WLF 448: Fish & Wildlife Population Ecology

IV. ESTIMATING POPULATION PARAMETERS - I

Recommended Readings: Braun 2005: 72-153, Cushing 1981:95-141.

A. Estimating Abundance

1. Introduction

• see Key to Census Methods

2. Indices (Relative Density)

a. Direct methods

b. Indirect methods

c. Advantages

d. Disadvantages

e. Statistics

f. Key assumption

g. Double sampling

3. Absolute Density

a. Total counts

i. Total counts over whole area

ii. Total counts on sample plots

• critical assumption
• examples
• application
• sample designs
• removing bias (methods)

iii. Aerial Survey (Aerialsu.pdf) - Sightability models

b. Line transect (Linetran.pdf,  see Lab Notes)

c. Variable circular plot

d. Mark-recapture (Markreca.pdf,  see Lab Notes)

i. History

• John Graunt (1662) - used to estimate the population of London.

• C. G. J. Petersen (1896) - used to estimate the harvestable stocks of Danish fish populations.

• F. C. Lincoln (1930) - U.S. Fish & Wildlife Service - used to estimate waterfowl abundance in flyways.

ii. Applications

• size of population
• rate of exploitation
• survival rate
• rate of recruitment
• rates of movement (immigration/emigration)

iii. Single recaptures (k=1): Closed populations

• fundamental concepts
• Lincoln-Petersen estimator
• assumptions
• potential violations and their effect

iv. Multiple recaptures (k>1): Closed populations

• fundamental concepts
• Schnabel estimator
• assumptions
• sources of variation in capture probability
• modern methods: program CAPTURE

v. Multiple recaptures (k>1): Open populations

• fundamental concepts
• Jolly-Seber estimators: M_i, N_i, B_i, Ø_i (phi)
• assumptions

e. Removal methods

i. Catch-effort

ii. Change-in-ratio

B. Student Responsibilities

• What are the strengths and weaknesses of density indices, total counts, line transect and mark-recapture methods?

• What assumptions are each of the methods studied based upon?

• To what sort of populations and situations is it appropriate to apply each of these methods? To what sort is it inappropriate?

• What requirements do each of the study methods impose upon the design and methodology of field studies?

• Distinguish between the mark-recapture methods and catch-effort methods in assumptions.

C. References on Censusing

General References:

Caughley, G. 1977. Analysis of vertebrate populations. John Wiley and Sons, New York. 234pp. Chapters 4 and 10.

Conner, R. N., J. G. Dickson, and J. H. Williamson. 1983. A comparison of breeding bird census techniques with mist netting results. Wilson Bull. 95:276-280.

Krebs, C. J. 1989. Ecological methodology. Harper and Row, Publ., New York. 654pp.

Lancia, R. A., J. D. Nichols, and K. H. Pollock. 1994. Estimating the number of animals in wildlife populations. Pages 215-253 in T. A. Bookhout, ed. Research and management techniques for wildlife and habitats. Fifth ed. The Wildlife Society, Bethesda, Md.

Overton, W. S. 1971. Estimating the numbers of animals in wildlife populations. pp. 403-456 in Giles, R. H., Jr. (ed.). Wildlife management techniques. The Wildlife Society, Washington, D.C. 633pp.

Ralph, C. J., and J. M. Scott. (eds.). 1981. Estimating numbers of terrestrial birds. Studies in Avian Biology No. 6. Allen Press Inc., Lawrence, Kansas. 630pp.

Ricker, W. E. 1975. Computation and interpretation of biological statistics of fish populations. Department of the Environment Fisheries and Marine Service, Ottawa. 382pp.

Seber, G. A. F. 1982. The estimation of animal abundance and related parameters, 2nd edition. Charles Griffin and Co., London.

Line Transect and Strip Census:

Anderson, D. R., J. L. Laake, B. R. Crain, and K. P. Burnham. 1979. Guidelines for line transect sampling of biological populations. J. Wildl. Manage. 43:70-78.

Anderson, D. R., K. P. Burnham, G. C. White, and D. L. Otis. 1983. Density estimation of small mammal populations using a trapping web and distance sampling methods. Ecology 64:674-680.

Anderson, D. R., and R. S. Pospahala. 1970. Correction of bias in belt transect studies of immobile objects. J. Wildl. Manage. 34(1):141-146.

Buckland, S. T., D. R. Anderson, K. P. Burnham, and J. L. Lake. 1993. Distance sampling: estimating abundance of biological populations. Chapman and Hall, London.

Burnham, K. P., D. R. Anderson, and J. L. Laake. 1980. Estimation of density from line transect sampling of biological populations. J. Wildl. Manage. 72. 202pp.

Eberhardt, L. L. 1978. Transect methods for population studies. J. Wildl. Manage. 42(1):1-31.

Emlen, J. T. 1971. Population densities of birds derived from transect counts. Auk 88:323-342.

Emlen, J. T. 1977. Estimating breeding season bird densities from transect counts. Auk 94:455-468.

Gates, C. E., W. H. Marshall, and D. P. Olson. 1968. Line transect method of estimating grouse population densities. Biometrics 24:135-145.

Hayne, D. C. 1949. An examination of the strip census method for estimating animal populations. J. Wildl. Manage. 13(2):145-157.

Robinette, W. L., C. Loveless, and D. A. Jones. 1974. Field tests of strip census methods. J. Wildl. Manage. 38(1):81-96.

