Plant Biogeography Research Articles

Plant biogeography of rock outcrops in South American tropical lowlands

Studies of rock outcrops in tropical South America have increased in recent years, but they have often been restricted to individual countries, single biomes or single disciplines (e.g. through a floristic, functional or genetic lens), limiting their generality. We review the current state of knowledge on the geological and floristic diversity of rock outcrops in tropical South America to identify knowledge gaps and generate testable hypotheses for future research into the biogeography and evolution of their plant communities. We find that the diversity of lowland rock outcrop vegetation is disparately documented and we know less about the evolutionary and biogeographic history of these island-like systems. Based on geological and edaphic factors, we classify South American rock outcrops into four main groups: granite/gneiss, quartzite/metamorphosed sandstone, limestone and ironstone. We hypothesise that these lithologies influence the floristic and evolutionary lineage composition of outcrop floras. However, elevation also plays a role through creating microclimatic conditions and by influencing the degree of insularity from the surrounding vegetation. Our literature review suggests that these lithologies support different floras, but confirming this requires further floristic surveys across the full geological diversity of outcrops. We suggest a research framework to: (i) improve knowledge of outcrop floras and how they relate to floras of surrounding biomes; (ii) investigate the relative roles of niche conservatism and evolution using floristic and phylogenetic approaches; and (iii) assess how outcrop species cope with living in naturally fragmented habitats through analysis of recruitment and gene flow using population genetics. Understanding the biogeography of rock outcrop floras can help provide information for conservation planning and decisions. Rock outcrops are in urgent need of study because they possess a distinctive and highly specialised flora that is threatened by climate and land-use changes. There is a need to increase the number of studies in some Latin American countries (e.g. Bolivia, Paraguay, Guyana, French Guiana and Suriname) and lithologies (e.g. limestone). We suggest that the major determinant of floristic composition on rock outcrops is lithology and outline how this can be tested using community-level floristic data. Inferring the phylogenetic relationships of the species endemic to rock outcrops and establishing the environments where their closest relatives occur will be a powerful approach to address questions of niche evolution and niche conservatism in the historical assembly of outcrop floras. Population genetic approaches focusing on plant species that occur both in outcrop habitats and the surrounding vegetation will elucidate their connectivity and, therefore, how insular and vulnerable these environments are.

Tracking hidden dimensions of plant biogeography from herbaria.

Plants are diverse, but investigating their ecology and evolution in nature across geographic and temporal scales to predict how species will respond to global change is challenging. With their geographic and temporal breadth, herbarium data provide physical evidence of the existence of a species in a place and time. The remarkable size of herbarium collections along with growing digitization efforts around the world and the possibility of extracting functional traits and geographic data from preserved plant specimens makes them invaluable resources for advancing our understanding of changing species distributions over time, functional biogeography, and conserving plant communities. Here, I synthesize core aspects of plant biogeography that can be gleaned from herbaria along changing distributions, attributes (functional biogeography), and conservation biogeography across the globe. I advocate for a collaborative, multisite, and multispecies research to harness the full potential of these collections while addressing the inherent challenges of using herbarium data for biogeography and macroecological investigations. Ultimately, these data present untapped resources and opportunities to enable predictions of plant species' responses to global change and inform effective conservation planning.

Phylogenetic origin of dioecious Callicarpa (Lamiaceae) species endemic to the Ogasawara Islands revealed by chloroplast and nuclear whole genome analyses.

Phylogenetic origin of dioecious Callicarpa (Lamiaceae) species endemic to the Ogasawara Islands revealed by chloroplast and nuclear whole genome analyses.

