Techniques for Classifying and Understanding Vegetation Alliances

• Activity Number: 261
• Type: Topic Contributed
• Date/Time: Tuesday, August 10, 2004 : 2:00 PM to 3:50 PM
• Sponsor: Section on Statistics and the Environment
• Author(s): Michael D. Jennings*+
• Companies: U.S. Geological Survey/University of Idaho
• Keywords: vegetation alliance classification ; Mantel ; MRPP ; NMDS

Abstract

Little is known about ecological characteristics of alliances described in the U.S. National Vegetation Classification, either generally or individually, yet they are commonly the fundamental unit of vegetation used in large-area spatial datasets of habitat and biodiversity. Few alliance descriptions are based directly on original field plot data, and such data are rarely available for reexamination. This presentation focuses on applications of the Mantel Test, Non Metric Multidimensional Scaling, and Multi-Response Permutation Procedures in (a) evaluating and testing standardized field plot data from heterogeneous sources, and (b) measuring the relationship between the dominant plant species of alliances (which are used to identify and delineate the occurrence of an alliance) and the understory species which make up the composition of an alliance. The work presented here is based on an initial dataset containing almost 40,000 field plot records of 11 different sources. Additional datasets of climate, biomass productivity, and morphological traits of plant species were integrated with the field plot data. The techniques presented are central to achieving a numerical description.