Benjamin Carroll Tharp

Background and Aims: Recent studies have focused on resolving the systematics of the tribe Gonolobinae of the family Apocynaceae, as well as the controversial genus Matelea s.l. However, many species within Matelea s.l. have not been evaluated phylogenetically. This is the case of M. gonoloboides, previously recognized as the type species of Urostephanus, and other taxa with similar floral morphology. The aim of this study is to test the monophyly of Urostephanus, including some species with morphology similar to M. gonoloboides. Furthermore, we evaluate the taxonomic position of the Urostephanus clade within the subtribe Gonolobinae and compare morphology among related clades. Methods: To assess phylogenetic relationships within Gonolobinae, we downloaded sequences from four loci for 94 species of the subtribe from GenBank. We extracted DNA and sequenced the trnL-F intergenic spacer and rps16 intron from four species of Dictyanthus and six species of Matelea, which are considered to belong to Urostephanus. We reconstructed the phylogeny with Bayesian inference using the maximum clade credibility tree. Based on the phylogenetic pattern, we performed morphological comparisons between the clades Dictyanthus, Polystemma, and Urostephanus. Key results: Phylogenetic analysis recovered Urostephanus as monophyletic and sister to Dictyanthus. Based on this phylogenetic pattern and floral morphology, we resurrect the genus Urostephanus. We propose eight new combinations for the species included in the phylogeny, as well as for those that share floral morphological similarity. We designate two lectotypes. Finally, we discuss aspects of morphology between Urostephanus and closely related groups. Conclusions: The current circumscription of Matelea s.l. includes species with high morphological diversity. With the phylogenetic and morphological evidence among related taxa, we support the resurrection of Urostephanus, more than 120 years after its description. These results contribute to the resolution of the systematics of Gonolobinae in Mesoamerica.

Updated records related to coexisting species, the presence of invasive species, and the presence or absence of Threatened, Endangered, or Species of Greatest Conservation Need are a necessary component of wildlife conservation. Here, we compile a list of historically documented fish species found in San Felipe Creek and report updated occurrence from recent sampling events. Of the anticipated 49 species within San Felipe Creek, we documented 16 between 2019 and 2022. We observed Devils River minnow (Dionda diaboli), a federally Threatened species, during all sampling events. Additionally, we confirmed the presence of three state Threatened species and one Species of Greatest Conservation Need. We also document continued presence of the invasive suckermouth catfish (Hypostomus plecostomus) and blue tilapia (Oreochromis aureus). Researchers may use species occurrence data provided by these efforts to assess future assemblage changes within the San Felipe Creek system.

Aim Species occurrence data are valuable information that enables one to estimate geographical distributions, characterize niches and their evolution, and guide spatial conservation planning. Rapid increases in species occurrence data stem from increasing digitization and aggregation efforts, and citizen science initiatives. However, persistent quality issues in occurrence data can impact the accuracy of scientific findings, underscoring the importance of filtering erroneous occurrence records in biodiversity analyses.InnovationWe introduce an R package, occTest, that synthesizes a growing open‐source ecosystem of biodiversity cleaning workflows to prepare occurrence data for different modelling applications. It offers a structured set of algorithms to identify potential problems with species occurrence records by employing a hierarchical organization of multiple tests. The workflow has a hierarchical structure organized in testPhases (i.e. cleaning vs. testing) that encompass different testBlocks grouping different testTypes (e.g. environmental outlier detection), which may use different testMethods (e.g. Rosner test, jacknife,etc.). Four different testBlocks characterize potential problems in geographic, environmental, human influence and temporal dimensions. Filtering and plotting functions are incorporated to facilitate the interpretation of tests. We provide examples with different data sources, with default and user‐defined parameters. Compared to other available tools and workflows, occTest offers a comprehensive suite of integrated tests, and allows multiple methods associated with each test to explore consensus among data cleaning methods. It uniquely incorporates both coordinate accuracy analysis and environmental analysis of occurrence records. Furthermore, it provides a hierarchical structure to incorporate future tests yet to be developed.Main conclusionsoccTest will help users understand the quality and quantity of data available before the start of data analysis, while also enabling users to filter data using either predefined rules or custom‐built rules. As a result, occTest can better assess each record's appropriateness for its intended application.

