Search

Summary: Many plant species are predicted to migrate poleward in response to climate change. Species distribution models (SDMs) have been widely used to quantify future suitable habitats, but they often neglect soil properties, despite the importance of soil for plant fitness. As soil properties often change along latitudinal gradients, higher‐latitude soils might be more or less suitable than average conditions within the current ranges of species, thereby accelerating or slowing potential poleward migration.In this study, we built three SDMs – one with only climate predictors, one with only soil predictors, and one with both – for each of 1870 plant species in Eastern North America, in order to investigate the relative importance of soil properties in determining plant distributions and poleward shifts under climate change.While climate variables were the most important predictors, soil properties also had a substantial influence on continental‐scale plant distributions. Under future climate scenarios, models including soil predicted much smaller northward shifts in distributions than climate‐only models (c. 40% reduction).Our findings strongly suggest that high‐latitude soils are likely to impede ongoing plant migration, and they highlight the necessity of incorporating soil properties into models and predictions for plant distributions and migration under environmental change. See also the Commentary on this article by Zettlemoyer, 241: 5–6. [ABSTRACT FROM AUTHOR]

Two new species belonging to the lichen genus Anaptychia are described from western North America. Anaptychia nevadensis is superficially similar to the Eurasian A. desertorum but is distinguished by having longer ascospores, in producing scant pruina only near the lobe tips, and in regularly producing variolaric acid. Anaptychia roemerioides is described to accommodate North American material which has previously been called A. ulotrichoides. It is macro-morphologically identical to the Asian species A. roemeri but differs in having longer ascospores and conidia. Both new species are strongly supported by phylogenetic analysis of ITS sequences. We also call attention to the existence of a further undescribed but possibly cryptic species within A. elbursiana. Variolaric acid is newly reported to occur occasionally in A. desertorum and A. elbursiana. A global key to the desert species of Anaptychia is provided. [ABSTRACT FROM AUTHOR]

Premise of research. A recurring North American disjunct distribution of vascular plants exists between western North America (WNA) and the Great Lakes region (GLR) where the isolated and often threatened GLR populations are sometimes considered to be glacial relicts. Using georeferenced specimen databases and inclusion of Canadian species ranges, the historical biogeography of this enigmatic distribution can be examined. Methodology. We (1) generate the WNA-GLR vascular plant taxa list using regional floras, georeferenced localities, and maps; (2) test historical phylogeographic hypotheses by projecting suitable climate niche space to the Last Glacial Maximum (LGM) and concurrently assessing phylogeographic congruence between taxa; and (3) annotate the post-1981 literature that has contributed to the understanding of this distribution. Pivotal results. There are at least 9 genera and 53 species with this distribution. Few studies since 1981 have focused on the biogeography of these taxa, although 52 articles have cited Marquis and Voss (1981). Conservatively, 44 of 53 species' historical niche models reject the hypothesis that the species were able to persist in a midwestern glacial refugium. Taxa have different projected suitable niche space at the LGM, providing support for pseudocongruent biogeographic histories. Conclusions. The updated WNA-GLR taxa list, the preliminary assessment of historical biogeography, and the review of the scientific literature indicate that this distribution has been understudied. Investigations of additional taxa in this system will enable detailed comparative analysis between taxa and prompt discussions of geographic speciation, local adaptations in the GLR, and future persistence in the GLR in the face of climate change. [ABSTRACT FROM AUTHOR]

