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Marija Vugdelic's Research
It has been recognized in conservation biology that once a species reaches very low population levels, demographic and stochastic events can rapidly induce changes in its genetic makeup. These are usually manifested as a loss of genetic variability. Reduced genetic variability can have a negative impact on individual fitness (by reducing survival and/or fecundity) and thus on population viability, increasingly the likelihood of extinction. Since it is also genetic variability that provides the basis of a species' potential to evolve in the face of changing environmental conditions, it is no wonder that the issue of genetics has increasingly been emphasized in the conservation programs.
Despite the work of the D.plantarius Recovery Programme over the past sixteen years, the population at the Redgrave and Lopham Fen NNR remained small and experienced breeding failure in some years. Even after restoration of the former hydrological regime, the population failed to show any significant or sustained recovery (Smith 2006). This suggested that D.plantarius may have suffered a reduction in fitness as a consequence of the loss of genetic variability following bottlenecks in population size. This prompted English Nature to include genetic analysis in the Recovery Program, in collaboration with Prof. Godfrey Hewitt's research group at the University of East Anglia.
Marija Vugdelic began a PhD studentship studying the conservation genetics of D.plantarius in autumn 2002 and completed her thesis in 2006. Her main aim was to determine the genetic makeup of D.plantarius, with the primary focus being on the endangered UK population at Redgrave and Lopham Fen. She also analysed populations from the entire distribution range and reconstructed the species phylogeny to give insight into the genetic partitioning within the species as whole, and the place UK populations within that context.
In her thesis she examines the implications of our new understanding of the genetic makeup of this species for future conservation management decisions. An abstract of her thesis can be downloaded here:
(25 KB).
For more detailed information on her research please contact Marija by email
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The future of the genetic study of D. plantarius
From 2007 work on the conservation genetic of Dolomedes is being continued by Dr Sara Goodacre, at the University of Nottingham. An important aspect of this work will be to continue to build the phylogenetic tree for this genus.
DNA for analysis can be extracted even from small and degraded tissue samples, by applying appropriate laboratory protocols. With such a rare species is important that the tissue collection should be as non-destructive as possible. The sources of DNA for genetic analysis include:
- Fresh tissue (even small quantities, such individual legs, which re-grow as juvenile spiders changes their skin) or recently killed individuals;
- Dry museum specimens;
- Ethanol-preserved specimens;
- Shed skins.
Although the latter three sources are usually degraded tissue samples, they can often yeild useful fragments of DNA.
If you have access to any such tissue samples, and would like to contribute to this study, please click here for more information.
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