John Macoun

Abstract The Montane Shrew, Sorex monticola, is a common and wide-ranging mammal throughout western North America. Previous studies identified multiple mitochondrial lineages, but limited geographic sampling constrained our understanding of distributional limits, phylogeographic variation, and biogeographic history. We used range-wide sampling and multi-model phylogenetic analyses to examine mitochondrial phylogeographic variation, evaluate niche differentiation, and test historical biogeographic hypotheses. We examined cytochrome b gene sequences from 462 individuals and 277 localities across the distribution of S. monticola and related species, including the first specimens from the Sierra Nevada (California, United States) and Sierra Madre Occidental (Durango and Chihuahua, Mexico). Estimated genealogical relationships, divergence times, and delimitation approaches identified 3 well-supported, deeply divergent, geographically structured clades consistent with previous estimates (Coastal, Southern, Northern). Sorex monticola was paraphyletic with S. sonomae and all species of North American water shrews. We also identified minimal divergence between Coastal S. monticola and 2 nominal species, S. pacificus and S. bairdii, that are sympatric in the Pacific Northwest. Demographic tests indicated that some lineages represent stable and isolated island and montane populations, while others represent populations that experienced demographic expansion since the Last Glacial Maximum. Niche differentiation tests revealed that each clade occupies distinctive environmental conditions, with projections of future conditions suggesting that populations isolated in southern mountains may face extirpation associated with warming climate and aridification. This range-wide assessment of geographic genetic variation lays a foundation for selecting samples from key populations for expanded genome-level investigations into evolutionary relationships and taxonomic limits, enabling tests of hypotheses related to Pleistocene climatic drivers of biotic diversification processes across western North America.

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.

The family Onocleaceae represents a small family of terrestrial ferns, with four genera and around five species. It has a circumboreal to north temperate distribution, and exhibits a disjunct distribution between Eurasia and North America, including Mexico. Historically, the taxonomy and classification of this family has been subject to debate and contention among scholars, leading to contradictory classifications and disagreements on the number of genera and species within the family. Furthermore, due to this disjunct intercontinental distribution and the lack of detailed study across its wide range, this family merits further study to clarify its distributional pattern. Maximum likelihood and Bayesian phylogenetic reconstructions were based on a concatenated sequence dataset for 17 plastid loci and one nuclear locus, which were generated from 106 ingroup and six outgroup taxa from three families. Phylogenetic analyses support that Onocleaceae is composed of four main clades, and Pentarhizidium was recovered as the first branching lineages in Onocleaceae. Molecular dating and ancestral area reconstruction analyses suggest that the stem group of Onocleaceae originated in Late Cretaceous, with subsequent diversification and establishment of the genera Matteuccia, Onoclea, Onocleopsis, and Pentarhizidium during the Paleogene and Neogene. The ancestors of Matteuccia, Onoclea, and Onocleopsis could have migrated to North America via the Beringian land bridge or North Atlantic land bridge which suggests that the diversification of Matteuccia + Onoclea + Onocleopsis closely aligns with the Paleocene-Eocene Thermal Maximum (PETM). In addition, these results suggest that Onocleaceae species diversity peaks during the late Neogene to Quaternary. Studies such as this enhance our understanding of the mechanisms and climatic conditions shaping disjunct distribution in ferns and lycophytes of eastern Asia, North America, and Mexico and contribute to a growing body of evidence from other taxa, to advance our understanding of the origins and migration of plants across continents.

