Albert Ernest Radford

Premise: Cacti are characteristic elements of the Neotropical flora and of major interest for biogeographic, evolutionary, and ecological studies. Here we test global biogeographic boundaries for Neotropical Cactaceae using specimen‐based occurrences coupled with data from visual observations, as a means to tackle the known collection biases in the family.MethodsSpecies richness and record density were assessed for preserved specimens and human observations and a bioregional scheme tailored to Cactaceae was produced using the interactive web application Infomap Bioregions based on data from 261,272 point records cleaned through automated and manual steps.Key ResultsWe find that areas in Mexico and southwestern USA, Eastern Brazil and along the Andean region have the greatest density of records and the highest species richness. Human observations complement information from preserved specimens substantially, especially along the Andes. We propose 24 cacti bioregions, among which the most species‐rich are: northern Mexico/southwestern USA, central Mexico, southern central Mexico, Central America, Mexican Pacific coast, central and southern Andes, northwestern Mexico/extreme southwestern USA, southwestern Bolivia, northeastern Brazil, Mexico/Baja California.ConclusionsThe bioregionalization proposed shows biogeographical boundaries specific to cacti, and can thereby aid further evolutionary, biogeographic, and ecological studies by providing a validated framework for further analyses. This classification builds upon, and is distinctive from, other expert‐derived regionalization schemes for other taxa. Our results showcase how observation data, including citizen‐science records, can complement traditional specimen‐based data for biogeographic research, particularly for taxa with specific specimen collection and preservation challenges and those that are threatened or internationally protected.This article is protected by copyright. All rights reserved.

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AbstractBackgroundGonopsis affinis (Uhler) is a stinkbug that represents a significant threat to the production of rice (Oryza sativa L.), sugarcane (Saccharum officinarum L.) and eulalia (Miscanthus sinensis (Andersson)), and has been listed as a sugarcane pest in Japan. Trissolcus mitsukurii Ashmead is an egg parasitoid of G. affinis. To determine the potential of T. mitsukurii to be a biological control agent for G. affinis, we aim to predict the current and future areas of suitable habitat for these two species and their overlap with areas of present crop production. We developed MaxEnt models using two different variable selection methods and compared the two for T. mitsukurii with a CLIMEX model.ResultsThe results showed extensive suitable areas for G. affinis under current climate conditions in East Asia, West Africa, Madagascar, and South America. These ranges overlap with areas currently being used for the production of the three crops in question. More than half overlap with areas of suitable habitat for T. mitsukurii. The most critical environmental variable determining habitat suitability for G. affinis was showed to be precipitation of warmest quarter, whilst for T. mitsukurii it was min temperature of the coldest month.ConclusionBased on our assessment we recommend the immediate implementation of monitoring and invasion prevention measures for G. affinis in southwest China, the Malay Archipelago and West Africa. We suggest that T. mitsukurii be considered for use as a biological control agent in East Asia, Madagascar, Florida and Brazil in the case of future invasions by G. affinis.This article is protected by copyright. All rights reserved.

Brassica napus , a versatile crop with significant socioeconomic importance, serves as a valuable source of nutrition for humans and animals while also being utilized in biodiesel production. The expansion potential of B. napus is profoundly influenced by climatic variations, yet there remains a scarcity of studies investigating the correlation between climatic factors and its distribution. This research employs CLIMEX to identify the current and future ecological niches of B. napus under the RCP 8.5 emission scenario, utilizing the Access 1.0 and CNRM-CM5 models for the time frame of 2040–2059. Additionally, a sensitivity analysis of parameters was conducted to determine the primary climatic factors affecting B. napus distribution and model responsiveness. The simulated outcomes demonstrate a satisfactory alignment with the known current distribution of B. napus , with 98% of occurrence records classified as having medium to high climatic suitability. However, the species displays high sensitivity to thermal parameters, thereby suggesting that temperature increases could trigger shifts in suitable and unsuitable areas for B. napus , impacting regions such as Canada, China, Brazil, and the United States.

