Thomas Cheeseman

Context Mapping the distribution of species from the genus Metrosideros is crucial for developing surveillance and management plans associated with species conservation in response to issues such as rapid ‘ōhi‘a death spread in the south-central Pacific region. Aims To support this endeavour, we recognised there was a need for open and reliable geographic information system data on island locations, extents, and occurrence data of Metrosideros species. Methods Using an open science framework, we reviewed six sources of island data and five sources of species occurrence data for availability, accuracy, and licencing criteria. Key results OpenStreetMap emerged as the optimal island location data, offering accuracy, precision, and open licencing, with this data improved and reprojected for mapping purposes. The Global Biodiversity Information Facility provided the majority of Metrosideros species occurrence data, but analysis of occurrence data from iNaturalist revealed common mis-identifications with regional biases that were corrected prior to compilation. The occurrence data of Metrosideros species was also supplemented by vegetation plot data, with HAVPlot and sPlotOpen providing key additional data for some species and islands. Conclusions Citizen science data via iNaturalist and OpenStreetMap formed the core of the compiled datasets. While such crowdsourced data can have quality issues, with additional crowdsourced curatorial effort these datasets will be significant and scalable sources of data into the future. Implications All compiled occurrence and GIS data are made openly available via permissive data licences to better support future biogeographical research in the south-central Pacific region.

The Southern Islands Vascular Flora (SIVFLORA) dataset is a globally significant, open-access resource that compiles essential biodiversity data on vascular plants from islands across the Southern Ocean. The SIVFLORA dataset was generated through five steps: study area delimitation, compiling the dataset, validating and harmonizing taxonomy, structuring dataset attributes, and establishing file format and open access. Covering major taxonomic divisions, SIVFLORA offers a comprehensive overview of plant occurrences, comprising 14,589 records representing 886 species, 95 families, and 42 orders. This dataset documents that 58.62% of the taxa are native, 9.61% are endemic, and 31.77% are alien species. The Falkland/Malvinas Archipelago, the most species-rich, contrast sharply with less diverse islands like the South Orkney Archipelago. SIVFLORA serves as a taxonomically harmonized, interoperable resource for investigating plant diversity patterns, ecosystem responses to climate change in extreme environments, island biogeography, endemism, and the effects of anthropogenic pressures on Southern Ocean flora.

Without appropriate and ongoing management interventions, weeds will continue to economically and environmentally disadvantage agricultural and natural ecosystems. For these management strategies to have long‐term sustained success, they need to carefully consider the biological aspects of the targeted weed. These strategies will also need to consider potential adaptations evolved by the targeted weed in response to a range of selection pressures imposed by anthropogenetic factors, climate change, changing environmental conditions, and inappropriate or unsuccessful management regimes. One group of weeds that has been observed to readily adapt to a wide range of conditions and has shown considerable challenges in their management is invasive grasses. Adding to these challenges is that several invasive grasses have also developed resistance to a range of herbicide modes of action, which, to date, has been one of the most commonly used methods of control. To address these challenges, this review explores the biology and ecology of the globally invasive annuals Echinochloa crus‐galli (Barnyard grass) and Panicum capillare (Witchgrass), and the perennial Sorghum halepense (Johnson grass) to identify (i) the most suitable management options for their control and (ii) potential research gaps that may assist in the future management direction of these species. Based on the findings of this review, it is clear that an integrated management approach that targets different aspects of the plant's biology, in combination with early detection and treatment and ongoing surveillance, is necessary for the long‐term control of these species. Although a combination of methods appears promising, further investigation still is required to evaluate their efficiency and long‐term success in a changing environment, all of which are further discussed within this review.

Cold tolerance strategies in plants vary from structural to biochemical permitting many plants to survive and grow on sites that experience freezing conditions intermittently. Although tree ferns occur predominantly across the tropics, they also occur in temperate zones and occasionally in areas that experience sub‐zero temperatures, and how these large ferns survive freezing conditions is unknown. Many temperate tree fern taxa are marcescent – retaining whorls of dead fronds encircling the upper trunk – or develop short or prostrate trunks, possibly to insulate against frost damage to their trunks and growing crowns. We asked the following questions: 1) do global growth patterns and traits of tree ferns respond to freezing conditions associated with latitude and elevation, 2) do growth patterns of tree ferns in New Zealand vary along a temperature‐related gradient, and 3) do marcescent tree fern skirts insulate the growing crown from sub‐zero temperatures? To establish what morphological adaptations permitted the Cyatheales to occur in biomes that experience intermittent sub‐zero temperatures and frost, we 1) reviewed the global distributions of these structural and morphological traits within the tree ferns (Cyatheales); 2) assessed the patterns of tree fern marcescence, and other traits potentially associated with cold tolerance (no trunk, prostrate, short‐trunked) of nine taxa of the Cyatheales along environmental gradients across New Zealand; and 3) conducted a field experiment to assess the thermal insulation properties of tree fern marcescent skirts. We identified significant trends among growth forms, marcescence, and environmental gradients consistent with our hypothesis that these are adaptations to tolerate cold. Our field experiments provide quantitative evidence that marcescent skirts have a strong insulating effect on tree fern trunks. The Cyatheales have evolved several strategies to protect the pith cores of their trunks from extreme cold temperatures in temperate forests allowing them to capture niche space in environments beyond the tropics.

