EXPERIMENTAL ANALYSIS OF GRASSLAND SUCCESSION
In the 1980's, I analyzed the mechanisms of successional change in a mediterranean coastal grassland undergoing post-grazing succession at Sea Ranch, northern California USA. The grassland is dominated by several species of perennials, occurring in patches. There are also patches dominated by annuals. At the time of this study, I could not find an example in the literature where the population level mechanisms driving successional change had been experimentally elucidated. Grasslands are ideal study systems for this purpose. My basic approach was to test the invasibility of patches dominated by different grass species, by introducing other co-occurring species. Densities of seed introductions were determined by comprehensive measures of natural seed input densities in each type of patch, i.e. the densities of potential invaders that actually occur in the field. I also tested the effects of disturbances by animals on invasion success. The invasibility of patches was altered by experimentally killing individual bunchgrasses. By combining the results of these experiments, I was able to predict the course of succession.
Publications - Grassland Succession
Peart, D.R. 1989. Species interactions in a successional grassland. I: seed rain and seedling establishment. Journal of Ecology 77:236-251.
Peart, D.R. 1989. Species interactions in a successional grassland. II: Colonization of vegetated sites. Journal of Ecology 77:252-266.
Peart, D.R. 1989. Species interactions in a successional grassland. III: Effects of canopy gaps, gopher mounds and grazing on colonization. Journal of Ecology 77:267-289.
Peart, D.R. and T.C. Foin. 1985. Analysis and prediction of population and community change: a grassland case study. In J. White and W.G. Beeftink (eds.), The population structure of vegetation. Junk, The Hague.