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OLD-FIELD SUCCESSIONAL DYNAMICS FOLLOWING INTENSIVE HERBIVORY
Citation:
ENGLE, D. E., S. J. Tunnell, E E. Jorgensen*, AND P. M. Mayer*. OLD-FIELD SUCCESSIONAL DYNAMICS FOLLOWING INTENSIVE HERBIVORY. Presented at Society of America, Annual Meeting, Tucson, AZ, 08/01/2002.
Description:
Community composition and successional patterns can be altered by disturbance and exotic species invasions. Our objective was to describe vegetation dynamics following cessation of severe disturbance, which was heavy grazing by cattle, in an old-field grassland subject to invasion by Festuca arundinacea Schreb., an exotic grass. We evaluated changes in plant community composition, and we investigated the relationship between species richness and litter accumulation and the relationship between species richness and abundance of Festuca. Vegetation data consisted of canopy cover by species, species richness, and litter mass collected on 16, 40 x 40-m plots within an old-field in southeastern Oklahoma, USA. Festuca, which increased in abundance over the three-year study period, altered the successional trajectory (i.e., annuals followed by perennial bunchgrasses and ending in mature prairie) characteristic of some old fields in the region. However, species richness was not correlated with abundance of Festuca. Litter accumulation and species richness are negatively correlated in mesic grasslands, and Festuca and species richness were negatively correlated in this old field. However, on plots in which Festuca increased, species richness did not decrease over the study period. Instead, Festuca increased most on species-poor plots and Festuca abundance remained low on species-rich plots. We conclude that not only does Festuca influence plant community composition, the dynamics of Festuca invasion are influenced by plant species richness.