Table 4 - uploaded by George W. Argus
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Context 1
... Table 4 for comparison with Salix rotundifolia and S. phlebophylla. Dwarf shrubs 2-5 cm, not clonal or forming clones by layering. ...
Context 2
... phlebophylla is a dwarf, mat-forming shrub characterized by bearing persistent, skeletonized leaves; catkins with many flowers; ovaries hairy, and nectaries shorter than the stipes. See Table 4 for a comparison with Salix rotundifolia and S. nummmularia and Table 5 for a comparison with other similar dwarf Salix. ...
Similar publications
We sampled shrub canopy volume (height times area) and environmental factors (soil wetness, soil depth of thaw, soil pH, mean July air temperature, and typical date of spring snow loss) on 471 plots across five National Park Service units in northern Alaska. Our goal was to determine the environments where tall shrubs thrive and use this informatio...
Citations
... The samples were collected in the Montreal Botanical Garden and on field trips to California (2018California ( , 2019California ( , 2022, Minnesota (2021), Washington (2022), and Alaska (2022). Individual plants were identified to the species level using the key of Argus (2010), his regional Salix identification guides (Argus, 2004(Argus, , 2012 and other identification literature (Viereck and Little, 1972;Collet, 2002;Hoag, 2005). We aimed to sample representatives of all sections. ...
Premise: The huge diversity of Salix subgenus Chamaetia/Vetrix clade in North America and the lack of phylogenetic resolution within this clade has presented a difficult but fascinating challenge for taxonomists to resolve. Here we tested the existing taxonomic classification with molecular tools. Methods: In this study, 132 samples representing 46 species from 22 described sections of shrub willows from the United States and Canada were analyzed and combined with 67 samples from Eurasia. The ploidy levels of the samples were determined using flow cytometry and nQuire. Sequences were produced using a RAD sequencing approach and subsequently analyzed with ipyrad, then used for phylogenetic reconstructions (RAxML, SplitsTree), dating analyses (BEAST, SNAP-PER), and character evolution analyses of 14 selected morphological traits (Mesquite). Results: The RAD sequencing approach allowed the production of a well-resolved phylogeny of shrub willows. The resulting tree showed an exclusively North American (NA) clade in sister position to a Eurasian clade, which included some North American endemics. The NA clade began to diversify in the Miocene. Polyploid species appeared in each observed clade. Character evolution analyses revealed that adaptive traits such as habit and adaxial nectaries evolved multiple times independently. Conclusions: The diversity in shrub willows was shaped by an evolutionary radiation in North America. Most species were monophyletic, but the existing sectional classification could not be supported by molecular data. Nevertheless, monophyletic lineages share several morphological characters, which might be useful in the revision of the taxonomic classification of shrub willows.
... From Alaska, it extends eastward across northern Canada to Baffin Island. It grows in a variety of habitats such as floodplains, river terraces, and wet meadows, as well as on drumlin fields and gravel ridges (Argus 2004), and displays notable phenotypic variation associated with local climate conditions (Walker 1987;Argus 2004). ...
... From Alaska, it extends eastward across northern Canada to Baffin Island. It grows in a variety of habitats such as floodplains, river terraces, and wet meadows, as well as on drumlin fields and gravel ridges (Argus 2004), and displays notable phenotypic variation associated with local climate conditions (Walker 1987;Argus 2004). ...
We assessed the response of Salix richardsonii, a deciduous shrub, to climate change by determining the combination of climatic factors that regulated its growth over the past half-century. We tested whether increasing arctic temperatures promote shrub growth and increased cover. We analyzed fifty-four stems (out of seventy sampled) from S. richardsonii shrubs near the Walker Bay research station in Nunavut, Canada (68°21′ N, 108°05′ W) and surveyed shrub cover in 1996 and 2010. We measured annual growth rings, removed the age-related pattern, and used a response function analysis to explore the climate–growth relationship. The standardized chronology was positively associated with mean July temperature, corroborating other evidence that summer temperature is an important driver of shrub radial growth. Basal area increment revealed a long-term increase in radial growth, although it has stabilized this century. Surveys showed no significant increase in shrub cover at Walker Bay from 1996 to 2010. Our results support a growing body of evidence that increased shrub growth does not necessarily translate into a prolonged increase in shrub cover. Instead, we conclude that the heterogeneity of the arctic shrub response to climate change may be associated with variation in the proximate factors limiting recruitment such as water table saturation and herbivory.
