Classification and ordination of southern boreal forests from the Hondo – Slave Lake area of central Alberta

1992 ◽  
Vol 70 (3) ◽  
pp. 614-628 ◽  
Author(s):  
George H. La Roi

Sixty-five undisturbed stands, spanning a wide range of physical habitats in the southern boreal subzone, were sampled in central Alberta using relevés, then classified with two-way indicator species analysis (TWINSPAN) and ordinated with detrended correspondence analysis (DECORANA), based on the estimated midsummer percent cover of 100 vascular plant species. Six floristically and ecologically distinct community types were recognized along soil-moisture and texture–nutrient gradients: oligotrophic PINUS BANKSIANA/ASTER LAEVIS on warm, xeromesic, nutrient-poor sand deposits; oligo-mesotrophic PINUS BANKSIANA/CORNUS CANADENSIS on cooler, xeromesic to submesic, low-nutrient sands; mesotrophic PICEA GLAUCA – POPULUS TREMULOIDES/ELYMUS INNOVATUS on mesic, medium-nutrient tills; eu-mesotrophic PICEA GLAUCA – POPULUS TREMULOIDES/RIBES TRISTE on mesic to hygromesic, nutrient-rich alluvium and till; oligotrophic PICEA MARIANA/RUBUS CHAMAEMORUS on cool, hygromesic to hygric, nutrient-poor peatlands; oligotrophic PICEA MARIANA/CAREX AQUATILIS on hygric to hydric, low-nutrient peatlands. The six community types and 19 species groups elucidated by TWINSPAN occupy distinct sectors on the two-dimensional DECORANA ordination that are associated with differences in moisture and nutrient availability. The community types are ecologically vicarious with boreal forest assemblages previously described for Alaska, central and eastern Canada, and northwestern Europe. Key words: cover, ecological series, gradient, moisture, nutrients, plant community, soil, vascular plant species, vegetation.


1997 ◽  
Vol 75 (8) ◽  
pp. 1363-1370 ◽  
Author(s):  
A. G. Schwarz ◽  
Ross W. Wein

Dry grasslands in Wood Buffalo National Park are unique biological features at 60°N latitude, since they contain plant species normally found in more southern grasslands at 50–55°N latitude. The objectives of this study were to inventory dry grasslands, classify them according to similarity of species cover, and establish relationships with understory species in Populus tremuloides and shrub communities. Dry grasslands were studied at nine sites; most were clustered in the Salt River and Peace Point areas. The largest unit of grassland was about 3.0 ha, and most units were less than 0.5 ha. This contrasts with the hundreds of hectares recorded earlier in the century. Of the 128 vascular plant species identified, 29 are considered as southern, and of these, 15 are regionally rare. Sixty-four plots were classified into nine community types, using two-way indicator species analysis. A group of six communities were dominated by grass and shrub species with a component of southern grassland species. Three communities, strongly dominated by Populus and shrubs, represent community types that invade dry grasslands. Ordination of plots using detrended correspondence analysis showed relationships among the community types and a clear separation of southern grassland species from those found in forest communities. Vascular plant diversity, as represented by mean species richness, ranged from about 15 to 28, and Shannon diversity indices ranged from 1.883 to 2.615. The cover of southern grassland species was negatively correlated (correlation coefficient of −0.524) with cover of tall shrubs and trees, suggesting that the dry grasslands of Wood Buffalo National Park are threatened by tree and shrub invasion, which is due, in part, to a lack of recent fires at these sites. Key words: northern grasslands, biodiversity, endangered species, endangered spaces.



2007 ◽  
Vol 49 (1) ◽  
pp. 37-43 ◽  
Author(s):  
Glen M. MacDonald

ABSTRACTPollen records are used to reconstruct vegetation in the continental Northwest Territories at 6 ka (6000 14C yr BP). Picea glauca, P mariana, Larix laricina, Populus tremuloides, P. balsamifera, Alnus crispa and A. incana were present throughout their modern ranges in the Boreal and Subarctic Forest Zones by 6000 BP. Pinus banksiana, however, had not yet reached its present northern limits. Population densities of the dominant trees, Picea glauca and Picea mariana, were close to, or as high as, present. In the Mackenzie Delta region the range limit of Picea glauca was approximately 25 km north of its modern location just prior to 6000 BP. In contrast, the northern limits of the forest in central Canada were similar to present. The tundra vegetation close to the edge of the forest was similar to modern Low Arctic Tundra. Development of extensive Sphagnum peatlands had begun in the forested areas and the adjacent Low Arctic Tundra. Palaeoecological information regarding vegetation at 6000 BP remains lacking for the northeastern half of the study area. Therefore, the nature of the vegetation in much of the area now occupied by Low Arctic and Middle Arctic Tundra remains unknown. Important vegetation changes that occurred following 6 ka include : (1) the advance of Pinus banksiana to its present northern range limits, (2) the retreat of the northern range limits of Picea glauca in the Mackenzie Delta region between 6000 and 3500 BP and (3) the rapid and marked increase in the population density of Picea mariana in the treeline zone of the central Northwest Territories at 5000 BP followed by a decline at 4000 BP.







