Poster presentation
Decline of Arnica montana in montane Nardus grasslands despite extensive conservation efforts - the role of habitat microstructures

09/2018
Event name: 48. Jahrestagung der Gesellschaft für Gesellschaft für Ökologie von Deutschland, Österreich und der Schweiz (GfÖ)


Description
The ongoing decline of the endangered plant species Arnica montana L. in species-rich Nardus grasslands, both highly protected by the EU Habitats Directive, receives high attention from both science and conservation practice to maintain remaining populations in a favourable status. The observed species’ decline within properly managed habitat sites goes beyond already identified deterioration effects such as eutrophication. Considering Arnica’s today's clumped distribution in montane Nardus grasslands, we suppose microstructures as an important controlling factor in its decline pattern and lacking generative reproduction in otherwise homogeneous habitat sites. To explore the importance of habitat microstructures, we address the research question if habitat microstructures are an influencing factor in Arnica’s decline process, present population size and occurrence pattern, and hypothesise that short swards dominated by Nardus grassland character species are positively associated with species’ presence. We surveyed plots with locally isolated Arnica populations and its potentially colonisable direct neighbourhood in the Rhön Mountains (Germany) in equally managed sites regarding habitat and community structures and site conditions at micro scale. Results indicate a distinct relationship between site conditions and specific co-occurring species and Arnica presence and absence plots, respectively. For example, presence plots are associated with low herb cover and canopy height, while absence plots are associated with competitive tall-growing species. The results suggest that near distant habitat areas, which would be potentially re-colonisable for Arnica montana at habitat scale, provide currently less suitable conditions at micro scale. Implications for conservation and habitat management arise from an enhanced understanding of declining patterns of this important target species and highlight the need of a management to promote diverse habitat structures at micro scale.

Last updated on 2019-20-08 at 22:06

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