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Identifying the correlates of extinction can help prioritize species for conservation effort, an important step when developing effective conservation policies. Most previous studies on extinction vulnerability have been restricted to a single predictor within a specific region. To understand the mechanism underlying predictors of extinction risk, an examination of the contribution of various factors at different scales is an important step. We investigated the contribution of phylogeny, ploidy level, habitat breadth, and life form on both provincial and national conservation ranks of Alberta’s prairie ecoregion plant species. We collected data on conservation status, chromosome number, habitat breadth, and life form for 1274 species. We used phylogenetic comparative models to assess (1) the relative contribution, significance, and possible interaction of predictor variables in determining extinction vulnerability, and (2) the possible underlying mechanisms governing observed patterns of extinction vulnerability at the provincial and national level. We find that the contribution, significance, and predictive power of variables were often scale-dependent. While the impact of habitat breadth was significant at both provincial and national scales, ploidy and life form was only significant at the national and provincial level, respectively. We also found a significant negative interaction between ploidy and habitat breadth at both geographical scales, such that among widespread species (species with a higher habitat breadth), diploids are less likely to be at risk than polyploids. Our study reveals the importance of the study scale on the accuracy of extinction prediction. We also suggest that discriminating between regionally restricted and non-restricted species could improve the predictability of sub-global extinction patterns.

Land use change, by disrupting the co-evolved interactions between plants and their pollinators, could be causing plant reproduction to be limited by pollen supply. Using a phylogenetically controlled meta-analysis on over 2200 experimental studies and more than 1200 wild plants, we ask if land use intensification is causing plant reproduction to be pollen limited at global scales. Here we report that plants reliant on pollinators in urban settings are more pollen limited than similarly pollinator-reliant plants in other landscapes. Plants functionally specialized on bee pollinators are more pollen limited in natural than managed vegetation, but the reverse is true for plants pollinated exclusively by a non-bee functional group or those pollinated by multiple functional groups. Plants ecologically specialized on a single pollinator taxon were extremely pollen limited across land use types. These results suggest that while urbanization intensifies pollen limitation, ecologically and functionally specialized plants are at risk of pollen limitation across land use categories., An insufficient amount of pollen transfer by pollinators (pollen limitation) could reduce plant reproduction in human-impacted landscapes. Here the authors conduct a global meta-analysis and find that pollen limitation is high in urban environments and depends of plant traits such as pollinator dependency.

Understanding the mechanisms underlying plant responses to climate change is an important step towards developing effective mitigation strategies. Polyploidy is an important evolutionary trait that can influence the capacity of plants to adapt to climate change. The environmental flexibility of polyploids suggests their resiliency to climate change, however, such hypotheses have not yet received empirical evidence. To understand how ploidy level may influence response to climate change, we modeled the current and future distribution of 54 Crataegus species under moderate to severe environments and compared the range change between diploids and polyploids.The majority of studied species are predicted to experience considerable range expansion. We found a negative interaction between ploidy and ecoregions in determining the response to climate change. In extreme environments polyploids are projected to experience a higher range expansion than diploids with climate change, while the opposite is true for moderate environments.The range expansion of Crataegus species can be attributed to their tolerance for a wide range of environmental conditions. Despite higher tolerance of polyploids to extreme environments, they do not necessarily outperform diploids in moderate environments, which can be attributed to the varying nature of species interactions along a stress gradient.

Description, A global dataset shows that animal pollinators are crucial for reproduction in half of wild flowering plants., Despite evidence of pollinator declines from many regions across the globe, the threat this poses to plant populations is not clear because plants can often produce seeds without animal pollinators. Here, we quantify pollinator contribution to seed production by comparing fertility in the presence versus the absence of pollinators for a global dataset of 1174 plant species. We estimate that, without pollinators, a third of flowering plant species would produce no seeds and half would suffer an 80% or more reduction in fertility. Pollinator contribution to plant reproduction is higher in plants with tree growth form, multiple reproductive episodes, more specialized pollination systems, and tropical distributions, making these groups especially vulnerable to reduced service from pollinators. These results suggest that, without mitigating efforts, pollinator declines have the potential to reduce reproduction for most plant species, increasing the risk of population declines.

Although often not collected specifically for the purposes of conservation, herbarium specimens offer sufficient information to reconstruct parameters that are needed to designate a species as 'at-risk' of extinction. While such designations should prompt quick and efficient legal action towards species recovery, such action often lags far behind and is mired in bureaucratic procedure. The increase in online digitization of natural history collections has now led to a surge in the number new studies on the uses of machine learning. These repositories of species occurrences are now equipped with advances that allow for the identification of rare species. The increase in attention devoted to estimating the scope and severity of the threats that lead to the decline of such species will increase our ability to mitigate these threats and reverse the declines, overcoming a current barrier to the recovery of many threatened plant species. Thus far, collected specimens have been used to fill gaps in systematics, range extent, and past genetic diversity. We find that they also offer material with which it is possible to foster species recovery, ecosystem restoration, and de-extinction, and these elements should be used in conjunction with machine learning and citizen science initiatives to mobilize as large a force as possible to counter current extinction trends.

The persistence of pollinators in a given habitat is determined in part by traits that affect their response to environmental variables. Here, we show that climate and habitat features are the main drivers of trait distribution in bees across spatially separated habitats. We determined that trait and clade filtering results in bee assemblages in Western Canada exhibiting clustering that is correlated with differences in temperature, humidity, and rainfall. Phylogenetic signals were detected in all traits associated with pollinator life-history strategies, including phenology. The Bombus Latreille, 1802 clade (including the social parasite subgenus Psithyrus Lepeletier, 1833) comprised a higher proportion of prairie bees, whereas assemblages in Garry oak sites exhibited higher representation from solitary bees (e.g., genera Osmia Panzer, 1806, Andrena Fabricius, 1775, Ceratina Latreille, 1802). Because these same traits influence which plant species are pollinated, this selective environmental occupancy within the two different habitats could promote local adaptation of flowering plant species pollinated by more social clades in prairies and more solitary bees in Garry oak.