... The subgeneric and sectional positions of Salix species follow the classification of Argus (1997), except for Salix integra Thunb., which is placed by Ohashi (2000) ( Stelter (1970) *Distribution records were based on the study by Newsholme (1992), except for information on Alaskan Salix species, which were based on the study by Argus (2004). ...
... Judging from genetic difference, 1-2 bp (0.27-0.53%), between populations in Poland, Russia and Alaska, the R. rosaria population probably came to Alaska ~0.12-0.27 Mya from northern Eurasia on S. pulchra, which is also distributed in Siberia (Argus, 2004). During this period, the Bering Land Bridge appeared and might allow R. rosaria to disperse from Siberia to Alaska (Fig. 4). ...
We analysed the COI gene of mitochondrial DNA extracted from larvae of Rabdophaga (Diptera: Cecidomyiidae) that induce rosette galls on Salix in the Holarctic Region. Genetic data show that they belong to species groups of Rabdophaga rosaria and Rabdophaga strobiloides. A maximum likelihood tree indicates that R. rosaria and R. strobiloides populations are divided into clades 1 and 2, respectively. Clade 1 is divided into subclades 1 and 2, and the latter is further divided into subclades 2A and 2B. Subclade 1 consists of populations on several Salix species of section Cinerella in subgenus Vetrix in Georgia and the UK. Subclade 2A contains populations on Salix alba (section Salix, subgenus Salix) in The Netherlands and the UK. Subclade 2B consists of populations on section Helix in Poland, Phylicifoliae in Alaska and Salix species in the Eastern Palaearctic Region. The genetic differences between populations of subclades 1, 2A and 2B range from 1.06 to 3.46%. We propose a possible diversification scenario of R. rosaria into sibling species through the expansion of host plant ranges. Clade 2 consists of R. strobiloides populations on two Alaskan Salix species of the sections Hastatae and Sitchenses in subgenus Vetrix.
... S. rotundifolia appears as a loose mat-forming or densely caespitose summer-green subshrub on Paekdu-San. This round and small-leaved willow is an amphi-Beringian species of the alpine tundra that occurs typically at the edge of sites with patterned ground (Kojima 1991;George 2004). As windswept dwarf subshrub stands, both communities contain conspicuous, large-and small-sized cushion-forming mosses, Racomitrium lanuginosum, R. canescens, Dicranum spadiceum, and Brachythecium brotheri. ...
We aim to provide a syntaxonomical scheme for the alpine tundra vegetation of volcano Mount Paekdu (Changbaishan) bordering China and North Korea. From the field investigations in 1991, 2004, and 2009 a total of 89 phytosociological relevés were sampled by the Braun-Blanquet method. Obtained data sets were analyzed by tabular hand-sorting technique. Syntaxonomic position and nomenclature of units were determined by comparison with mainly Japanese relevant communities. Ten rankless units in four physiognomic vegetation types were classified: alpine desert vegetation (Papaver radicatum var. pseudoradicatum community, Minuartia arctica community, Polytrichastrum alpinum-Minuartia macrocarpa var. koreana community), alpine windswept dwarf vegetation (Chrysanthemum zawadskii var. alpinum-Festuca ovina var. koreano-alpina community, Scirpus maximowiczii community, Oxytropis anertii-Salix rotundifolia community, Carex longirostrata-Dryas octopetala var. asiatica community), snow-bed vegetation (Phyllodoce caerulea-Tofieldia coccinea community, Viola biflora-Calamagrostis langsdorfii community), and colluvial drainage channel vegetation (Carex atrata-Sanguisorba stipulata var. riishiriensis community). The variation of the vegetation resulted from primarily the rock and soil particle size and soil mobility, and slope inclination. Some of the plant communities were regarded as local and endemic types. Yet we firmly believe that further researches are requested by much richer materials and syntaxonomical comprehensive evaluation in between elsewhere in the Pan-East Sea (Sea of Japan).
... S. glauca is a circumboreal-polar deciduous shrub (Elven et al., 2011), varying from 0.3 to over 2 m in height, that is highly polymorphic and, because of its complexity, has been described as a very widespread species or species group (Suda and Argus, 1968). Although they do not form large colonies, sizeable clones can form via root shoots, rhizomes, layering, or branch fragmentation (Argus, 2004). Individual ramets of congeners can live for over 70 years (Forbes et al., 2010;Schmidt et al., 2006;Zalatan and Gajewski, 2006), and ramets of S. glauca in our study area can also live for many decades (Young et al., 2016). ...
