Harold Norman Moldenke

Non‐native annual grasses can dramatically alter fire frequency and reduce forage quality and biodiversity in the ecosystems they invade. Effective management techniques are needed to reduce these undesirable invasive species and maintain ecosystem services. Well‐timed management strategies, such as grazing, that are applied when invasive grasses are active prior to native plants can control invasive species spread and reduce their impact; however, anticipating the timing of key phenological stages that are susceptible to management over vast landscapes is difficult, as the phenology of these species can vary greatly over time and space. To address this challenge, we created range‐wide phenology forecasts for two problematic invasive annual grasses: cheatgrass (Bromus tectorum), and red brome (Bromus rubens). We tested a suite of 18 mechanistic phenology models using observations from monitoring experiments, volunteer science, herbarium records, timelapse camera imagery, and downscaled gridded climate data to identify the models that best predicted the dates of flowering and senescence of the two invasive grass species. We found that the timing of flowering and senescence of cheatgrass and red brome were best predicted by photothermal time models that had been adjusted for topography using gridded continuous heat‐insolation load index values. Phenology forecasts based on these models can help managers make decisions about when to schedule management actions such as grazing to reduce undesirable invasive grasses and promote forage production, quality, and biodiversity in grasslands; to predict the timing of greatest fire risk after annual grasses dry out; and to select remote sensing imagery to accurately map invasive grasses across topographic and latitudinal gradients. These phenology models also have the potential to be operationalized for within‐season or within‐year decision support.

AbstractPremiseClines—or the geographic sorting of phenotypes across continual space—provide an opportunity to understand the interaction of dispersal, selection, and history in structuring polymorphisms.MethodsIn this study, we combine field‐sampling, genetics, climatic analyses, and machine learning to understand a flower color polymorphism in the wide‐ranging desert annual Encelia farinosa.ResultsWe find evidence for replicated transitions in disk floret color from brown to yellow across spatial scales, with the most prominent cline stretching ~100 km from southwestern United States into México. Because population structure across the cline is minimal, selection is more likely than drift to have an important role in determining cline width.ConclusionsGiven that the cline aligns with a climatic transition but there is no evidence for pollinator preference for flower color, we hypothesize that floret color likely varies as a function of climatic conditions.

The first record of Xenoglossa (Cemolobus) ipomoeae (Robertson, 1891) (Apidae: Eucerini) for the state of Mississippi, USA is reported. This species is a rarely encountered specialist bee that is known to forage on Ipomoea pandurata (L.) G.F.W. Mey (Convolvulaceae), potentially along with other closely related plants in the genus Ipomoea. A single female was collected in Bolivar County during 2017 that a represents a significant southwestern range expansion for this bee species.

