The Analysis of Population Persistence: An Outlook on the Practice of Viability Analysis

  • Martha J. Groom
  • Miguel A. Pascual


One of the critical challenges in conservation biology is to develop quantitative methods for evaluating the fate of populations that are threatened by human activities (Soulé 1987). Predicting population responses to various perturbations, such as habitat destruction, harvest, or supplementation via reintroduction, requires some practical analyses of population viability. These “population viability analyses” (PVAs) have come into increasing usage, and every indication is that their importance will rise in the future. A recent National Research Council panel convened to evaluate the Endangered Species Act vigorously recommended even greater reliance on viability models (NRC 1996), as have many other groups of biologists seeking to improve management of endangered and rare species (e.g., Carroll et al. 1996; Mangel et al. 1996; Ruggiero, Hayward, and Squires 1995; Schemske et al. 1994).


Ecological Application Conservation Biology Wildlife Management Vital Rate Biological Conservation 


Unable to display preview. Download preview PDF.

Unable to display preview. Download preview PDF.

Literature Cited

  1. Alvarez-Buylla, E. and M. Slatkin. 1991. Finding confidence limits on population growth rates. Trends in Ecology and Evolution 6:221–224.*Google Scholar
  2. Anderson, M.C. and D. Mahato. 1995. Demographic models and reserve designs for the California spotted owl. Ecological Applications 5:639–647.*Google Scholar
  3. Armbruter, P. and R. Lande. 1993. A population viability analysis for African Elephant (Loxodonta africana): How big should reserves be? Conservation Biology 7:602–610.*Google Scholar
  4. Arnqvist, G. and D. Wooster. 1995. Meta-analysis: Synthesizing research findings in ecology and evolution. Trends in Ecology and Evolution 10:236–240.Google Scholar
  5. Barlow, N.D. and M.N. Clout. 1983. A comparison of three-parameter, single-species population models, in relation to the management of bushtail possum in New Zealand. Oecologia 60:250–258.Google Scholar
  6. Bayliss, P. 1989. Population dynamics of magpie geese in relation to rainfall and density: Implications for harvest models in fluctuating environments. Journal of Applied Ecology 26:913–924.Google Scholar
  7. Beier, P. 1993. Determining minimum habitat area and habitat corridors for cougars. Conservation Biology 7:94–108.*Google Scholar
  8. Beissinger, S.R. 1995. Modeling extinction in periodic environments: Everglades water levels and snail kite population viability. Ecological Applications 5:618–631.*Google Scholar
  9. Belovsky, G. 1987. Extinction models and mammalian persistence. In Viable Populations for Conservation, ed. M.E. Soulé, 35–57. Cambridge: Cambridge University Press.Google Scholar
  10. Beudels, R.C., S.M. Durant, and J. Harwood. 1992. Assessing the risks of extinction for local populations of roan antelope Hippotragus equinus. Biological Conservation 61:107–116.*Google Scholar
  11. Bierzychudek, P. 1982. The demography of jack-in-the-pulpit-a forest perennial that changes sex. Ecological Monographs 52:335–351.Google Scholar
  12. Bowman, T.D., P.F. Schempf, and J.A. Bernatowicz. 1995. Bald eagle survival and population dynamics in Alaska after the Exxon Valdez oil spill. Journal of Wildlife Management 59:317–324.*Google Scholar
  13. Box, G.E.P. and G.C. Tiao. 1973. Bayesian inference in statistical analysis. Reading, MA: Addison-Wesley.Google Scholar
  14. Boyce, M. 1992. Population viability analysis. Annual Review of Ecology and Systematics 23:481–506.Google Scholar
  15. Burgman, M., D. Cantoni, and P. Vogel. 1992. Shrews in suburbia: an application of Goodman’s extinction model. Biological Conservation 61:117–123.*Google Scholar