Climate change is causing rapid shifts in species’ range limits, leading to poleward expansions and range losses toward the equator. However, ‘climate debt’, the gap between required and realized range shifts under changing climates, can accumulate when species are unable to track shifting conditions sufficiently rapidly to keep pace with climate changes. Currently, we do not know the rate at which species will keep pace via dispersal to track their climate envelopes, yet understanding potential differences in climate debt is central to estimating how climate change will influence extinction risk. Here, we use historical observations of 155 butterfly species found in Canada to construct climate‐based environmental niche models for each species and then compare projections with observed modern distributions to quantify climate debts. This approach suggests that high levels of climate debt are accumulating within the vast majority of these species. Such failure to track changing climates may arise from some combination of interspecific interactions such as particular food availability for specialists, abiotic barriers such as mountain ranges, or species’ intrinsic dispersal capacities. Our linear models relating climate debt to a variety of biological predictors suggest that the debts we documented are accumulating independently of dispersal ability, diet breadth, and phylogeny. A proxy for range size is the only significant predictor of climate debt, with species with narrower ranges accumulating more debt: this suggests that species with narrow ranges may be at risk from both a reduction of suitable habitat in their current range and the failure to colonize newly available habitat. Identifying the factors, whether intrinsic or imposed by local environmental conditions, that limit species’ capacities to colonize areas beyond their historical limits is vital to conservation planning.

The relationship between range and diversification is an enduring evolutionary question. The rich angiosperm diversity stems from several factors including variations in geographical distribution and floral morphology, which tend to correlate with different pollinator preference in many taxa. Pollinator diversity varies among different regions, thus range shifts can play an important role in increasing divergence by predisposing clades to floral shifts. Antirrhineae is an ideal model to examine the effect of range shifts and pollination modes on diversification, because the tribe is distributed in the Old World and the New World with representatives exhibiting hummingbird pollination in the New World, and bee pollination in the Old World and the New World. Using ancestral reconstructions and phylogenetic modeling, this study investigated the effects of geographic distribution and pollination modes on the macroevolution of the tribe Antirrhineae. Our age-range correlation analysis showed young nodes had more range overlap than older nodes in the phylogeny, suggesting sympatric speciation as a contributing factor to the diversification of the tribe. We observed similar rates of diversification throughout time with no evident rate shifts within the tribe. Old World and New World lineages have similar speciation rates in Antirrhineae, and pollination mode did not have a significant effect on the diversification of the tribe. However, we found evidence for increased diversification rates through long-distance dispersal events, which occurred between the Old World and the New World four times throughout the evolutionary history of Antirrhineae. Therefore, we conclude that long-distance dispersal was a strong contributor to the diversity within Antirrhineae.

Because establishing a new population often depends critically on finding mates, individuals capable of uniparental reproduction may have a colonization advantage. Accordingly, there should be an over-representation of colonizing species in which individuals can reproduce without a mate, particularly in isolated locales such as oceanic islands. Despite the intuitive appeal of this colonization filter hypothesis (known as Baker's law), more than six decades of analyses have yielded mixed findings. We assembled a dataset of island and mainland plant breeding systems, focusing on the presence or absence of self-incompatibility. Because this trait enforces outcrossing and is unlikely to re-evolve on short timescales if it is lost, breeding system is especially likely to reflect the colonization filter. We found significantly more self-compatible species on islands than mainlands across a sample of > 1500 species from three widely distributed flowering plant families (Asteraceae, Brassicaceae and Solanaceae). Overall, 66% of island species were self-compatible, compared with 41% of mainland species. Our results demonstrate that the presence or absence of self-incompatibility has strong explanatory power for plant geographical patterns. Island floras around the world thus reflect the role of a key reproductive trait in filtering potential colonizing species in these three plant families.

Sexual system is a key determinant of genetic variation and reproductive success, affecting evolution within populations and within clades. Much research in plants has focused on evolutionary transitions away from the most common state of hermaphroditism and toward the rare state of dioecy (separate sexes). Rather than transitions predominantly toward greater sexual differentiation, however, evolution may proceed in the direction of lesser sexual differentiation. We analyzed the macroevolutionary dynamics of sexual system in angiosperm genera that contain both dioecious and nondioecious species. Our phylogenetic analyses encompass a total of 2145 species from 40 genera. Overall, we found little evidence that rates of sexual system transitions are greater in any direction. Counting the number of inferred state changes revealed a mild prevalence of transitions away from hermaphroditism and away from dioecy, toward states of intermediate sexual differentiation. We identify genera in which future studies of sexual system evolution might be especially productive, and we discuss how integrating genetic or population-level studies of sexual system could improve the power of phylogenetic comparative analyses. Our work adds to the evidence that different selective pressures and constraints act in different groups, helping maintain the variety of sexual systems observed among plants.

The role of pollination in the success of invasive plants needs to be understood because invasives have substantial effects on species interactions and ecosystem functions. Previous research has shown both that reproduction of invasive plants is often pollen limited and that invasive plants can have high seed production, motivating the questions: How do invasive populations maintain reproductive success in spite of pollen limitation? What species traits moderate pollen limitation for invaders? We conducted a phylogenetic meta-analysis with 68 invasive, 50 introduced noninvasive and 1931 native plant populations, across 1249 species. We found that invasive populations with generalist pollination or pollinator dependence were less pollen limited than natives, but invasives and introduced noninvasives did not differ. Invasive species produced 3× fewer ovules/flower and >250× more flowers per plant, compared with their native relatives. While these traits were negatively correlated, consistent with a tradeoff, this did not differ with invasion status. Invasive plants that produce many flowers and have floral generalisation are able to compensate for or avoid pollen limitation, potentially helping to explain the invaders' reproductive successes.

