Disturbance and biomass removal enhance population reinforcement of a plant species of European conservation concern

ABSTRACT

Background

Arnica montana is a threatened plant species that highly depends on species-specific conservation action.

Aims

We conducted three experiments in montane heathlands to quantify the role of disturbance for population reinforcement of A. montana.

Methods

In the first experiment, clusters of A. montana were raked to remove biomass and promote vegetative growth. In two other experiments, we analysed what kind of disturbance intensity is necessary to promote the establishment of A. montana by seeding and planting, respectively. Different traits with respect to population structure and growth of A. montana (e.g. abundance of rosettes and flowering stems) were measured.

Results

Raking resulted in the removal of bryophytes and parts of the herb layer and strongly fostered vegetative reproduction of A. montana. In general, disturbance enhanced the establishment of A. montana by seeding, however, the establishment rate was low. By contrast, planting of A. montana in plots whose surface was disturbed greatly increased the populations of A. montana.

Conclusion

Our study highlights that populations of A. montana much depend for re­production on the disturbance of the above-ground vegetation. We identified (i) disturbance of vegetation within existing populations for fostering vegetative reproduction and (ii) planting of A. montana in previously disturbed vegetation as the most suitable measures for reinforcing populations of this species of European conservation concern.

KEYWORDS:

• Arnica montana
• biodiversity conservation
• heathland ecosystem
• microsite limitation
• semi-natural habitat
• species introduction
• vegetation gap

Acknowledgements

We are grateful to Regina Saller (Landschaftspflegeverband Landkreis und Stadt Hof e.V.) for helpful comments on conducting experiment I. The regional authorities provided all necessary permits to conduct the field studies. We are grateful to three anonymous reviewers and Laszlo Nagy for valuable comments on earlier versions of the manuscript.

Disclosure statement

No potential conflict of interest was reported by the authors.

Additional information

Funding

The study was funded by the Deutsche Bundesstiftung Umwelt (DBU; German Federal Environmental Foundation; grant number: AZ 33472- 01)