Evolutionary correlations between chemical defense and protection by mutualist bodyguards have been long predicted, but tests of these pattern remain rare. We use a phylogenetic framework to test for evolutionary correlations indicative of trade-offs or synergisms between direct defense in the form of plant secondary metabolism, and indirect defense in the form of leaf domatia, across 33 species in the wild grape genus, Vitis. We also performed a bioassay with a generalist herbivore to associate our chemical phenotypes with herbivore palatability. Finally, we tested whether defensive traits correlate with the average abiotic characteristics of each species’ contemporary range and whether these correlations were consistent with plant defense theory. We found a negative evolutionary correlation between domatia size and the diversity of secondary metabolites in Vitis leaf tissue across the genus, and also that leaves with a higher diversity and richness of secondary metabolites were less palatable to a generalist herbivore, consistent with a trade-off in chemical and mutualistic defense investment. Predictions from plant defense theory were not supported by associations between investment in defense phenotypes and abiotic variables. Our work demonstrates an evolutionary pattern indicative of a trade-off between indirect and direct defense strategies across the Vitis genus.

The threat of invasive species to biodiversity and ecosystem structure is exacerbated by the increasingly concerning outlook of predicted climate change and other human influences. Developing preventative management strategies for invasive plant species before they establish is crucial for effective management. To examine how climate change may impact habitat suitability, we modeled the current and future habitat suitability of two terrestrial species, Geranium lucidum and Pilosella officinarum , and two aquatic species, Butomus umbellatus and Pontederia crassipes , that are relatively new invasive plant species regionally, and are currently spreading in the Pacific Northwest (PNW, North America), an area of unique natural areas, vibrant economic activity, and increasing human population. Using North American presence records, downscaled climate variables, and human influence data, we developed an ensemble model of six algorithms to predict the potential habitat suitability under current conditions and projected climate scenarios RCP 4.5, 7.0, and 8.5 for 2050 and 2080. One terrestrial species ( P. officinarum ) showed declining habitat suitability in future climate scenarios (contracted distribution), while the other terrestrial species ( G. lucidum ) showed increased suitability over much of the region (expanded distribution overall). The two aquatic species were predicted to have only moderately increased suitability, suggesting aquatic plant species may be less impacted by climate change. Our research provides a template for regional-scale modelling of invasive species of concern, thus assisting local land managers and practitioners to inform current and future management strategies and to prioritize limited available resources for species with expanding ranges.

Polyploidization can provide a wealth of genetic variation for adaptive evolution and speciation, but understanding the mechanisms of subgenome evolution as well as its dynamics and ultimate consequences remains elusive. Here, we report the telomere-to-telomere (T2T) gap-free reference genome of allotetraploid horseradish ( Armoracia rusticana ) sequenced using a comprehensive strategy. The (epi)genomic architecture and 3D chromatin structure of the A and B subgenomes differ significantly, suggesting that both the dynamics of the dominant long terminal repeat retrotransposons and DNA methylation have played critical roles in subgenome diversification. Investigation of the genetic basis of biosynthesis of glucosinolates (GSLs) and horseradish peroxidases reveals both the important role of polyploidization and subgenome differentiation in shaping the key traits. Continuous duplication and divergence of essential genes of GSL biosynthesis (e.g., FMO GS-OX , IGMT , and GH1 gene family) contribute to the broad GSL profile in horseradish. Overall, the T2T assembly of the allotetraploid horseradish genome expands our understanding of polyploid genome evolution and provides a fundamental genetic resource for breeding and genetic improvement of horseradish. Horseradish is a spicy root vegetable and it also produces horseradish peroxidase, an enzyme widely used in biochemistry applications. Here, the authors report its telomere-to-telomere reference genome, reveal subgenome diversification and the effect on the biosynthesis of glucosinolates and horseradish peroxidases.

