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Gewählte Master / Diploma Thesis:

Rinzin Dorji (2018): Effect of drought on feeding intensity by insect herbivores on the two Himalayan oak tree species, Quercus griffithii and Quercus lanata.
Master / Diploma Thesis - Institut für Forstentomologie, Forstpathologie und Forstschutz (IFFF), BOKU-Universität für Bodenkultur, pp 50. UB BOKU obvsg

Data Source: ZID Abstracts
Abstract:
In the Himalayas region, monsoon failures would cause mega-drought with strong consequences on the dynamics of Bhutan's vegetation. They are supposed to occur more frequently under changing climate conditions and will particularly impact the transition zones between different forest communities – like the east–west ranging mixed broad-leaved forest consisting of Quercus lanata, Q. griffithii and Rhododendron arboreum between 1860- 2540m asl. This study was designed to establish the influence of drought on activity of leaf feeding herbivores of the two oak species, Q.griffithii and Q. latana from roofed and unroofed plots. Roofed plots simulated reduced monsoon precipitation by excluding through-fall during the vegetation season. To study indirectly the intensity of leaf feeding activity by herbivores we: a) protected leaves against feeding by covering the branches with mesh bags; b) calculated the missing part of a damaged leaf by replenishing the part of a whole projected leaf; and c) collected the dropped frass particles under the crown of sample trees. The data revealed that most of the mesh protected leaves of both oak species showed lower damage than unprotected ones and most of the leaves had only low damage symptoms (<30% of the leaf area). There was no difference in the damage intensity of leaves between roofed and unroofed sites for both oak species. One third of Q. griffithii-leaves and nearly half of Q.lanata-leaves did not show any damage symptoms, while only less than 10% of leaves from both oak species exhibited more than 30% damage. Feeding activity was not influenced by water stress in both oak species and did not correlate with precipitation or temperature. Marginal feeding was recorded as the highest occurring leaf damage type followed by hole and surface feeding for both oak species.

Beurteilende(r): Schopf Axel
1.Mitwirkender: Gratzer Georg

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