Plant reproduction relies on transfer of pollen from anthers to stigmas, and the majority of flowering plants depend on biotic or abiotic agents for this transfer. A key metric for characterizing if pollen receipt is insufficient for reproduction is pollen limitation, which is assessed by pollen supplementation experiments. In a pollen supplementation experiment, fruit or seed production by flowers exposed to natural pollination is compared to that following hand pollination either by pollen supplementation (i.e. manual outcross pollen addition without bagging) or manual outcrossing of bagged flowers, which excludes natural pollination. The GloPL database brings together data from 2969 unique pollen supplementation experiments reported in 927 publications published from 1981 to 2015, allowing assessment of the strength and variability of pollen limitation in 1265 wild plant species across all biomes and geographic regions globally. The GloPL database will be updated and curated with the aim of enabling the continued study of pollen limitation in natural ecosystems and highlighting significant gaps in our understanding of pollen limitation.

Gnetum (Gnetales) has long been regarded as insect pollinated due to its range-restricted distribution in tropical rain forests, where wind pollination is supposed to be detrimental. However, ubiquitous pollen limitation in the tropics might cause transition to anemophily, or even ambophily for reproductive assurance, especially for gymnosperms such as Gnetum, which exhibit various anemophilous syndromes, including absence of petals, greenish color of strobili, dioecy and uniovulate flowers. Pollination treatments applied to Gnetum parvifolium in southern China revealed this rare and endangered species to be pollen limited and incapable of apomixis. Pollen grains of G. parvifolium did not adhere to each other and could be trapped by interception traps near the male and female strobili. Seed set in the netted treatment (anemophily) was significantly higher than in the bagged treatment (apomixis) but lower than open pollination (anemophily and entomophily), indicating that both wind and biotic pollination contributed to seed production of G. parvifolium. The occurrence of ambophily in Gnetum and the prevalence of anemophily in Ehpedra and Welwitschia suggest that wind may also play a role in the pollination of the ancient Gnetales.

Dioecy, the sexual system in which male and female organs are found in separate individuals, allows greater specialization for sex-specific functions and can be advantageous under various ecological and environmental conditions. However, dioecy is rare among flowering plants. Previous studies identified contradictory trends regarding the relative diversification rates of dioecious lineages vs their nondioecious counterparts, depending on the methods and data used. We gathered detailed species-level data for dozens of genera that contain both dioecious and nondioecious species. We then applied a probabilistic approach that accounts for differential speciation, extinction, and transition rates between states to examine whether there is an association between dioecy and lineage diversification. We found a bimodal distribution, whereby dioecious lineages exhibited higher diversification in certain genera but lower diversification in others. Additional analyses did not uncover an ecological or life history trait that could explain a context-dependent effect of dioecy on diversification. Furthermore, in-depth simulations of neutral characters demonstrated that such bimodality is also found when simulating neutral characters across the observed trees. Our analyses suggest that - at least for these genera with the currently available data - dioecy neither consistently places a strong brake on diversification nor is a strong driver.

Species diversity is remarkably unevenly distributed among flowering plant lineages. Despite a growing toolbox of research methods, the reasons underlying this patchy pattern have continued to perplex plant biologists for the past two decades. In this review, we examine the present understanding of transitions in flowering plant evolution that have been proposed to influence speciation and extinction. In particular, ploidy changes, transitions between tropical and nontropical biomes, and shifts in floral form have received attention and have offered some surprises in terms of which factors influence speciation and extinction rates. Mating systems and dispersal characteristics once predominated as determining factors, yet recent evidence suggests that these changes are not as influential as previously thought or are important only when paired with range shifts. Although range extent is an important correlate of speciation, it also influences extinction and brings an applied focus to diversification research. Recent studies that find that past diversification can predict present-day extinction risk open an exciting avenue for future research to help guide conservation prioritization.

Areas hosting hotspots of low-latitude marginal populations of cold-adapted plant species could be key areas for understanding geographical attributes that result in refugia during climatic shifts as well as the conservation of genetic diversity in the face of climate change. Low-latitude populations of cold-adapted plants are important because they may harbour the combination of alleles that foster persistence in a warmer climate. Consequently, identification of areas where arctic-alpine, circumpolar and circumboreal species reach the low-latitude ends of their distribution will present a unique opportunity to uncover processes that shaped current biogeographical patterns, as well as prepare for future scenarios. Here, we identify 35 main marginal population hotspots (19 and 16 areas in North America and Europe, respectively) of 183 plant taxa. These hotspots represent areas where southern marginal populations of cold-adapted species co-occur. The identification of hotspots was based on geographic overlap of southernmost locations of the target species, in a 50×50km grid. With a threshold of two species in a single grid cell or in two contiguous cells, the analysis revealed that hotspots are in most cases located in the southern portion of major mountain chains. However, hotspots also occur in lowland areas at high latitudes (Fennoscandia, Alaska, Hudson Bay) which do not necessarily correspond to known cold- or warm-stage refugia (e.g. Alps). Rockies and Sierra Nevada both in California and Spain, Apennines, and the southern Scandes, maintain their hotspot status even with more stringent cut-off thresholds (>3 and >5 species per cell group). From a conservation point of view, our analysis reveals that only a small portion of the hotspots are currently included within protected areas. We discuss the importance of marginal population hotspots to future research on climate change and, finally, outline how conservation strategies can capitalize on the knowledge gained from studying climate change effects on cold-adapted plants.

