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Resource typeDissertation
Title(s)Testing paradigms in conservation biology: spatio-temporal dimensions of habitat fragmentation in a stenotopic woodland ground beetle
Alternative title(s)Testparadigmen in der Erhaltungsbiologie: Räumlich-zeitliche Dimensionen der Lebensraumfragmentierung in einem stenotopischen Waldbodenkäfer
CreatorMarcus, Tamar
RefereeAßmann, Thorsten  0000-0002-9203-769X  1051421667
Ganzhorn, Jörg U.  0000-0003-1395-9758  111094488
Brandmayr, Pietro
AdvisorAßmann, Thorsten  0000-0002-9203-769X  1051421667
AbstractThe effects of habitat fragmentation and land use changes are usually studied by relating patterns of genetic diversity and differentiation to environmental factors, habitat history, landscape structure, or to a combination thereof. However, these three drivers are rarely addressed simultaneously. In addition, these studies are usually carried out in conservation-driven contexts, and therefore tend to concentrate on hyper-fragmented landscapes and on rare or endangered species. However, how habitat fragmentation and land use affect widespread species in more typical landscapes has not been fully investigated. This thesis addresses these two gaps. Abax parallelepipedus, a flightless ground beetle with low dispersal power, was used as a model species to test how environmental factors, habitat history, and landscape structure affect genetic diversity and genetic differentiation in three study regions located across Germany. Although all of the study regions represent fairly typical rural landscapes for central Europe, each consisting of a complex matrix of land uses, they differ from one another in terms of environmental factors, habitat history, and landscape structure, and thus can serve as three test cases. In the first stage of the work, the investigator identified polymorphic microsatellite loci which could potentially be used to study genetic diversity and differentiation in A. parallelepipedus. She then developed PCR and genotyping protocols for two suites of loci, in the end selecting to use the set of 14 fully multiplexed loci for the study. After having developed the needed study system, she genotyped over 3300 beetles from 142 study sites. In her investigation of how environmental factors and habitat history affect genetic diversity and genetic differentiation, and found that genetic diversity was being driven by variables that could be related to population sizes rather than by habitat history. She also did not find evidence of an influence of habitat history on the genetic differentiation patterns. Although populations of A. parallelepipedus in the past were probably smaller due to deforestation, they apparently remained large enough to prevent rapid genetic drift. In addition, the researcher carried out a landscape genetics analysis of the genetic differentiation patterns found in each of her study regions, in which she examined the relationship between genetic differentiation and landscape structure. She tested whether she could find patterns of isolation by distance, isolation by resistance, or isolation by barriers in the study regions. No effects of land use or of fragmentation were found. Based on the importance of population sizes found in the previous study, combined with the beetle's known avoidance of non-wooded areas and its inability to cross roads, the investigator concludes that although there is probably little gene flow across the study regions, large population sizes are preventing the rapid development of genetic differentiation. Models simulating the development of genetic differentiation over time in populations of different starting sizes support this conclusion.
KeywordsKäfer; Wald; Lebensraum
Date of defense2017-02-16
Year of publication in PubData2017
Publishing typeFirst publication
Date issued2017-04-10
Creation contextResearch
Granting InstitutionLeuphana Universität Lüneburg
Published byMedien- und Informationszentrum, Leuphana Universität Lüneburg
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