Patterns of frequency in species-rich vegetation in pine savannas: Effects of soil moisture and scale

摘要: Our principal objective was to document dominant plant composition and the species frequency pattern in a community type, longleaf pine savanna, known for its extraordinary number of vascular species. We also tested whether an important habitat factor, soil moisture, affected resulting patterns, patterns were scale-dependent. began with collection 120 sample plots (1- × 1-m) wet coastal plain savanna. These contained 126 The 3 by cover Rhynchospora gracilenta (15.37%), Schizachyrium tenerum (13.36%), Scleria pauciflora (10.07%). distribution skewed unimodal most occurring infrequently, less than 10% plots. There no evidence bimodality. To test moisture we sorted into 2 groups: 60 representing wetter conditions drier conditions. Measured percent cover, dominants R. gracilenta, Dichanthelium scabriusculum, S. pauciflora, whereas area they tenerum, Ilex glabra, D. dichotomum. similar both dry (χ2 = 8.97, P > 0.05). explore possible effects on this pattern, sampled further 75 larger tract De Soto National Forest, using 4 areas 0.1, 1, 10, 100 m2. Again, distributions all had pattern. are consistent other studies savannas but do not appear bimodal reported from some grasslands. Further will determine degree generality such their relationship mechanistic processes communities.