A growing number of studies have reported an effect of invasive species on the pollination and reproductive success of co-flowering plants, over and above direct competition for resources. In this study, we investigate the effect of the invader Scotch broom (Cytisus scoparius) on the visitation, pollen deposition, and female reproductive output of three co-flowering species (two native, one exotic) of the critically endangered Garry oak grassland ecosystem on the Saanich peninsula of Vancouver Island. The presence of C. scoparius was largely neutral, with the exception of some facilitation of pollen deposition to the native Camassia leichtlinii, the one species exhibiting pollinator overlap with Scotch broom. Yet, this pattern occurred despite a decreased visitation rate from pollinators. There was little observed effect of the invader on the native Collinsia parviflora or the exotic Geranium molle. Because broom was not favourited by any of the observed pollinators, this study provides evidence that the spread of Scotch broom is not due to the reduction of pollination success of natives nor is C. scoparius likely to be facilitating the pollination of other exotics in Garry oak ecosystem remnants.

Plant-pollinator mutualisms can be disrupted in fragmented and isolated populations. Isolated populations attract fewer and less diverse pollinators, but it is not generally known whether this is due to reductions in the abundance and/or diversity of flowers at a site or to the biogeography of pollinators (or both). Islands represent one system potentially suitable to analyze the effects of spatial isolation. Here, we examine the contribution that differences in visitor composition make to increased selfing and seed production by examining the major visitors to Plectritis congesta in populations on the Gulf Islands and Vancouver Island. We find that (1) connectivity is more strongly associated with visitor assemblages and seed production than components of the floral community and (2) taking phylogeny into account suggests that increased visitation by solitary bees as opposed to other functional groups increases female fitness in P. congesta.

Floral nectar usually functions as a pollinator reward, yet it may also attract herbivores. However, the effects of herbivore consumption of nectar or nectaries on pollination have rarely been tested. We investigated Iris bulleyana , an alpine plant that has showy tepals and abundant nectar, in the Hengduan Mountains of SW China. In this region, flowers are visited mainly by pollen-collecting pollinators and nectarivorous herbivores. We tested the hypothesis that, in I. bulleyana , sacrificing nectar and nectaries to herbivores protects tepals and thus enhances pollinator attraction. We compared rates of pollination and herbivory on different floral tissues in plants with flowers protected from nectar and nectary consumption with rates in unprotected control plants. We found that nectar and nectaries suffered more herbivore damage than did tepals in natural conditions. However, the amount of tepal damage was significantly greater in the flowers with protected nectaries than in the controls; this resulted in significant differences in pollinator visitation rates. These results provide the first evidence that floral nectar and nectaries may be ‘sacrificed’ to herbivores, leading to reduced damage to other floral tissues that are more important for reproduction.

Floral nectar usually functions as a pollinator reward, yet it may also attract herbivores. However, the effects of herbivore consumption of nectar or nectaries on pollination have rarely been tested. We investigated Iris bulleyana, an alpine plant that has showy tepals and abundant nectar, in the Hengduan Mountains of SW China. In this region, flowers are visited mainly by pollen-collecting pollinators and nectarivorous herbivores. We tested the hypothesis that, in I. bulleyana, sacrificing nectar and nectaries to herbivores protects tepals and thus enhances pollinator attraction. We compared rates of pollination and herbivory on different floral tissues in plants with flowers protected from nectar and nectary consumption with rates in unprotected control plants. We found that nectar and nectaries suffered more herbivore damage than did tepals in natural conditions. However, the amount of tepal damage was significantly greater in the flowers with protected nectaries than in the controls; this resulted in significant differences in pollinator visitation rates. These results provide the first evidence that floral nectar and nectaries may be ‘sacrificed’ to herbivores, leading to reduced damage to other floral tissues that are more important for reproduction.

The vast diversity of floral colours in many flowering plant families, paired with the observation of preferences among pollinators, suggests that floral colour may be involved in the process of speciation in flowering plants. While transitions in floral colour have been examined in numerous genera, we have very little information on the consequences of floral colour transitions to the evolutionary success of a clade. Overlaid upon these patterns is the possibility that certain floral colours are more prevalent in certain environments, with the causes of differential diversification being more directly determined by geographical distribution. Here we examine transition rates to anthocyanin + carotenoid rich (red/orange/fuschia) flowers and examine whether red/orange flowers are associated with differences in speciation and/or extinction rates in Mimulus. Because it has been suggested that reddish flowers are more prevalent at high elevation, we also examine the macroevolutionary evidence for this association and determine if there is evidence for differential diversification at high elevations. We find that, while red/orange clades have equivalent speciation rates, the trait state of reddish flowers reverts more rapidly to the nonreddish trait state. Moreover, there is evidence for high speciation rates at high elevation and no evidence for transition rates in floral colour to differ depending on elevation.

While pollinators are widely acknowledged as important contributors to seed production in plant communities, we do not yet have a good understanding of the importance of pollinator specialists for this ecosystem service. Determination of the prevalence of pollinator specialists is often hindered by the occurrence of cryptic species and the limitations of observational data on pollinator visitation rates, two areas where DNA barcoding of pollinators and pollen can be useful. Further, the demonstrated adequacy of pollen DNA barcoding from historical records offers opportunities to observe the effects of pollinator loss over longer timescales, and phylogenetic approaches can elucidate the historical rates of extinction of specialist lineages. In this Viewpoint article, we review how advances in DNA barcoding and metabarcoding of plants and pollinators have brought important developments to our understanding of specialization in plant-pollinator interactions. We then put forth several lines of inquiry that we feel are especially promising for providing insight on changes in plant-pollinator interactions over space and time. Obtaining estimates of the effects of reductions in specialists will contribute to forecasting the loss of ecosystem services that will accompany the erosion of plant and pollinator diversity.

