Estimation of Bird Community Dynamics from Breeding Bird Survey Data

Using Program COMDYN

Background

The BBS provides a unique source of information about bird communities, and many investigators use BBS data to evaluate change in species richness over time and space (e.g., Boulinier 1998a).  Unfortunately, the naive estimate of total number of observed species on a BBS routes is biased, as all observers have some chance of missing species during the counts and this chance is well known to differ among observers and routes (Boulinier et al. 1998b).  This is a very real problem, and investigators who use simple counts of species on BBS routes in ecological studies must recognize that their estimates of species richness and change in richness are flawed and could be subject to criticism or rebuttal.

Luckily, estimators of species richness have been developed to estimate detection rates of species, and to accommodate variation in detection rates among species and sites (e.g.  Burnham and Overton 1979).  Nichols et al. (1998a,b) have developed a series of estimators for change in communities that incorporate the possibility of variation in detection rates among species.  Program COMDYN (Hines et al. 1999) implements these estimators of change over time and space for the North American Breeding Bird Survey.  Detailed descriptions of the estimators in program COMDYN can be found in Nichols et al. (1998a, 1998b). These papers, along with papers describing other examples and applications of species richness estimation methods, are available either from this website (as pdf files) or from the authors.

Using Program COMDYN


To use the program, enter the state/province and routes to be compared, and the years to include in the comparison. Note: routes are indexed by numbers. To obtain the names of routes, consult either the Analysis website or the Electronic National Atlas. The program also allows you to choose whether "occurrence" is summarized at the scale of individual stops (Analyze stops individually) or over groups of 10 stops (Analyze stops in groups of 10). For bootstrap confidence interval estimation, users can (optionally) choose number of replicates and a random number seed. Then, choose "Select species" to initiate the program and generate a list of species found on the routes.

The program will respond with a list of species found on the routes, and the user must choose the appropriate species for the analysis. The default is that all species are included (all are "checked"). You can either select (or unselect) species by clicking on the buttons, or by selecting from the selection bars under the species list. Note that "Select no species" and "Select all species" are options on the list. Then, select "Compute estimates" to run the program. Results are presented on a new page, and definitions of parameters and estimates are provided below the numeric outputs.

LITERATURE CITED

Boulinier, T, J. D. Nichols, J. E. Hines, J. R. Sauer, C. H. Flather, and K. H. Pollock. 1998a. Higher temporal variability of forest bird communities in fragmented landscapes. Proc. Nat. Acad. Sci. 95:7497-7501.Download PDF

Boulinier, T, J. D. Nichols, J. R. Sauer, J. E. Hines, and K. H. Pollock. 1998b. Estimating species richness to make inference in community ecology: The importance of heterogeneity in species detectability as shown from capture-recapture analyses of North American Breeding Bird Survey Data. Ecology 79:1018-1028.Download PDF

Burnham, K. P. and W. S. Overton. 1979. Robust estimation of population size when capture probabilities vary among animals. Ecology 60:927-936. View Abstract

Hines, J.E., T. Boulinier, J.D. Nichols, J.R. Sauer, and K.H. Pollock. 1999. COMDYN: software to study the dynamics of animal communities using a capture-recapture approach. Bird Study 46 (suppl.):S209-217. View Abstract

Nichols, J. D., T. Boulinier, J. E. Hines, K. H. Pollock, and J. R. Sauer. 1998a. Estimating rates of local species extinction, colonization, and turnover in animal communities. Ecological Applications 8:1213-1225.Download PDF

Nichols, J. D., T. Boulinier, J. E. Hines, K. H. Pollock, and J. R. Sauer. 1998b. Inference methods for spatial variation in species richness and community composition when not all species are detected. Conservation Biology 12:1390-1398. View Abstract

ADDITIONAL REFERENCES ON COMMUNITY DYNAMICS ESTIMATION

Cam, E., J. R. Sauer, J. D. Nichols, J. E. Hines, and C. H. Flather. 2000. Geographic analysis of species richness and community attributes of forest birds from survey data in the mid-atlantic integrated assessment region Environmental Monitoring and Assessment 63:81-94.Download PDF

Cam, E., J. D. Nichols, J. E. Hines, and J. R. Sauer. 2000. Inference about nested subsets structure when not all species are detected. Oikos 91: 428-434.

Nichols, J. D., J. R. Sauer, J. E. Hines, and T. Boulinier, and K. H. Pollock. 2001. Estimation of Species Richness and Parameters Reflecting Community Dynamics Using Data from Ecological Monitoring Programs. Pages 181- 187 in Conservation of biological diversity: A key to the restoration of the Chesapeake Bay Ecosystem and Beyond. G. D. Therres, Ed. Maryland Department of Natural Resources, Annapolis, MD.

Boulinier, T. Nichols, J. D., J. E. Hines, J. R. Sauer, C. H. Flather, and K. H. Pollock. 2001. Forest fragmentation and bird community dynamics: inference at regional scales. Ecology 82:1159-1169.Download PDF

Sauer, J. R., J. D. Nichols, J. E. Hines, T. Boulinier, C. H. Flather, and W. L. Kendall. 2001. Regional patterns in proportion of bird species detected in the North American Breeding Bird Survey Pages 293-296 In R. Field, R. J. Warren, H. Okarma, and P. R. Sievert, editors. Wildlife, land, and people: priorities for the 21st century. Proceedings of the. 2nd. International Wildlife Congress. The Wildlife Society, Bethesda, MD, USA.

Cam, E., J. D. Nichols, J. E. Hines, J. R. Sauer, R. Alpizar-Jara, and C. H. Flather. 2002. Disentangling sampling and ecological explanations underlying species-area relationships. Ecology 83:1118-1130.Download PDF

Cam, E., J. D. Nichols, , J. R. Sauer J. E. Hines. 2002. On the estimation of species richness based on the accumulation of previously unrecorded species. Ecography 25:102-108. View Abstract