Precipitation and Temperature Impact on Woody Plant Invaders in the Flint Hills Region of Kansas

The Flint Hills region of Kansas represents one of the largest tracts of tallgrass prairie remaining in North America. Among others, a persistent threat to tallgrass prairie is invasion by native woody plants. Fire is frequently used to combat this threat, but numerous species remain able to encroach upon prairie. We conducted a survey of three habitat types (prairie, a transitional woodland, and a forest edge) to identify potential prairie invaders, their influence on graminoid cover, and the influence of climatic variability on woody plant growth. A total of 71 trees were cut and sampled for annual woody growth rate and were used as a centroid for collection of understory plant cover data. There was a generally positive correlation between increased precipitation and increased woody growth. However, temperature had very little influence on woody plant growth. There were significant intraspecific differences in woody plant growth among habitat types. Similarly, there were differences among species within each habitat area. Graminoid cover was inversely related to overstory canopy cover.