Fire - caribou - winter range relationships in northern Canada

Abstract

We needed data on temporal changes in caribou forages after fire and relative use of age-classes of forests by caribou to help devise a fire suppression priority strategy for caribou winter range in north-central Canada. Consequently, from 1983 through 1986, we estimated the abundance of vegetation and relative use by caribou at 197 sites in western and eastern study areas on the winter range of the Beverly herd of caribou {Rangifer tarandus). Species of lichens attained peak biomass at different periods after fire - as early as 40-60 years for Cladonia spp. to > 150 years for Cladina rangiferina and Cetraria nivalis. Biomass of the primary "caribou lichen", Cladina mitis, increased rapidly from 21-30 years after fire to 41-50 years and attained maximum biomass at 81-90 yeats in the west and 41-60 years in the east. However, total lichen biomass increased with age of forest to 100-150 years because biomass of Stereocaulon spp. did not peak until after 100 years. The biomass of "caribou lichens" {Cladina spp. and Cetraria nivalis) stabilized after 61-80 years in the west and 41-60 years in the east. The biomass of terrestrial lichen species can be predicted from their cover. Caribou lichen abundance apparently was only one of several factors that caused caribou to use stands 151-250 years after fire more than othet age classes

Effects of Modern Forest Management on Winter Grazing Resources for Reindeer in Sweden

“…Fire greatly decreases the ground lichen cover in the short term (Morneau and Payette 1989;Thomas et al 1996), but the long term effects depend on the forest type. Burning of lichen-rich ground benefits shrubs and has thus significant negative effects on reindeer herding.…”

“…The final successional phase in a plant community dominated by reindeer lichens is reached ca. 100 years after complete burning (Morneau and Payette 1989;Thomas et al 1996). However, burned areas may be used for reindeer foraging much earlier, depending on the distance to dispersal sources.…”

Predation risk and optimal foraging trade-off in the demography and spacing of the George River Herd, 1958 to 1993

“…Additionally with the predicted increase in snow depths it will require more energy for animals to dig feeding craters. Studies of lichen abundance have been legion during the past 40 years; some of us have spent endless field days looking in feeding craters and measuring lichen abundance (Bergerud, 1974c;1971;1988;Miller, 1976;Thomas et al, 1996). No demographic impacts have been documented in these investigations.…”

“…Thomas & Kiliaan (1998) showed that the condition of the Beverly herd in March of 8 years 1980 to 1987 was superior to the condition of caribou in the Kaminuriak Herd in early April in 3 years (1966¬ 68). The superior condition of the Beverly Herd compared to the Kaminuriak occurred despite the finding that there were reduced lichen supplies on the Beverly Herd compared to the Kaminuriak in both the 1960s and 1980s as a result of forest fires, and despite the fact that densities were 3-4 times greater for the Beverly in the 1980s than the Kaminuriak in the 1960s (Parker, 1972;Miller, 1976ab;Thomas et al, 1996, Thomas & Kiliaan, 1998. We might rank these four major herds that have been investigated as to late winter body condition (Porcupine-1980s, George River1980s, Kaminuriak-1960s, Beverly-1980s) There is no obvious relationship between snow cover, lichen abundance, animal densities or physical con¬ dition.…”

“…Lichens are the primary winter food of the large migratory herds on the mainland of North America. These lichens are less common north of trees than in the taiga (Kelsall, 1968;Skoog, 1968;Bergerud, 1971;, Thomas et al, 1996 and are especially limit¬ ed on the high elevation tundra of Labrador (Bergerud, 1988b). Caribou may have forfeited weight and condition to occupy these wind-swept safer environments with less phytomass in both (Tables 8, 9, and 10).…”