Traits associated with successful biological invasions across environmental gradients or geographical distances may vary depending on processes such as founder effects, ecological sorting, or adaptation to local conditions. Consequently, drivers of success are not necessarily consistent throughout the invasive range. We evaluate how plant traits, reproductive success and climatic preferences vary in populations of a naturalized orchid on islands in the Atlantic, Pacific and Indian oceans. Populations of Arundina graminifolia (bamboo orchid) were located on Puerto Rico, Hawaiian Islands (Hawai’i, O’ahu, Kaua’i), and Mauritius. Vegetative and reproductive traits were measured, and male and female success were assessed. Populations were compared using multivariate approaches. Species distribution modeling was used to assess potential climatic preferences within and among islands. Floral morphology differed among islands but considerable overlap in trait distributions exists. Reproductive success significantly differed among islands and was linked to floral traits, local pollinator pools and perhaps variable levels of florivory. Hawaiian populations occupied the broadest climatic niche space and Mauritius the most restricted. The effectiveness of using present points from the native range to reveal climatic suitability on invaded islands varied among islands. Successful invasions across a broad geographical range can occur even when morphology, reproductive success and climatic conditions are variable. As expected, some aspects of this global invasion are similar, but others differ among islands underscoring the context dependency of biological invasions and the difficulty of overall predictions. Los rasgos asociados a las invasiones biológicas exitosas a través de gradientes ambientales o distancias geográficas pueden variar dependiendo de procesos tales como el efecto fundador, el sorteo ecológico, o las adaptaciones a las condiciones locales. Consecuentemente, los impulsores del éxito no son necesariamente consistentes a través de la distribución invadida. Nosotros evaluamos cómo los rasgos, el éxito reproductivo y las preferencias climáticas varían en poblaciones de una orquídea naturalizada en islas de los océanos Atlántico, Pacífico e Índico. Las poblaciones de Arundina graminifolia (orquídea bambú) estaban localizadas en Puerto Rico, las Islas Hawaianas (Hawai’i, O’ahu, Kaua’i) y en la Isla de Mauricio. Los rasgos vegetativos y reproductivos fueron medidos, y el éxito reproductivo masculino y femenino fue evaluado. Comparamos las poblaciones usando enfoques estadísticos multivariados. También usamos modelos de distribución de especies para evaluar las preferencias climáticas tanto dentro de las islas, así como entre ellas. La morfología floral difirió entre islas, pero existe un sobrelapamiento considerable en la distribución de rasgos. El éxito reproductivo fue significativamente diferente entre islas, y estuvo ligado a los rasgos florales, el conjunto de polinizadores locales y, quizá, a niveles variables de florivoría. Las poblaciones hawaianas ocuparon el nicho climático más amplio mientras que las mauricianas ocuparon el más restringido. La efectividad de usar puntos de presencia de la distribución nativa para revelar la adecuación climática de las islas invadidas varió entre islas. Encontramos que las invasiones exitosas a través de una distribución geográfica amplia pueden ocurrir a pesar de la variabilidad en morfología, éxito reproductivo y condiciones climáticas. Como era de esperarse, algunos aspectos de esta invasión global son similares, pero otros difieren entre islas, haciendo hincapié en la dependencia del contexto de las invasiones biológicas y la dificultad de hacer predicciones generalizadas. Les traits associés aux invasions biologiques sur des gradients environnementaux ou des distances géographiques peuvent varier en fonction de processus tels que les effets fondateurs, le tri écologique ou l'adaptation aux conditions locales. Par conséquent, les facteurs de réussite ne sont pas nécessairement cohérents dans l'ensemble de l'aire de répartition de l'invasion. Nous évaluons comment les caractéristiques des plantes, le succès de la reproduction et les préférences climatiques varient dans les populations d'une orchidée naturalisée sur des îles des océans Atlantique, Pacifique et Indien. Les populations d'Arundina graminifolia (orchidée bambou) ont été localisées à Porto Rico, dans les îles hawaïennes (Hawai'i, O'ahu, Kaua'i) et à l'île Maurice. Les traits végétatifs et reproductifs ont été mesurés, et le succès reproductifs des mâles et des femelles a été évalué. Les populations ont été comparées à l'aide d'approches multivariées. La modélisation de la distribution des espèces a été utilisée pour évaluer les préférences climatiques potentielles au sein des îles et entre elles. La morphologie florale diffère d'une île à l'autre, mais il existe un chevauchement considérable dans la répartition des caractéristiques. Le succès de la reproduction diffère significativement entre les îles et est lié aux caractéristiques florales, aux réservoirs locaux de pollinisateurs et peut-être à des niveaux variables de florivorie. Les populations hawaïennes ont occupé la niche climatique la plus large et les populations mauriciennes la plus restreinte. L'efficacité de l'utilisation de points de présences dans l'aire de répartition indigène pour révéler l'adéquation climatique des îles envahies varie d'une île à l'autre. Des invasions réussies sur une vaste aire de répartition géographique peuvent se produire même lorsque la morphologie, le succès de la reproduction et les conditions climatiques sont variables. Comme prévu, certains aspects de cette invasion mondiale sont similaires, mais d'autres diffèrent d'une île à l'autre, ce qui souligne l’importance du contexte des invasions biologiques et la difficulté des prédictions globales.