Simple Summary: The deciduous shrub Comptonia is a monotypic genus of Myricaceae, which currently is distributed only in eastern North America, with a smaller range than that in other periods of the Cenozoic. By analyzing the macroscopic and microscopic characteristics of the leaves, we describe a new species of Comptonia (i.e., Comptonia hirsuta) from the Hannuoba Formation in Zhuozi, Inner Mongolia, North China. The co-occurring fruits were also studied based on their morphological characteristics, which were assigned to Comptonia tymensis. Variation in the distribution range of Comptonia indicates the influence of global cooling on the expansion of this plant. Furthermore, the Bering Land Bridge played an important role in the migration from North America to East Asia. The Thulean route may have provided an opportunity for plant exchange between western Europe and eastern North America. Moreover, the reason for the disappearance of Comptonia from China according to the analysis of the changes in both the global climate and the distribution of Comptonia fossils is also discussed. It is suggested that the climatic changes after the late Miocene and the progenitive pattern of Comptonia together caused the disappearance of Comptonia in China. Comptonia (Myricaceae) is well known as a monotypic genus living only in eastern North America; however, fossils show that the genus occurred extensively in the Northern Hemisphere during the Cenozoic. We observed dozens of Comptonia leaf fossils from the early Miocene in Zhuozi, China. The leaf architecture characteristics and epidermal features of the fossil specimens are described in detail here for the first time, and they were assigned to a new species: Comptonia hirsuta. The fruit fossils collected simultaneously from the same layer were assigned to Comptonia tymensis. The global fossil records indicate that the spatial distribution range of Comptonia reached its peak in both the Eocene and Miocene as two warm periods and then gradually decreased in the Oligocene, as well as after the late Miocene, because of the cooling global climate. Furthermore, the Comptonia taxon in East Asia may have migrated from North America via the Bering route in the late Paleocene or Eocene. Plant exchange between western Europe and eastern North America possibly occurred during the Eocene via the Thulean route. Phytogeographic variation in the Comptonia fossils from China also indicates that the reason for the disappearance of Comptonia from China may not only be due to the prolonged cooling and drying after the late Miocene, but also due to its progenitive pattern. [ABSTRACT FROM AUTHOR]

The Asteraceae is the largest family of plants in North America and is widely used as medicine by Indigenous peoples. This study investigated the medicinal ethnobotany of North American Asteraceae to identify taxa that appear preferentially selected or avoided for general and specific medicinal uses. Asteraceae-specific ethnobotanical reports recorded in the Native American Ethnobotany database were compiled and, using residual and binomial analyses, 14 tribes were compared and ranked as either over- or under-selected for medicine, food, or technology, and for different categories of medicinal applications. Statistical analysis supported the hypothesis that the selection of species for ethnobotanical purposes is non-random and does not depend on the size of the flora. The Anthemideae tribe was identified as over-selected for all types of applications, including most therapeutic categories, most significantly as pulmonary and orthopedic aids. Subsequent analysis revealed that the over-representation of this tribe was attributed mainly to Achillea millefolium L. and Artemisia spp. The significance of Anthemideae, particularly of Achillea and Artemisia species as highly selected medicinal taxa, emphasizes their cultural importance to Indigenous North Americans. Residual and binomial statistics generally provided parallel results, but supplementary statistical methods, further in-depth investigation of other use categories, and inclusion of plant distribution data may provide greater insight into traditional uses of Asteraceae in North America. [ABSTRACT FROM AUTHOR]

Aim: The regionalized patterns of biodiversity distributions are actively studied in terrestrial and marine ecosystems, but much less is known on the geographical patterns of ecoregions founded on freshwater taxa. Here, we studied, for the first time, how well existing freshwater ecoregions describe the geographical distribution of inland water plants. Location: Greenland, continental Canada and USA. Taxon: Freshwater vascular plants of all taxa and multiple functional groups (i.e. growth forms). Methods: Using newly available fine‐grained data on freshwater plant distributions, we studied how ecoregions founded on fish are suitable for freshwater plant regionalization across North America. Specifically, we calculated internal homogeneity and distinctness among neighbouring ecoregions in relation to species replacements and richness differences. We also explored how a complex suite of ecogeographical characteristics affect ecoregion delineation of freshwater plants using spatially explicit regression routines. Results: We found a clear geographical patterning of ecoregion robustness for North American freshwater plants, with communities being more internally homogeneous and more similar to one another in Polar and Subtropical inland waters. The degree of internal homogeneity and ecoregion distinctness were almost equally driven by species replacements and richness differences. Considering different life‐forms, ecoregion delineation performed best for emergent and floating‐leaved plants. Finally, within‐ecoregion homogeneity and distinctness were best explained by annual mean temperature and terrain ruggedness, respectively, with mean water alkalinity, ecoregion area and late Quaternary glacial legacies having supplementary effects. Main conclusions: Our findings suggest that selection through climate filtering (e.g. mean annual temperature) is likely the main mechanistic driver of freshwater plant ecoregions. Geographical regionalizations founded on a particular organismal group may not be directly applicable for all taxa but can be a good basis for further adjustments. Our study is a promising starting point for further investigations of geographical delineations for freshwater taxa other than fish. [ABSTRACT FROM AUTHOR]

