LIMITED GENETIC DIFFERENTIATION AMONG WILD ORYCTOLAGUS-CUNICULUS L (RABBIT) POPULATIONS IN ARID EASTERN AUSTRALIA

A systems approach is necessary for effective control of feral rabbit (Oryctolagus cuniculus L.) populations in the arid environments of Aus tralia. Localized control procedures may result in local extinctions, but the persistence of the overall population will depend on the proba bility of recolonization, and hence, the degree of isolation of each l ocal population unit. Genetic markers obtained using allozyme electrop horesis, temperature gradient gel electrophoresis (TGGE) and heterodup lex analysis (HA) were used to characterize the degree of structuring and extent of gene flow among rabbit populations in arid Queensland, A ustralia. Allozyme allele frequency data showed that there was no sign ificant differentiation among sites (average F-ST = 0.005) and no isol ation-by-distance or environmental discontinuity effects. TGGE/HA resu lts also revealed no significant differentiation in mitochondrial DNA Control Region haplotype frequencies among sites and low interpopulati on nucleotide divergence estimates (N-ST = 0.013). Therefore, rabbit p opulations exhibited a high degree of gene flow over large geographica l areas (1600 km(2)) and were essentially a single panmictic unit. Unp redictable environmental conditions together with the spatial configur ation of habitats which possess different probabilities of extinction may have resulted in repeated local extinctions followed by recoloniza tion and homogenizing gene flow. These data suggest that current rabbi t control strategies based on individual warren management may not ach ieve effective control in arid Queensland.