A Five-Year Ecological and Ethnobotanical Study of Vegetation Recovery After the Long Mesa fire of July 1989, Mesa Verde National Park, Colorado Study Period: July 1990 - June 1994: Final report

Adams, Karen

Ecological and ethnobotanical data were gathered from July 1990 until June 1994 on Long Mesa, Mesa Verde National Park, following a July 1989 lightning-caused fire. Two burned plant communities included in this study were a Pinus edulis/Juniperus osteosperma (pinyon/juniper) woodland, and an Artemisia tridentata, A. nova/Purshia tridentata (sagebrush/bitterbrush) shrubland. At the same time, two corresponding unburned control communities were also examined. In the five years following the fire, vegetation in the burned pinyon/juniper woodland and sagebrush/bitterbrush shrubland has changed continuously, in contrast to nearby unburned control plots. In the burned pinyon/juniper plot, Quercus and other stump-sprouting shrubs dominate. Chrysothamnus became established there by seed. Herbaceous plant diversity doubled between 1990 and 1991, with some species (Nicotiana attenuata, Chenopodium spp., Schoencrambe linifalia, and Poafendleriana) displaying significant vigor and vitality early in recovery. This burned plot has a wider diversity of taxa than its counterpart unburned plot. The recovery in the burned sagebrushlbitterbrushplot has been dominated by stumpsprouting Amelanchier and Symphoricarpos. Herbaceous plant diversity is high, with coverage and frequency of a number of plants differing notably from those in the unburned plot. Coverage and frequency of bare soil and litter varied between burned and unburned plots as well. Comparisons of the burned pinyon/juniper plot to an earlier fire recovery study on Morfield Mesa revealed some differences in their recovery trajectories. Dominant herbaceous species in the first two years following each fire differed, likely in part due to purposeful seeding on Morfield to speed recovery. Shrubs shared in common between the two mesas also displayed higher coverages and frequencies on Long Mesa. The present Long Mesa mosaic habitat provides humans a wide range of resources, simply because of the fire. The burned pinyon/juniper area has offered a changing array of edible and useful plants, starting first with a large amount of sound, usable firewood. The vigorous nature of some plants has diminished with time, revealing an important role for fire in their maintenance. Flexible stems for material culture needs have been promoted by vigorous stump-sprouting. For a wide variety of herbaceous plants, differences between burned and unburned plots extend to which taxa are present, and their frequencies and coverages.