Two pioneer dune grasses: Calamovilfa longifolia and Agropyron dasystachyum.

Abstract

Perhaps the two most important abiotic factors controlling the formation of sand dunes are wind and a source of sand. Without these two necessities, dune succession would not take place. Another important factor is pioneer vegetation, which anchors sand and stabilizes the dunes. Two important dune stabilizers are the grasses Calamovilfa longifolia and Agropyron dasystachyum (Krebs 1985). These two plants have similarities and differences morphologically. Both are in the family Gramineae, and thus share characters such as streamlined aspect, reduced flowers lacking perianths, and arrow-shaped anthers. both spread using underground rhizomes, which assist in the sand-binding process. In appearance, the two grasses are quite different. calamovilfa is often taller than Agropyron, with a wide open slender inflorescence and a completely hairy stem. Agropyron is very glaucous, and sports a bluish-green tint. Calamofilfa has a very thick, scaly rhizome, whereas that of Agropyron is much thinner. Both grasses grow in the same general habitat: sandy shores and dunes of the Great Lakes (Voss, 1972). Both species are also prairie grasses in the west. In studying these two plants, I set out to observe their specific habitats. My biggest question was whether they grew in the exact same places, or if there were some environmental, morphological, or biological differences controlling their habitats. I saw at least one of each species at 5 different locations, for a total of 9 specific sites. In conclusion, my observations have shown me that: 1. Calamovilfa longifolia is present in a wider variety of habitats than Agropyron dasystachyum. 2. Calamovilfa longifolia is adapted to survival in disturbed habitats. 3. Calamovilfa longifolia prefers dune crests, while Agropyron dasystachyum prefers flatter, lower areas. 4. Calamovilfa longifolia appears to exist in places that represent an earlier time in successional history. 5. Calamovilfa longifoia has thick, scaly rhizomes that may assist in its establishment and maintenance in areas in which Agropyron is unable to live.