Accessing the rich biodiversity in tropical ecosystems has been of great interest to scientists across the globe. While several species have been underutilized despite their wide distribution, many others are faced with continuous population decline across their native range. Here, we amassed occurrence data and environmental variables to estimate the spatial distribution and habitat suitability of six important Pelargonium species whose conservation status in South Africa has been of concern. These were combined and used to project the future habitats under 2 Global Climate Models (GCMs) and 2 Scenarios (RCP 4.5 & 8.5). We overlayed our area maps and conducted a gap analysis to identify priority areas for the conservation of our focal species. Results showed a distribution pattern driven by temperature and precipitation, and unstable suitable areas by the years 2050 and 2070. Five temperature and precipitation variables (Bio2, Bio4, Bio12, Bio14, and Bio18) were identified as primary contributors to the habitat suitability of the selected Pelargonium species. Our model evaluation demonstrated a strong performance, with an AUC score >0.8, providing robust support for its replicability in monitoring the spatial distribution of other related taxa. We identified key areas for conservation activities in a bid to expand the current known habitats of the species in focus. While we leveraged SDM approach for explaining the area of occupancy and the spatial extent of Pelargonium species across in South Africa, we posit that attention should be drawn to the preservation of the remaining populations of the species and their associated habitats, towards mitigating their extinction.

Colocasia esculenta (taro), native to tropical Southeast Asia, is an emergent aquatic plant with a wide global distribution. Valued for its agricultural, horticultural, medicinal, and cultural uses, it also has become invasive in some places, spreading unaided along slow-flowing water courses through corm division. Colocasia esculenta was introduced to South Africa at least a century ago (∼ 1918), but widespread invasions are recent, raising concerns that the species could become a harmful invader in the country. This study reviews the history of introduction, invasions, and impacts of C. esculenta around the world; maps its current and potential distribution in South Africa; and, based on a risk analysis, develops recommendations for its management and regulation. Colocasia esculenta has been introduced to at least 180 territories (countries or island states), with records of invasion from 21 of these (9 island and 12 mainland territories). The negative environmental impacts were scored as ‘Moderate’ with the formation of dense mats leading to declines in local native populations; and socioeconomic impacts scored as ‘Minor’ as it has irritant properties if not properly handled and prepared. In South Africa, C. esculenta is found in six provinces but most extensively in the Western Cape and KwaZulu-Natal. Based on a species distribution model, C. esculenta could substantially expand its range in areas where it is already established. Colocasia esculenta was classified as ‘high risk’ for South Africa, with high socio-economic benefits, and as such is identified as a potential conflict generating species. We recommend it is regulated as category 2 (permits are required to carry out any restricted activity) under the South African regulations and suggest exemptions on subsistence farming but prohibitions on all farming in riparian zones. Further investigation is needed for potential management options, including biological control. Recommendations should be reviewed after determining whether some of the subspecific entities present in the country pose a low risk, as then further exemptions or prohibitions might be appropriate.

Abstract Ceratapion basicorne (Illiger) (Coleoptera: Apionidae), a weevil native to Europe and western Asia, shows promise for enhancing the control of yellow starthistle (Centaurea solstitialis L.), an invasive annual forb in the western United States. However, a paucity of data on this biocontrol agent’s environmental constraints has made it difficult to assess the suitability of potential release locations. Climate matching models were developed for C. basicorne to help identify areas of the western United States with similar climates to the source area of breeding colonies being used for releases (home location). The models used climate variables derived from daily estimates of minimum temperature, maximum temperature, precipitation, and soil moisture for a 30-yr period spanning 1991–2020 at 1 km2 resolution. Of the areas where C. solstitialis is known to occur, the Central California Foothills, Eastern Cascades Foothills, Columbia Plateau, and mountainous parts of northcentral Utah had the most similar climates to the home location. Of these areas, the Eastern Cascades foothills in northeastern California and Wasatch Range in Utah occurred at a similar latitude as the home location, which may be important to consider if C. basicorne has photoperiodic diapause. The least similar climates occurred in wet coastal regions, high-elevation (cold) mountains, and hot deserts; however, C. solstitialis has not been detected in most of these areas. The development of process-based models for predicting the establishment of this agent will require a more detailed understanding of the agent’s requirements for development and survival.