Background: Plant species in biodiversity hotspots suffer more from pollen limitation than those in lower diversity regions, though this pattern is largely restricted to self-incompatible species. It is unknown whether higher pollen limitation is due to increased pollinator sharing or declines in pollinator abundance. Aims: Macroecological examinations of pollen limitation have been challenged by statistical confounds of phylogenetic non-independence and interrelationships between variables. Here, we perform phylogenetically corrected analyses of pollen limitation, examining an ensemble dataset of endemicity, abundance, species diversity, breeding system, floral symmetry, and pollinator richness. Methods: We apply model selection and path analysis to a large dataset of published studies of pollen limitation on 275 plant species distributed worldwide. Results: Plant diversity and breeding system were included in the best model. Even the best model explained only 13% of the among-species variation in pollen...

Increased human land use has resulted in the increased homogenization of biodiversity between sites, yet we lack sufficient indicators to predict which species decline and the consequence of their potential loss on ecosystem services. We used comparative phylogenetic analysis to (1) characterize how increasing conversion of forest and grasslands to grazing pasturelands changes plant diversity and composition; (2) examine how changes in land use relate to declines in functional trait diversity; and (3) specifically investigate how these changes in plant composition affect the prevalence of zygomorphy and the possible consequences that these changes may have on pollinator functional groups. As predicted, we found that the conversion to grazing pasturelands negatively impacted species richness and phylogenetic composition. Clades with significantly more represented taxa in grasslands (GL) were genera with a high representation of agricultural weeds, while the composition was biased towards clades of subalpine herbaceous wildflowers in Mixed Forest (MF). Changes in community composition and structure had strong effects on the prevalence of zygomorphic species likely driven by nitrogen-fixing abilities of certain clades with zygomorphic flowers (e.g., Fabaceae). Land conversion can thus have unexpected impacts on trait distributions relevant for the functioning of the community in other capacities (e.g., cascading effects to other trophic levels (i.e., pollinators). Finally, the combination of traits represented by the current composition of species in GL and MF might enhance the diagnostic value of productivity and ecosystem processes in the most eroded ecosystems.

Floral colors are widely believed to be an adaptation to attract pollinators. Recently, our understanding of floral reflectance has broadened to include colors that are beyond the spectrum that human eyes can perceive (such as ultraviolet (UV) reflectance), yet we still know relatively little about which plant species reflect UV light or its effectiveness in attracting pollinators. We investigated the effect of UV reflectance in Mimulus guttatus in a number of different populations in British Columbia, Canada. We found that M. guttatus had distinct regions of the corolla where UV light was reflected and absorbed. When we manipulated the degree of contrast between the reflection and absorption area, we found that pollinator visitation was severely disrupted, in terms of frequency and foraging patterns observed. Despite the bright yellow (bee-green) coloration and visible nectar guides in M. guttatus, we conclude that UV reflectance is critical in pollinator attraction.

PREMISE OF THE STUDY Antirrhineae is a large tribe within Plantaginaceae. Mostly concentrated in the Mediterranean Basin, the tribe members are present both in the Old World and the New World. Current Antirrhineae phylogenies have different views on taxonomic relationships, and they lack homogeneity in terms of geographic distribution and ploidy levels. This study aims to investigate the changes in the chromosome numbers along with dispersal routes as definitive characters identifying clades. METHODS With the use of multiple DNA regions and taxon sampling enriched with de novo sequences, we provide an extensive phylogeny for Antirrhineae. The reconstructed phylogeny was then used to investigate changes in ploidy levels and dispersal patterns in the tribe using ChromEvol and RASP, respectively. KEY RESULTS Antirrhineae is a monophyletic group with six highly supported clades. ChromEvol analysis suggests the ancestral haploid chromosome number for the tribe is six, and that the tribe has experienced several duplications and gain events. The Mediterranean Basin was estimated to be the origin for the tribe with four long-distance dispersals from the Old World to the New World, three of which were associated with genome duplications. CONCLUSIONS On an updated Antirrhineae phylogeny, we showed that the three out of four dispersals from the Old World to the New World were coupled with changes in ploidy levels. The observed patterns suggest that increases in ploidy levels may facilitate dispersing into new environments.

Current evidence suggests that plants in biodiversity hotspots suffer more from pollen limitation of reproduction than those in lower diversity regions, primarily due to the response of self-incompatible species. Species in biodiversity hotspots may thus be more at risk of limited reproduction and subsequent population decline. Should these species have restricted ranges (i.e. be endemics to a certain region), pollen limitation within highly diverse regions may pose an important threat to global plant biodiversity. We further dissect the global pattern by exploring whether pollen limitation of range-restricted (endemic) species is distinctive and/or relates differently to species diversity than that of widespread (non-endemic) species. To provide a preliminary test of this prediction we conducted both cross-species and comparative phylogenetic meta-analyses to determine the effect of endemism on the magnitude of pollen limitation and its relationship with regional species richness. Our data set included 287 plant species belonging to 78 families distributed world-wide. Our results revealed that endemism and self-compatibility contribute to the global association between pollen limitation and species richness. Self-incompatible species were more pollen limited than self-compatible ones, and the PICs analysis indicated that transitions to endemism were associated with transitions to self-compatibility. The relationship between pollen limitation and species richness was significant only for the self-incompatible species, and was monotonically increasing in non-endemic species but accelerating in the endemic species. Thus, self-incompatible endemic species from biodiversity hotspots are at the greatest risk of pollination failure, a previously unknown aspect suggesting this group of species as a top priority for future development of conservation strategies. In contrast, reproduction of self-compatible species appears to be unrelated to plant diversity, although we caution that current data do not account for the reproductive limitation due to the quality of pollen received. Understanding the mechanisms underlying these patterns requires further investigation into plant-plant pollinator mediated interactions and the dynamics of pollen transfer in communities differing in species diversity. © 2009 The Authors.

