Long-Term Success of Seeded Species and Their Influence on Native Species Invasion at Abandoned Rig Site A-01 Caribou Hills, N.W.T., Canada

Abstract

Seeding tests were established on an abandoned rig site in the Caribou Hills, N.W.T., in June 1973 to determine the cover success of selected grasses when seeded separately and in a mixture and the influence of various seed applications on natural succession.

The study, monitored over a 12-yr period, confirmed that although slower establishing, Nugget Kentucky bluegrass and Arctared creeping red fescue are winter-hardy and can provide a maintenance-free, long-lasting cover in this region. However, an extremely dense root mat and litter layer, produced by both species, curtailed invasion by native species to less than 15% cover after 12 yr.

The seed mix containing the above species as well as Engmo timothy, Frontier reed canary-grass, and Prolific spring rye provided high first year cover (40%) which died back considerably following the first winter. By the third growing season, however, the cover produced by the long-lived species plus the litter provided a total cover (75%) approaching that achieved individually by Nugget Kentucky bluegrass and Arctared creeping red fescue (80%). Invasion of native species into these plots was significantly higher than in the other seeded plots, reaching 25% cover by year 3 and equalling that (80%) in unseeded control plots by year 12.