My research involves a study of the use of effective population size and other population size and other population parameters to study the probability of extinction as related to minimum viable population size. There is considerable interest in developing criteria for the evaluation of the threat of extinction for endangered species as related to population size. Of particular interest is the maintenance of genetic variability in the population as a buffer to environmental change, and to ward off inbreeding depression. One such concept is minimum viable population size. Unfortunately, there is no single size which can be used for all organisms. My research focuses on the derivation of objective criteria for the development and evaluation of minimum viable population sizes.

My research project is two-fold:

• Treatment of inbreeding effective population size. I have identified several special cases where I am trying a mathematical treatment. These include: seed banks; temporally varying population sizes; and the situation where the family size is not Poisson. The method of analysis will be similar to Emigh & Pollak (1979).
  
  
• Treatment of population crashes. I am using effective population size and effective lethal load in my study of population crashes. I am looking at the natural history of various species that have become extinct, or have been under the threat of extinction and have survived. I hope to characterize the probability that a certain population will become extinct based on the effective size, intrinsic rate of increase, and the effective lethal load.

Selected Publications:

Reed, J.M., J.R. Walters, and T.H. Emigh. 1993. Effective population size in red-cockaded woodpeckers: Population and model differences. Conservation Biology 7: 302. [Abstract]

Miyashita, N., Laurie-Ahlberg, C.C., Wilton, A.N., and Emigh, T.H. 1986. Quantitative analysis of X chromosome effects on the activities of the glucose 6-phosphate and 6-phosphogluconate dehydrogenases of Drosophila melanogaster. Genetics 113: 321-335.

Laurie-Ahlberg, C.C., Barnes, P.T., Curtsinger, J.W., Emigh, T.H., Karlin, B., Morris, R., Norman, R.A., and Wilton, A.N. 1985. Genetic variability of flight metabolism in Drosophila melanogaster. II. Relationship between power output and enzyme activity levels. Genetics 111: 845-868.

Wilton, A.N., Laurie-Ahlberg, C.C., Emigh, T.H., and Curtsinger, J.W. 1982. Naturally occurring enzyme activity variation in Drosophila melanogaster. II. Relationships among enzymes. Genetics 102: 207-221.

Laurie-Ahlberg, C.C., Wilton, A.N., Curtsinger, J.W., and Emigh, T.H. 1982. Naturally occurring enzyme activity variation in Drosophila melanogaster. I. Sources of variation for 23 enzymes. Genetics 102:191-206.

Emigh, T.H. and E. Pollak. 1979. Fixation probabilities and effective population numbers in diploid populations with overlapping generations. Theoretical Population Biology 15: 86. [Abstract]

Dr. Ted H. Emigh
Department of Genetics
N.C. State University
Raleigh, NC 27695-7614
Tel: (919) 515-5753
E-mail: emigh@ncsu.edu