  16. Burgman, M.A., S. Ferson, and H.R. Akcakaya. 1993. Risk assessment in conservation biology. London: Chapman and Hall.Google Scholar
  17. Burton, M.P. 1994. Alternative projections of the decline of the African elephant. Biological Conservation 70:183–188.*Google Scholar
  18. Campagna, C., C. Bisioli, F. Quintana, and A. Vila. 1992. Group breeding in sea lions: pups survive better in colonies. Animal Behavior 43:541–54.Google Scholar
  19. Carroll, R., C. Augspurger, A. Dobson, J. Franklin, G. Orians, W. Reid, R. Tracy, D. Wilcove, and J. Wilson. 1996. Strengthening the use of science in achieving the goals of the Endangered Species Act: An assessment by the Ecological Society of America. Ecological Applications 6:1–11.Google Scholar
  20. Carpenter, S.R., A. Muñoz del Rio, S. Newman, P.W. Rasmusen, and A.M. Johnson. 1994. Interactions of anglers and walleyes in Escanaba Lake, Wisconsin. Ecological Applications 4:822–832.*Google Scholar
  21. Caswell, H. 1989. Matrix population models. Sunderland, MA: Sinauer Press.Google Scholar
  22. Cattan, P.E. and A.A. Glade. 1989. Management of the vicuña Vicugna vicugna in Chile: Use of a matrix model to asses harvest rates. Biological Conservation 49:131–140.*Google Scholar
  23. Caughley, G. 1994. Directions in conservation biology. Journal of Animal Ecology 63:215–244.Google Scholar
  24. Crouse, D., L. Crowder, and H. Caswell. 1987. A stage-based population model for loggerhead seaturtles and implications for conservation. Ecology 68:1412–1423.Google Scholar
  25. Crowder, L.B., D.T. Crouse, S.S. Heppell, and T.H. Martin. 1994. Predicting the impact of turtle excluder devices in loggerhead sea turtle populations. Ecological Applications 4:437–445.*Google Scholar
  26. Croze, H., A.K.K. Hillman, and E.M. Lang. 1981. Elephants and their habitats: How do they tolerate each other. In Dynamics of Large Mammal Populations, eds. C.W. Fowler and T.D. Smith, 297–31. New York: Wiley.Google Scholar
  27. Dennis, B. 1989. Allee effects: Population growth, critical density, and the chance of extinction. Natural Resource Modeling 3:481–538.Google Scholar
  28. Dennis, B., P.L. Munholland, and J.M. Scott. 1991. Estimation of growth and extinction parameters for endangered species. Ecological Monographs 61:115–143.Google Scholar
  29. Deriso, R.B., S.H. Hoag, and D.A. McCaughran. 1986. Two hypotheses about factors controlling production of Pacific halibut. International North Pacific Fisheries Commission Bulletin 47:167–173.Google Scholar
  30. Doak, D.F. 1989. Spotted owls and old growth logging in the Pacific Northwest. Conservation Biology 3:389–396.*Google Scholar
  31. Doak, D.F. 1995. Source-sink models and the problem of habitat degradation: General models and applications to the Yellowstone grizzly. Conservation Biology 9:1370–1379.Google Scholar
  32. Doak, D.F., P. Kareiva, and B. Klepetka. 1994. Modeling population viability for the desert tortoise in the Western Mojave Desert. Ecological Applications 4:446–460.*Google Scholar
  33. Durant, S.M. and J. Harwood. 1992. Assessment of monitoring and management strategies for local populations of the Mediterranean monk seal Monachus monachus. Biological Conservation 61:81–92.*Google Scholar
  34. Edwards, W., H. Lindman, and L.J. Savage. 1963. Bayesian inference for psychological research. Psychological Review 70:193–242.Google Scholar
  35. Fernandez-Duque, E. and C. Valeggia. 1994. Meta-Analysis: A valuable tool in conservation research. Conservation Biology 8:555–561.Google Scholar
  36. Ferson, S. and M.A. Burgman. 1995. Correlations, dependency bounds and extinction risk. Biological Conservation 73:101–105.Google Scholar
  37. Ferson, S., L. Ginzburg, and A. Silvers. 1989. Extreme event risk analysis for age-structured populations. Ecological Modeling 47:175–87.Google Scholar
