Evaluation of tropical–temperate transitions: an example of climatic characterization in the Asian Palmate group of Araliaceae

Premise: There has been a great increase in using climatic data in phylogenetic studies over the past decades. However, compiling the high-quality spatial data needed to perform accurate climatic reconstructions is time-consuming and can result in poor geographical coverage. Therefore, researchers often resort to qualitative approximations. Our aim was to evaluate the climatic characterization of the genera of the Asian Palmate Group (AsPG) of Araliaceae as an exemplar lineage of plants showing tropical–temperate transitions. Methods: We compiled a curated worldwide spatial database of the AsPG genera and created five raster layers representing bioclimatic regionalizations of the world. Then, we crossed the database with the layers to climatically characterize the AsPG genera. Results: We found large disagreement in the climatic characterization of genera among regionalizations and little support for the climatic nature of the tropical–temperate distribution of the AsPG. Both results are attributed to the complexity of delimiting tropical, subtropical, and temperate climates in the world and to the distribution of the study group in regions with transitional climatic conditions. Conclusions: The complexity in the climatic classification of this example of the tropical–temperate transitions calls for a general climatic revision of other tropical–temperate lineages. In fact, we argue that, to properly evaluate tropical–temperate transitions across the tree of life, we cannot ignore the complexity of distribution rangesThis study was supported by the Spanish Ministry of Economy, Industry and Competitiveness (CGL2017‐87198‐ P) and the Spanish Ministry of Science an Innovation (PID2019‐106840GA‐C22). M.C.d.l.I. was supported by the Youth Employment Initiative of European Social Fund and Community of Madrid (PEJ‐2017‐AI‐AMB‐6636 and CAM2020PEJD‐2019‐11 PRE/AMB‐15871

High rate of species misidentification reduces the taxonomic certainty of European biodiversity databases of ivies (Hedera L.)

Abstract The digitization of natural history specimens and the popularization of citizen science are creating an unprecedented availability of large amounts of biodiversity data. These biodiversity inventories can be severely affected by species misidentification, a source of taxonomic uncertainty that is rarely acknowledged in biodiversity data management. For these reasons, taxonomists debate the use of online repositories to address biological questions at the species level. Hedera L. (ivies) provides an excellent case study as it is well represented in both herbaria and online repositories with thousands of records likely to be affected by high taxonomic uncertainty. We analyze the sources and extent of taxonomic errors in the identification of the European ivy species by reviewing herbarium specimens and find a high misidentification rate (18% on average), which varies between species (maximized in H. hibernica: 55%; H. azorica: 48%; H. iberica: 36%) and regions (maximized in the UK: 38% and Spain: 27%). We find a systematic misidentification of all European ivies with H. helix behind the high misidentification rates in herbaria and warn of even higher rates in online records. We compile a spatial database to overcome the large discrepancies we observed in species distributions between online and morphologically reviewed records

Climatic niche pre-adaptation facilitated island colonization followed by budding speciation in the Madeiran ivy (Hedera maderensis, Araliaceae)

The path followed by species in the colonization of remote oceanic islands ultimately depends on their phylogenetic constraints and ecological responses. In this study, we aim to evaluate the relative role of geographical and ecological forces in the origin and evolution of the Madeiran ivy (Hedera maderensis), a single-species endemic belonging to the western polyploid clade of Hedera. To determine the phylogenetic placement of H. maderensis within the western polyploid clade, we analyzed 40 populations (92 individuals) using genotyping-by-sequencing and including Hedera helix as outgroup. Climatic niche differences among the study species were evaluated using a database with 867 records representing the entire species ranges. To test species responses to climate, 13 vegetative and reproductive functional traits were examined for 70 populations (335 individuals). Phylogenomic results revealed a nested pattern with H. maderensis embedded within the south-western Iberian H. iberica. Gradual niche differentiation from the coldest and most continental populations of H. iberica to the warm and stable coastal population sister to H. maderensis parallels the geographical pattern observed in the phylogeny. Similarity in functional traits is observed for H. maderensis and H. iberica. The two species show leaves with higher specific leaf area (SLA), lower leaf dry matter content (LDMC) and thickness and fruits with lower pulp fraction than the other western polyploid species H. hibernica. Acquisition of a Macaronesian climatic niche and the associated functional syndrome in mainland European ivies (leaves with high SLA, and low LDMC and thickness, and fruits with less pulp content) was a key step in the colonization of Madeira by the H. iberica/H. maderensis lineage, which points to climatic pre-adaptation as key in the success of island colonization (dispersal and establishment). Once in Madeira, budding speciation was driven by geographical isolation, while ecological processes are regarded as secondary forces with a putative impact in the lack of further in situ diversification

Climatic niche pre-adaptation facilitated island colonization followed by budding speciation in the Madeiran ivy (Hedera maderensis, Araliaceae)

The path followed by species in the colonization of remote oceanic islands ultimately depends on their phylogenetic constraints and ecological responses. In this study, we aim to evaluate the relative role of geographical and ecological forces in the origin and evolution of the Madeiran ivy (Hedera maderensis), a single-species endemic belonging to the western polyploid clade of Hedera. To determine the phylogenetic placement of H. maderensis within the western polyploid clade, we analyzed 40 populations (92 individuals) using genotyping-by-sequencing and including Hedera helix as outgroup. Climatic niche differences among the study species were evaluated using a database with 867 records representing the entire species ranges. To test species responses to climate, 13 vegetative and reproductive functional traits were examined for 70 populations (335 individuals). Phylogenomic results revealed a nested pattern with H. maderensis embedded within the south-western Iberian H. iberica. Gradual niche differentiation from the coldest and most continental populations of H. iberica to the warm and stable coastal population sister to H. maderensis parallels the geographical pattern observed in the phylogeny. Similarity in functional traits is observed for H. maderensis and H. iberica. The two species show leaves with higher specific leaf area (SLA), lower leaf dry matter content (LDMC) and thickness and fruits with lower pulp fraction than the other western polyploid species H. hibernica. Acquisition of a Macaronesian climatic niche and the associated functional syndrome in mainland European ivies (leaves with high SLA, and low LDMC and thickness, and fruits with less pulp content) was a key step in the colonization of Madeira by the H. iberica/H. maderensis lineage, which points to climatic pre-adaptation as key in the success of island colonization (dispersal and establishment). Once in Madeira, budding speciation was driven by geographical isolation, while ecological processes are regarded as secondary forces with a putative impact in the lack of further in situ diversification.Ministerio de Economía, Industria y CompetitividadMinisterio de Ciencia e InnovaciónComunidad de Madrid/Fondo Social EuropeoConsejo superior de Investigaciones Científicas (CSIC)Universidad Autónoma de MadridDepto. de Biodiversidad, Ecología y EvoluciónFac. de Ciencias BiológicasTRUEpu