Zettel Jürg
Habitat management in the xeric steppes of Pfynwald (VS, CH): what will be the influence of grazing on insects (Sphecidae, Orthoptera, Heteroptera)?
Project Number: CH-4998
| Project Type: |
Master |
| Project Duration: |
04/01/2004 - 09/30/2005 project completed |
| Funding Source: |
other , |
| Leading Institution: |
Universität Bern, Zoologisches Institut |
| Project Leader: |
Prof. em. Jürg Zettel
Biologe
Speichergasse 8
3150 Schwarzenburg
Phone: +41 31 971 34 44
|
Research Areas:
Disciplines:
Keywords:
Pfynwald, xeric steppes, Sphecidae, Orthoptera, Heteroptera
Abstract:
The aim of this study was to characterize the present state of a defined areas in the Rottensand, Pfynwald (VS, Switzerland), which will be used in a planned grazing experiment with cattle. Two adjacent sites of dry steppe were chosen, each being subdivided into 30 plots of 5x5 metres. The vegetation, its abundance and the composition of the soil surface were recorded. The plan cover was similar on both sites; moss was significantly more abundant on site B than on A (29% and 11%, resp.), mineral soil covered more surfaces on site A than on site B (46% and 12%, resp.).
Sampling of selected indicator species (Sphecidae, Orthoptera and Heteroptera) was carried out between end of June and beginning of September 2004.
From the Sphecidae 3 of the taxa depending on compacted sand soil for nesting were monitored (Ammophila, Prionyx and Sphex). All occurring Orthoptera (4 Ensifera, 7 Caelifera and 1 Mantid species) were recorded according to the different soil surface parameters. From the Heteroptera, 40 species were observed and used as indicator species for vegetation composition.
In contrast to the expectation, the Sphecidae were more numerous and nesting behaviour was more frequently observed on site B than A (mainly true for Prionyx kirbii), in spite of the significantly smaller sand surface available (2% and 14%, resp.). The most important flowering plants were Thymus praecox and Asperula aristata.
From the Orthoptera more individuals were monitored on site A than B. A Canonical Correspondance Analysis (CCA) showed a clear correlation of the species with their preferred soil surface parameters. The presence of the species is influenced by the structure and density of the vegetation cover as well as the occurrence of mineral soil surface, which is important for some rare and xero-thermophilic species (e.g. Sphingonotus caerulans).
More Heteroptera species and individuals were collected on site B. Most abundant families were the Pentatomidae and the Lygaeidae. 40% of the individuals were observed on Centaurea vallesiaca, the most important host plant.
In order to maintain the open steppe habitat (reducing the growth of woody plants and removing the moss cover on the former sandy soil surface) grazing experiments will be carried out in the near future.
Leading questions:
The aim of this study was to collect data as a basis for comparisons after grazing experiments with different domestic animals.
Publications:
Bärtschi D. 2005. Habitat management in the xeric steppes of Pfynwald (VS, CH): what will be the influence of grazing on insects (Sphecidae, Orthoptera, Heteroptera)? Zoologisches Institut, Abteilung Synökologie, Universität Bern
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Last update: 7/18/17
Source of data: ProClim- Research InfoSystem (1993-2024)
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