Plant biogeography, endemism and vegetation types of Dena Mts, Zagros, West Iran

Questions: The highest mountain peak of Zagros is located in the Dena mountain system (4409 m a.s.l.), which is identified as the second richest center of plant endemism of Zagros. In this study we (1) investigate floristic affinities of Dena Mts to adjacent mountain ranges based on the endemic species of the Iranian Plateau, (2) identify the species reaching the subnival zone, and (3) characterize the plant communities of the subnival zone of Dena Mts. Study area: Dena Mts is a calcareous mountain system in southern Zagros, Iran. Methods: The list of taxa endemic to the Iranian Plateau present also in Dena Mts was taken from our previously published data. Novel vegetation data were collected using the methodology of Braun-Blanquet. Classification was carried out in JUICE using the Modified TWINSPAN method. Results: Of the 242 taxa endemic to the Iranian Plateau present in Dena Mts, 22 taxa are endemic to the latter. Dena Mts have the strongest floristic affinity with the Yazd-Kerman massif, with which they share 84 taxa compared to 51 taxa shared with Alborz, 37 taxa shared with the Azerbaijan Plateau, and 15 taxa shared with Kopet Dagh-Khorassan. In Dena Mts, 38 taxa reach the subnival zone, most of them being endemic to the Iranian Plateau (68%). From scree habitats in the subnival zone, two new plant associations are described, Aethionemetum umbellati and Zerdanetum anchonioidei. These constitute a newly described alliance Galion pseudokurdici, classified within the class Didymophyso aucheri-Dracocephaletea aucheri. Conclusions: Although Dena Mts lie within a protected area, this will not prevent shrinking of alpine and subnival habitats due to global warming. Consequently, strong attention to the conservation of all range-restricted species of this mountain system, especially of alpine and subnival species, is highly recommended. Taxonomic reference: Flora of Iran (Assadi et al. 1989–2021) and, for families not yet covered in the previous source, Flora Iranica (Rechinger 1963–2015).

Darwin’s Digestion Myth: Historical and Modern Perspectives on Our Understanding of Seed Dispersal by Waterbirds

Internal transport (endozoochory) and external transport (epizoochory) by migratory waterbirds are key mechanisms of long-distance dispersal for seeds and other diaspores of plants lacking a fleshy fruit. Beginning with Darwin in 1859, we review how opinions about the relative importance of epizoochory and endozoochory have changed repeatedly over time and how this allows us to reassess our modern understanding of plant dispersal. Darwin was mistaken in asserting that diaspores cannot survive passage through the gut of waterbirds or other granivorous birds. This “digestion myth” led him to underestimate endozoochory and overstate the importance of epizoochory, an approach which is echoed throughout the literature until the present day. Darwin also focused on aquatic plants, yet it is now clear that waterbirds are also major vectors of terrestrial plants. Based on their empirical observations and experiments, other less influential scientists (notably Hesselman in 1897, Guppy in 1906 and Proctor in the 1960s) argued that endozoochory is the more important mechanism for waterbirds. Modern field and experimental studies demonstrate the dominant role for endozoochory. Unfortunately, avian endozoochory of dry-fruited plants continues to be ignored as a dispersal mechanism by many plant ecologists, which we attribute to Darwin’s continuing influence. However, this endozoochory has major implications for plant biogeography and requires wider recognition and research.

Investigating historical drivers of latitudinal gradients in polyploid plant biogeography: A multiclade perspective.

The proportion of polyploid plants in a community increases with latitude, and different hypotheses have been proposed about which factors drive this pattern. Here, we aimed to understand the historical causes of the latitudinal polyploidy gradient using a combination of ancestral state reconstruction methods. Specifically, we assessed whether (1) polyploidization enables movement to higher latitudes (i.e., polyploidization precedes occurrences in higher latitudes) or (2) higher latitudes facilitate polyploidization (i.e., occurrence in higher latitudes precedes polyploidization). We reconstructed the ploidy states and ancestral niches of 1032 angiosperm species at four paleoclimatic time slices ranging from 3.3 million years ago to the present, comprising taxa from four well-represented clades: Onagraceae, Primulaceae, Solanum (Solanaceae), and Pooideae (Poaceae). We used ancestral niche reconstruction models alongside a customized discrete character evolution model to allow reconstruction of states at specific time slices. Patterns of latitudinal movement were reconstructed and compared in relation to inferred ploidy shifts. No single hypothesis applied equally well across all analyzed clades. While significant differences in median latitudinal occurrence were detected in the largest clade, Poaceae, no significant differences were detected in latitudinal movement in any clade. Our preliminary study is the first to attempt to connect ploidy changes to continuous latitudinal movement, but we cannot favor one hypothesis over another. Given that patterns seem to be clade-specific, more clades must be analyzed in future studies for generalities to be drawn.

