Modeling of vegetation dynamics in the Mississippi River deltaic plain

An analysis was made of vegetation phenomena associated with cyclic river delta building and abandonment in the Mississippi River deltaic plain, Louisiana. Markov models of vegetation succession were completed for the new Atchafalaya delta and for the abandoned Lafourche delta. Transition matrices representing different flood conditions in the Atchafalaya delta (1979–1984) were used separately and in combinations based on long term river discharge data. Effect of grazing was introduced into the model as a special transition matrix. Succession during active delta building is heavily dependent on a particular sequence of flood conditions and, apparently, on the intensity of grazing. Natural vegetation changes and land losses in the abandoned Lafourche delta were simulated using a transition matrix based on air photographs from 1945 and 1956. A general flow diagram of long cyclic vegetation changes in the Mississippi deltaic plain was completed.We are grateful to G. W. Peterson, R. K. Abernethy, D. E. Parton, W. B. Johnson, D. A. Fuller, C. Neill, J. W. Day, R. E. Turner, F. Sklar, R. Costanza and M. G. Barbour for help and advice during this study.Nomenclature follows D. T. MacRoberts, 1984. The vascular plants of Louisiana. Bull. Mus. Life Sci., Louisiana State University in Shreveport 6: 1–165.Part of this work was supported by the Louisiana Sea Grant College Program maintained by NOAA, U.S. Department of Commerce.