Aim: Differences in physiography have been proposed to explain the diversity anomaly for vascular plants between environmentally similar regions of eastern Asia (EAS) and eastern North America (ENA). Here, we use plant species within disjunct genera to examine whether differences in topography contribute to the diversity anomaly and whether the richness–environment relationships differ between regions. Disjunct plants are used to ensure that the diversity anomaly relates to post‐disjunction evolution and diversification rather than regional differences in clade ages or immigration. Location: EAS and ENA. Time period: Current. Major taxa studied: Plant taxa disjunctly distributed in EAS and ENA. Methods: We compiled county‐level plant distribution data, and calculated species richness and variables of topography and climate within unit grid cells. We compared estimated coefficients of region effects among models, where richness was fitted with or without topography and climate. Topography and climate were also used to separately model within‐region spatial diversity patterns using spatial simultaneous autoregressive error models. Results: The coefficients of region effects varied from −.776 for the model only including region to −.309 when topography was controlled for, but remained significant. Climate dominated the spatial diversity patterns in ENA. In contrast, the influence of climate (14.2%) on species richness was weaker than that of topography (18.3%) in the warm area of EAS. Relations to elevation and temperature varied between regions, shifting between positive and negative relationships in several cases. Main conclusions: Our results demonstrate that variability in local topography contributes to the strong regional anomaly in plant species richness between EAS and ENA. Nevertheless, the diversity anomaly persists after controlling for local topography and climate. EAS and ENA also exhibit contrasting richness–environment relationships, providing another divergent aspect between the EAS–ENA disjunct floras. Our findings highlight that regional differences in topography or other environmental factors may underlie the diversity anomaly. [ABSTRACT FROM AUTHOR]

The moss Exobryum fragilicuspis (Broth.) R.H.Zander is reported from the Rocky Mountains of Alberta, Canada, in Jasper National Park. The species is synonymous with several previously recognized taxa, including Didymodon fragilicuspis Broth., Didymodon gaochienii B.C.Tan & Y.Jia, Didymodon murrayae Otnyukova, and Vinealobryum murrayae (Otnyukova) R.H.Zander. Exobryumfragilicuspis is distinctive in having specialized caducous propagules with barrel-shaped segments at the leaf apices. These detach readily and cause the apices of developed leaves to appear broken. Despite these distinctive features, the species is rarely reported in North America, where it was previously known from three sites in Alaska and British Columbia. The collection from Alberta is the most recent in 30 years in North America, and provides new insights into the species' distribution and ecology. Features of Exobryum fragilicuspis are compared to other related species from North America. [ABSTRACT FROM AUTHOR]

The tribe Plantagineae (Lamiales) is a group of plants with worldwide distribution, notorious for its complicated taxonomy and still unresolved natural history. We describe the result of a broadly sampled phylogenetic study of tribe. The expanded sampling dataset is based on the trnL-F spacer, rbcL, and ITS2 markers across all three included genera (Aragoa, Littorella and Plantago) and makes this the most comprehensive study to date. The other dataset uses five markers and provides remarkably good resolution throughout the tree, including support for all of the major clades. In addition to the molecular phylogeny, a morphology database of 114 binary characters was assembled to provide comparison with the molecular phylogeny and to develop a means to assign species not sampled in the molecular analysis to their most closely related species that were sampled. Based on the molecular phylogeny and the assignment algorithm to place unsampled species, a key to sections is presented, and a revised classification of the tribe is provided. We also include the description of new species from North America. [ABSTRACT FROM AUTHOR]