Biogeography of freshwater plants in four major lakes in Kenya

Freshwater plants play a pivotal role in the health and functioning of freshwater ecosystems, and they also offer a variety of benefits to humans. Despite their importance, there is a significant gap in our understanding of the macroecology of freshwater plants in tropical regions, where biodiversity is typically high, and ecosystems face substantial pressures from human activities. To bridge this knowledge gap, we conducted extensive field surveys and applied statistical methods to understand the patterns of distribution, density, and diversity of freshwater plants and their relationship with abiotic components in four freshwater lakes in Kenya. We aimed to answer four key questions: (1) How many freshwater plant species occur in these lakes? (2) What proportion of these freshwater plant species are native and alien to Kenya? (3) What proportion of these species have a history of being invasive somewhere in the world, including in Kenya? (4) Which water and sediment characteristics are significantly associated with the presence, density, and diversity of freshwater plants in the lakes? We inventoried a total of 163 freshwater plant species, of which 114 were native to Kenya and 49 were alien. Online database searches revealed that 114 species had a history of invasion globally, with 22 species already invasive in Kenya. Our statistical analysis showed that the presence and density of plant species were positively correlated with pH and turbidity, but negatively correlated with soluble reactive phosphorus in both water and sediments, ammonia-nitrogen in sediments, and nitrate-nitrogen in water. Shannon-Wiener diversity of the plant species was positively correlated with ammonia-nitrogen in water and nitrate-nitrogen in sediments but negatively correlated with longitude and electrical conductivity of the water. Pielou’s evenness within the communities showed positive correlations with soluble reactive phosphorus in both water and sediments, ammonia-nitrogen in sediments, and nitrate-nitrogen in water but was negatively correlated with water turbidity and pH. The number of species with a history of invasion was positively correlated with longitude and electrical conductivity but negatively correlated with ammonia-nitrogen and nitrate-nitrogen in water. This extensive inventory not only enriches our understanding of the biodiversity within these freshwater plant communities but also highlights the potential risks posed by species with a history of being invasive. The findings regarding environmental variables linked to the presence, density, diversity, and invasive potential of these species underscore the complexity of freshwater ecosystems and the array of factors influencing the composition of freshwater plant communities.

Holocene vegetation and flora dynamics of the west Cork/Kerry region, south-western Ireland

Sediments from a small lake, Loch Beag, in Barrees, Beara peninsula, south-western Ireland, provide a record of vegetation history that spans most of the Lateglacial and Holocene (14–0.43 ka). The detailed part of the record relates to the Holocene, which is the focus of this paper. The investigations carried out include pollen and macrofossil analyses, loss-on-ignition measurements and 14C dating. As well as providing records for tree and shrub taxa, and especially Pinus, Quercus, Ulmus, Fraxinus and Taxus, other taxa mainly with Atlantic and/or Lusitanian distributions are also considered. These include Arbutus unedo (strawberry tree) and fern species such as Osmunda regalis, and the filmy ferns Hymenophyllum tunbrigense, H. wilsonii and Trichomanes speciosum (Killarney fern). Detailed records for a suite of bog/heath taxa, including ericoid species (Erica tetralix and E. cinerea), Narthecium ossifragum, Hypericum elodes and Myrica gale, are presented. The results of 14C dating of bog-pines from western Ireland are summarised. Results of other investigations, including key Holocene pollen diagrams, and charcoal and fossil-wood records from archaeological excavations that relate mainly to the Bronze Age in the wider west Cork/Kerry region, are reviewed. Vegetation dynamics, human impact and plant biogeography are discussed in the light of the considerable data now available for the region.

