Theodore Dru Alison Cockerell

Abstract Trichomes are diverse and functionally important plant structures that vary in response to selection pressures across ecological gradients and evolutionary timescales. Classic hypotheses predict higher investment in trichomes in arid environments, at lower latitudes, and in long-lived species, as well as shifts in trichome production to reduce conflict between defense traits and mutualisms. However, tests of these hypotheses often rely on aggregate trichome metrics and neglect the rich diversity of trichome phenotypes. Here, we collected data on fine-scale patterns of trichome length, density, and type in 52 species of blazingstars (Mentzelia: Loasaceae) and tested whether individual trichome traits were consistent with existing adaptive hypotheses. Contrary to longstanding hypotheses, we found that Mentzelia species tend to display greater trichome investment in less arid environments and at higher latitudes. Barbed trichomes are significantly less common on the upper surface of the leaf, possibly reducing defense-pollination conflict. Species with larger petals (a proxy for reliance on insect pollinators) also shift investment away from insect-trapping hairs on the underside of the leaf. Examining trichome types separately revealed that different morphologies show distinct responses to abiotic and biotic factors, demonstrating the need to consider multiple axes of diversity when testing adaptive hypotheses for complex traits.

AbstractPremiseBiotic disjunctions have attracted scientific attention for the past 200 years. Despite being represented in many familiar plants (such as bald cypress, flowering dogwood, sweetgum, partridgeberry, etc.), the eastern North American (ENA)–Mexican (M) disjunction remains poorly understood. Major outstanding questions include the divergence times of taxa exhibiting the disjunction and environmental/geological processes that may underlie the disjunction. Symphyotrichum Nees (Asteraceae), one of the most diverse genera in the eastern USA, displays several examples of disjunct ENA–M taxa.MethodsWe generated target capture data using the Angiosperms353 baitset and generated the first well‐sampled phylogenomic hypothesis for Symphyotrichum and its close relatives. Focusing on S. subgenus Virgulus, we used MCMCTREE to perform divergence time estimation and the R package BioGeoBEARS to infer ancestral regions and biogeographic transitions between North America and Mexico. Finally, we used the ancestral niche reconstruction method Utremi to test for a role of historical aridification in generating the disjunction.ResultsOur molecular data suggest a recent radiation of Symphyotrichum at the Plio‐Pleistocene boundary (~2.5 mya), with early connections to Mexico in ancestral lineages that closed off shortly after and were followed by vicariance across this region. Except for some present‐day broadly distributed species, there is a complete lack of movement between ENA and M after ~0.5 mya.ConclusionsA reconstructed disjunct distribution of suitable habitat in Pleistocene climatic models corroborates results from biogeographic modeling and confirms glacial cycles are more likely to be associated with the breakup of ENA–M biogeographic connections.

Given the heightened vulnerability of deserts to climate change, this study aims to provide a comprehensive analysis of avian species diversity across ten global deserts to identify distinct diversity gradients and relatedness. Identify the difference from global patterns in avian migratory proportions and the underlying drivers for assessing the vulnerability and resilience of these desert ecosystems. Crowd-sourced avian diversity data of 2374 species from GBIF.org was used as a key analytical tool to study the diversity gradient across the ten major deserts. The variance in correlation patterns between avian ecological and behavioral traits across deserts were analyzed employing data of 1930 common avian species from AVONET. The analysis included comparisons of bird diversity, migratory patterns and trophic niches between Tropic of Cancer (TCan) and Tropic of Capricorn (TCap) deserts. Significant variations in bird diversity among the deserts were found. Deserts near the TCan exhibited higher bird diversity than in TCap deserts. TCan deserts had a higher prevalence of migratory species, facilitated by a broader niche breadth among sedentary species, which reduces niche competition and allows the influx of migratory invertivores. Proportion of migratory birds is higher in TCan deserts due to wider trophic niche but is significantly lower than the global average for the same latitude range. The findings highlight the need for targeted conservation strategies to protect avian diversity in the TCan deserts and mitigate extinction risks in TCap deserts, ensuring the resilience of these critical ecosystems.

