Loss of genetic diversity and fitness in Common Toad (Bufo bufo) populations isolated by inimical habitat
Article first published online: 23 NOV 2002
Journal of Evolutionary Biology
Volume 11, Issue 3, pages 269–283, May 1998
How to Cite
Hitchings, S. P. and Beebee, T. J. C. (1998), Loss of genetic diversity and fitness in Common Toad (Bufo bufo) populations isolated by inimical habitat. Journal of Evolutionary Biology, 11: 269–283. doi: 10.1046/j.1420-9101.1998.11030269.x
- Issue published online: 23 NOV 2002
- Article first published online: 23 NOV 2002
- Received 9 January 1997; revised 20 February 1997; accepted 26 March 1997.
- Cited By
- Population genetics;
Measures of genetic diversity (including heterozygosity), survival and developmental homeostasis were found to be significantly lower in small, urban populations of the Common Toad (Bufo bufo) than in larger, rural populations of the same region. The autecology and genetic analysis of this relatively sedentary species suggested that the causal mechanism was genetic drift, arising from barriers to migration created by urban development. The pre-metamorphic survival of larvae cultured in identical conditions increased positively with the mean number of alleles at a locus and the percentage of polymorphic loci. Observed heterozygosity in urban garden and rural populations was correlated inversely with the number of observed physical abnormalities (used as a measure of developmental homeostasis) in the developing tadpoles. Genetic distances between town sites of mean 2.2 km separation were significantly higher than those between rural sites of mean 37 km separation. Genetic data were based on allozyme analysis of 27 loci in 8 urban and 4 rural populations. A subset of these sites (3 urban, 2 rural) were also assessed at 3 minisatellite loci and a positive correlation found between the average number of alleles per locus detected by the two methods. Estimates of Nei's 1972 genetic distance, derived separately from the DNA and protein data, were not, however, correlated. The reduction in genetic diversity and fitness observed in these urban toads provides an example of the effect on population persistence that longer term depletion in numbers and habitat fragmentation can have in the wider environment.