333.7 Natürliche Ressourcen, Energie und Umwelt
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- 2017 (3) (entfernen)
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- Englisch (3) (entfernen)
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- Ökosystem (2)
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- Citizen Science (1)
- Grundschüler (1)
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Institut
- Institut für Ökologie (IE) (3) (entfernen)
The 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.
Wood-pastures have been present in Europe for thousands of years. This form of grazed landscape, combining herbaceous vegetation with trees and shrubs, has often co-evolved with its human users into complex social-ecological systems (SES). Wood-pastures are associated with high cultural and biodiversity values and are an example of the sustainable use of resources. However, due to their often relatively labour-intensive management and low productivity, large areas of wood-pastures have been lost over the last century. The loss of these areas means not only the loss of biodiversity on both local and landscape scales, but also the loss of traditional farming and cultural heritage in some regions. Across the European Union, wood-pastures are facing different problems and are embedded in different social systems and ecological environments. Yet they are all affected by global change and common European policies. To understand the challenges for wood-pastures in a changing world, a holistic approach combining different disciplines is needed. This dissertation therefore is analyzing wood-pastures across Europe as a Social-ecological System, combining ecology and social science with the aim to identify the barriers and drivers for wood-pastures persistence into the future.
A solid knowledge about nature is essential to understand the consequences of biodiversity loss, the limitation of natural resources and the need for a sustainable development. Inspired by these challenges, the researcher investigated in her dissertation seed predation, an important ecosystem function, as part of citizen science project. As seed predation has only rarely been investigated along urban-rural gradients and to integrate the question if the background (urban vs. rural) of primary school children affects their environmental knowledge, she selected study sites in and around Lüneburg and Hamburg, in Northern Germany. In her ecological experiments, it was found that slugs are important seed predators that independently of urbanization predated about 30% of all seeds in the anthropogenically used landscapes investigated. Also, for the first time, primary school children could be integrated in a citizen science approach into this research and it could be shown that even seven year old children can record data as reliable as a scientist. Finally, the researcher investigated the native species knowledge from the children taking part as citizen scientists in her research, considering possible differences due to their urban or rural background. Contrary to her expectation, the urban or rural background had no significant effect on the species knowledge. However, the work provides a good foundation to transfer the approach of introducing a basic foundation of a taxonomical species concept in primary school to foster further understanding on biodiversity and ecosystem functions.