ABSTRACTAimCryptic invasions are an understudied phenomenon among species invasions, especially in freshwater invertebrates. We study the gastropod family Physidae, including the global invaders Physella acuta and several enigmatic Stenophysa species, their phylogenetic relationships and the presence of native species among African Physidae. We infer distribution pattern, colonisation history and invasion ecology across Africa. Finally, we reconstruct the colonisation pathways and their timing into, across (and out of) Africa and model future dispersal.LocationGlobal, with a focus on Africa and Indian Ocean islands.MethodsBased on extensive sampling, multi‐gene phylogenetic, phylogeographic and ecological analyses, including species distribution modelling, we here examine Physidae globally.ResultsThe Physidae probably originated in the Lower Cretaceous. A robust phylogeny showed four strongly supported genus‐level clades corresponding to Physella, Physa, Stenophysa and Aplexa. Physella acuta thrives in continental African countries and Indian Ocean islands. The African continent was colonised at least six times independently.For Stenophysa, the phylogeny suggests two independent transoceanic dispersal events into Africa and the Indian Ocean islands. Physella acuta occurs not only in artificial or highly disturbed habitats but also in large natural lakes. Stenophysa marmorata is ecologically flexible. The SDM for S. marmorata based on the selected climate variables predicted high probabilities of future occurrence in equatorial Africa and regions in the Indo‐Malayan Archipelago, New Guinea and eastern Australia.Main ConclusionsPhysidae contains examples of both intraspecific cryptic and interspecific cryptic invasions, with an intraspecific invasion of Physella acuta and a prime example of an interspecific cryptic invasion of Stenophysa spp. This study highlights the importance of cryptic invasions in freshwaters and also calls for their management. Stenophysa is likely to become pan‐tropical in the future. Physidae are an excellent model to study differential patterns and processes of intra‐ versus interspecific invasions at global and regional scales.

To understand how and where biodiversity is threatened, it is imperative to build historical baselines that accurately characterize the present and past states of biodiversity across environments. Botanical collections provide important ecological, evolutionary, and biogeographic information on the diversity and distributions of plant taxa, yet biases in collection efforts across spatial, temporal, and taxonomic scales are well known. Here, we characterize and quantify trends in botanical collections made from across different abiotic, biotic, and sociopolitical boundaries within the present‐day state of New Mexico. Using a biodiversity informatics approach applied toward a regional case study, we identify opportunities for efficiently improving natural history collection coverage and analyses of botanical diversity. Accurate representation of botanical biodiversity, preserved for future generations through vouchered plant specimens deposited in herbaria, depends on collection decisions made now. This work aims to provide a useful workflow for synthesizing digitized regional botanical collections as researchers prioritize current and future resources in the face of global change.

ABSTRACTAimUndersampling and other sources of sampling bias pose significant issues in marine macroecology, particularly when shaping conservation and management decisions. Yet, determining the extent to which such biases impact our understanding of marine diversity remains elusive. Here, utilising empirical data on sampling efforts, we sampled from virtually established species distributions to evaluate how deep is the influence of sampling bias on estimations of the latitudinal gradient in marine diversity.LocationAtlantic Ocean.Time PeriodPresent.Taxa StudiedOphiuroidea.MethodsWe developed a computer simulation that implements two null models of species distribution (the geometric constraints and the area model) in a two‐dimensional domain, replicates the latitudinal distribution of historical sampling efforts and then quantifies diversity metrics (observed and estimated species richness) and sample completeness for each grid cell and latitudinal band.ResultsWe found consistent patterns of observed species richness across models, noting peaks at midlatitudes regardless of whether the true richness was unimodal or flat. Dips in equatorial diversity persisted even after using different methods of species richness estimation. Additional simulations showed that estimators' accuracy improved with increased sampling efforts, but only when samples were randomly distributed. Spatially aggregated samples inflate completeness without necessarily enhancing estimators' accuracy.Main ConclusionsThis finding emphasises the imperative of bolstering sampling efforts at tropical latitudes and deploying robust statistical techniques to mitigate undersampling effects. Meanwhile, we suggest considering sampling bias as an alternative null hypothesis for recorded marine diversity patterns.

