Burning history, time of burning, and year effects on plant community structure and heterogeneity in Fescue Prairie

Abstract

Structure, as well as spatial and temporal heterogeneity in plant species composition were studied in a Festuca hallii (Vasey) Piper – dominated Prairie in Canada for 6 years following burning before, during, or after the growing season on sites burned 1× or 3×. Structure, spatial heterogeneity, and temporal heterogeneity were never (P > 0.05) influenced by the time of burning. Diversity and richness of graminoids, perennial forbs, and shrubs fluctuated among years after burning, but were unaffected by burning history. Excepting shrubs, canopy cover of plant functional groups positively correlated with precipitation. After a single burn, spatial heterogeneity in species composition increased with years after burning, indicating plant communities were becoming patchier, whereas those burned 3× did not change predictably through time. Spatial heterogeneity in species composition between consecutive years was positively correlated, but temporal heterogeneity in species composition did not correlate with spatial heterogeneity. Burning history and precipitation appear important in controlling the plant community structure and spatial heterogeneity in species composition in Fescue Prairie.