Background Approximately 33% of plant species face extinction due to climate change. Polyploidisation, a process resulting in more than two complete sets of chromosomes, may be promoted by periods of climate fluctuations. Ecological niche modelling (ENM) using occurrences of endemic plants in the North American Coastal Plain (NACP) biodiversity hotspot could be used to evaluate the potential effects of climate change on cytotype distributions. Aims We used known diploid and polyploid taxa endemic to the NACP to test hypotheses that diploids and polyploids differed in habitat preferences, considerable overlap existed between cytotypes, and polyploid distributions would increase under climate change projections. Methods We examined niche identity and overlap of 28 congeneric ploidy level pairs and performed ENM to evaluate how climate change could affect these groups. Results Congeneric ploidy level pairs differed significantly in niche identity, and overlap varied across genera. Eleven genera showed greater than 100% increases in habitat suitability and six genera showed almost no remaining suitable habitat in at least one future climate scenario. Conclusions With 70% of the species that showed substantial declines in projected suitable habitat being of conservation concern, we propose that future studies of these genera should be a primary focus in the NACP.

Paleogene flower-insect interactions and paleo-pollination processes are, in general, poorly understood and fossil evidence for such floral and faunal interactions are rarely reported. To shed light on angiosperm flower-insect interactions, we investigated several hundred fossil flowers and insects from the middle Eocene Fossil Lagerstätte of Eckfeld, Germany. During our work, we discovered a unique fossil Ludwigia flower (bud) with in situ pollen. The ecological preferences (climate, biome, habitat, etc.) of extant Ludwigia and the paleoecological configurations of the fossil plant assemblage support the taxonomic affiliation of the flower bud and an Eocene presence of Ludwigia in the vicinity of the former Lake Eckfeld. Today’s Ludwigia are mostly pollinated by Hymenoptera (bees). Therefore, we screened all currently known hymenopteran fossils from Eckfeld but found no Ludwigia pollen adhering to any of the specimens. On the contrary, we discovered Ludwigia pollen adhering to two different groups of Coleoptera (beetles). Our study suggests that during the Eocene of Europe, Ludwigia flowers were visited and probably pollinated by beetles and over time there was a shift in primary flower visitors/pollinators, from beetles to bees, sometime during the late Paleogene to Neogene.

Aim Fruit selection by animal dispersers with different mobility directly impacts plant geographical range size, which, in turn, may impact plant diversification. Here, we examine the interaction between fruit colour, range size and diversification rate in palms by testing two hypotheses: (1) species with fruit colours attractive to birds have larger range sizes due to high dispersal ability and (2) disperser mobility affects whether small or large range size has higher diversification, and intermediate range size is expected to lead to the highest diversification rate regardless of disperser. Location Global. Time Period Contemporary (or present). Major Taxa Studied Palms (Arecaceae). Methods Palm species were grouped based on likely animal disperser group for given fruit colours. Range sizes were estimated by constructing alpha convex hull polygons from distribution data. We examined disperser group, range size or an interaction of both as possible drivers of change in diversification rate over time in a likelihood dynamic model (Several Examined State-dependent Speciation and Extinction [SecSSE]). Models were fitted, rate estimates were retrieved and likelihoods were compared to those of appropriate null models. Results Species with fruit colours associated with mammal dispersal had larger ranges than those with colours associated with bird dispersal. The best fitting SecSSE models indicated that the examined traits were not the primary driver of the heterogeneity in diversification rates in the model. Extinction rate complexity had a marked impact on model performance and on diversification rates. Main Conclusions Two traits related to dispersal mobility, range size and fruit colour, were not identified as the main drivers of diversification in palms. Increased model extinction rate complexity led to better performing models, which indicates that net diversification should be estimated rather than speciation alone. However, increased complexity may lead to incorrect SecSSE model conclusions without careful consideration. Finally, we find palms with more mobile dispersers do not have larger range sizes, meaning other factors are more important determinants of range size.