Avoiding impacts of phylogenetic tip‐state‐errors on dispersal and extirpation rates in alpine plant biogeography

AbstractAimMany biogeographic analyses require some form of automated state assignment to tips of phylogenetic trees, reflecting a species presence or absence in a particular area, e.g., a biome. As datasets get exponentially larger, such procedures may increasingly induce errors (here called tip‐state‐error), but the specific algorithmic cause and consequence on downstream estimation of dispersal and extinction rates remains poorly known. We aim to improve automated tip‐scoring methods in the context of the alpine biome by leveraging elevation information. We document the profound effect of tip‐state‐errors on Dispersal‐Extirpation‐Cladogenesis (DEC) models.LocationThe European Alpine Arc.TaxonThree thousand three hundred seventeen vascular plant species, emphasizing six focal genera: Campanula, Carex, Festuca, Ranunculus, Saxifraga, and Viola.MethodsWe use GBIF data to classify whether species occur above the upper climatic treeline using a newly developed algorithm ElevDistr or a gridded landscape model of thermal belts, under various filtering thresholds. We compared classification performance using the Flora Alpina as validation data. To determine if tip‐state‐error biases the dispersal and extirpation rate estimation, we fit DEC models for selected clades using tip‐states from different classification models.ResultsElevDistr is less error prone than other approaches. Filtering thresholds lower the false positive rate but increase the false negative rate. Inflated false positive rates bias the dispersal rate estimation upward, while inflated false negative rates lead to upward bias in extirpation rate estimation.Main ConclusionsEven moderate tip‐state‐error may lead to profound systematic bias in dispersal and extinction rate estimation if an unbalanced ratio between false positive and false negative rates occurs. Therefore, careful validation is imperative, though ElevDistr alleviates this problem in the context of the alpine environment. Overall, our results suggest contrasting rates of alpine biome shifts across the studied genera and have major implications for studies addressing the likelihood of niche evolution versus geographic dispersal.

Revising the global biogeography of annual and perennial plants

There are two main life cycles in plants—annual and perennial1,2. These life cycles are associated with different traits that determine ecosystem function3,4. Although life cycles are textbook examples of plant adaptation to different environments, we lack comprehensive knowledge regarding their global distributional patterns. Here we assembled an extensive database of plant life cycle assignments of 235,000 plant species coupled with millions of georeferenced datapoints to map the worldwide biogeography of these plant species. We found that annual plants are half as common as initially thought5–8, accounting for only 6% of plant species. Our analyses indicate that annuals are favoured in hot and dry regions. However, a more accurate model shows that the prevalence of annual species is driven by temperature and precipitation in the driest quarter (rather than yearly means), explaining, for example, why some Mediterranean systems have more annuals than desert systems. Furthermore, this pattern remains consistent among different families, indicating convergent evolution. Finally, we demonstrate that increasing climate variability and anthropogenic disturbance increase annual favourability. Considering future climate change, we predict an increase in annual prevalence for 69% of the world’s ecoregions by 2060. Overall, our analyses raise concerns for ecosystem services provided by perennial plants, as ongoing changes are leading to a higher proportion of annual plants globally.

The Changes of Phyllosphere Fungal Communities among Three Different Populus spp.

As an ecological index for plants, the diversity and structure of phyllosphere microbial communities play a crucial role in maintaining ecosystem stability and balance; they can affect plant biogeography and ecosystem function by influencing host fitness and function. The phyllosphere microbial communities reflect the immigration, survival, and growth of microbial colonists, which are influenced by various environmental factors and leaves' physical and chemical properties. This study investigated the structure and diversity of phyllosphere fungal communities in three different Populus spp., namely-P. × euramaricana (BF3), P. nigra (N46), and P. alba × P. glandulosa (84K). Leaves' chemical properties were also analyzed to identify the dominant factors affecting the phyllosphere fungal communities. N46 exhibited the highest contents of total nitrogen (Nt), total phosphorus (Pt), soluble sugar, and starch. Additionally, there were significant variations in the abundance, diversity, and composition of phyllosphere fungal communities among the three species: N46 had the highest Chao1 index and observed_species, while 84K had the highest Pielou_e index and Simpson index. Ascomycota and Basidiomycota are the dominant fungal communities at the phylum level. Results from typical correlation analyses indicate that the chemical properties of leaves, especially total phosphorus (Pt), total nitrogen (Nt), and starch content, significantly impact the structure and diversity of the phyllosphere microbial community. However, it is worth noting that even under the same stand conditions, plants from different species have distinct leaf characteristics, proving that the identity of the host species is the critical factor affecting the structure of the phyllosphere fungal community.

