Morphologic and allozymic variation between long-term grazed and non-grazed populations of the bunchgrass Schizachyrium scoparium var. frequens

• Published in: Oecologia Vol. 66; no. 3; pp. 332 - 337
• Main Authors: Carman, J.G, Briske, D.D
• Format: Journal Article
• Language: English
• Published: Berlin Springer-Verlag 01-06-1985; Springer
• Subjects: Animal and plant ecology; Animal, plant and microbial ecology; Biological and medical sciences; Biomass; Defoliation; Enzymes; Fundamental and applied biological sciences. Psychology; genotype; Genotypes; Grazing; Herbivores; Phenotypes; plant anatomy; plant ecology; Plant morphology; Plants; Schizachyrium scoparium; Synecology; Terrestrial ecosystems; Tillers; Grassland; Herbivorous animal; Genotype; Animal effect; Allozyme; Morphology
• ISSN: 0029-8549; 1432-1939
• DOI: 10.1007/BF00378294

Plant populations of Schizachyrium scoparium var. frequens with a history of long-term grazing by domestic herbivores were characterized by shorter and narrower leaf blades and tillers of lower weight than plants from populations with a history of no grazing. Following four biweekly defoliation events plants from the grazed populations additionally displayed lower specific leaf weights, lower amounts of biomass removed per tiller upon defoliation and a greater number of new and regrowing tillers. Production values per plant remained similar between the two populations because of a greater number of tillers per plant in the grazed population. A large amount of allozymic polymorphism was observed in both the grazed and non-grazed populations. Results of the electrophoretic analyses indicated that a minimum of 66% of the plants sampled represented separate genotypes. No distinction could be made between grazed and non-grazed populations in terms of allozymic partitioning. The morphological variation observed between these two populations may represent a shift in the relative dominance of a series of genotypes variously adapted to herbivory.