Addition to the Flora of Canada? A Specimen from the Arctic Archipelago, Northwest Territories Links Two Allopatric Species of Alkali Grass, Puccinellia

A single herbarium specimen from Banks Island in the Canadian National Herbarium, Ottawa, is closest to Puccinellia wrightii (Puccinellia sect. Pseudocolpodium). This would represent a species new to Canada and an extension of over 1100 km from the previously known range in NW Alaska and NE Russia. The morphological characteristics of this specimen are compared with all taxa in P. section Pseudocolpodium and the North American P. arctica aggregate. Principal components analysis supports placement of this specimen in P. section Pseudocolpodium near P. wrightii, where it contributes to a morphological continuum between this species and P. vahliana. The new combination Puccinellia wrightii var. flava is made and a map of the current known distribution of the species in P. section Pseudocolpodium is presented

Balsam Poplar (Populus balsamifera; Salicaceae) Beyond the Tree Line in the Western Canadian Mainland Arctic (Northwest Territories)

Balsam poplar is the northernmost tree species in North America, with a reported range that extends generally to the tree line across the continent and beyond the tree line in Alaska, where extralimital stands growing in Arctic ecosystems on the North Slope have been documented and studied. Here we summarize existing information and report new data on extralimital stands of balsam poplar from the Arctic ecozone in the northeastern mainland Northwest Territories. These occurrences extend the geographical and ecological range of the species fully into the mainland Canadian Arctic. In this region, balsam poplar is known from four sites: two in Tuktut Nogait National Park and two along the Hornaday and Brock rivers just beyond the northwestern Park boundary. Balsam poplar was first reported from two of these sites more than 50 years ago, but those data have not been considered in most subsequent floristic and ecological work. A balsam poplar grove in Tuktut Nogait National Park consists of four discrete stands of shrubby plants growing on a low ridge adjacent to the Hornaday River; their tallest ramets measure 1.1 – 1.86 m. A larger grove along the edge of the lower Brock River consists of three large stands, the tallest ramets measuring 3.5 – 4 m. The boreal and subarctic regions of the Northwest Territories and Nunavut have large areas where balsam poplar has not been documented by herbarium specimens, including most of the forest-tundra and tree-line zones. Collections from these areas and other potential extralimital sites in the Canadian Arctic are urgently needed to document the current distribution of balsam poplar. Such data could serve as a baseline for assessing potential future alteration of the range of this species as a result of climate change.Le peuplier baumier est l’espèce arborescente qui pousse le plus au nord de l’Amérique du Nord. Son aire d’extension s’étendrait généralement jusqu’à la limite forestière du continent et au-delà de la limite forestière de l’Alaska, où des peuplements extralimites qui croissent dans les écosystèmes arctiques ont été répertoriés et étudiés sur le versant nord. Nous résumons ici des données recueillies antérieurement et publions de nouvelles données sur les peuplements extralimites de peupliers baumiers de l’écozone arctique se situant dans la partie continentale nord-est des Territoires du Nord-Ouest. Ces occurrences ont pour effet d’étendre la portée géographique et écologique de l’espèce entièrement sur la partie continentale de l’Arctique canadien. Dans cette région, le peuplier baumier se retrouve dans quatre emplacements : deux d’entre eux se trouvent dans le parc national Tuktut Nogait et les deux autres, le long des rivières Hornaday et Brock, juste au-delà de la limite nord-ouest du parc. Le peuplier baumier a été signalé dans deux de ces emplacements il y a plus de 50 ans, mais ces données n’ont pas été considérées dans la plupart des études floristiques et écologiques subséquentes. Un bocage de peupliers baumiers du parc national Tuktut Nogait consiste en quatre peuplements discrets de végétation arbustive poussant sur une dorsale basse adjacente à la rivière Hornaday; les plus grands ramets y mesurent de 1,1 à 1,86 mètre. Un bocage plus volumineux le long du rivage de la rivière Brock inférieure est composé de trois gros peuplements, où les ramets les plus grands mesurent de 3,5 à 4 mètres. Les régions boréale et subarctique des Territoires du Nord-Ouest et du Nunavut sont dotées de grandes sections où le peuplier baumier n’a pas été répertorié dans les échantillons d’herbiers, ce qui comprend la plus grande partie de la toundra forestière et les zones de limite forestière. Il faudrait procéder promptement à la collecte d’échantillons de ces régions et d’autres emplacements extralimites potentiels de l’Arctique canadien afin de pouvoir consigner la répartition actuelle du peuplier baumier. De telles données pourraient servir de point de référence pour évaluer la modification éventuelle de l’aire d’extension de cette espèce, modification attribuable au changement climatique