Prioritizing potential invasive alien species, introduction pathways, and likely places susceptible to biological invasions is collectively critical for developing the targeting of management strategies at pre‐border, border, and post‐border. A framework for prioritizing the invasion management that considered all these elements in combination is lacking, particularly in the context of potential coinvasion scenarios of multispecies. Here, for the first time, we have constructed a coupling framework of biological invasions to evaluate and prioritize multiple invasion risks of 35 invasive alien mealybugs (IAMs) that posed a significant threat to the agri‐horticultural crops in China. We found that the imported tropical fruits from free trade areas of the Association of Southeast Asian Nations to entry ports of southern China were the primary introduction pathway for IAMs, vectored on various fruit commodities. There was also a high probability for cointroductions of potential multi‐IAMs with a single imported tropical fruit. The potential distribution of such IAMs with dissimilar net relatedness were mainly located in southern China. These distributions, however, are likely to expand to the higher latitudes of northern China under future climate and land use/land cover changes. Temperature and anthropogenic factors were both independently and collectively determining factors for the diversity and distribution patterns of imported IAMs under near‐current climate conditions. Our findings highlight that these multiple components of global change have and will continue to facilitate the introduction and establishment risks of IAMs in southern China, as well as the spread risk into northern China. Additionally, our findings, for the first time, demonstrated management prioritization across the continuous invasion stages of 35 IAMs in China, and provide additional insights into the development of targeting of their biosecurity and management decisions.

Island ecosystems have significant conservation value owing to their higher endemic biotas. Moreover, studies of regional communities that compare differences in species composition (species dissimilarity) among islands and the mainland suggest that community assembly on islands is different from that on the mainland. However, the uniqueness of island biotic assembly has been little studied at the global scale, nor have phylogenetic information or alien species been considered in these patterns. We evaluate taxonomic and phylogenetic change from one community to the next, focusing on differences in species composition between mainland-mainland (M-M) pairs compared to differences between mainland-island pairs (M-I) and between island-island pairs (I-I), using herpetofauna on islands and adjacent mainland areas worldwide. Our analyses detect greater taxonomic and phylogenetic dissimilarity for M-I and I-I comparisons than predicted by M-M model, indicating different island herpetofauna assembly patterns compared with mainland counterparts across the world. However, this higher M-I dissimilarity has been significantly decreased after considering alien species. Our results provide global evidence on the importance of island biodiversity conservation from the aspect of both the taxonomic and phylogenetic uniqueness of island biotic assembly.

Predicting global change effects poses significant challenges due to the intricate interplay between climate change and anthropogenic stressors in shaping ecological communities and their function, such as pest outbreak risk. Termites are ecosystem engineers, yet some pest species are causing worldwide economic losses. While habitat fragmentation seems to drive pest-dominated termite communities, its interaction with climate change effect remains unknown. We test whether climate and habitat fragmentation interactively alter interspecific competition that may limit pest termite risk. Leveraging global termite co-occurrence including 280 pest species, we found that competitively superior termite species (e.g., large bodied) increased in large and continuous habitats solely at high precipitation. While competitive species suppressed pest species globally, habitat fragmentation drove pest termite risk only in humid biomes. Unfortunately, hu- mid tropics have experienced vast forest fragmentation and rainfall reduction over the past decades. These stressors, if not stopped, may drive pest termite risk, potentially via competitive release.

AbstractBees (Hymenoptera: Apoidea) are vital components of global ecosystems, yet knowledge of their distribution is limited in many regions. Washington state is located in an ecologically diverse part of North America and encompasses habitat types and plant communities known for high bee species richness. To establish a baseline for future studies on bee communities in the state, we used published and unpublished datasets to develop a preliminary annotated checklist of bees occurring in Washington state. We document, with high confidence, 565 species of bees in Washington and identify an additional 102 species likely to occur in the state. We anticipate future research survey efforts, such as the newly initiated Washington Bee Atlas, will discover several species that have the potential to occur in Washington and provide new data for 84 species which have not been recorded in more than 50 years.