  38. Ferson, S. and S. Uryasev. 1996. Sensitivity of extinction risk. Supplement to the Bulletin of the Ecological Society of America 77:140.Google Scholar
  39. Gilpin, M.E. 1990. Extinction of finite metapopulations in correlated environments. In Living in a patchy environment, eds. B. Shorrocks and I.R. Swingland, 177–186. Oxford: Oxford Science Publications.Google Scholar
  40. Gilpin, M.E. and M.E. Soulé. 1986. Minimum viable populations: The processes of population extinction. In Conservation Biology: Science of scarcity and diversity, ed. M.E. Soulé, 13–34. Sunderland, MA: Sinauer.Google Scholar
  41. Ginsberg, J.R. and E.J. Milner-Gulland. 1994. Sex-biased harvesting and population dynamics in ungulates: Implications for conservation and sustainable use. Conservation Biology 8:157–166.*Google Scholar
  42. Ginzburg, L.R., B. Slobodkin, K. Johnson, and A.G. Bindman. 1982. Quasiextinction probabilities as a measure of impact on population growth. Risk Analysis 2:171–181.Google Scholar
  43. Ginzburg, L.R., S. Ferson, and H.R. Akcakaya. 1990. Reconstructability of density dependence and the conservative assessment of extinction risks. Conservation Biology 4:63–70.Google Scholar
  44. Goldingay, R. and H. Possingham. 1995. Area requirements for viable populations of the Australian gliding marsupial Petaurus australis. Biological Conservation 73:161–167.*Google Scholar
  45. Goldwasser, L., M.J. Groom, and P. Kareiva. 1993. The effects of model structure and annual variability on population viability analyses of the Northern Spotted Owl (Strix occidentalis caurina). Technical Report to the California Forestry Association, Sacramento, CA.Google Scholar
  46. Goodman, D. 1987a. Consideration of stochastic demography in the design and management of biological reserves. Natural Resources Modeling 1:205–234.Google Scholar
  47. Goodman, D. 1987b. The demography of chance extinction. In Viable populations for conservation, ed. M.E. Soulé, 59–68. Cambridge: Cambridge University Press.Google Scholar
  48. Green, R.E. and G.J.M. Hirons. 1991. The relevance of population studies to the conservation of threatened birds. In Bird Population Studies: Relevance to conservation and management, eds. C.M. Perrins, J.-D. Lebreton, and G.J.M. Hirons, 594–633. New York: Oxford University Press.Google Scholar
  49. Groom, M.J., L. Goldwasser, and P. Kareiva. 1993. Evaluating the influence of model structure on the results of population viability simulations. Technical Report to the California Forestry Association, Sacramento, CA.Google Scholar
  50. Groom, M.J. 1996. Reproductive failure in an annual plant when critical isolation thresholds are exceeded. In review. Nature.Google Scholar
  51. Haig, S.M., J.R. Belthoff, and D.H. Allen. 1993. Population viability analysis for a small population of Red-Cockaded Woodpeckers and an evaluation of enhancement strategies. Conservation Biology 7:289–301.*Google Scholar
  52. Hamilton, S. and H. Moller. 1995. Can PVA models using computer packages offer useful conservation advice? Sooty shearwaters Puffinus griseus in New Zealand as a case study. Biological Conservation 73:107–117.*Google Scholar
  53. Hanski, I. and C.D. Thomas. 1994. Metapopulation dynamics and conservation: a spatially explicit model applied to butterflies. Biological Conservation 68:167–180.Google Scholar
  54. Harper, J. 1977. Population biology of plants. New York: Academic Press.Google Scholar
  55. Harris, R.B., L.A. Maguire, and M.L. Shaffer. 1987. Sample sizes for minimum viable population estimation. Conservation Biology 1:72–75.Google Scholar
  56. Harrison, S. and J. Quinn. 1989. Correlated environments and the persistence of metapopulations. Oikos 56:293–298.Google Scholar
  57. Heppell, S.S., L.B. Crowder, and D.T. Crouse. 1996. Models to evaluate headstarting as a management tool for long-lived turtles. Ecological Applications 6:556–565.*Google Scholar
