Midslope Positions Research Articles

Natural vegetation and ecology of abandoned coal-mined land, Rocky Mountain Foothills, Alberta, Canada

The natural vegetation and spoils of two abandoned, unreclaimed coal mines in the Mountain Park area were studied quantitatively in 34 stands. After 26 years of abandonment the vegetation of both Townsite and West Mine was sparse. Total plant cover was usually < 10% and isolated plants were common. The communities were dominated by perennial grasses and forbs. Seven plant community types were recognized: (i) Festuca rubra – Epilobium angustifolium, (ii) Agropyron latiglume –Agropyron repens, and (iii) Agropyron spp. – Artemisia borealis on the Townsite; and (iv) Equisetum arvense – Potentilla fruticosa, (v) Agoseris glauca – Crepis nana, (vi) Agropyron latiglume – Crepis elegans, and (vii) Crepis nana – Eriogonum androsaceum on the West Mine. The spoil materials were generally coarse textured and structureless, consisting of rock fragments and loose single grains. Spoil samples were analysed for 20 physical and chemical properties. Variation in spoil properties appeared to strongly influence plant distribution and community development. Total plant cover and species richness were correlated with several spoil properties; highest correlations were with fine earth content (<2 mm) and clay content on the Townsite and West Mine sites, respectively. Slope position strongly influenced plant distribution on both study sites. Total plant cover, species richness, and the frequency of most species were highest at the slope base and lowest at the upper slope, midslope, and (or) crest positions. The sites were only 1.2 km apart, differed only 30 m in elevation, and were abandoned for the same length of time. Nevertheless, they differed edaphically and supported significantly different plant communities.