Few studies have examined how the number and identity of species in the neighbouring community influences the reproductive success of particular focal species. Pollen delivery, an important component of fitness of sexual plants, is a function of not just the floral traits of any particular individual, but of features of the population and community as it depends on pollinator abundance and preferences. Many pollinators in flowering communities will prefer patches with high floral abundance or diversity yet may exhibit lower floral constancy when more flowering species are present. Thus, pollination efficiency could increase or decrease with increased species richness and this will alter the selection pressures placed upon the floral traits (such as floral colour or reward) of any member of a particular community. Moreover, recent studies have indicated that plant-pollinator networks are phylogenetically structured (pollinators visit related plant species more than expected by chance) and this may be an important factor structuring flowering plant communities. Thus, the sheer number of species within a patch may be less important than the number of closely-related species. We investigate whether species richness or phylogenetic proximity of coflowering species influences the amount and proportion of conspecific pollen delivered to nodding onion, Allium cernuum, in fragment patches of Garry Oak meadows in South Western British Columbia, Canada. We find that pollen delivery depended upon the presence of close relatives far more than on species richness or population density, indicating a central role of the community structure on pollination in flowering plant communities. Insofar as pollen delivery relates to the relative number of seeds produced by members of the community, pollination may in turn determine the community structure of the next generation.

Worldwide, humans have access to a greater range of food plants than does any other species. Examination of phylogenetic patterns in plants consumed by animals has recently uncovered important ecological processes. The same techniques, however, have not been applied to our own species. Here we show that although humans tend to eat more species in certain families (e.g., Rosaceae) and fewer in others (e.g., Orchidaceae), the proportion of edible species in most families is similar to random expectations. Phylogenetic patterning in angiosperm edibility is also weak. We argue that the remarkable breadth of the human diet is the result of humans' huge geographic range, diverse food-collection methods, and ability to process normally inedible items. Humans are thus generalist feeders in the broadest sense. Cross-cultural analyses of diversity in the plant diet of humans could represent a fascinating new field of research linking ecology, anthropology, history, and sociology.

Because of the separation of sexual function to male and female individuals, dioecious species have fewer pollen and seed bearers and thus experience disadvantages due to increased aggregation of reproductive function. Because of this disadvantage, models predict that dioecious females must have substantially more than twice the fecundity of hermaphrodites, yet empirical data suggest that female fecundity advantages are commonly much lower. Here, we incorporate animal foraging dynamics--and the heightened dispersal of seeds that may accompany increases in fecundity of dioecious females--into a spatially explicit mathematical model. We focus on the competition for germination sites with varying seed production, seed dispersal ability, and mortality, and we find that preferential foraging on dioecious females reduces the stringent fecundity requirements of dioecy to values in accordance with empirical estimates. This finding contributes to our understanding of the correlation between dioecy and fleshy fruits and highlights the importance of mutualist dispersers to dioecious species.

Species richness and body size often vary predictably along latitudinal and elevational gradients. Although these patterns have been well documented for a variety of taxa, the vast majority of studies have focused on terrestrial plants and animals. We used species lists of predaceous diving beetles (Coleoptera: Dytiscidae) collected from >400 lentic water bodies in southern Alberta to investigate the influences of latitude and elevation on species richness and body size. Because our data were based on species lists, we used proportion of, and probability of encountering at least one, large (i.e., mean body length >10 mm) diving beetle species as surrogates for the mean body size of diving beetles in a given water body. Species richness did not change with latitude and displayed a hump-shaped relationship with elevation, peaking at mid-elevations. High elevation (>2000 m) water bodies had markedly low species richness. Proportion of large species increased with latitude, although there was no effect on probability of occupancy by large species. Conversely, both measures tended to decrease with elevation, suggesting that large species are less prevalent at high elevations. We discuss potential factors contributing to the observed responses to latitude and elevation, with an emphasis on the potential impacts of oxygen limitation, productivity, and isolation at high elevation.

Baker's law refers to the tendency for species that establish on islands by long-distance dispersal to show an increased capacity for self-fertilization because of the advantage of self-compatibility when colonizing new habitat. Despite its intuitive appeal and broad empirical support, it has received substantial criticism over the years since it was proclaimed in the 1950s, not least because it seemed to be contradicted by the high frequency of dioecy on islands. Recent theoretical work has again questioned the generality and scope of Baker's law. Here, we attempt to discern where the idea is useful to apply and where it is not. We conclude that several of the perceived problems with Baker's law fall away when a narrower perspective is adopted on how it should be circumscribed. We emphasize that Baker's law should be read in terms of an enrichment of a capacity for uniparental reproduction in colonizing situations, rather than of high selfing rates. We suggest that Baker's law might be tested in four different contexts, which set the breadth of its scope: the colonization of oceanic islands, metapopulation dynamics with recurrent colonization, range expansions with recurrent colonization, and colonization through species invasions.

Polyploidy has been described both as an evolutionary dead end and as a major engine of diversification for angiosperms. Two recent studies have found that genera with higher proportions of polyploid species are more species rich. Here, we investigate patterns of diversification and polyploidy by performing traditional and phylogenetically corrected analyses within the Rosaceae. We find that polyploidy is associated with increased species richness and then differentiate between three alternative hypotheses for this pattern: (1) that polyploidy is associated with herbaceous growth habit, a trait that is in turn associated with increased species richness; (2) that polyploid clades are more evolutionarily successful (i.e., experience increased speciation and/or fewer extinction events) than diploid clades, perhaps because of the increase in genomic content or the increase in plant/flower size that often accompanies polyploidization; and (3) that the polyploidization events themselves, along with the reproduc...

▪ Abstract Quantifying the extent to which seed production is limited by the availability of pollen has been an area of intensive empirical study over the past few decades. Whereas theory predicts that pollen augmentation should not increase seed production, numerous empirical studies report significant and strong pollen limitation. Here, we use a variety of approaches to examine the correlates of pollen limitation in an effort to understand its occurrence and importance in plant evolutionary ecology. In particular, we examine the role of recent ecological perturbations in influencing pollen limitation and discuss the relation between pollen limitation and plant traits. We find that the magnitude of pollen limitation observed in natural populations depends on both historical constraints and contemporary ecological factors.