  58. Heppell, S.S., J.R. Walters, and L.B. Crowder. 1994. Evaluating management alternatives for redcockaded woodpeckers: A modeling approach. Journal of Wildlife Management 58:479–487.*Google Scholar
  59. Heyde, C.C. and J.E. Cohen. 1985. Confidence intervals for demographic projections based on products of random matrices. Theoretical Population Biology 27:120–53.Google Scholar
  60. Kenney, J.S., J.L.D. Smith, A.M. Starfield, and C.W. McDougal. 1995. The long-term effects of tiger poaching on population viability. Conservation Biology 9:1127–1133.*Google Scholar
  61. Kinnaird, M.F. and T.G. O’Brien. 1991. Viable populations for an endangered forest primate, the Tana River crested mangabey (Cercocebus galeritus galeritus). Conservation Biology 5:203–213.*Google Scholar
  62. Lamberson, R.H., K. McKelvey, B.R. Noon, and C. Voss. 1992. A dynamic analysis of northern spotted owl viability in a fragmented forest landscape. Conservation Biology 6:505–512.*Google Scholar
  63. Lamberson, R.H., B.R. Noon, C. Voss, and K.S. McKelvey. 1994. Reserve design for territorial species: the effects of patch size and spacing on the viability of the northern spotted owl. Conservation Biology 8:185–195.*Google Scholar
  64. Lancia, R.A., K.H. Pollock, J.W. Bishir, and M.C. Conner. 1988. A white-tailed deer harvesting strategy. Journal of Wildlife Management 54:589–595.*Google Scholar
  65. Lande, R. 1987. Extinction thresholds in demographic models of territorial populations. American Naturalist 130:624–635.Google Scholar
  66. Law, R., and M.T. Edley. 1990. Transient dynamics of populations with age- and size-dependent vital rates. Ecology 71:1863–70.Google Scholar
  67. Leigh, E.G., Jr. 1971. The average lifetime of a population in a varying environment. Journal of Theoretical Biology 90:213–239.Google Scholar
  68. Levins, R. 1970. Extinction. In Lectures on mathematics in life sciences, ed. M. Gerstenhaber, 77–107. Providence: American Mathematical Society.Google Scholar
  69. Lindenmayer, D.B., R.B. Cunningham, M.T. Tanton, and A.P. Smith. 1990. The conservation of arboreal marsupials in the montane ash forests of the Central Highlands of Victoria, southeast Australia. II. The loss of trees with hollows and its implications for the conservation of Leadbeater’s Possum Gymnobelideus leadbeateri McCoy (Marsupialia: Petauridae). Biological Conservation 54:133–145.*Google Scholar
  70. Lindenmayer, D.B. and R.C. Lacy. 1995a. A simulation study of the impacts of population subdivision on the mountain brushtail possum Trichosurus caninus in Southeastern Australia. I. Demographic stability and populations persistence. Biological Conservation 73:119–129.*Google Scholar
  71. Lindenmayer, D.B. and R.C. Lacy. 1995b. Metapopulation viability of Leadbeater’s possum, Gymnobelideus leadbeateri, in fragmented old-growth forests. Ecological Applications 5:164–182.*Google Scholar
  72. Lindenmayer, D.B. and R.C. Lacy. 1995c. Metapopulation viability of arboreal marsupials in fragmented old-growth forests: comparisons among species. Ecological Applications 5:183–199.*Google Scholar
  73. Lindenmayer, D.B. and H.P. Possingham. 1995. The conservation of arboreal marsupials in the montane ash forests of the central highlands of Victoria, south-eastern Australia. VII. Modeling the persistence of Leadbeater’s possum in response to modified timber harvesting practices. Biological Conservation 73:239–257.*Google Scholar
  74. Lindenmayer, D.B. and H.P. Possingham. 1996. Ranking conservation and timber management options for Leadbeater’s possum in Southeast Australia using Population Viability Analysis. Conservation Biology 10:235–251.*Google Scholar
  75. Liu, J., J.B. Dunning, and H.R. Pulliam. 1995. Potential effects of a forest management plan on Bachman’s sparrows (Aimophila aestivalis): linking a spatially explicit model with GIS. Conservation Biology 9:62–75.*Google Scholar