Evolutionary imbalance, climate and human history jointly shape the global biogeography of alien plants.

Human activities are causing global biotic redistribution, translocating species and providing them with opportunities to establish populations beyond their native ranges. Species originating from certain global regions, however, are disproportionately represented among naturalized aliens. The evolutionary imbalance hypothesis posits that differences in absolute fitness among biogeographic divisions determine outcomes when biotas mix. Here, we compile data from native and alien distributions for nearly the entire global seed plant flora and find that biogeographic conditions predicted to drive evolutionary imbalance act alongside climate and anthropogenic factors to shape flows of successful aliens among regional biotas. Successful aliens tend to originate from large, biodiverse regions that support abundant populations and where species evolve against a diverse backdrop of competitors and enemies. We also reveal that these same native distribution characteristics are shared among the plants that humans select for cultivation and economic use. In addition to influencing species' innate potentials as invaders, we therefore suggest that evolutionary imbalance shapes plants' relationships with humans, impacting which species are translocated beyond their native distributions.

Climate and ant diversity explain the global distribution of ant‐plant mutualisms

Biotic interactions play an important role in shaping species geographic distributions and diversity patterns. However, the role of mutualistic interactions in shaping global plant diversity patterns remains poorly understood, particularly with respect to interactions with invertebrates. It is unclear how the nature of different mutualisms interacts with abiotic drivers and affects the distribution of mutualistic organisms. Here, we present a global‐scale biogeographic analysis of three distinct ant‐plant mutualisms, differentiating between plants bearing domatia, extrafloral nectaries (EFNs), and elaiosomes, based on comprehensive geographic distributions of ~ 19 000 flowering plants and ~ 13 000 ant species. Domatia and extrafloral nectaries involve indirect plant defences provided by ants, while elaiosomes attract ants to disperse seeds. Our results reveal distinct biogeographic patterns of different ant‐plant mutualisms, with domatium‐ and EFN‐bearing plant diversity decreasing sharply from the equator towards the poles, while elaiosome‐bearing plants prevail at mid‐latitudes. Present climate, especially mean annual temperature and precipitation, emerge as the strongest predictors of ant‐associated plant diversity. In hot and moist regions, typically the tropics, the representation of EFN‐bearing plants increases with the proportion of potential ant partners while domatium‐bearing plants show no correlation with ants. In dry regions, plants with elaiosomes are strongly linked to interacting ant seed dispersers. Our results suggest that ants in combination with climate drive the spatial variation of plants bearing domatia, extrafloral nectaries, and elaiosomes, highlighting the importance of mutualistic interactions for understanding plant biogeography.

A trait-based approach to determining principles of plant biogeography.

Lineage-specific traits determine how plants interact with their surrounding environment. Unrelated species may evolve similar phenotypic characteristics to tolerate, persist in, and invade environments with certain characteristics, resulting in some traits becoming relatively more common in certain types of habitats. Analyses of these general patterns of geographical trait distribution have led to the proposal of general principles to explain how plants diversify in space over time. Trait-environment correlation analyses quantify to what extent unrelated lineages have similar evolutionary responses to a given type of habitat. In this synthesis, I give a short historical overview on trait-environment correlation analyses, from some key observations from classic naturalists to modern approaches using trait evolution models, large phylogenies, and massive data sets of traits and distributions. I discuss some limitations of modern approaches, including the need for more realistic models, the lack of data from tropical areas, and the necessary focus on trait scoring that goes beyond macromorphology. Overcoming these limitations will allow the field to explore new questions related to trait lability and niche evolution and to better identify generalities and exceptions in how plants diversify in space over time.

