Zettel Jürg

True bugs (Heteroptera) of steppes and extensive meadows in the Pfynwald (VS, Switzerland)

Project Number: CH-4994

Project Type:	Master
Project Duration:	04/01/2001 - 06/30/2002 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

related to this project.

for which the project has a relevance.

Research Areas:

Biodiversity

Disciplines:

zoology

Keywords:
Heteroptera, true bugs, grassland, management

Abstract:
In this investigation the heteropteran fauna of unmanaged and managed xeric grassland was studied in the Pfynwald (VS, Switzerland). The main scope was to analyse the responses of true bugs to management with a focus on diversity of bug communities and the effects of mowing.

Samples were collected between July and September 2001 on 10 different plots : 3 steppes, 1 semi-natural grassland and 6 extensively managed meadows, situated in the Milljeren, part of the Pfynwald.

The true bugs were periodically sampled with the sweep-net, by visual search and the beating method. Additionally different environmental factors were measured such as the structure and the composition of the vegetation.

A total of 144 bug species were found. 2 species are new for Switzerland and 41 species are new for the canton of Valais. Therefore the region can be considered as rich in true bugs when compared with other Swiss areas.

On average the unmanaged steppes have a greater richness of species and higher abundances than the managed meadows.

Some species (indicators) were singled out with a great affinity either for steppes, semi-natural grassland or managed meadows.

A cluster analysis was carried out to dectect the faunistical relationships between the Heteropteran fauna of the 10 sites.

The relationships between the bug communities and the environmental variables were analysed with canonical correspondence analysis (CCA). The percentage of open ground, number of plant species, total cover of shrubs and structure of vegetation are the decisive factors for the bug communities of the steppes. The bug community of the semi-natural grassland is best defined by the total cover of shrubs and the structure of the vegetation. For the extensive meadows the humidity and the value of nitrification of the soil – measured indirectly via the mean indicator values of the plant species – are determined.

By mowing the number of species and individuals were significantly reduced, predatory and ground-dwelling species less than phytophagous ones.

Leading questions:
How management of grassland (unmanaged vs. managed) influences responses of the true bugs?

Publications:
Joris C. 2002. True bugs (Heteroptera) of steppes and extensive meadows in the Pfynwald (VS, Switzerland). Zoologisches Institut, Abteilung Synökologie, Universität Bern.
pdf Diplomarbeit



Last update: 7/18/17
Source of data: ProClim- Research InfoSystem (1993-2024)
Update the data of project: CH-4994

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