Impact of fire in the taiga of southeastern Manitoba on wildlife, vegetation, and value to resource users

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Martin, H.V.P.
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During the summer of 1982, trapping and vegetation surveys were carried out on permanent study plots within 6 of 7 different types of plant communities within the South-eastern Manitoba Taiga, which had been subjected to fire in May of 1980. A unique feature of this study area was the existence of an 8 year pre-fire data base. A total of 129 mammals, 123 of which are typified as "small mammals" were captured in 2100 trap nights. The number captured in each plant community were as follows: Jack Pine Ridge 19, Alder Jack Pine Ecotone 30, Alder Tamarack Bog 20, Jack Pine Sand Plain 5, Black Spruce Bog 5, Aspen Upland 21, Black Spruce Tamarack Bog 29. Pre-fire small mammal data for the permanent study plots were available, and up to ten years of data were used for comparative evaluation of fire effects. The effects of the fire vary according to the severity of the burn, but small mammal population numbers and biomass estimates for most plots increased the fall immediately after the burn, and then dropped in 1981. Specifically, Clethrionomys gapperi and Peromyscus maniculatus increased with the fire, and Sorex cinereus continued to fluctuate. Three growing seasons after the fire, population numbers and biomass estimates have declined, but are equal to or above minimum pre-fire levels. The effects of fire on other local wildlife, such as ungulates, fur bearers, and birds are discussed briefly. Current vegetation data were compared with pre-fire data and some basic post-fire reproductive strategies were observed. Pioneer or fugitive species with numerous light-weight wind-disseminated seeds, or those with Long-lived seeds stored in soil seed banks, which grow and mature rapidly were present. Frugivores are also suspected to have been an agent of post-fire seed dispersal. Vegetative reproduction through root sprouting or suckering was a dominant strategy observed on some plots. Relatively slow growing, late maturing species with larger, heavier seeds were also observed, and these are expected eventually to regain their upper canopy status. In an attempt to place a dollar value on the study area, the user's willingness to pay for benefits from use of the resources of the area, was combined with the potential attainable revenue from exploitation of local resources. The combined value is calculated to be in excess of $597,208.93. Interest in timber resources 80 years hence could present a conflict for land use management. It is recommended that the Taiga Biological Station study area be protected in its natural state, with controlled educational, research, traditional, and recreational activities permitted.
Taiga, Boreal forest, Fire, Ecosystem