[Truncated abstract] Habitat degradation and modification for agricultural purposes have become a leading cause of species decline worldwide. The loss of suitable habitat has the most drastic effects on population persistence, however even when fragments of habitat are retained, remnant populations are still vulnerable. If the altered environment between populations is not conducive to dispersal and therefore gene flow, populations can become isolated and suffer from genetic erosion, reducing their evolutionary potential. In light of this, there has been a dramatic increase in the amount of research investigating the genetic effects of landscape changes. However, because the extensive loss and fragmentation of habitat typically occur together, it is difficult to discern the specific effects of fragmentation on patterns of gene flow and genetic variation. In this thesis, I examined the genetic effects of land clearing while minimising the effects of habitat loss. This was done by comparing patterns of genetic variation, as well as levels of ectoparasite infection, in populations of the agamid lizard, Ctenophorus ornatus, in agricultural and pristine natural landscapes. The ornate dragon lizard exclusively inhabits granite outcrops, which have been spared direct clearing for agriculture. Outcrop populations of C. ornatus in cleared land have therefore experienced drastic changes to their surrounding environments but only minimal habitat loss. In addition, the nature of the granite outcrops and their location within cleared and uncleared landscapes means that comparisons between numerous replicate populations in both environments can be conducted. To begin, I describe the development of 20 microsatellite markers used to assess patterns of genetic structure and variation in C. ornatus. Next, assessment of the phlyogeographic history and population genetic structure across the entire species range was carried out.
|Doctor of Philosophy
|Unpublished - 2012