Earl B Alexander

Ultramafic Geoecology of North America Earl B Alexander

Geoecology is an interdisciplinary endeavor that involves geology, soils, and plant communities. All of these features were observed and studied in representative ultramafic landscapes from the ancient continental platform and accreted terranes along the Pacific and Atlantic coasts to the Caribbean area. Understanding the geology and soils is very important for understanding the distributions of plant communities. Plant communities in ultramafic landscapes are of special interest to botanists, because they have unique "serpentine" vegetation, commonly with many endemic plant species. Descriptions of the plant communities are presented along with the soils of cold to hot and arid to humid climates in all kinds of ultramafic terranes. The plant communities are represented by the dominant species of trees, shrubs, and forbs. Also, bryophytes and lichens are mentioned as important ground cover in some subarctic and boreal landscapes. The plant communities range from barrens to dense forests and include alpine tundra and fell-fields, chaparral, savanna, open canopy forests, sagebrush, desert, and fens. Hundreds of plant species are mentioned in the characterization of these plant communities.