An Ecological Classification System for the National Forests and Adjacent Areas of the West Gulf Coastal Plain

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We developed a multifactor ecological classification system (ECS) for the National Forests and adjacent lands of Texas and Louisiana. The ECS classifies lands into ecosystem types: repeating combinations of potential natural vegetation, soils, and physiography. This paper uses results of a portion of this effort from the northern part of Louisiana's Kisatchie National Forest as an example. Forest stands were sampled across a range of soil and topographic situations. Non-metric multidimensional scaling ordinations and TWINSPAN classification of the samples based on ground-layer vegetation corresponded to gradients of topographic position, fire frequency, disturbance, and soil nutrients. A separate ordination of only upland stands clarified relationships between upland vegetation and soil texture. Ordination and TWINSPAN results formed the basis for a final classification of the sample stands and for descriptions and dichotomous keys for seven “land-type phases”—local ecosystem types that share soil and topographic attributes, natural plant communities, and responses to management or disturbance. ECS provides an ecologically relevant way to stratify the landscape for inventory, conservation, research, or management and gives the Forest Service and other professionals a valuable tool to aid in making ecologically informed decisions. Future goals include mapping ecological units on National Forest lands and expansion of the area covered.