Modeling the influence of topographic barriers on treeline advance at the forest-tundra
ecotone in northwestern Alaska.
Cryosolic soils of three geographic zones of Yakutia: taiga forests, tundra and forest-tundra
were objects of research (see Fig.
Previous surveys of small mammals in Alaska (Cook and MacDonald 2004, 2006) identified a contact zone between 2 closely related species of the cinereus complex of shrews (Van Zyll de Jong 1991; Demboski and Cook 2003) along the forest-tundra
ecotone in northern Alaska.
The Koryaks are native to northeastern Siberia, on the northern part of the Kamchatka Peninsula and on the adjoining mainland, from the Taigonos Peninsula to the Bering Sea, areas that are characterised by sub-Arctic forest-tundra
Moose appeared in the forest-tundra
zones in the 1950s, occupied the Ponoy River area in the 1960-1970s, and population growth occurred to the north of the forest zone along the tributaries and rivers flowing into the Barents Sea.
Most well-drained sites in the northern Quebec forest-tundra
are colonized by lichen-heath communities and scattered black spruce (Picea mariana (Mill.
These taxa are restricted to the tundra pollen assemblage zones F1, F2, and F4, and are generally found in tundra or forest-tundra
today (Porsild and Cody 1980), although V.
As expected, transects separated by the greatest difference in elevation were the least similar (higher beta diversity/species turnover); however, species turnover between the forest and forest-tundra
transects was higher than it was between forest-tundra
and alpine-tundra transects, even though the latter were separated by a greater elevation.
To test both hypotheses, we analyzed macrofossil remains across a long transect from forest-tundra
to tundra, to determine whether or not the eastern Canadian forest limit shifted in unison with climate change during the late Holocene.
2A-D); these spanned the tree line from the boreal forest to the tundra, with one measurement site located in the tundra (TR1), one in the forest-tundra
transition zone (TR2), and two in the open forest (TR3 and TR4).
ecotone is expected to experience some of the initial effects of climate change.
Structure and Composition of Tree Islands and Krummholz within the Forest-Tundra
Ecotone in Central and Eastern Canada.