Drylands cover ca. 40% of the land global surface and deliver significant ecosystem services. These regions are the most sensitive, prone to suffer the effects of climate and distribution changes, so estimates on projected range shifts are crucial to complement traditional approaches to biodiversity conservation and sustainability. Shrubs of the Monte Desert dominate the largest temperate dryland in South America. Our goal is to assess the spatial distribution and niche overlap of three native shrubs (Larrea cuneifolia (LC), L. divaricata (LD), and L. nitida (LN)), under present climate conditions, to retrodict their potential past distribution, and anticipate their predicted range under future climate scenarios. We used ecological niche modeling that were projected to the past (LGM and Mid Holocene) and future (2050 and 2070) under two scenarios of greenhouse gas emissions and two model of global circulation. All species have high niche overlap (67–89%), but showed species-specific responses, highlighting the need to develop mitigation measures particularly for LD and LN in the face of climate change and land use pressures. Global South deserts are being highly degraded and information on future potential ranges of endemic species can support the development of sustainable conservation and management plans.

Dense branching and spines are common features of plant species in ecosystems with high mammalian herbivory pressure. While dense branching and spines can inhibit herbivory independently, when combined, they form a powerful defensive cage architecture. However, how cage architecture evolved under mammalian pressure has remained unexplored. Here we show how dense branching and spines emerged during the age of mammalian radiation in the Combretaceae family and diversified in herbivore-driven ecosystems in the tropics. Phylogenetic comparative methods revealed that modern plant architectural strategies defending against large mammals evolved via a stepwise process. First, dense branching emerged under intermediate herbivory pressure, followed by the acquisition of spines that supported higher speciation rates under high herbivory pressure. Our study highlights the adaptive value of dense branching as part of a herbivore defence strategy and identifies large mammal herbivory as a major selective force shaping the whole plant architecture of woody plants. This study explores the evolution of two traits, branching density and spine presence, in the globally distributed plant family Combretaceae. These traits were found to have appeared in a two-step process in response to mammalian herbivory pressure, revealing the importance of large mammals in the evolution of plant architecture diversity.

Organisms use diverse strategies to thrive in varying habitats. While life history theory partly explains these relationships, the combined impact of resource availability and disturbance frequency on life form strategy evolution has received limited attention.We use Chamaecrista species, a legume plant lineage with a high diversity of plant life forms in the Neotropics, and employ ecological niche modeling and comparative phylogenetic methods to examine the correlated evolution of plant life forms and environmental niches.Chamaephytes and phanerophytes have optima in environments characterized by moderate water and nutrient availability coupled with infrequent fire disturbances. By contrast, annual plants thrive in environments with scarce water and nutrients, alongside frequent fire disturbances. Similarly, geophyte species also show increased resistance to frequent fire disturbances, although they thrive in resource‐rich environments.Our findings shed light on the evolution of plant strategies along environmental gradients, highlighting that annuals and geophytes respond differently to high incidences of fire disturbances, with one enduring it as seeds in a resource‐limited habitat and the other relying on reserves and root resprouting systems in resource‐abundant habitats. Furthermore, it deepens our understanding of how organisms evolve associated with their habitats, emphasizing a constraint posed by low‐resource and high‐disturbance environments.

Passiflora foetida is a climbing vine, native to the Neotropical Region that is causing major economic and ecological damage in Australia, where it is rapidly spreading. Traditional control options, such as cutting, manual uprooting, and herbicide applications are only effective for local management. Currently, the plant bug Engytatus passionarius is the most promising biological control agent. Specificity tests performed in its native range in Argentina suggest it is highly specific to the plant, and it has not been observed in the field associated with other plants. As climate determines the establishment of insects, knowing if the environmental conditions suit their requirements is key to introducing a species in a region. Also, an overlap between the climatic niches of species is an indicator of similar requirements. To explore the possibilities of a successful establishment of E. passionarius in Australia, ecological niche models (ENM) were built for the plant bug and for the vine and their overlap was measured. The ENM projected to Australia recognized suitable environmental conditions for the establishment of E. passionarius in several regions where P. foetida is present, both for current and future scenarios. Moreover, the niche of the plant bug is almost completely overlapped with that of the vine. All the aforementioned evidence seems to indicate that E. passionarius has a good chance to become an effective biological control agent of P. foetida.

