Seedling dynamics of some cotton grass tussock tundra species during the natural revegetation of small disturbed areas

Abstract

The dynamics of seedling establishment, and growth of native cotton grass‐tussock tundra species were studied during the natural revegetation of small bare areas excavated in tussock tundra. The seedlings of Eriophorum vaginatum spp. spissum and Carex bigelowii, two sedge species, established most successfully. Few seedlings of nonsedge species emerged with the small disturbances. Most seedling emergence occurred early in the first growing season following the excavation of the bare areas. The density of emerged seedlings was higher in bare areas excavated in the autumn preceding the observations, rather than in bare areas excavated at the start of the first season of observation. After two growing seasons, survival of seedlings was not affected by the time the seedling emerged within the growing season. Eriophorum vaginatum was the most abundant species because it: (1) had the highest seedling emergence rates, particularly early in the growing season: (2) produced more tillers per seedlings; and (3) had a higher growth rate per seedling than C. bigelowii.

Carex bigelowii Torrey ex Schweinitz (C. rigida Good., non Schrank; C. hyperborea Drejer)

“…Where nitrogen fertilizer had been applied, however, c. 400 seedlings per m 2 were recorded. Similar high densities of seedlings were reported by Chester & Shaver (1982b).…”

Successful Plant Colonizers on Disturbances in Tundra Areas of Northwestern Canada

“…This discrepancy was due mainly to the later identification of nonvascular plant species whose cover had been recorded by genus (e.g., Cladonia species) or by plant groups (e.g., crustose lichens; acrocarpous mosses). (Hernandez, 1973;Johnson et al, 1978;Chapin and Chapin, 1980;Chester and Shaver, 1982;Ebersole and Webber, 1983;Gartner et al, 1983;Ebersole, 1985Ebersole, , 1987, this volume). Of the 207 taxa observed in the borrow pit quadrats, 155 were recorded from one corridor only.…”

“…Although the Ogilvie Mountain sites in the Dempster Highway corridor were at approximately the same latitude as the northern section of the CANOL Project corridor pits and were 24 to 11 years younger, they supported plant covers from 1.7 to 4.3 times greater than the older disturbances (Figure 2). This relatively rapid rate of plant re-establishment along the Dempster Highway corridor could be a product of a number of factors such as propagule availability (Chester and Shaver, 1982;Gartner, 1983;Gartner et al, 1983), climatic controls (Brown and Johnston, 1976), local ecotypes (Vaartnou, 1981), substrate nutrients (Chapin and Chapin, 1980;Shaver et al, 1983), or other variables operating independently or in association. Testing to determine which are the important limiting factors is beyond the scope of this paper.…”

Clonal Diversity and Allozyme Variation in Populations of the Arctic Sedge Carex Bigelowii (Cyperaceae)

“…However, no seedling recruitment has been observed at the study sites or elsewhere in undisturbed vegetation (Callaghan 1976;J6nsd6ttir & Callaghan 1988;Carlsson & Callaghan 1990a;J6nsd6ttir 1995). Seedlings have been found in disturbed sites on Iceland (Kershaw 1962;J6nsd6ttir 1995) and in Alaska (Chapin & Chapin 1980;Chester & Shaver 1982;Gartner et al 1986), but have not been recorded in natural populations on Icelandic lava-fields. C. bigelowii is established on newly created lava-fields at a later successional stage than many other vascular plant species (Bjarnason 1991).…”