Citation

Field SG, Lange M, Schulenburg H, Velavan TP, Michiels NK. Anim. Conserv. 2007; 10(2): 162-175.

Copyright

(Copyright © 2007, John Wiley and Sons)

DOI

10.1111/j.1469-1795.2006.00084.x

PMID

unavailable

Abstract

Habitat fragmentation can seriously affect the population biology and persistence of small isolated populations. We evaluated the interplay between the patch size of natural habitats, genetic diversity, immunocompetence and parasite load in an urban metapopulation of the earthworm Lumbricus terrestris. Large-scale genetic analysis of earthworm populations was accomplished using newly established mtDNA markers in combination with single-strand conformation polymorphism haplotype screening. Our analysis yielded the following: (1) parasite load varied significantly among patches, but small versus large patches did not differ; a similar pattern was found for immunocompetence and genetic diversity; (2) in general, the urban metapopulation showed genetic structuring, which seems to be due to restricted gene flow among small and large patches; (3) the overall genetic variability of the patch has little or no effect on parasite load, as it was not significantly associated with parasite load; (4) small patches do not show molecular patterns associated with a general reduction in genetic diversity. These findings are in accordance with the view that among- and within-patch components of genetic diversity approach equilibrium values at differing rates and suggest that the date of isolation (i.e. patch age) could be too recent for the expected pattern between genetic diversity, immunocompetence and parasite load to become evident. Our study provides initial insights into the population genetics of one of the most economically important soil organisms and, as such, will prove valuable as a primer for future research regarding the human impact on soil environments.