Date of Award:


Document Type:


Degree Name:

Master of Science (MS)


Natural Resources

Department name when degree awarded

Range Science

Committee Chair(s)

Thadis W. Box


Thadis W. Box


Ray Brown


Art H. Holmgren


Dale Bartos


Don Sisson


Chuck Romesburg


Large areas within alpine and subalpine tundra have been x disturbed by mining during this century. The most promising method for retarding deterioration of these areas is revegetation with native species through both seeding and transplants. One natural process of revegetation which occurs on portions of many existing disturbances seems to be the establishment of a few species that expand with time to form matts of plants.

At the McLaren Mine, located at 3000 m elevation in the Beartooth Mountains, Montana, active succession is occurring and is dominated by Carex species. Seed viability and successional patterns studies were conducted on the mine. The objectives included: 1) determinations of seed viability on the spoils, 2) determine to what extent the Carex communities enhanced seedling survival, 3) to quantify the vegetation characteristics within the Carex communities and adjacent mine spoil, and 4) determine the effect that Carex communities have on microenvironmental factors. Greenhouse tests were used to determine seed viability in soil samples taken from the mine. Paired observations in field studies were used to compare vegetational and microenvironmental differences between Carex communities and adjacent bare areas.

Statistical analyses of the data collected showed that there was an adequate source of viable seeds of various species in the spoils to encourage natural revegetation if they could become established. Seedling mortality was reduced in Carex communities, apparently by decreasing soil disruption caused by frost action. Carex communities altered the microenvironment by reducing soil temperatures, wind speed, and radiation flux, and by providing a richer source of nitrogen and potassium than did the bare areas. Carex communities did not alter ?oil pH, phosphorus or soil water. Measurement of microenvironmental factors varied between the center and edge locations within the Carex communities. Species diversity and percent litter cover increased with increase in community size.