  76. Ludwig, D. 1996. Uncertainty and the assessment of extinction probabilities. Ecological Applications, in press.Google Scholar
  77. Ludwig, D. and C.J. Walters. 1985. Are age-structured models appropriate for catch-effort data? Canadian Journal of Fisheries and Aquatic Sciences 42:1066–1072.Google Scholar
  78. Maguire, L.A. 1991. Risk analysis for conservation biologists. Conservation Biology 5:123–125.Google Scholar
  79. Maguire, L.A., U.S. Seal, and P.F. Brussard. 1987. Managing critically endangered species: the Sumatran rhino as a case study. In Viable Populations for Conservation, ed. M.E. Soulé, 141–158. Cambridge: Cambridge University Press.Google Scholar
  80. Maguire, L.A., G.F. Wilhere, and Q. Dong. 1995. Population viability analysis for red-cockaded woodpeckers in the Georgia piedmont. Journal of Wildlife Management 59:533–542.*Google Scholar
  81. Mangel, M., L.M. Talbot, G.K. Meffe, M.T. Agardy, D.L. Alverson, J. Barlow, D.B. Botkin, G. Budowski, T. Clark, J. Cooke, R.H. Crozier, P.K. Dayton, D.L. Elder, C.W. Fowler, S. Funtowicz, J. Giske, R.J. Hofman, S.J. Holt, S.R. Kellert, L.A. Kimball, D. Ludwig, K. Manusson, B.S. Malayang, III, C. Mann, E.A. Norse, S.P. Northridge, W.F. Perrin, C. Perrings, R.M. Peterman, M.P. Sissenwine, T.D. Smith, A. Starfield, R.J. Taylor, M.F. Tillman, C. Toft, J.R. Twiss, Jr., J. Wilen, and T.P. Young. 1996. Principles for the conservation of wild living resources. Ecological Applications 6:338–362.Google Scholar
  82. Mangel, M. and C. Tier. 1993. A simple direct method for finding persistence times of populations and application to conservation problems. Proceedings of the National Academy of Sciences 90:1083–1086.Google Scholar
  83. Manly, B.F.J. 1990. Stage-structured populations: Sampling, analysis and simulation. Chapman and Hall, London.Google Scholar
  84. Marschall, E.A., and L.B. Crowder. 1996. Assessing population responses to multiple anthropogenic effects: A case study with brook trout. Ecological Applications 6:152–167.*Google Scholar
  85. Mattson, D.J., S. Herrero, K.G. Wright, and C.M. Pease. 1996. Science and the management of Rocky Mountain grizzly bears. Conservation Biology 10:1013–1025.*Google Scholar
  86. McCarthy, M.A., D.C. Franklin, and M.A. Burgman. 1994. The importance of demographic uncertainty: An example from the helmeted honeyeater Lichenostomus melanops cassidix. Biological Conservation 67:135–142.*Google Scholar
  87. McCarthy, M.A., M.A. Burgman, and S. Ferson. 1995. Sensitivity analysis for models of population viability. Biological Conservation 73:93–100.Google Scholar
  88. McKelvey, K., B.R. Noon, and R.H. Lamberson. 1992. Conservation planning for species occupying fragmented landscapes: The case of the Northern Spotted Owl. In Biotic interactions and global change., eds. P. Kareiva, J.G. Kingsolver, and R.B. Huey, 424–450. Sunderland, MA: Sinauer.Google Scholar
  89. Menges, E.S. 1990. Population viability analysis for an endangered plant. Conservation Biology 4:52–62. *Google Scholar
  90. Menges, E.S. 1992. Stochastic modeling of extinction in plant populations. In Conservation Biology: The theory and practice of nature conservation, preservation and management., ed. P.L. Fiedler and S.K. Jain, 253–276. New York: Chapman & Hall.Google Scholar
  91. Moehlman, P.D., G. Amato, and V. Runyoro. 1996. Genetic and demographic threats to the Black Rhino population in the Ngorongoro Crater. Conservation Biology 10:1107–1114.*Google Scholar
  92. Moloney, K.A. 1986. A generalized algorithm for determining category size. Oecologia 69:176–180.Google Scholar
  93. Montopoli, G.J. and D.A. Anderson. 1991. A logistic model for the cumulative effects of human intervention on bald eagle habitat. Journal of Wildlife Management 55:290–293.*Google Scholar