Retrogressive thaw slumps (RTS) are large (> 1 ha) depressions of exposed mineral soil on hillslopes caused by the thaw and displacement of ice-rich permafrost soils in high-latitude regions; since the 1980s the number of RTS observed on Alaska’s North Slope has increased by two-thirds. Some RTS in the Toolik Lake area are filled with tall (≥ 0.5 m) willow thickets, likely within decades after disturbance. Tall shrub thickets are different in structure and function from mixed dwarf tundra communities and may have different long-term impacts on ecosystems and wildlife. Currently it is unknown to what degree seedlings versus clonal recruitment contribute to shrub thickets. We assessed size and distribution of clones (modular stems of individuals) using eight microsatellite (SSR) markers to genotype leaf tissue of 223 willow ramets (stems) at two sites: an RTS aged 11–30 years since disturbance, and nearby undisturbed moist acidic tussock (MAT) tundra. Genotypes of known clones from excavated ramets were used to determine the mutation rate of clones. Spatial arrangement of ramets within clones was assessed in 18 × 18 m sampling grids nested at 2 m (“far clones”), 1 m (intermediate), and 0.25 m (“near clones”) between ramets. We identified 121 genotypes including 10 clonal genotypes in the RTS, and 63 genotypes including 11 clonal genotypes in the undisturbed MAT. Percent distinguishable was greater than 76% at both sites. Mean spatial distance between clonal ramets was not different at either site but among far clones, ramets were separated 7–16 m downslope in the RTS. Salix pulchra was the dominant willow at both sites; a third of willow genotypes in the RTS were identified as S. glauca, a disturbance colonizer. Rarer and hybrid species comprised 4–20% of all genotypes but were more abundant in the RTS. At both sites, within-species expected heterozygosity (HT) ranged from 0.49 - 0.85. Our results suggest: 1) sexual recruitment and low clonal expansion likely explain genetic diversity of willows in disturbed and late-successional sites; and 2) downslope separation of far clones in the RTS suggests disturbance effects; and 3) species richness was higher in the disturbed site.
... S. glauca is a circumboreal-polar deciduous shrub (Elven et al., 2011), varying from 0.3 to over 2 m in height, that is highly polymorphic and, because of its complexity, has been described as a very widespread species or species group (Suda and Argus, 1968). Although they do not form large colonies, sizeable clones can form via root shoots, rhizomes, layering, or branch fragmentation (Argus, 2004). Individual ramets of congeners can live for over 70 years (Forbes et al., 2010;Schmidt et al., 2006;Zalatan and Gajewski, 2006), and ramets of S. glauca in our study area can also live for many decades (Young et al., 2016). ...
The recent expansion of arctic deciduous shrubs has been well documented across a range of habitats, but the phenomenon is not universal. Their spread is often associated with increases in temperature and other abiotic factors, while variation in habitat moisture and herbivory can mediate the location and rate of this rise in abundance. Much less is known about the mode of increase of arctic shrubs. For one such shrub, Salix glauca, we used microsatellite markers to assess the prevalence of clonal growth (i.e. vegetative spread) and sexual reproduction (i.e. recruitment from seed) at sites with maritime and continental climates and differing in the density of large herbivores. We sampled individuals in plots reflecting the spatial scale of expansion in locations where S. glauca recently increased in abundance. The 400 samples collected across the four sites comprised 310 genotypes. Though evidence of sexual recruitment was common across all sites, coastal sites contained both more and larger clonal genotypes. While we expected soil conditions would be influential, the factors that best predicted the likelihood of clonality, genet size and vascular plant cover, suggest the light environment is of primary importance. Furthermore, in spite of the large distances between sites, there was no suggestion of genetic differentiation into distinct populations. These results indicate that differences in climate and herbivory can influence not only where and how extensively deciduous shrubs spread, but how they are likely to do so. We suggest future research integrating how mode of increase is associated with the rate of spread will advance projections of change in arctic ecosystems.
... Most Salix species will vary phenotypically in response to moisture, nutrients, shade, and wind. Sometimes normally prostrate species growing in a protected niche may be erect or the leaves of a usually small leaved species may be very large in nutrient rich sites, and under shade conditions leaves may be very large [26]. ...
