West North America Research Articles

Discovering the Untouched Perspective of Endangered North American Herb Actaea racemosa.

Actaea racemosa (AR), sometimes also known as black cohosh, is a perennial herb that grows in the Ranunculaceae family that effloresces in the middle of summer. This herb is currently present throughout south and west North America despite being endangered in the eastern section of the continent. Certain information about the photochemistry and biological potential of this herb is available. In accordance with the scant available ethno-medical reports, this herb possesses antioxidant, antidiabetic, anti-inflammatory, antiosteoporosis, and anticancer properties. As per the available literature, caffeic acid, isoferulic acid, actein, 23-epi-26 deoxycatein, cimicifugoside, and ferukinolic acid are the key components found in different parts of AR. To date, no thorough research or systematic review has been done to highlight the traditional, biological, and phytochemical benefits of this herb. Consequently, further research is needed to gain a deeper understanding of this therapeutic herb, particularly about its separation and pharmacological screening of its insulating portion for a range of biological functions. The goal of this review was to compile the most recent data on the phytochemical presence of AR. in relation to its ethnomedical applications, methods of extraction, pharmacological applications, and future potential.

Multivariate global agricultural drought frequency analysis using kernel density estimation

Drought frequency analysis provides valuable information for drought risk assessment. Nonparametric kernel density estimation (KDE) is applied for agricultural drought frequency analysis at the global scale. Agricultural drought over 1950–2020 is described by the standardized soil moisture index (SSMI), and drought variables (i.e., duration, severity, and peak) are extracted using run theory. The univariate and multivariate joint distributions of drought variables are established by KDE. Given that the averages for drought duration, severity, and peak are 3.10 (months), 1.59, and 0.60, respectively, the spatial distributions of multivariate return periods are mapped to determine regions with higher drought risk. The results showed that: (1) The mean values of drought duration, severity, and peak over different regions were in the ranges of 1.94–5.18 (months), 0.92–2.81, and 0.49–0.72, respectively. (2) Drought severity had higher correlations with drought duration (0.83) and peak (0.91), while the correlation coefficient between drought duration and peak was lower (0.73). (3) KDE can establish reliable joint distributions of drought variables after passing Kolmogorov-Smirnov (KS) and Anderson-Darling (A-D) tests at the 5% significance level with an average root-mean-square error of 0.04. (4) When the univariate return period was equal to 100 years, the multivariate joint return period of the “or” case was generally less than 70 years but that of the “and” case was mainly greater than 200 years. (5) Compared with other regions, West North America, North-East Brazil, Southeastern South America, Central Asia, and the Tibetan Plateau experienced higher drought risks. Accordingly, countermeasures should be established in these regions to alleviate drought impacts.

The Effect of Modeling Strategies on Assessments of Differential Warming Impacts of 0.5°C

AbstractThe differential climatic impact between the 1.5° versus 2°C warmer worlds is a global concern on the post‐Paris science agenda. The recently released Intergovernmental Panel on Climate Change (IPCC) special report “Global Warming of 1.5ºC” (hereafter SR15) concludes robustly avoided impacts from climate extremes from the 0.5°C less warming globally, based on multiple lines of evidence. However, the methodological uncertainties, including those arising from modeling strategy (i.e., different pathways to achieve the temperature targets), remain a knowledge gap. Here, by comparing simulations with the common Community Atmosphere Model (CAM5) using different modeling strategies (i.e., fully coupled transient, fully coupled quasi‐equilibrium, and atmosphere‐only quasi‐equilibrium simulations), we explored the uncertainty from modeling strategy in the reduced impacts of climate extremes from the half‐degree less warming. While the globally aggregated reduced impacts are reasonably consistent among modeling strategies, substantial quantitative uncertainties of reduced impact exist at regional scales. For temperature extremes, the largest methodological uncertainty exists in northern high‐latitudes, especially in Europe and North America, with spread exceeding 0.8°C. For precipitation extremes, large uncertainties (even opposite signs) are expected scatteredly over the globe, particularly in the populous South Asia for wet extremes, and in South‐East Asia, West North America, and the Amazon for dry extremes, with spread of ∼5%. The different regional responses among modeling strategies result from multiple physical processes, dominated by the transient versus quasi‐equilibrium responses, prescribed sea surface temperatures and aerosol forcing. The comparisons improve the understanding of methodological uncertainties in the projected impacts in light of model setups.

