Evaluation of in situ conservation strategies for English yew (Taxus baccata L.) in Bad Bleiberg by the use of population viability risk management (PVRM) [German]

摘要

Population viability risk management (PVRM) is used for development and evaluation of six in situ conservation strategies for an endangered English yew population (Taxus baccata L.) in Bad Bleiberg, As part of a population viability analysis (PVA), a decision tree is used to evaluate the conservation strategies with regard to viability of the English yew population. The viability of the yew population is described based on the results of an analysis of the current environmental state and a characterization of the ecological parameters of the English yew population. The most significant risk factors include man-induced damage (tree cuttings), deer (browsing, bark-peeling), tree competition and other environmental effects such as disease or fungi. Within the risk analysis, the viability effects of the conservation strategies are determined through a qualitative assessment of the probability of a decrease of the yew population along with various environmental scenarios. A strategy combining silvicultural measurements to increase growth of the yew crowns and measures to increase public awareness seems to be the most effective. The probability of survival increases by 75-95% using this strategy as compared to the mere inclusion in a natural forest reserve. The conservational use of population viability analysis techniques within the formal process of population viabilty risk management is discussed.