Functional biogeography of plants: research progresses and challenges

Functional biogeography of plants: research progresses and challenges

Nitrogen-fixing symbiotic bacteria act as a global filter for plant establishment on islands

Island biogeography has classically focused on abiotic drivers of species distributions. However, recent work has highlighted the importance of mutualistic biotic interactions in structuring island floras. The limited occurrence of specialist pollinators and mycorrhizal fungi have been found to restrict plant colonization on oceanic islands. Another important mutualistic association occurs between nearly 15,000 plant species and nitrogen-fixing (N-fixing) bacteria. Here, we look for evidence that N-fixing bacteria limit establishment of plants that associate with them. Globally, we find that plants associating with N-fixing bacteria are disproportionately underrepresented on islands, with a 22% decline. Further, the probability of N-fixing plants occurring on islands decreases with island isolation and, where present, the proportion of N-fixing plant species decreases with distance for large, but not small islands. These findings suggest that N-fixing bacteria serve as a filter to plant establishment on islands, altering global plant biogeography, with implications for ecosystem development and introduction risks.

New Developments and Future Vision of the Nomenclatural Database IPNI and the Taxonomic Database WCVP

IPNI (International Plant Names Index) has been providing nomenclatural data in one form or another for the past 138 years. Over the past decade, great progress has been made in improving the data and making it accessible via a new website. We will be showcasing the new features that have been added to the website, in particular the latest addition, name registration. While obligatory name registration has already been in place for fungi for a decade, we will be highlighting the opportunities it will bring to vascular plant sciences and our ever-increasing pace of data needs. Name registration will lighten the burden of finding newly published names and entering them into the IPNI database, allowing the IPNI curation team to focus on other aspects that have been left behind, like data standardisation. We will also be revisiting some of the longstanding features of IPNI like the LSID (Life Sciences Identifier), which has been used on the IPNI website since its launch in the year 2000, even though new projects still continue to invent their own identifiers. We will look into why this is and how these can improve the efficiency of curating databases that contain plant names, including WFO (World Flora Online). For the past 34 years, the IPNI data have been the basis for the taxonomic database, WCVP (World Checklist of Vascular Plants), which records both synonymy and biogeography of vascular plants. Since 2014, both these datasets are curated as part of the same team resulting in greater coordination and data improvements on both sides. WCSP contains some 200,000 names that are not in IPNI and the process has now started to add them to IPNI. IPNI LSIDs have also been added to WCVP, increasing the opportunities of linking to other programmes, like WFO. A widespread utilisation of IPNI LSIDS would offer the opportunity to combine different global plant checklists, allowing users to choose under which taxonomy they want to see data and forego the requirement for one globally agreed taxonomy. However, IPNI and WCVP are still stand-alone legacy database systems, which limit their functionality in a continually changing landscape of user needs. Although half of the WCVP data have been reviewed by experts, more integrated access is needed to speed up the review of the other half and continued direct access by these expert groups, including some of the TENs (Taxonomic Expert Networks) established for WFO. We will investigate the possible synergies that may be possible by combining the day-to-day grind of WCVP data management and expert input.

A catalogue, revision, and regional perspective of Eastern Palaearctic and Oriental oak gall wasps and their inquilines (Hymenoptera: Cynipidae: Cynipini, Synergini, Ceroptresini).