The genetic composition of founding populations is likely to play a key role in determining invasion success. Individual genotypes may differ in habitat preference and environmental tolerance, so their ability to colonize novel environments can be highly variable. Despite the importance of genetic variation on invasion success, its influence on the potential distribution of invaders is rarely investigated. Here, we integrate population genomics and ecological niche models (ENMs) into a single framework to predict the distribution of globally invasive common ragweed (Ambrosia artemisiifolia) in Australia. We identified three genetic clusters for ragweed and used these to construct cluster‐specific ENMs and characterize within‐species niche differentiation. The potential range of ragweed in Australia depended on the genetic composition and continent of origin of the introduced population. Invaders originating from warmer, wetter climates had a broader potential distribution than those from cooler, drier ones. By quantifying this change, we identified source populations most likely to expand the ragweed distribution. As prevention remains the most effective method of invasive species management, our work provides a valuable way of ranking the threat posed by different populations to better inform management decisions.

Quercus arkansana (Arkansas oak) is at risk of becoming endangered, as the total known population size is represented by a few isolated populations. The potential impact of climate change on this species in the near future is high, yet knowledge of its predicted effects is limited. Our study utilized the biomod2 R package to develop habitat suitability ensemble models based on bioclimatic and topographic environmental variables and the known locations of current distribution of Q. arkansana . We predicted suitable habitats across three climate change scenarios (SSP1-2.6, SSP2-4.5, and SSP5-8.5) for 2050, 2070, and 2090. Our findings reveal that the current suitable habitat for Q. arkansana is approximately 127,881 km 2 across seven states (Texas, Arkansas, Alabama, Louisiana, Mississippi, Georgia, and Florida); approximately 9.5% is encompassed within state and federally managed protected areas. Our models predict that all current suitable habitats will disappear by 2050 due to climate change, resulting in a northward shift into new regions such as Tennessee and Kentucky. The large extent of suitable habitat outside protected areas suggests that a species-specific action plan incorporating protected areas and other areas may be crucial for its conservation. Moreover, protection of Q. arkansana habitat against climate change may require locally and regionally focused conservation policies, adaptive management strategies, and educational outreach among local people.

AbstractAimSpreading infectious diseases associated with introduced pathogens can have devastating effects on native biota and human livelihoods. We analyse the global distribution of 100 major alien fungal and oomycete pathogens with substantial socio‐economic and environmental impacts and examine their taxonomy, ecological characteristics, temporal accumulation trajectories, regional hot‐ and coldspots of taxon richness and taxon flows between continents.LocationGlobal.TaxonAlien/cryptogenic fungi and fungus‐like oomycetes, pathogenic to plants or animals.MethodsTo identify over/underrepresented classes and phyla, we performed Chi2 tests of independence. To describe spatial patterns, we calculated the region‐wise richness and identified hot‐ and coldspots, defined as residuals after correcting taxon richness for region area and sampling effort via a quasi‐Poisson regression. We examined the relationship with environmental and socio‐economic drivers with a multiple linear regression and evaluated a potential island effect. Regional first records were pooled over 20‐year periods, and for global flows the links between the native range to the alien regions were mapped.ResultsPeronosporomycetes (Oomycota) were overrepresented among taxa and regional taxon richness was positively correlated with area and sampling effort. While no island effect was found, likely due to host limitations, hotspots were correlated with human modification of terrestrial land, per capita gross domestic product, temperate and tropical forest biomes, and orobiomes. Regional first records have increased steeply in recent decades. While Europe and Northern America were major recipients, about half of the taxa originate from Asia.Main ConclusionsWe highlight the putative importance of anthropogenic drivers, such as land use providing a conducive environment, contact opportunities and susceptible hosts, as well as economic wealth likely increasing colonisation pressure. While most taxa were associated with socio‐economic impacts, possibly partly due to a bias in research focus, about a third show substantial impacts to both socio‐economy and the environment, underscoring the importance of maintaining a wholescale perspective across natural and managed systems.