The distribution, abundance, and diversity of plant species in a landscape are related to factors such as disturbance history, landform, and climate. In examining the potential effects of landscape structure on the distribution of plant species of the southeast Missouri Ozarks, we sampled a 10,000-m transect in a south-north direction. In September 1997, two 1 x 1 m plots were placed every 10 m along the transect to tally canopy cover, overstory type, coverage of all understory species, and micro-topographic features. We calculated Shannon and Simpson's diversity and species richness for all plots and used correlation and wavelet analyses to examine changes in these variables with elevation across different scales. Of the 332 species recorded along the transect, 104 species occurred only once. Desmodium nudiflorum
and Parthenocissus quinquefolia
were the two most frequent species (48.8 percent and 37.0 percent of plots, respectively), while 323 of the 332 species occurred within < 10 percent of the plots. Seventy-one plots contained no species and another 71 plots had only one species. Most plots contained one to seven species. Over 95 percent of the total species were found in < 10 percent of the quadrats. Species richness, Shannon diversity, and Simpson's diversity all correlated negatively with elevation. Distribution of plant species in the landscape was significantly related to position in the landscape, measured by relative elevation (R? = 0.78). Plots near riparian areas contained more species (> 30 species/plot) than any other plots along the transect. The patterns of patches of elevation and species diversity were most visible at the 1,800-m scale, but the spatial relationship between these patterns was best revealed at scales between 1,340 and 1,400 m. Changes in wavelet variance suggested that multiple scales should be examined when exploring potential influences of landscape structure on plant species.
Chen, Jiquan; Huebner, Cynthia D.; Saunders, Sari C.; Song, Bo. 2002. Plant distribution and diversity across an Ozark landscape. In: Shifley, S. R.; Kabrick, J. M., eds. Proceedings of the Second Missouri Ozark Forest Ecosystem Project Symposium: Post-treatment Results of the Landscape Experiment. Gen. Tech. Rep. NC-227. St. Paul, MN: U.S. Dept. of Agriculture, Forest Service, North Central Forest Experiment Station. 45-65.