PARENT SESSION
Oral Session #9: Theoretical Ecology -- Populations, interactions.
Presiding: D. Srivastava
Monday, August 5. 8:00 AM to 11:30 AM. Grand Ballroom Central, Radisson.

A comparison of methods to use genetic information to quantify inter-population movement.

BRENNAN, JULIE^*,1, FAHRIG, LENORE¹, TISCHENDORF, LUTZ², ¹ Carleton University, Ottawa, Ontario, Canada² Researcher, Ottawa, Ontario, Canada

ABSTRACT- Movement of organisms between populations is linked to the survival, and thus the conservation, of these populations. Recent reviews suggest a potential for using genetic information to quantify inter-population movement, noting advantages over more traditional measures of movement (e.g., mark and recapture) including lower cost and reduced disturbance of rare or endangered organisms. The theoretical basis for this approach is that genetic differentiation between populations is inversely related to inter-population migration. However, genetic differentiation can be measured in several ways (F_ST, G_ST, , private alleles, N_ST, R_ST, the genetic assignment test, and coalescent theory estimates of migration). Not all of these methods perform equally well under conditions common in conservation studies (e.g., for recently isolated smaller populations). To compare how reliably these methods can be used to measure inter-population movement we used an object-oriented simulation model with individual-level demography and genetics. In experimental simulations we manipulated inter-population movement and then estimated the amount of movement based on the genetic measures. We also manipulated population size, number of loci, and time since isolation. We compared the genetically-derived estimates to the actual amount of movement and calculated the variance for this difference over 100 trials for each parameter set. Overall, the genetic measures provided estimates of movement that were generally consistent with the actual movement amount. However, the variance in some of these estimates under certain conditions was very high (e.g., F_ST) casting doubt on their usefulness in the field, while lower for others (e.g., the genetic assignment test) suggesting they would be more reliable. These results are discussed in the context of establishing a "road map" for the appropriate use of genetic information for estimating movement in the field.

KEY WORDS: movement, population isolation, genetic measures of movement, object-oriented and/or individual-based models