Ordination of woody vegetation in a Ouachita National Forest watershed

Species response to competition and other environmental gradients has important implications for forest ecosystem managers who desire to both maintain diversity and provide a sustained flow of forest goods and services. Woody species on a 140-acre watershed in the Ouachita National Forest are ordinated with detrended correspondence analysis (DCA) and canonical correspondence analysis (CCA) to identify the important influences on species distribution at this scale. Species composition is found to respond primarily to a moisture gradient, and secondarily to competition with shortleaf pine (Pinus echinata Mill.). Centrifugal organization of species along gradients is suggested by the relative locations of species in the ordination diagrams.