Home › Biology |
Biological Data Gateway: Introduction
The first of these is species, both plant and animal. Maps for a wide variety of species exist, some delineating distribution, some detailing abundance, and some demonstrating seasonal ranges. Other maps provide long-range views of how species populations and habitats have changed across recent years or even decades. Biologists and ecologists think of the second category, places, in two distinct ways. Ecoregions, as the term itself suggests, are defined regionally. Along with the land cover and soil conditions that contribute to their identities, geographical placement upon the continent itself is a primary component in distinguishing one ecoregion from another. Ecosystems, on the other hand, are habitat and community types that can occur, with some degree of variation, in various regions. Wetlands, for instance, are widespread and can be found in all 50 States. Third, there are special issues. Something of a catchall category, special issues cut across place and species considerations to focus on problems of special concern. Invasive species, endangered species, biodiversity, contaminants, climate change, and wildlife mortality have been identified by the Nation's ecologists and biologists as among the most pressing challenges confronting species and habitats today. Biological Data Gateway: Species An increased interest in the ecological sciences and the emergence of modern digital mapping techniques, however, have helped to create a level of geographically referenced species data undreamed of in Jefferson's day. For example, herpetologists - scientists who specialize in reptiles and amphibians - have created comprehensive range and abundance maps of numerous species since the 1950s. Likewise, national-scale maps exist for fishes, mammals, vegetation, and, in addition to moths and butterflies, other invertebrates as well. |
||||
National Atlas of the United States® and The National Atlas of the United States of America® are registered trademarks of the United States Department of the Interior Privacy Statement, Disclaimer, Accessibility, FOIA http://nationalatlas.gov/biology.html Last modified: April 29, 2008 15:54 |