Recent years have seen rapid advances in the study of Fagaceae-associated gall wasps (Hymenoptera: Cynipidae) of the Eastern Palaearctic and the Oriental (EPO) regions, for both the gall inducing Cynipini (commonly termed oak gall wasps though many species gall non-oak Fagaceae) and the predominantly inquiline tribes Synergini and Ceroptresini. This process has propagated some taxonomic errors and involves many taxa whose taxonomic status is uncertain. To provide a stable foundation for further advance, here we review the taxonomic status of the 212 species (133 oak gall wasps and 79 oak cynipid inquilines) that have been described or recorded in these regions. Of this total, we treat 171 as valid species names (103 oak gall wasps and 68 oak cynipid inquilines) in 20 genera; 22 as synonym names, 13 as incertae sedis, three as nomen dubium, and three as species inquirenda. Callirhytis kunugicola Shinji, 1944 is proposed as syn. nov. of C. kunugicola Shinji, 1943, as Shinji described the same species twice. For all valid species names, we provide taxonomic references, synonyms, and geographical distributions. We summarize what is known of host plant associations and gall locations for gall inducers, and host associations for inquilines. We discuss geographic patterns in the known richness of currently valid species for both groups of organisms, and place this in the context of the biogeography of available Fagaceae host plants. We provide a brief historical review of the study of oak gall wasps and their inquilines in the EPO regions.

Understanding the diversity and biogeography of Colombian edible plants

Despite being the second most biodiverse country in the world, hosting more than 7000 useful species, Colombia is characterized by widespread poverty and food insecurity. Following the growing attention in Neglected and Underutilized Species, the present study will combine spatial and taxonomic analysis to unveil their diversity and distribution, as well as to advocate their potential as key resources for tackling food security in the country. The cataloguing of Colombian edible plants resulted in 3805 species. Among these, the most species-rich genera included Inga, Passiflora, Miconia, Solanum, Pouteria, Protium, Annona and Bactris. Biogeographic analysis revealed major diversity hotspots in the Andean humid forests by number of records, species, families, and genera. The departments of Antioquia, Boyacá, Meta, and Cundinamarca ranked first both in terms of number of unique georeferenced records and species of edible plants. Significant information gaps about species distribution were detected in the departments of Cesar, Sucre, Atlántico, Vichada, and Guainía, corresponding to the Caribe and Llanos bioregions, indicating the urgent need for focusing investigation in these areas. Furthermore, a significant level of geographic specificity was found in edible plant species’ distributions between 13 different bioregions and 33 departments, hinting the adoption of tailorized prioritisation protocols for the conservation and revitalization of such resources at the local level.

The Cenozoic history of palms: Global diversification, biogeography and the decline of megathermal forests

AbstractAimMegathermal rain forests and mangroves are much smaller in extent today than in the early Cenozoic, primarily owing to global cooling and drying trends since the Eocene–Oligocene transition (c. 34 Ma). The general reduction of these biomes is hypothesized to shape the diversity and biogeographical history of tropical plant clades. However, this has rarely been examined owing to a paucity of good fossil records of tropical taxa and the difficulty in assigning them to modern clades. Here, we evaluate the role that Cenozoic climate change might have played in shaping the diversity and biogeography of tropical plants through time.LocationGlobal.Time periodCenozoic, 66 Ma to present.Major taxa studiedFour palm clades (Calaminae, Eugeissoneae, Mauritiinae and Nypoideae) and their fossil pollen record.MethodsWe compiled fossil pollen occurrence records for each focal palm lineage to reconstruct their diversity and biogeographical distribution throughout the Cenozoic. We use climatic niche models to project the distribution of climatically suitable areas for each lineage in the past, using palaeoclimatic data for the Cenozoic.ResultsFor most palm lineages examined, global pollen taxonomic diversity declined throughout the Cenozoic. Geographical ranges for each focal lineage contracted globally and experienced regional‐scale extinctions (e.g., Afrotropics), particularly after the Miocene. However, climatic niche models trained on extant species of these focal lineages often predict the presence of climatically suitable habitat in areas where these lineages went extinct.Main conclusionsGlobally, the decline in megathermal rain forest and mangrove extent might have led to declines in diversity and range contractions in some megathermal plant taxa throughout the Cenozoic. Although global climatic trends are an important backdrop for the biogeography and diversity of tropical groups at global scales, their continental‐ or regional‐scale biogeographical trajectories might be more dependent on regional abiotic and biotic contexts.