Polar Record ◽  
2004 ◽  
Vol 40 (3) ◽  
pp. 235-243 ◽  
Author(s):  
J. Whinam ◽  
P.M. Selkirk ◽  
A.J. Downing ◽  
Bruce Hull

Buildings were constructed and artefacts left behind on sub-Antarctic Heard Island, associated with Antarctic research expeditions since 1926. Both bryophytes and vascular plants are colonising many parts of the now derelict buildings. On these structures and artefacts, the authors recorded four species of vascular plants out of the 11 that occur on Heard Island and nine species of mosses out of the 37 recorded from Heard Island. The vascular plant species most frequently recorded colonising structures and artefacts was Pringlea antiscorbutica (288 occurrences), with the area colonised varying from 0.3 cm2 to 430.0 cm2. Muelleriella crassifolia was the moss species that was most frequently recorded (14 occurrences), colonising areas from 2.1 cm2 to 12.9 cm2. The highest number of bryophyte species (seven) was recorded on the stone and cement of the ‘water tank.’ Pringlea antiscorbutica, Poa cookii, Azorella selago, Muelleriella crassifolia, Bryum dichotomum, Dicranoweisia brevipes and Schistidium apocarpum are all expected to continue to colonise the ANARE ruins, as well as areas that have become available since building removal and also possibly areas bared by further deglaciation.



2020 ◽  
Vol 41 (2) ◽  
pp. 213-220
Author(s):  
Fermín Del Egido ◽  
Patricio Bariego ◽  
Alberto Rodríguez ◽  
María Santos Vicente

We provide new records and notes on 25 protected and/or threatened vascular plant species in Castilla y León. Some of them illustrate not only new findings but also an interesting expansion of their geographic range. Eight taxa are reported for the first time in some provinces, while eleven of them were two or three times previously reported.



2021 ◽  
Vol 16 (4) ◽  
pp. 290-302
Author(s):  
Dmytrash-Vatseba I.I. ◽  
Shumska N.V. ◽  
Gniezdilova V.I.

The paper contains a synopsis of rare component of flora of Halych National Nature Park forest ecosystems, as well as evaluation of distribution trends of rare vascular plant species and the state of their populations. Being established in 2004, the Park is located in Halych district of Ivano-Frankivsk region on the area of 14684.8 ha. Forests occupy the biggest part of its territory (81.1 %), among which predominate poor and mixed oak (Querceta roboris), beech (Fageta sylvaticae) and hornbeam (Carpineta betuli) woods. Inventory check of plant cover of the forest ecosystems has been done between 2008-2019 years. According to the results of our study, within the forests and forest margins grow 303 vascular plant species, out of which 63 are rare (20.8 %). The list of rare species is composed of species included to the Red Data Book of Ukraine, of species protected by international conventions and directives and complemented by species that are threatened within the study region. Species were considered as threatened if the number of localities and / or population size were small. Regionally rare species were selected based on the analyzes of results of our field survey and materials of herbarium collections. We have found that the third part of rare species (33.3 %) has high coenotic amplitude and a bit less species (26.2 %) favor forest margins. Rare species having low coenotic amplitude are confined to beech woods (19.1 %). Rare species are considerably distinguished by occurrence. Species with scarce occurrence predominate. For instance, 61 % of the species were found in 1-5 localities, of which 25 species occur only in one or two sites. Share of species growing in 6-10 localities within the Park is equal to 26.6 %. Only a small percentage (6.2 %) of rare species comprises species with relatively frequent occurrence (11–20 localities as well as more than 20 cites). Rare species of the Park forests with the highest occurrence rate are Lilium martagon and some members of Orchidaceae family. Predominantly, rare species have populations of small size, for instance, 81.2 % of the species were found in quantities of a few plants – several hundreds of individuals. The most threatened are species general number of which at the Park area is several plants (15.6 %). These species are as follows: Circaea alpina, Atropa bella-donna, Campanula latifolia, Phyteuma spicatum, Epipactis atrorubens etc. The biggest groups comprise species with general number of few tens and several hundreds of individuals (totally 65.6 %). Species with big populations represent far smaller part of forest rare species. Nine rare species grow in the number of several thousands of plants within the Park and three species (Allium ursinum, Galanthus nivalis and Leucojum vernum) – over a million. It has been established that 52.4 % of rare species populations taken together remain in critically bad state, 28.6 % of the populations – in bad state, 14.3 % – in satisfactory state. Only 4.8 % of populations are in good state. Our results show that about 95 % of species are in need of protection and continuous monitoring of population number. Furthermore, 51 species of rare plants,having low number and bad state of populations, require to work out and implement management plans for their restoration. Key words: rare species, vascular plants, population state, species occurrence, population number



Science ◽  
2017 ◽  
Vol 358 (6370) ◽  
pp. 1614-1617 ◽  
Author(s):  
Carmen Ulloa Ulloa ◽  
Pedro Acevedo-Rodríguez ◽  
Stephan Beck ◽  
Manuel J. Belgrano ◽  
Rodrigo Bernal ◽  
...  


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