Plant species with small habitat ranges and specific edaphic requirements are highly vulnerable to extinction and thus require enhanced attention in biodiversity conservation. This study was designed to explore the challenges of protecting such plant species by evaluating the in situ and ex situ conservation capacities available for Thailand's species of the mega‐diverse plant genus Begonia L. A comprehensive assessment of occurrence records across the country was conducted to evaluate the spatial distribution of Begonia diversity in Thailand, identify biodiversity hotspots, assess the extinction threats faced by the 60 Begonia species known in the country, and identify existing conservation capacities and potential gaps. The results show that 78% of Begonia species in Thailand are vulnerable to extinction, with the Northern floristic region identified as both a Begonia species hotspot and a region with major conservation gaps. While in situ conservation efforts have been successful in covering over 88% of the species, they have failed to provide the protection required to achieve zero extinction. Ex situ conservation capacities are poorly developed, with only 13% of species present in botanical gardens, and no seed banking or other related activities have been initiated. This evaluation presents a sharply contrasting message: on one hand, Thailand has assembled substantial capacities to protect these plants through established national parks and other protected areas, but on the other hand, essential capacities are still lacking to render the zero extinction target achievable. We advocate for the implementation of a multi‐component conservation strategy to enable Thailand to move towards zero species extinction, even for plant species with narrow habitat ranges and high edaphic specialisation.

Premise of research. Little is known about the establishment success of grasses after their introduction into new areas. Using herbarium data, we investigated temporospatial patterns in the survival, establishment, and spread of grasses introduced to eastern North America through solid ballast deposition from the pre-twentieth-century shipping trade. Methodology. We identified 95 grass species introduced to New Jersey via ballast deposition and used 2729 digitized and georeferenced plant specimens from 63 herbaria to quantify their establishment and dispersion. Anselin Local Moran’s I measure of local spatial autocorrelation revealed the earliest and most recent areas of invasion by ballast grasses irrespective of collection intensity. Species’ native ranges were used to evaluate the differential establishment and dispersion of species from different biogeographic realms. Pivotal results. Of all the species (95), 51% did not survive after ballast deposition ended (waifs), 8% died out shortly thereafter (short-term), and 41% became established in New Jersey. Of the established species, 41% are widespread (established-widespread), and 59% are still primarily found near shipping ports and railroads (established–limited spread). These species are mostly native to the Palearctic (77%; 44% to the Mediterranean and 33% to northern Europe), followed by the Neotropics (11%), the Afrotropics (10%), and the southeastern United States (4%). The establishment proportion for species native to more than one biogeographic region (72%) was four times greater than that for species native to a single region (18%). Additionally, 95% of established species, including all established-widespread species, are native to the Eastern Hemisphere. Conclusions. We present the first analysis of the establishment proportion for a large set of grasses introduced through a single vector to a single area. We show the impact of biogeographic origin on the establishment proportion of introduced grasses and highlight the utility of herbarium collections for studying nonnative species’ history.

Premise Cleomaceae is an important model clade for studies of evolutionary processes including genome evolution, floral form diversification, and photosynthetic pathway evolution. Diversification and divergence patterns in Cleomaceae remain tangled as research has been restricted by its worldwide distribution, limited genetic sampling and species coverage, and a lack of definitive fossil calibration points.MethodsWe used target sequence capture and the Angiosperms353 probe set to perform a phylogenetic study of Cleomaceae. We estimated divergence times and biogeographic analyses to explore the origin and diversification of the family. Seed morphology across extant taxa was documented with multifocal image‐stacking techniques and morphological characters were extracted, analyzed, and compared to fossil records.ResultsWe recovered a well‐supported and resolved phylogenetic tree of Cleomaceae generic relationships that includes 236 (~86%) species. We identified 11 principal clades and confidently placed Cleomella as sister to the rest of the family. Our analyses suggested that Cleomaceae and Brassicaceae diverged ~56 mya, and Cleomaceae began to diversify ~53 mya in the Palearctic and Africa. Multiple transatlantic disjunct distributions were identified. Seeds were imaged from 218 (~80%) species in the family and compared to all known fossil species.ConclusionsOur results represent the most comprehensive phylogenetic study of Cleomaceae to date. We identified transatlantic disjunctions and proposed explanations for these patterns, most likely either long‐distance dispersals or contractions in latitudinal distributions caused by climate change over geological timescales. We found that seed morphology varied considerably but mostly mirrored generic relationships.

