PWRC web-site link USGS web-site link

ComDyn - Community Dynamics

COMDYN was developed to estimate parameters associated with community dynamics using presence/absence data from 2 locations or time periods. The basic estimator for species richness underlying all estimators is the jackknife estimator proposed by Burnham and Overton (1979; Ecology 60:927-936). Application of this estimator to species richness estimation is described and justified by Boulinier, Nichols, Sauer, Hines, and Pollock ("Estimating species richness : the importance of heterogeneity in species detectability, Ecology [1998] 79:1018-1028). The estimators for community-dynamic parameters and their variances are presented by Nichols, Boulinier, Hines, Pollock, and Sauer (" Inference methods for spatial variation in species richness and community composition when not all species are detected, Conservation Biology, in press; Estimating rates of local species extinction, colonization and turnover in animal communities, Ecological Applications [1998] 8:1213-1225).

    COMDYN3 - Compares 2 routes/years from BBS allowing the data to be subset by individual species or allowing data for eastern forest bird species to be subset by area-sensitivity, based on Robbisn, Dawson and Dowell (" Habitat area requirements of breeding forest birds of the middle Atlantic states", Wildlife Monographs [1989] No. 103)

    COMDYN4 - Compares 2 routes/years from user input

Species Richness Computations

    SPECRICH - Computes "species richness" or total number of species from empirical species abundance distribution data. Program written by J.E. Hines based on the limiting form of the jackknife estimators as described by Burnham and Overton (1979).
     Burnham, K.P., and W.S. Overton. 1979. Robust Estimation
     of Population Size When Capture Probabilities Vary
     Amoung Animals.  Ecology 60(5).  pp. 927-936.
    SPECRICH2 - Estimates the total number of species from species presence-absence data on multiple sample sites or occasions using the jackknife estimator for model M(h) from program CAPTURE. (Closed model capture-recapture analysis: model with heterogeneous capture probabilities)

     White, G.C., K.P. Burnham, D.L. Otis, and D.R. Anderson. 1978.
     User's Manual for Program CAPTURE, Utah State Univ. Press,
     Logan, Utah. 
     Rexstad, E., and K.P. Burnham.  1991. User's Guide for Interactive
     Program CAPTURE.  Colorado Cooperative Fish & Wildlife Research
     Unit, Colorado State University, Fort Collins, Colorado.

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