Dioecious clades have been observed to have lower species richness than their non-dioecious sister groups indicating that dioecious species experience higher extinction rates and (or) lower speciation rates. To determine whether current threats to biodiversity may exacerbate this pattern, we examined the threat to exclusively dioecious families of angiosperms among the 13,013 species of threatened plants included in the IUCN Red List of Threatened Species. When examined phylogenetically, dioecious families had proportionally more species listed than their sister groups. We then examined whether ecological traits correlated with dioecy, namely tropical distribution, woody growth form, and fleshy fruits, are associated with having higher proportions of threatened species. Ignoring breeding system, woody growth form was the only trait that was associated with a greater than expected proportion of threatened species per family. Red-Listed dioecious families were more likely to have a woody growth form than non-dioecious families. Woody growth habit is likely contributing to the higher incidence of dioecious species being at risk of extinction but is not solely responsible for the pattern because higher risk within dioecious groups was also apparent in a comparison of exclusively woody sister-group pairs. Our results indicate that dioecious plants may warrant special attention in conservation practices.

Dioecy is reported to be correlated with a number of ecological traits, including tropical distribution, woody growth form, plain flowers, and fleshy fruits. Previous analyses have concentrated on determining whether dioecy is more likely to evolve in lineages possessing these traits, rather than considering the speciation and extinction rates of dioecious lineages with certain combinations of traits. To address the association between species richness in dioecious lineages as a function of the ecological traits, we compared the evolutionary success (i.e., relative species richness) of dioecious focal lineages with that of their nondioecious sister groups. This test was repeated for the evolutionary success of randomly chosen nondioecious lineages (control lineages) compared with their nondioecious sister groups. If the possession of certain ecological traits enhances the evolutionary success of dioecious lineages, we predict an association between the presence of these traits and relative species richness in the former, but not latter, set of sister-group comparisons. Dioecious focal lineages with a higher number of these traits experienced higher evolutionary success in sister-group comparisons, whereas no trend was found for the control focal lineages. The increase in evolutionary success was especially true for dioecious focal lineages that had a tropical distribution or fleshy fruit. We discuss how these results provide strong support for differential evolutionary success theories for the correlations between dioecy and the ecological traits considered.

We report on a phylogenetic analysis of correlations between the occurrence of dioecy and several ecological and life-history attributes: tropical distribution, woody growth form, abiotic pollination, small inconspicuous flowers and inflorescences, many-flowered inflorescences and fleshy fruits. Various hypotheses have been proposed to explain why associations occur between dioecy and several of these attributes, yet most assume that dioecy originates more often in clades with these traits than in clades with alternative character states. To investigate correlations between dioecy and these attributes, and to provide insights into the potential evolutionary pathways that have led to these associations, we assigned states of these traits to genera on a large-scale molecular phylogeny of the angiosperms; we then used maximum-likelihood analysis to analyse the presence of correlations and the sequence of acquisition of traits. Phylogenetic analysis revealed correlations between dioecy and six of the seven attributes; only many-flowered inflorescences exhibiting no association with the dioecious condition. The particular correlations that were revealed and the strength of the association differed among the three main monophyletic groups of angiosperms (Rosids, Asterids, and Eumagnoliids). Our analysis provided no general support for the hypothesis that dioecy is more likely to evolve in lineages already possessing the seven attributes we considered. Further analysis of the intercorrelations of the seven attributes provided evidence for non-independence between some of the traits, implying that functional associations among these traits have influenced the ecology and evolution of dioecious species.

This paper presents the results of a consensus-driven process identifying 50 priority research questions for historical ecology obtained through crowdsourcing, literature reviews, and in-person workshopping. A deliberative approach was designed to maximize discussion and debate with defined outcomes. Two in-person workshops (in Sweden and Canada) over the course of two years and online discussions were peer facilitated to define specific key questions for historical ecology from anthropological and archaeological perspectives. The aim of this research is to showcase the variety of questions that reflect the broad scope for historical-ecological research trajectories across scientific disciplines. Historical ecology encompasses research concerned with decadal, centennial, and millennial human-environmental interactions, and the consequences that those relationships have in the formation of contemporary landscapes. Six interrelated themes arose from our consensus-building workshop model: (1) climate and environmental change and variability; (2) multi-scalar, multi-disciplinary; (3) biodiversity and community ecology; (4) resource and environmental management and governance; (5) methods and applications; and (6) communication and policy. The 50 questions represented by these themes highlight meaningful trends in historical ecology that distill the field down to three explicit findings. First, historical ecology is fundamentally an applied research program. Second, this program seeks to understand long-term human-environment interactions with a focus on avoiding, mitigating, and reversing adverse ecological effects. Third, historical ecology is part of convergent trends toward transdisciplinary research science, which erodes scientific boundaries between the cultural and natural.

Interaction webs, or networks, define how the members of two or more trophic levels interact. However, the traits that mediate network structure have not been widely investigated. Generally, the mechanism that determines plant-pollinator partnerships is thought to involve the matching of a suite of species traits (such as abundance, phenology, morphology) between trophic levels. These traits are often unknown or hard to measure, but may reflect phylogenetic history. We asked whether morphological traits or phylogenetic history were more important in mediating network structure in mutualistic plant-pollinator interaction networks from Western Canada. At the plant species level, sexual system, growth form, and flower symmetry were the most important traits. For example, species with radially symmetrical flowers had more connections within their modules (a subset of species that interact more among one another than outside of the module) than species with bilaterally symmetrical flowers. At the pollinator species level, social species had more connections within and among modules. In addition, larger pollinators tended to be more specialized. As traits mediate interactions and have a phylogenetic signal, we found that phylogenetically close species tend to interact with a similar set of species. At the network level, patterns were weak, but we found increasing functional trait and phylogenetic diversity of plants associated with increased weighted nestedness. These results provide evidence that both specific traits and phylogenetic history can contribute to the nature of mutualistic interactions within networks, but they explain less variation between networks.