Submerged macrophytes remediation is a commonly used technique for improving water quality and restoring habitat in aquatic ecosystems. However, the drivers of success in the submerged macrophytes assembly process and their specific impacts on methane emissions are poorly understood. Thus, we conducted a mesocosm experiment to test the growth plasticity and carbon fixation of widespread submerged macrophytes (Vallisneria natans) under different nutrient conditions. A refined dynamic chamber method was utilized to concurrently collect and quantify methane emission fluxes arising from ebullition and diffusion processes. Significant correlations were found between methane flux and variations in the physiological activities of V. nantas by the fluorescence imaging system. Our results show that exceeding tolerance thresholds of ammonia in the water significantly interfered with the photosynthetic systems in submerged leaves and the radial oxygen loss in adventitious roots. The recovery process of V. natans accelerated the consumption of dissolved oxygen, leading to increase in the populations of methanogen (153.3 % increase of mcrA genes) and subsequently elevating CH4 emission fluxes (23.7 %) under high nutrient concentrations. Conversely, V. natans increased the available organic carbon under low nutrient conditions by radial oxygen loss, further increasing CH4 emission fluxes (94.7 %). Quantitative genetic and modeling analyses revealed that plant restoration processes drive ecological niche differentiation of methanogenic and methane oxidation microorganisms, affecting methane release fluxes within the restored area. The speciation process of V. natans is incapable of simultaneously meeting improved water purification and reduced methane emissions goals.

The Khanka Lowland forest-steppe is the most eastern outpost of the Eurasian steppe biome. It includes unique grassland plant communities with rare steppe species. These coenosis have changed under the influence of anthropogenic activity, especially during the last 100 years and included both typical steppe species and nemoral mesophytic species. To distinguish these ecological groups of plants the random forest method with three datasets of environmental variables was applied. Specifically, a model of classification with the most important bioindices to predict a mesophytic ecological group of plants with a sensitivity greater than 80% was constructed. The data demonstrated the presence of steppe species that arrived at different times in the Primorye Territory. Most of these species are associated with the Mongolian-Daurian relict steppe complex and habit in the Khanka Lowland. Other species occur only in mountains in Primorye Territory and do not persist in the Khanka Lowland. These findings emphasize the presence of relict steppe communities with a complex of true steppe species in the Khanka Lowland. Steppe communities exhibit features of anthropogenic influence definitely through the long land use period but are not anthropogenic in origin. The most steppe species are located at the eastern border of distribution in the Khanka Lowlands and are valuable in terms of conservation and sources of information about steppe species origin and the emergence of the steppe biome as a whole.

The solitary oil-collecting bees of the tribes Centridini, Tapinotaspidini, and Tetrapediini inhabit areas from the southern part of the Nearctic Region through the Patagonian in southern South America, including the Caribbean. These bees are morphologically and behaviorally specialized in collecting oils as a reward from specialized floral glandular structures present in oil-producer plants. Oil-producer plants and oil-collecting bees have a mutualistic relationship in which the latter potentially pollinate the formers while collecting oils from their flowers. The main objective of this work is to infer the species richness and the key areas for conservation, research, and sustainable use of oil-collecting bees of the tribes Centridini, Tapinotaspidini, and Tetrapediini in the Americas. We collected occurrence records for 528 species of oil-collecting bees and estimated the species richness for each tribe and genus. In total, we estimated 664 species across the three mentioned tribes. With that baseline information, we created models of the richness and rarity patterns of the entire group of species and each tribe as a criterion to highlight key areas, along with richness and rarity centers for the American oil-collecting bees. We identified several critical areas that can be prioritized for conservation and research projects, including territories in Panama, Costa Rica, the Central and Northern Andes, the Amazon basin, and the biogeographic provinces of Cerrado, Atlantic Forest, Pampean, and Chacoan. Here we provide crucial information on key diversity areas for oil-collecting bees across the Americas. This information can be used for the conservation, research, and sustainable use of this important group of insect pollinators.