  94. Myers, R.A. and N.G. Cadigan. 1995. Was an increase in natural mortality responsible for the collapse of northern cod? Canadian Journal of Fisheries and Aquatic Sciences 52:1274–1285.Google Scholar
  95. Nantel, P., D. Gagnon, and A. Nault. 1996. Population viability analysis of American Ginseng and Wild Leek harvested in stochastic environments. Conservation Biology 10:608–621.*Google Scholar
  96. National Research Council. 1996. Science and the Endangered Species Act. Washington, D.C.: US Government Printing Office.Google Scholar
  97. Noon, B.R. and C.M. Biles. 1990. Mathematical demography of spotted owls in the Pacific Northwest. Journal of Wildlife Management 54:18–26.*Google Scholar
  98. Nordheim, E.V., D.B. Hogg, and S. Chen. 1989. Leslie matrices for insect populations with overlapping generations. In Estimation and analysis of insect populations. Lecture Notes in Statistics 55, eds. L.L. McDonald, B.F.J. Manly, J.A. Lockwood, and J.A. Logan, 289–98. Berlin: Springer Verlag.Google Scholar
  99. Olmstead, I. and E.R. Alvarez-Buylla. 1995. Sustainable harvesting of tropical trees: Demography and matrix models of two palm species in Mexico. Ecological Applications 5:484–500.*Google Scholar
  100. Pascual, M.A. and M.D. Adkison. 1994. The decline of the Steller sea lion in the northeast Pacific: Demography, harvest or environment. Ecological Applications 4:393–403.*Google Scholar
  101. Pascual, M.A. and R. Hilborn. 1995. Conservation of harvested populations in fluctuating environments: the case of the Serengeti wildebeest. Journal of Applied Ecology 32:468 – 480.Google Scholar
  102. Pascual, M.A., P. Kareiva, and R. Hilborn. In press. The influence of model structure on conclusions about the viability and harvesting of Serengeti wildebeest. Conservation Biology.Google Scholar
  103. Pfister, C.A. and A. Bradbury. 1996. Harvesting red sea urchins: Recent efforts and future predictions. Ecological Applications 6:298–310.*Google Scholar
  104. Possingham, H.P., D.B. Lindenmayer, T.W. Norton, and I. Davies. 1994. Metapopulation analysis of the greater glider Petauroides volans in a wood production area. Biological Conservation 70:227–236.*Google Scholar
  105. Powell, R.A., J.W. Zimmerman, D.E. Seaman, and J.F. Gilliam. 1996. Demographic analysis of a hunted black bear population with access to a refuge. Conservation Biology 10:224–234.*Google Scholar
  106. Price, M.V. and P.A. Kelly. 1994. An age-structured demographic model for the endangered Stephens’ kangaroo rat. Conservation Biology 8:810–821.*Google Scholar
  107. Pulliam, H.R., J.B. Dunning, Jr., and J. Liu. 1992. Population dynamics in complex landscapes: A case study. Ecological Applications 2:165–177.*Google Scholar
  108. Quinn, J.F. and A. Hastings. 1987. Extinction in sub-divided habitat. Conservation Biology 1:198–209.Google Scholar
  109. Raiffa, H. 1970. Decision analysis. Reading, MA: Addison-Wesley.Google Scholar
  110. Ralls, K. and A.M. Starfield. 1995. Choosing a management strategy: Two structured decisionmaking methods for evaluating the predictions of stochastic simulation models. Conservation Biology 9:175–181.Google Scholar
  111. Reed, J.M., P.D. Doerr, and J.R. Walters. 1988. Minimum viable population size of the red-cockaded woodpecker. Journal of Wildlife Management 52:385–391.*Google Scholar
  112. Richter-Dyn, N. and N.S. Goel. 1972. On the extinction of a colonizing species. Theoretical Population Biology 3:406–433.Google Scholar
  113. Ruckelshaus, M., C. Hartway, and P. Kareiva. In press. Assessing the data requirements of spatially explicit dispersal models. Conservation Biology.Google Scholar
  114. Ruggiero, L.F., G.D. Hayward, and J.R. Squires. 1994. Viability analysis in biological evaluations: Concepts of population viability analysis, biological population and ecological scale. Conservation Biology 8:364–372.Google Scholar
