MECHANISMS OF PRIMARY SUCCESSION - INSIGHTS RESULTING FROM THE ERUPTION OF MOUNT ST-HELENS

The chapter studies Mount St. Helens in an effort to clarify many of the questions raised which include the mechanics of population expansion on devastated landscapes; the role of mycorrhizae; how root systems develop under different conditions; and how established plants influence invading plants. The chapter explores several mechanisms of succession on Mount St. Helens and show how the understanding of these mechanisms revised to include the potentially anomalous early stages of primary succession under stressful volcanic conditions. The principal descriptive analysis is of permanent plots and grids resampled for at least several years in sequence. The chapter discusses novel findings on survivors, local extinction, lower plants, primary succession is slow, dispersal and establishment, pioneers and complex species, physical amelioration and microsites, nurse plants, weeds, and evaluation mechanism. © 1993, Academic Press Limited.