Wilson, K. R. 1983. Evaluation of a new trapping web design and analysis method for estimating density of small mammal populations. Unpub. M.S. Thesis, Utah State Univ., Logan, Utah. 88pp.

Mark-Recapture:

Arnason, A. N., and L. Baniuk. 1980. A computer system for mark-recapture analysis of open populations. J. Wildl. Manage. 44:325-332.

Bishop, J. A., and P. M. Sheppard. 1973. An evaluation of two capture-recapture models using the technique of computer simulation. pp. 235-251 in Bartlett, M. S. and R. W. Hiorns (eds.). The mathematical theory of the dynamics of biological populations. Academic Press, New York. 347pp.

Cormack, R. M. 1973. Common sense estimates from capture-recapture studies. pp. 225-234 in Bartlett, M. S. and R. W. Hiorns (eds.). The mathematical theory of the dynamics of biological populations. Academic Press, New York. 347pp.

Jolly, G. M. 1965. Explicit estimates from capture-recapture data with death and immigration-stochastic model. Biometrika 52(1):225-247.

_____. 1982. Mark-recapture models with parameters constant in time. Biometrics 38:301-321.

Otis, D. L., K. P. Burnham, G. C. White, and D. R. Anderson. 1978. Statistical inference from capture data on closed animal populations. Wildl. Manage. No. 62. 135pp.

Otis, D. L., K. P. Burnham, G. C. White, and D. R. Anderson. 1980. Corrections to Wildlife Monograph 62. J. Wildl. Manage. 44:666-667.

Pollock, K. H. 1982. A capture-recapture sampling design robust to unequal catchability. J. Wildl. Manage. 46:752-757.

_____, J. D. Nichols, C. Brownie, and J. E. Hines. 1990. Statistical inference for capture-recapture experiments. Wildl. Monogr. 107. 97pp.

Schnabel, Z. E. 1938. Estimation of the total fish population of a lake. Amer. Math. Monthly 45:348-352.

Schumacher, F. X., and R. W. Eschmeyer. 1943. The estimate of fish populations in lakes or ponds. J. Tenn. Acad. Sci. 18:228-249.

White, G. C., D. R. Anderson, K. P. Burnham, and D. L. Otis. 1982. Capture-recapture and removal methods for sampling closed populations. Report LA-8787-NERP, Los Alamos National Laboratory, Los Alamos, New Mexico. 235pp.

Spot Mapping:

Best, L. B. 1975. Interpretational errors in the "Mapping Method" as a census technique. Auk 92:452-460.

International Bird Census Committee. 1970. Recommendations for a mapping method in bird census work. Aud. Field Notes 24:722-726.

Kendeigh, S. C. 1944. Measurement of bird populations. Ecol. Monogr. 14:67-106.

Plot Size:

Eberhardt, L., and R. C. Van Etten. 1956. Evaluation of the pellet-group count as a deer census method. J. Wildl. Manage. 20:70-74.

Robinette, W. L., R. B. Ferguson, and J. S. Gashwiler. 1958. Problems involved in the use of deer pellet-group counts. Trans. N. Am. Wildl. Conf. 23:411-425.

Van Etten, R. C., and C. L. Bennett, Jr. 1965. Some sources of error in using pellet-group counts for censusing deer. J. Wildl. Manage. 29:723-729.

White, G. C., and L. E. Eberhardt. 1980. Statistical analysis of deer and elk pellet-group data. J. Wildl. Manage. 44:121-131.

Indices to Wildlife Abundance:

Braun, C. E., R. K. Schmidt, Jr., and G. E. Rogers. 1973. Census of Colorado white-tailed ptarmigan with tape-recorded calls. J. Wildl. Manage. 37:90-93.

Davis, J. 1965. The "Singing Male" method of censusing birds: a warning. Condor 67:86-87.

Freddy, D. J., and D. C. Bowden. 1983. Sampling mule deer pellet-group densities in juniper-pinyon woodland. J. Wildl. Manage. 47:476-485.

Gates, J. M. 1966. Crowing counts as indices to cock pheasant populations in Wisconsin. J. Wildl. Manage. 30:735-744.

Harrington, F. H., and L. D. Mech. 1982. An analysis of howling response parameters useful for wolf pack censusing. J. Wildl. Manage. 46:686-693.

Kimball, J. W. 1949. The crowing count pheasant census. J. Wildl. Manage. 13:101-120.

Linhart, S. B., and F. F. Knowlton. 1975. Determining the relative abundance of coyotes by scent station lines. Wildl. Soc. Bull. 3:119-124.

Neff, D. J. 1968. The pellet-group count technique for big game trend, census, and distribution: a review. J. Wildl. Manage. 32:597-614.

Newman, D. E. 1959. Factors influencing the winter roadside count of cottontails. J. Wildl. Manage. 23:290-294.

Parr, D. E., and M. D. Scott. 1978. Analysis of roosting counts as an index to wood duck population size. Wilson Bull. 90:423-437.

Rodgers, R. D. 1981. Factors affecting ruffed grouse drumming counts in southwestern Wisconsin. J. Wildl. Manage. 45:405-418.

Roughton, R. D., and M. W. Sweeny. 1982. Refinements in scent-station methodology for assessing trends in carnivore populations. J. Wildl. Manage. 46:217-229.

Updated 30 July 1996