The story of endurance: Biogeography and the evolutionary history of four Holarctic butterflies with different habitat requirements

AbstractAimBiogeographical studies on the entire ranges of widely distributed species can change our perception of species’ range dynamics. We studied the effects of Pleistocene glacial cycles on current butterfly species distributions, aiming to uncover complex biogeographic patterns in the Holarctic, a region dramatically affected by Cenozoic climate change.LocationEurasia and North America.TaxonBoloria chariclea, Agriades optilete, Carterocephalus palaemon, Oeneis jutta.MethodsWe reconstructed the biogeographic history of four butterfly species differing in habitat preferences (B. chariclea – tundra, A. optilete – bogs, C. palaemon – temperate grasslands, O. jutta – taiga), using one mitochondrial and two nuclear DNA markers and species distribution modelling.ResultsExcept for B. chariclea, all species originated in Eurasia. The open habitat species A. optilete and C. palaemon formed widely distributed east‐west genetic clusters in continental Asia and clusters separated from them in Europe. Genetic clusters of the taiga species O. jutta were not geographically separated in Eurasia, suggesting Pleistocene fragmentation and recent reconnection. The glaciated North America was recolonized from Beringian and southerly situated refugia by all four species.Main conclusionsThe Pleistocene mammoth steppe allowed a widespread continuous distribution of open habitat butterflies, while in contrast the distribution of a taiga‐specialist species was more limited. In the mostly flat and continental North Asia, the butterflies of various types of open habitats survived ice age in widely distributed east‐west belts. In the mountainous and oceanic regions of Europe, Beringia and west North America, all four species persisted in contracted areas during the glacials. After deglaciation, they expanded their ranges and formed contact zones among populations. To conclude, the harsh climate of the glacials did not represent an obstacle for butterflies. Instead, different habitat specialists selected their own ways to thrive in the dynamic conditions of Quaternary glacial periods.

Large negative effect of non-native trout and minnows on Pyrenean lake amphibians

High mountain lakes are mostly naturally fishless ecosystems that have received numerous trout introductions over the world. Extensive studies mostly developed in west North America have shown a large negative effect of these introductions on amphibians, although no extensive studies are available from other continents such as Europe. Fish were also introduced extensively in the Pyrenees (southern Europe), mainly trout for angling and minnows for their use as live bait for fishing trout. We studied the effect of non-native trout and minnows on the occurrence of amphibian species inhabiting Pyrenean lentic habitats. Chi-square tests and Generalized Additive Models were applied on a dataset of 12 environmental descriptors from 1739 water bodies surveyed from 2006 to 2016. After accounting for environmental characteristics we found a large negative effect of non-native trout and minnows on Pyrenean amphibians. Trout was negatively associated with four of the six studied species. Since minnows were only introduced in trout present lakes, they were only significant for Rana temporaria, the most distributed amphibian in the area. None of the palatable amphibians have been able to recolonise the lakes where minnow remain as the only fish species indicating a strong negative effect. Minnow is the non-native fish with a higher introduction rate in the mountain range indicating that it might be a threat for other species in the future. Therefore, the control of trout stocking and minnow release in high mountain lakes is necessary to preserve European and worldwide amphibian populations in these ecosystems.

Molecular and morphometric characterisation of the invasive signal crayfish populations in Croatia

The signal crayfish Pacifastacus leniusculus (Dana, 1852) is a native species to North America. It was introduced to Europe and Japan where it rapidly spread as an invasive species. In Croatia, it is recorded in the rivers Mura and Drava, where it spread downstream from Slovenia, and in the Korana River, where it has been recently illegally introduced. In the invaded areas, signal crayfish outcompetes native crayfish species. Since the knowledge on the genetic diversity of this invasive species is limited, microsatellite markers and sequences of mitochondrial gene for 16S rRNA were analysed to explore the genetic relations between the two Croatian populations (Mura and Korana rivers) as well as their relation to other already studied European populations. Moreover, 16S rRNA sequence fragments of Croatian samples were compared with those from the native range in the west North America. Morphometric characteristics were also studied to determine if there are significant differences between studied populations and if these are concordant with the genetic analyses results. Also, morphometric data were used to assign Croatian signal crayfish into subspecies classification according to Miller’s discriminant function formula, and to compare claw surface area among Croatian, Japanese and North American populations. Based on the results of morphometric characteristics Croatian samples showed Pacifastacus leniusculus leniusculus -like morphology. Phylogenetic reconstruction based on 16S rRNA, positioned Croatian samples into P. leniusculus sensu Larson et al. (2012). Results on microsatellite markers showed that the genetic diversity of P. leniusculus in the Mura River population is slightly higher compared to the Korana River population, but these two populations do not form separated genetic clusters. This study contributes to the knowledge on genetic variability and morphometric characteristics of signal crayfish in Europe and further understanding of its success as an invasive species.

Is the sword moss (Bryoxiphium) a preglacial Tertiary relict?

