Response of spider communities to a large scale bark beetle infestation

The Aim of the study was to test the hypothesis that the average niche position of spider communities is changing due to openings in the forest through a large scaled bark beetle infestation. The average niche position was divided into the mean shading position and the mean moisture position on a plot, which were predicted to move towards brightness and towards humidity.

Study site
Both samplings were situated in the Bavarian Forest, a national park in the southeast of Germany. In the 1990s a large outbreak of bark beetle began, and as nothing was done against it, big openings emerged. Spider sampling was conducted in affected as well as in non affected areas, and in mountain mixed forest as well as in highmountainous pure spruce stands.
I used two studies: one from 1991 and one from 2005. Within these it was sampled with pitfall traps on a total of 150 plots. 186 spider species were caught, and the average shading and moisture position of the spider communities on the plots were determined. A canonical correspondence analysis and a linear model were used to find the factors with most effect on the species composition.

Copyright: © Eigenbeiträge der Autoren
Source: Jahrgang 2010 (Dezember 2010)
Pages: 33
Price: € 0,00
Autor: Malkin Saar

Send Article Display article for free Comment article

These articles might be interesting:

Ecological and sanitary risk associated with organochlorine compound bioaccumulation in populations of anguilla from Mediterranean coastal waters
© Aristotle University of Thessaloniki (6/2009)
Eels are particularly vulnerable to persistent and bioaccumulable pollutants because they have an high content of fats, are univoltine and being benthic, can live for long time - during their growth phase in European fresh and brackish waters - in direct contact with the bottom environment, that in certain cases may be very polluted.

Meso- and macrofauna of the soil as the bio-indicators of the meadow soil polluted by heavy metals
© Aristotle University of Thessaloniki (6/2009)
In order to evaluate the soil contamination by heavy metals and their influence on macrofauna, six habitats have been chosen. The first was situated right next to the motorway the others were 20, 30,40, 150 and approximately1500m away from the motorway. The content of heavy metals was determined in the soil. Humidity and pH of the soil were evaluated as well. The density and diversity of the groups of the fauna analyzed were estimated. The greatest diversity of the macrofauna was detected in the area furthest away from the motorway, where the content of the Pb, Zn, Cd, and Cu was the lowest. It was detected that the density and diversity of the analysed pedofauna groups are affected not only by the content of metals such as Pb, Cd and Zn in the soil, but also by the humidity and pH rate.

Growth, accumulation and antioxidant response in juvenile carp (Cyprinus carpio) fed a selenium diet
© Aristotle University of Thessaloniki (6/2009)
The effects of two Se diets (HSe 1.0 mg kg-1 and LSe 0.25 mg kg-1) were investigated on growth, accumulation and antioxidant response in juveniles of Cyprinus carpio at 0, 30 and 60 days. HSe carp had slightly higher mean weight (W) values than LSe group at 60 days and the Fulton condition factor (K) indicated good fish health for both diet groups.

The risk of red palm weevil Rhynchophorus ferrugineus (Olivier) (Coleoptera: Curculionidae) infestation on the native greek palm tree Phoenix theophrasti Greuter (Arecales: Arecaceae)
© Aristotle University of Thessaloniki (6/2009)
The red palm weevil (RPW), Rhynchophorus ferrugineus Olivier (Coleoptera: Curculionidae), the most important pest of palm trees in the world, has invaded during the last decade the Mediterranean basin where it caused severe damage to date palm cultivations as well as to ornamental palm trees. R. ferrugineus has been found in Greece, for the first time, in Hersonissos (Heraklion district, Crete) on November , 2005, infesting Phoenix canariensis.

Macronutrient and heavy metal accumulation in a Greek fir ecosystem of Taygetos mountain in Peloponnese
© Aristotle University of Thessaloniki (6/2009)
Macronutrient and heavy metals accumulation in the forest floor and soil were investigated in three undisturbed natural forest sites of Greek fir ecosystem of Taygetos mountain in Peloponnese. Dry weight and organic matter of the forest floor ranged greatly, from a high of about 67 and 57 t/ha under to a low of 27 and 14 t/ha respectively.



 Keep me signed in

Forgot your password?