Mapping a changing world: The importance of good classifications in mapping and modeling ecosystem patterns

Background/Question/Methods Vegetation mapping has long been used by biogeographers and ecologists for ecological context in global ecological distributions, and regional landscape patterns. More recently, vegetation mapping has played an increasing role in conservation planning and management at many scales. Today conflicting ideas on use of natural resources have become more contentious. Thus, decisions based on vegetation patterns at all scales have become more critical. Current issues include the need for: 1) precision in locating vegetation for a variety of uses and conservation purposes and, 2) accurate and rigorous standards for identification and discrimination of vegetation patterns. Addressing these issues has provided a strong impetus for the use of a standardized, hierarchical, and defensible classification system (e.g., the US National Vegetation Classification, USNVC), techniques of appropriate scale, and associated attributes depicting important information. Despite numerous advances in GIS, Remote Sensing, and analysis of large data-sets, some issues remain difficult to resolve. The main difficulties stem from: 1) proper sequencing of data from classifying to mapping, 2) translation of ecological information to the map, 3) limited thematic mapping information based on cost, and 4) maximizing the efficiency of both manual and automated mapping processes.

Results/Conclusions Experience with a variety of mapping concepts and techniques has led to the following conclusions. Vegetation mapping comes best from a strong field-based classification and with the mapper’s understanding of it. Stands, the basic unit of vegetation, are not equally visually distinct, and the hierarchy should be used at the appropriate level based on the mapper’s ability to discriminate. Vegetation classification includes both floristic and structural information. These should be depicted in the map. Stand-based attributes, such as site quality can be especially useful in vegetation maps developed for conservation and management plans. When relying on basic rules of vegetation classification and mapping, these products are extremely useful for landscape-level monitoring, but only if the map classification and resolution can be held constant through the time sequence. Vegetation maps can be tied to elements of plant and animal species’ habitat, and are often key in developing detailed habitat modeling. Many highly valuable analyses stem from structural and specific site-based information tied to vegetation polygons. Most users are not aware of the kinds of information a vegetation map can provide and do not see mapping as a time- and cost-saving endeavor. Continued education and outreach is needed to clarify these advantages.