Aerial photographs from 1949 and 1997 were used to conduct spatial vegetation pattern and transition analyses of 287,000 ha of the montane ecoregion in Jasper National Park, Alberta. Metrics for quantifying montane landscape pattern included total patch area, number of patches, mean patch size, and edge density. In total, 16 vegetated and non-vegetated cover classes were used.

Results showed large shifts in vegetation pattern across the montane landscape of Jasper National Park. Vegetation transition largely followed natural successional development. Patch number and total area of grassland, forb, wetland, and complex vegetation cover classes decreased, thus increasing relative rarity of these cover types across the montane landscape. Total patch edge decreased in nearly all vegetation classes. Significant increases occurred in mean patch sizes of vegetation cover, total forest cover, and coniferous cover. Patches of closed and dense canopy coniferous forest also showed significant increases in mean patch size with equivalent decreases in sparse and open coniferous canopy density. Encroachment and ingrowth of coniferous forest into grassland areas was indicated. In conjunction, fewer and larger patches of the dominant coniferous forest cover coupled with decreases in area and number of patches of historically and relatively rare vegetation classes indicated that the montane landscape became more uniform and homogeneous over the 48year period of this study.

The natural range of landscape pattern variability likely affects a variety of ecological processes at multiple scales. Disturbances such as fire maintain a relatively fine-grained pattern of vegetation patches in various stages of succession. In the absence of disturbance, an increasingly homogeneous landscape poses potentially severe consequences to native flora and fauna, and increases the potential for large-scale, catastrophic fires. Significant changes in landscape vegetation structure since the early 1900's have been noted in numerous studies across North America and have been attributed to historical fire regime variation, natural succession, decoupling of indigenous peoples from the landscape, and fire suppression.