... The flowers are very simple; staminate flowers consist of stamens and a reduced perianth consisting of one or more nectaries; pistillate flowers consist of an ovary and one or more nectaries. Each flower is subtended by a floral bract and they are aggregated into catkins, which may be sessile on the branch or borne on a short, vegetative shoot [26]. ...
It is well known—almost a truism—that contamination of the environment (especially soil) and the impacts of this contamination on animals and humans is a major worldwide problem. Phytoextraction is one of the methods that can be applied for soil reclamation and can lead to improvement. The general tendency in transport of metals to particular tree organs and their accumulation there is as follows: roots > leaves > stem. Vertical distribution of metals in trees depends both on the kind of element and tree species. The mobility and bioavailability of trace elements depends on several soil factors, e.g., pH; organic matter content; soil granulation; content of iron, manganese, and aluminum oxides; cation exchange capacity; water properties; contaminating metal; soil salinity; and soil biological properties. The potential of trees and bushes is mainly related to their ability to uptake elements from soil, followed by their possible transport and accumulation in aerial plant parts. Phytoextraction is limited to selected elements only.
... Vandewalle et al. (2010) propose standard procedures to integrate different components of species-based functional traits into biodiversity monitoring schemes across trophic levels and disciplines where the development of indicators using functional traits could complement, rather than replace, existing biodiversity monitoring. The frequent use of confamilial or congeneric 'means' or species data, often from wide-ranging locations (Jackson et al. 1996;Duru et al. 2010;Moles et al. 2011;Ordoñez et al. 2010), runs the risk of misleading matches as illustrated, for example, by phenotypic plasticity within certain species of arctic or boreal Salix (Argus 2004) or tropical Rubiaceae (e.g. Psychotria, A.N. Gillison pers. ...
This chapter covers plant functional types and traits at the community, ecosystem, and world level, with sections on form and function, the development of a functional typology, plant strategies, trade-offs, and functional types, the mass ratio hypothesis, functional diversity and complexity, and the move to a trait-based ecology. Plant functional types and traits as bioindicators, environmental monitoring, trait-based climate modeling, and scaling across the community, ecosystem, and world level are also covered.
... Vandewalle et al. (2010) propose standard procedures to integrate different components of species-based functional traits into biodiversity monitoring schemes across trophic levels and disciplines where the development of indicators using functional traits could complement, rather than replace, existing biodiversity monitoring. The frequent use of confamilial or congeneric 'means' or species data, often from wide-ranging locations (Jackson et al. 1996;Duru et al. 2010;Moles et al. 2011;Ordoñez et al. 2010), runs the risk of misleading matches as illustrated, for example, by phenotypic plasticity within certain species of arctic or boreal Salix (Argus 2004) or tropical Rubiaceae (e.g. Psychotria, A.N. Gillison pers. ...
... We selected these groups because individual species within them are known to cluster well by functional effects, with the caveat that some species within the groups may respond individualistically to climate warming (Chapin et al. 1996;Dorrepaal 2007;Klein et al. 2007). We also investigated the responses of shrubs grouped by height rather than leaf-longevity, classifying species according to their maximum potential heights as recorded in online flora [Argus (2001) , with dwarf shrubs < 15 cm tall, low-shrubs 15-50 cm, and tall shrubs > 50 cm, as two of the most important ecosystem effects of shrubs (snow trapping and spring albedo) are directly linked to canopy height (Sturm et al. 2001). ...
Ecology Letters (2011)
Understanding the sensitivity of tundra vegetation to climate warming is critical to forecasting future biodiversity and vegetation feedbacks to climate. In situ warming experiments accelerate climate change on a small scale to forecast responses of local plant communities. Limitations of this approach include the apparent site-specificity of results and uncertainty about the power of short-term studies to anticipate longer term change. We address these issues with a synthesis of 61 experimental warming studies, of up to 20 years duration, in tundra sites worldwide. The response of plant groups to warming often differed with ambient summer temperature, soil moisture and experimental duration. Shrubs increased with warming only where ambient temperature was high, whereas graminoids increased primarily in the coldest study sites. Linear increases in effect size over time were frequently observed. There was little indication of saturating or accelerating effects, as would be predicted if negative or positive vegetation feedbacks were common. These results indicate that tundra vegetation exhibits strong regional variation in response to warming, and that in vulnerable regions, cumulative effects of long-term warming on tundra vegetation – and associated ecosystem consequences – have the potential to be much greater than we have observed to date.
