ferns and lycopods. Seven are registered for the first time in the Yucatan Peninsula and one is a new species for Mexico. These species do not follow the latitudinal pattern expected if ecological factors, such as humidity and rainfall, were the most important in determining their distributions. Groups of areas recognized with parsimony analysis of endemicity could not be defined as provinces as a result of the lack of endemic species. Nevertheless, a regionalization scheme based on maximum entropy distribution data and supported by track analyses is proposed. Two separate districts are recognized within the Yucatan Peninsula: arid/dry Yucatan in the north and El Peten (humid) in the south. © 2009 The Linnean Society of London, Biological Journal of the Linnean Society, 2009, 98, 775-786.

Recent years have witnessed the advent and rapid development of massive sequencing technology, commonly known as Next Generation Sequencing (NGS). This technology allows for rapid, massive and inexpensive sequencing of genome regions or entire genomes, making possible genomic studies of non-model organisms and has seen great progress in metagenomic studies. The promise of this information-rich era is to expand the molecular approach of ecological and evolutionary studies towards urgent issues related with conservation and management of biological diversity in the face of global change. Among the current NGS technologies, there are fundamental differences that impact DNA sequence accuracy, length and range of applications. Key differences among platforms are the procedure for library preparation (when needed) and the sequencing process itself (e.g., pyrosequencing, synthesis). In this review we describe the technical details of commercially available platforms for massive sequencing. We discuss their potential applications for specific biodiversity analyses, from model to non-model organisms, from Single Nucleotide Polymorphism (SNPs) to entire genome analysis and metagenomic approaches of microbial communities, including possible taxonomic, phylogenetic, conservation biology and ecosystem applications of NGS methods in the study of biodiversity. We also provide a to-date estimation of the associated costs for each approach and the computational implications for the analyses of sequences derived from these platforms.

"En este trabajo describimos la comunidad procarionte de una muestra de agua marina del canal de Yucatán. Para la determinación de la diversidad microbiana se usaron tres métodos moleculares: 1) T-RFLPs. 2) Secuenciación de amplicones (bibliotecas de clones). 3) Secuenciación shotgun de un metagenoma. Como un segundo objetivo, se presenta una comparación de los alcances y los límites de cada uno de estos tres métodos. Para esta comparación, se tomaron en cuenta tres criterios: el número de unidades taxonómicas detectadas, la precisión en la asignación taxonómica y el costo del estudio. Los taxa más abundantes fueron Candidatus Portiera OTU 3744 (equivalente al clado SAR86) y Candidatus Pelagibacter. Los resultados mostraron que la estrategia de secuenciación shotgun de ADN es la más poderosa en términos de unidades taxonómicas detectadas, mientras que los datos que se obtuvieron por T-RFLPs y con la biblioteca de clones, representan sólo una submuestra de la biblioteca de fragmentos generados mediante shotgun. En cuanto a resolución filogenética (determinación taxonómica), la aproximación más precisa fue la secuenciación de bibliotecas de clones. Los costos de las tres estrategias varían considerablemente, pero sus alcances también lo hacen. Por lo tanto, es importante tomar en consideración que algunas preguntas ecológicas y evolutivas sólo pueden ser contestadas específicamente por una u otra metodología."

BackgroundCloud forests, characterized by a persistent, frequent or seasonal low-level cloud cover and fragmented distribution, are one of the most threatened habitats, especially in the Neotropics. Tree ferns are among the most conspicuous elements in these forests, and ferns are restricted to regions in which minimum temperatures rarely drop below freezing and rainfall is high and evenly distributed around the year. Current phylogeographic data suggest that some of the cloud forest-adapted species remainedin situor expanded to the lowlands during glacial cycles and contracted allopatrically during the interglacials. Although the observed genetic signals of population size changes of cloud forest-adapted species including tree ferns correspond to predicted changes by Pleistocene climate change dynamics, the observed patterns of intraspecific lineage divergence showed temporal incongruence.MethodsHere we combined phylogenetic analyses, ancestral area reconstruction, and divergence time estimates with climatic and altitudinal data (environmental space) for phenotypic traits of tree fern species to make inferences about evolutionary processes in deep time. We used phylogenetic Bayesian inference and geographic and altitudinal distribution of tree ferns to investigate ancestral area and elevation and environmental preferences of Mesoamerican tree ferns. The phylogeny was then used to estimate divergence times and ask whether the ancestral area and elevation and environmental shifts were linked to climatic events and historical climatic preferences.ResultsBayesian trees retrievedCyathea, Alsophyla, GymnosphaeraandSphaeropterisin monophyletic clades. Splits for species in these genera found in Mesoamerican cloud forests are recent, from the Neogene to the Quaternary, Australia was identified as the ancestral area for the clades of these genera, except forGymnosphaerathat was Mesoamerica. Climate tolerance was not divergent from hypothesized ancestors for the most significant variables or elevation. For elevational shifts, we found repeated change from low to high elevations.ConclusionsOur data suggest that representatives of Cyatheaceae main lineages migrated from Australia to Mesoamerican cloud forests in different times and have persisted in these environmentally unstable areas but extant species diverged recentrly from their ancestors.