The vast majority of eukaryotic organisms reproduce sexually, yet the nature of the sexual system and the mechanism of sex determination often vary remarkably, even among closely related species. Some species of animals and plants change sex across their lifespan, some contain hermaphrodites as well as males and females, some determine sex with highly differentiated chromosomes, while others determine sex according to their environment. Testing evolutionary hypotheses regarding the causes and consequences of this diversity requires interspecific data placed in a phylogenetic context. Such comparative studies have been hampered by the lack of accessible data listing sexual systems and sex determination mechanisms across the eukaryotic tree of life. Here, we describe a database developed to facilitate access to sexual system and sex chromosome information, with data on sexual systems from 11,038 plant, 705 fish, 173 amphibian, 593 non-avian reptilian, 195 avian, 479 mammalian, and 11,556 invertebrate species.

Summary: Species community composition is known to alter the network of interactions between two trophic levels, potentially affecting its functioning (e.g. plant pollination success) and the stability of communities. Phylogenies vary in shape with regard to the rate of evolutionary change across a tree (influencing tree balance) and variation in the timing of branching events (affecting the distribution of node ages in trees), both of which may influence the structure of species interaction networks. Because related species are likely to share many of the traits that regulate interactions, the shape of phylogenetic trees may provide some insights into the distribution of traits within communities, and hence the likelihood of interaction among species. However, little attention has been paid to the potential effects of changes in phylogenetic diversity (PD) on interaction networks. Phylogenetic diversity is influenced by species diversity within a community, but also how distantly-related the constituent species are from one another. Here, we evaluate the relationship between two important measures of phylogenetic diversity (tree shape and age of nodes) and the structure of plant-pollinator interaction networks using empirical and simulated data. Whereas the former allows us to evaluate patterns in real communities, the latter allows us to evaluate more systematically the relationship between tree shape and network structure under three different models of trait evolution. In empirical networks, less balanced plant phylogenies were associated with lower connectance in interaction networks indicating that communities with the descendants of recent radiations are more diverged and specialized in their partnerships. In simulations, tree balance and the distribution of nodes through time were included in the best models for modularity, and the second best models for connectance and nestedness. In models assuming random evolutionary change through time (i.e. Brownian motion), less balanced trees and trees with nodes near the tips exhibited greater modularity, whereas in models with an early burst of radiation followed by relative stasis (i.e. early-burst models) more balanced trees and trees with nodes near roots had greater modularity. Synthesis. Overall, these results suggest that the shape of phylogenies can influence the structure of plant-pollinator interaction networks. However, the mismatch between simulations and empirical data indicate that no simple model of trait evolution mimics that observed in real communities. Fil: Chamberlain, Scott. University Fraser Simon; Canadá Fil: Vazquez, Diego P.. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mendoza. Instituto Argentino de Investigaciones de las Zonas Áridas. Provincia de Mendoza. Instituto Argentino de Investigaciones de las Zonas Áridas. Universidad Nacional de Cuyo. Instituto Argentino de Investigaciones de las Zonas Áridas; Argentina. Universidad Nacional de Cuyo. Facultad de Ciencias Exactas y Naturales; Argentina Fil: Carvalheiro, Luisa. University Of Leeds; Reino Unido. Naturalis Biodiversity Center; Países Bajos Fil: Elle, Elizabeth. University Fraser Simon; Canadá Fil: Vamosi, Jaca C.. University of Calgary; Canadá

Understanding the evolution of specialization in host plant use by pollinators is often complicated by variability in the ecological context of specialization. Flowering communities offer their pollinators varying numbers and proportions of floral resources, and the uniformity observed in these floral resources is, to some degree, due to shared ancestry. Here, we find that pollinators visit related plant species more so than expected by chance throughout 29 plant–pollinator networks of varying sizes, with “clade specialization” increasing with community size. As predicted, less versatile pollinators showed more clade specialization overall. We then asked whether this clade specialization varied with the ratio of pollinator species to plant species such that pollinators were changing their behavior when there was increased competition (and presumably a forced narrowing of the realized niche) by examining pollinators that were present in at least three of the networks. Surprisingly, we found little evidence that variation in clade specialization is caused by pollinator species changing their behavior in different community contexts, suggesting that clade specialization is observed when pollinators are either restricted in their floral choices due to morphological constraints or innate preferences. The resulting pollinator sharing between closely related plant species could result in selection for greater pollinator specialization.

Ten years after DNA barcoding was initially suggested as a tool to identify species, millions of barcode sequences from more than 1100 species are available in public databases. While several studies have reviewed the methods and potential applications of DNA barcoding, most have focused on species identification and discovery, and relatively few have addressed applications of DNA barcoding data to ecology. These data, and the associated information on the evolutionary histories of taxa that they can provide, offer great opportunities for ecologists to investigate questions that were previously difficult or impossible to address. We present an overview of potential uses of DNA barcoding relevant in the age of ecoinformatics, including applications in community ecology, species invasion, macroevolution, trait evolution, food webs and trophic interactions, metacommunities, and spatial ecology. We also outline some of the challenges and potential advances in DNA barcoding that lie ahead.

The tremendous variation in species richness observed among related clades across the tree of life has long caught the imagination of biologists. Recently, there has been growing attention paid to the possible contribution of range size variation, either alone or in combination with putative key innovations, to these patterns. Here, we review three related topics relevant to range size evolution, speciation, and extinction. First, we provide a brief overview of the debate surrounding patterns and mechanisms for phylogenetic signal in range size. Second, we discuss some recent findings regarding the joint influence of traits and range size on diversification. Finally, we present the preliminary results of a study investigating whether range size is negatively correlated with contemporary extinction risk in flowering plants.