Some plant lineages remain within the same biome over time (biome conservatism), whereas others seem to adapt more easily to new biomes. The c. 398 species (14 genera) of subfamily Cercidoideae (Leguminosae or Fabaceae) are found in many biomes around the world, particularly in the tropical regions of South America, Asia and Africa, and display a variety of growth forms (small trees, shrubs, lianas and herbaceous perennials). Species distribution maps derived from cleaned occurrence records were compiled and compared with existing biome maps and with the literature to assign species to biomes. Rainforest (144 species), succulent (44 species), savanna (36 species), and temperate (10 species) biomes were found to be important in describing the global distribution of Cercidoideae, with many species occurring in more than one biome. Two phylogenetically isolated species-poor temperate ( Cercis ) and succulent ( Adenolobus ) biome lineages are sister to two broadly distributed species-rich tropical clades. Ancestral state reconstructions on a time-calibrated phylogeny suggest biome shifts occurred throughout the evolutionary history of the subfamily, with shifts between the succulent and rainforest biomes, from the rainforest to savanna, from the succulent to savanna biome, and one early occurring shift into (or from) the temperate biome. Of the 26 inferred shifts in biome, three are closely associated with a shift from the ancestral tree/shrub growth form to a liana or herbaceous perennial habit. Only three of the 13 inferred transcontinental dispersal events are associated with biome shifts. Overall, we find that biome shifts tend to occur within the same continent and that dispersals to new continents tend to occur within the same biome, but that nonetheless the biome-conserved and biogeographically structured Cercidoideae have been able to adapt to different environments through time.

Herbarium specimens provide an important and central resource for biodiversity research. Making these records digitally available to end-users represents numerous challenges, in particular, transcribing metadata associated with specimen labels. In this study, we used the citizen science initiative ‘Les Herbonautes’ and the Récolnat network to transcribe specific data from all herbarium specimen labels stored at the Muséum national d’Histoire naturelle in Paris of the large tropical plant family Annonaceae. We compared this database with publicly available global biodiversity repository data and expert checklists. We investigated spatial and taxonomic advances in data availability at the global and country scales. A total of 20 738 specimens were transcribed over the course of more than two years contributing to and significantly extending the previously available specimen and species data for Annonaceae worldwide. We show that several regions, mainly in Africa and South East Asia not covered by online global datasets, are uniquely available in the P herbarium, probably linked to past history of the museum’s botanical exploration. While acknowledging the challenges faced during the transcription of historic specimens by citizen scientists, this study highlights the positive impact of adding records to global datasets both in space and time. This is illustrative for researchers, collection managers, policy makers as well as funders. These datasets will be valuable for numerous future studies in biodiversity research, including ecology, evolution, conservation and climate change science.

Invasive sandburs (Cenchrus spp.), tropical and subtropical plants, are preferred in grasslands and agricultural ecosystems worldwide, causing significant crop production losses and reducing native biodiversity. Integrating phylogenetic relatedness and potentially suitable habitats (PSHs) to identify areas at risk of invasion is critical for prioritizing management efforts and supporting decisions on early warning and surveillance for sandbur invasions. However, despite risk assessments for individual Cenchrus species, the combined analysis of suitable habitats and phylogenetic relationships remains unclear. Therefore, this study aims to assess the invasion risk regions—including PSHs, species richness (SR), and phylogenetic structure—of eight invasive and potentially invasive sandburs in China, to quantify their niche overlap and identify driving factors. Our results showed that the phylogenetic distance of potentially invasive sandburs was closely related to invasive sandburs. Especially, three potentially invasive sandburs, C. ciliaris, C. setigerus, and C. myosuroides, possessed invasion potential resulting from close phylogenetic relatedness and high climatic suitability compared with invasive sandburs. The PSHs for invasive sandburs were distributed in wider regions except northwest China and had higher suitability to different environmental conditions. Potentially invasive sandburs were primarily located in southwestern and southern China driven by precipitation, especially, being inspected in Guangdong, Hainan, and Yunnan on numerous occasions, or potentially introduced in Guangxi, Taiwan, and Fujian for sandburs invasion hotspots. The phylogenetic clustering for eight sandburs occurred in the eastern, center, and southern coastal China, where higher SR in distribution was correlated with invasion hotspots. The SR and phylogenetic relatedness metrics were related to temperature and topographic variables. Totally, the expansion and invasion risk could be increased toward higher latitudes under future global warming. These findings offer novel insights for the prevention and management of sandburs invasions.