The disjunction of floras between East Asia, Southeast North America, West North America, and Southwest Eurasia has been interpreted in terms of the fragmentation of a once continuous mixed mesophytic forest that occurred throughout the Northern Hemisphere due to the climatic and geological changes during the late Tertiary. The sword moss, Bryoxiphium, exhibits a distribution that strikingly resembles that of the mesophytic forest elements such as Liriodendron and is considered as the only living member of an early Tertiary flora in Iceland. These hypotheses are tested here using molecular dating analyses and ancestral area estimations. The results suggest that the extant range of Bryoxiphium results from the fragmentation of a formerly wider range encompassing North America and Southeast Asia about 10 million years ago. The split of continental ancestral populations is too recent to match with a continental drift scenario but is spatially and temporally remarkably congruent with that observed in Tertiary angiosperm relict species. The timing of the colonization of Iceland from Macaronesian ancestors, about two million years ago, is, however, incompatible with the hypothesis that Bryoxiphium is the only living member of an early Tertiary flora of the island. Alaska was recurrently colonized from East Asia. The ability of Bryoxiphium to overcome large oceanic barriers is further evidenced by its occurrence on remote oceanic archipelagos. In particular, Madeira was colonized twice independently from American and East Asian ancestors, respectively. The striking range disjunction of Bryoxiphium is interpreted in terms of its mating system, as the taxon exhibits a very singular pattern of spatial segregation of the sexes.

The world's biogeographical regions revisited: global patterns of endemism in Tipulidae (Diptera).

This paper explores the distributional data of 4,224 Tipulidae (Insecta: Diptera) species to search for endemism patterns in a worldwide scale and to test the extent to which the global patterns of endemism of the group fit into previously proposed regionalization schemes, particularly Wallace's system and recent revisions of it. Large scale areas of endemism are assessed using the grid-based method implemented in VNDM. VNDM depends on the prior definition of the grid size for analysis, but a criterion for choosing beforehand a particular grid size is not clear. The same holds for the choice of the level of similarity in species composition selected for the calculation of consensus areas. In our study, we developed a methodological approach that helped defining objective criteria for choosing suitable values for these critical variables. Large-scale areas of endemism around the globe are identified and ranked according to endemicity levels: 1--West Palaearctic, 2--Nearctic, 3--East Palaearctic-Oriental, 4--West North America, 5--Australia, 6--Neotropical, 7--Sub-Saharan Africa, 8--Palaearctic, and 9--Middle East. Our main conclusion is that there are still some limitations in applying biogeographical classifications proposed mostly on the basis of vertebrate distribution to other taxonomic groups, such as the Tipulidae. While there is a general congruence of the broad-scale areas of endemism of tipulids with previously proposed regionalization schemes, for some areas, the sharpness of boundaries between traditional regions is not so acute, due to a great level of overlap of part of its biotic elements.

Assessment of the global potential distribution of the predatory land planarianArtioposthia triangulata(Dendy) (Tricladida: Terricola) from ecoclimatic data

Abstract Artioposthia triangulata was originally described from New Zealand in 1895 but was subsequently found to have spread to Northern Ireland in 1963 and Scotland and England in 1965. It is now widespread in both Ireland and Scotland, where it has been shown to reduce earthworm numbers to below detectable levels. Ecoclimatic data were used in the computer program CLIMEX to estimate the potential spread of A. triangulata to Europe and the rest of the world. Results indicated it could establish in agricultural land in most of north‐western Europe, and persist in domestic gardens throughout much of central Europe, east and west North America, Australia, southern South America, and South Africa. It is difficult to assess either the extent to which earthworm numbers and diversity would be decreased or how far the effect of their loss to soil structure, nutrient cycling, or wildlife would be detrimental in these areas.

The limits of the picturesque in British North America

Just as eighteenth-century English gardenists sought to adapt the canons of continental art and gardening to the characteristic diversity and variety of English topography, so English explorers and travellers of the late eighteenth and early nineteenth centuries discovered that the wonderful variety of nature displayed in the New World demanded a further adaptation of the schemata for landscape appreciation that had been formulated at home. Fixed principles in the scientific world could no better accommodate the diversity of nature being found in the South Pacific and North and West North America than the fixed principles in European landscape gardening could echo the genius loci of English landscapes. The English desire for less controlled landscapes than those executed by French gardenists was at once widely answered in explorers' accounts of new and unpopulated realms. Moreover, the taste for lessartificially arranged and specificallyemblematic natural scenesthat grew during the second half of the eighteenth century, and which, as John Dixon Hunt has comprehensively shown in The Figure in the Landscape (1976), occupied British poets and painters no lessthan gardenists, could be brilliantly echoed at times in the accounts of natural terrain which no European hand had yet touched but which seemed nevertheless to possess inherent aesthetic capabilities. This paper will briefly canvass some of the pictorial and narrative efforts by exploring and travelling Britons to realize these capabilities in the landscapes they encountered. For the most part, attention will be paid to points in western and northern British North America where the vastness of grassland or tundra placed a great strain on the traveller's customary deployment of the English schema of the picturesque.