Dispersal ability may play a major role in determining whether a species will persist under climate change. We used models of dispersal, employing a wide range of intrinsic species-specific dispersal factors, in conjunction with ecological niche models (ENM) and climate predictions to simulate whether distributions of North American cold-adapted amphibians will increase or decrease, and which aspects of dispersal most influence this prediction. We used ENM values as a proxy for habitat suitability, predicted a changing climate under three shared socio-economic pathways (SSP2-4.5, SSP3-7.0, and SSP5-8.5) representing three carbon emission scenarios, and conducted a sensitivity analysis on the effect of dispersal factors on range dynamics. We then used simulations focused only on the southern edge of ranges to determine the likelihood of individuals colonizing towards the core. Predicted range shifts depended on emission scenario, dispersal factors, and species’ initial geography. Inclusion of dispersal parameters was critical in predicting range shifts, in particular for high carbon-emission scenarios where contraction was more likely than expansion, although specific responses varied with species initial geography. Dispersal distance, probability of dispersal, and long-distance dispersal were often the most important parameters for predicting final range size. Similarly, dispersal parameters results in complete loss to complete emigration of southern range individuals towards the core. These models predict that for some species in the more rapid warming scenarios, translocation efforts will be needed to mitigate potential loss of genetic variation at the southern edges and the overall size of the species’ ranges unless carbon emissions are reduced.

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.

(no abstract available)

The checklist includes a listing of the genera and species of North American Bryophyta thought to occur in the continental United States and Canada. The floras of Mexico, Hawaii and Greenland are not included. The current list recognizes 1565 species, 12 subspecies, 34 varieties and one form (for a total of 1612 taxa) in 366 genera and 100 families. As a preface to the list, a systematic arrangement of the families and included genera for North America is presented. Many changes from the previous checklist are documented via footnotes that provide references to where changes were made. Only synonymy since the previous checklist is included. Twenty nomenclatural changes are made. These include 19 new combinations: Bryum brassicoides (≡ Gemmabryum brassicoides), B. pacificum (≡ Ptychostomum pacificum), B. torenii (≡ Imbribryum torenii), B. vinosum (≡ Gemmabryum vinosum), Chionoloma maragniphyllum (≡ Oxystegus maragniphyllus), Lescuraea tribulosa (≡ Pseudoleskea tribulosa), Pterygoneurum 3kieneri (≡ P. subsessile var. kieneri Habeeb), Pylaisiadelpha canadensis (≡ Brotherella canadensis), Streblotrichum convolutum var. eustegium (≡ Barbula eustegia), Streblotrichum convolutum var. gallinula (≡ Barbula convoluta var. gallinula), Voitia angustata (≡ Splachnum angustatum), V. mnioides (≡ Splachnum mnioides), V. pallida (≡ Tetraplodon pallidus), V. paradoxa (≡ Splachnum paradoxum), V. urceolata (≡ Splachnum urceolatum), Warnstorfia badia (≡ Hypnum badium), W. straminea (≡ Hypnum stramineum), W. straminea var. patens (Lindb.) (≡ Amblystegium stramineum var. patens), W. wickesiae (≡ Calliergon wickesiae). A new order is also introduced: Rhizogemmales W.R.Buck & Goffinet (≡ Rhizogemmaceae Bonfim Santos, Siebel & Fedosov).

Protected areas (PAs) are geographical spaces intended to conserve populations, communities, and ecosystems, in which species richness must be maximized, the conserved area must be minimized, and anthropogenic pressure must be reduced. The present study analyzed the representativeness, complementarity, and degree of risk of 25 garter snake species of the genus Thamnophis in the PAs of Mexico. This study proposes that at least 17% of the potential geographic distribution (PGD) of species will be found inside PAs and in areas (Aichi Target 11) with a low human footprint (HF). The PGD of species was associated with the PAs and HF layers to identify where and which species could be at local extirpation risk by human activities. The results indicate that the federal PAs contain 85.2% of the species, while the state PAs contain 77.7% of the species. An average of 13.4% of the PGD of these species is found inside PAs, and two species are found outside. In 13 federal PAs and 10 state PAs, the Thamnophis species present high local extirpation risk from human activities. In total, 37% of species are found in PAs with a medium to very high human footprint; therefore, their persistence could be at local extirpation risk. Compared to other taxa, species of the genus Thamnophis are well represented. However, the PDG of more than half of the species achieves Aichi Target 11.

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.

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.