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Abstract

Population size, relocation and competitive behaviour of Pulsatilla oenipontana DT. & SARNTH.

Pulsatilla oenipontana is one of the most endangered species in the calcareous grasslands (Mesobrometum) in the surroundings of Innsbruck. The main aim of this thesis was to study the remnant populations: the number of individuals, the size of the areas, the density per area and the number of flowers and fruits.
A significant decline was found: from 1761 individuals in 1995 to 181 individuals in 2000.

The total area of Pulsatilla oenipontana was 517 m2 in 1999 with a mean density of 0.9 plants per m². Not only the number of tillers per plant declined but also the number of leaves per tiller. Depending on the decrease of vegetative fitness also the generative fitness declined by counting less flowering individuals. In 2000, only 1.75 flowering tillers per plant were found compared to 1.81 in 1994 (GANAHL unpublished). Only the number of fruits per flower seemed to be constant over the years.

The planting experiment in the nature reserve in Arzl / Innsbruck in summer 1999 was successful.
54.9 % of the planted seedlings where still alive in the following spring. The highest survival and the largest amount of individuals were observed on the microsites of low vegetation and in vegetation gaps.

A density experiment showed the reaction of Pulsatilla oenipontana in competition with
Brachypodium pinnatum. The biomass of Pulsatilla oenipontana was significantly suppressed by Brachypodium pinnatum. Pulsatilla oenipontana also showed a high root / shoot - ratio whereas Brachypodium pinnatum invested more assimilates to the shoots. Brachypodium pinnatum showed the highest biomass production in pots with 5 individuals.

The examinations presented in this thesis show that the populations of Pulsatilla oenipontana are highly threatened. An extinction of this species during the next few years has to be assumed. Management and restoration arrangements are highly necessary. The most important restoration activities are as follows: Mowing the sites twice a year, once in early summer, followed by sheep grazing in autumn, respectively. In order to obtain these restoration goals it is necessary to announce the habitats of Pulsatilla oenipontana as NATURA 2000 areas in order to organize the restoration measures and to pay the restoration costs by official authorities.

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