  115. Ryan, M.R., B.G. Root, and P.M. Mayer. 1993. Status of piping plovers in the Great Plains of North America: A demographic simulation model. Conservation Biology 7:581–585.*Google Scholar
  116. Saltz, D. and D. Rubenstein. 1995. Population dynamics of a reintroduced asiatic wild ass (Equus hemionus) herd. Ecological Applications 5:327–335.*Google Scholar
  117. Schemske, D.W., B.C. Husband, M.H. Ruckelshaus, C. Goodwillie, I.M. Parker, and J.G. Bishop. 1994. Evaluating approaches to the conservation of rare and endangered plants. Ecology 75:584–606.Google Scholar
  118. Schneider, R.R. and P. Yodzis. 1994. Extinction dynamics in the American marten (Martes americana). Conservation Biology 7:1058–1068.*Google Scholar
  119. Shaffer, M.L. 1981. Minimum population size for species conservation. BioScience 31:131–34.Google Scholar
  120. Shrader-Frechette, K.S. and E.D. McCoy. 1993. Method in ecology: Strategies for conservation. New York: Cambridge University Press.Google Scholar
  121. Slade, N. and H. Levenson. 1984. The effect of skewed distributions of vital statistics on growth of age-structured populations. Theoretical Population Biology 26: 361–366.Google Scholar
  122. Soulé, M.E., ed. 1987. Viable populations for conservation. New York: Cambridge University Press.Google Scholar
  123. Southgate, R. and H.P. Possingham. 1995. Modeling the reintroduction of the greater bilby Macrotis lagotis using the metapopulations model analysis of the likelihood of extinction. Biological Conservation 73:151–160.*Google Scholar
  124. Stacey, P.B. and M. Taper. 1992. Environmental variation and the persistence of small populations. Ecological Applications 2:18–29.*Google Scholar
  125. Starfield, A.M. and A.M. Herr. 1991. A response to Maguire. Conservation Biology 5:435.Google Scholar
  126. Starfield, A.M., J.D. Roth, and K. Ralls. 1995. “Mobbing” in Hawaiian monk seals (Monachus schauinslani): The value of simulation modeling in the absence of apparently crucial data. Conservation Biology 9:166–174.*Google Scholar
  127. Taylor, B.L. and T. Gerrodette. 1993. The uses of statistical power in conservation biology: The Vaquita and Northern Spotted Owl. Conservation Biology 7:489–500.Google Scholar
  128. Taylor, M.K., D.P. DeMaster, F.L. Bunnell, and R.E. Schweinsburg. 1987. Modeling the sustainable harvest of female polar bears. Journal of Wildlife Management 51:811–820.*Google Scholar
  129. Tuljapurkar, S.D. 1990. Population dynamics in variable environments. Lecture notes in biomathematics no. 85. New York: Springer-Verlag.Google Scholar
  130. Vandermeer, J. 1979. Choosing category size in a stage projection matrix. Oecologia 32:199–225.Google Scholar
  131. Walters, C.J. 1986. Adaptive management of renewable resources. New York: Macmillan.Google Scholar
  132. Walters, C.J. and R. Hilborn. 1976. Adaptive control of fishing. Journal of the Fisheries Research Board of Canada 33:145–159.Google Scholar
  133. Wennergren, U., M. Ruckelshaus, and P. Kareiva. 1995. The promise and limitations of spatial models in conservation biology. Oikos 74:349–356.Google Scholar
  134. Williams, B.K, F.A. Johnson, and K. Wilkins. 1996. Uncertainty and the adaptive management of waterfowl harvests. Journal of Wildlife Management 60:223–232.Google Scholar
  135. Wood, P.B. and M.W. Collopy. 1993. Effects of egg removal on Bald Eagle productivity in Northern Florida. Journal of Wildlife Management 57:1–9.*Google Scholar
  136. Wootton, J.T. and D.A. Bell. 1992. A metapopulation model of the Peregrine Falcon in California: viability and management strategies. Ecological Applications 2:307–321.*Google Scholar

Copyright information

© Springer Science+Business Media Dordrecht 1998

Authors and Affiliations

  • Martha J. Groom
  • Miguel A. Pascual

There are no affiliations available

Personalised recommendations