(I) Background. Conflicts emerge when populations of protected species grow to sizes that cause noticeable economic damage - like in the case of the fish consuming Great Cormorant (Phalacrocorax carbo sinensis). One possible approach for reconciliation is to regulate the size of the population in question. In doing so, regulation strategies have to meet multiple targets: 1) population size has to be reduced; 2) the viability of the population has to be maintained; 3) strategies have to adhere to the available budget. This thesis focuses on the regulation of populations that are structured into two groups - breeders and mature non-breeders. The pool of non-breeders provides a reserve for the breeders, whereby they may enable the population to resist regulation attempts. (II) Aims. 1) Development of a modeling framework and a conceptual model to provide an understanding of the functioning and effect of the population structure induced by non-breeders on population dynamics in a fluctuating environment. 2) Uncover the relation between non-breeder characteristics and the performance of regulation strategies. 3) Application of the modeling approach to the regulation of the Cormorant in order to evaluate the results from the conceptual model and find statements to support decisions on management strategies. (III) Methods. A conceptual stochastic time-discrete model, based on the logistic map with overlapping generations, is developed. Different types of threshold regulation strategies are applied. Strategies differed in which part of the model was affected by regulation. Resulting rules from the conceptual model are tested by applying them to a second age-structured model of a cormorant population, parametrized with data gained from a cormorant colony in Denmark. Analyzes of this model focus on the ecological-economic performance of regulation strategies and result in rankings of regulation options. Regulation performance is judged from different economic perspectives.
| Identifer | oai:union.ndltd.org:uni-osnabrueck.de/oai:repositorium.ub.uni-osnabrueck.de:urn:nbn:de:gbv:700-2010012713 |
| Date | 25 January 2010 |
| Creators | Zeibig, Sten |
| Contributors | Prof. Dr. Horst Malchow, PD Dr. Karin Frank, Prof. Dr. Bernd Blasius |
| Source Sets | Universität Osnabrück |
| Language | English |
| Detected Language | English |
| Type | doc-type:doctoralThesis |
| Format | application/zip, application/pdf |
| Rights | http://rightsstatements.org/vocab/InC/1.0/ |
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