A new species of alkali grass (Puccinellia, Poaceae) from the western North American Arctic

Volume: 18Start Page: 16End Page: 2

DNA Barcoding the Canadian Arctic Flora: Core Plastid Barcodes (<i>rbcL</i> + <i>matK</i>) for 490 Vascular Plant Species

<div><p>Accurate identification of Arctic plant species is critical for understanding potential climate-induced changes in their diversity and distributions. To facilitate rapid identification we generated DNA barcodes for the core plastid barcode loci (<i>rbcL</i> and <i>matK</i>) for 490 vascular plant species, representing nearly half of the Canadian Arctic flora and 93% of the flora of the Canadian Arctic Archipelago. Sequence recovery was higher for <i>rbcL</i> than <i>matK</i> (93% and 81%), and <i>rbcL</i> was easier to recover than <i>matK</i> from herbarium specimens (92% and 77%). Distance-based and sequence-similarity analyses of combined <i>rbcL</i> + <i>matK</i> data discriminate 97% of genera, 56% of species, and 7% of infraspecific taxa. There is a significant negative correlation between the number of species sampled per genus and the percent species resolution per genus. We characterize barcode variation in detail in the ten largest genera sampled (<i>Carex</i>, <i>Draba</i>, <i>Festuca</i>, <i>Pedicularis</i>, <i>Poa</i>, <i>Potentilla</i>, <i>Puccinellia</i>, <i>Ranunculus, Salix</i>, and <i>Saxifraga</i>) in the context of their phylogenetic relationships and taxonomy. Discrimination with the core barcode loci in these genera ranges from 0% in <i>Salix</i> to 85% in <i>Carex</i>. Haplotype variation in multiple genera does not correspond to species boundaries, including <i>Taraxacum</i>, in which the distribution of plastid haplotypes among Arctic species is consistent with plastid variation documented in non-Arctic species. Introgression of <i>Poa glauca</i> plastid DNA into multiple individuals of <i>P. hartzii</i> is problematic for identification of these species with DNA barcodes. Of three supplementary barcode loci (<i>psbA–trnH</i>, <i>psbK–psbI</i>, <i>atpF–atpH</i>) collected for a subset of <i>Poa</i> and <i>Puccinellia</i> species, only <i>atpF–atpH</i> improved discrimination in <i>Puccinellia</i>, compared with <i>rbcL</i> and <i>matK</i>. Variation in <i>matK</i> in <i>Vaccinium uliginosum</i> and <i>rbcL</i> in <i>Saxifraga oppositifolia</i> corresponds to variation in other loci used to characterize the phylogeographic histories of these Arctic-alpine species.</p> </div

Resolution (%) of genera, species, and additional infraspecific taxa for <i>rbcL</i>, <i>matK</i>, and <i>rbcL</i> + <i>matK</i> in neighbour joining trees and BLAST searches.

<p>Neighbour joining trees were generated from single-family alignments using uncorrected <i>p</i>-distances. Numbers in parentheses are the numbers of genera or species sampled in each data set. BLAST searches were not conducted for the combined <i>rbcL</i> + <i>matK</i> data.</p

Scatterplots of the number of species sampled in each genus against the percentage of species resolved in each genus with <i>rbcL</i>, <i>matK</i>, and <i>rbcL</i> + <i>matK</i>.

<p>A. rbcL-175 genera (Pearson correlation coefficient r = 0.4180, n = 175, P < 0.0001), R² = 0.1747. B. matK-159 genera (Pearson correlation coefficient r = 0.3685, n = 159, P < 0.0001), R² = 0.1358. C. rbcL + matK-153 genera (Pearson correlation coefficient r = 0.3636, n = 153, P < 0.0001), R² = 0.1322. Species resolution was scored in neighbour joining trees generated from uncorrected <i>p</i>-distances calculated from single-family alignments.</p