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Published byTimothy Alfred Barnett Modified over 6 years ago
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Herbivores of the tree of heaven along a spatial rural-urban gradient in Freiburg
by Michele Deis Part of Bachelor thesis at the Albert-Ludwig University Freiburg In November 2015 Supervisor: Dr. Gesine Pufal For the course „Academic Skills & Forests Sciences“ © Michele Deis
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3rd most invasive species in Europe
Ailanthus altissima = Tree of heaven Introduced in Germany 1751 abundant in urban environments & transport corridors efficient sexual reproduction, clonal growth, pollution tolerance causes health issues, economical damage & changes ecosystems © Michele Deis
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How to control? manual, mechanical and chemical methods
biological control??? Required to study potential herbivores and enemies
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In previous studies: 46 phytophagus anthropod species in China
2 insects species & generalist herbivore snail in Europe mulberry moth ailanthus silk moth white-lipped snail
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Enemy Release Hypothesis (ERH)
Introduced plants in non-native regions are decreasingly regulated by herbivores and other natural enemies ensuing a rapid spread in distribution and abundance No general validity
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Research Question Is there a change in the richness of herbivorous insect species, that feed on A. altissima along a rural-urban gradient? With other words: connection between the richness of insect herbivores to the rural-urban gradient in Freiburg
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Methods Study site: Herbivor sampling:
35 trees on rural-urban gradient rural-urban gradient = in ArcGis with buffer tool 25m Buffer around each location & percentages of sealed and unsealed area recorded Herbivor sampling: Insect collecting using a beating tray & identification Statistical analysis in software “R”
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Herbivor Sampling Results
No herbivores on 43% of trees 55 individuals of 27 species: 16 aphids species 11 other insect species
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Distribution of insect herbivores
no significant (p-vaulue= 0,385) effect
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Conculsion No connection between richness of insect herbivores to rural-urban gradient ERH is valid 27 potential herbivore species
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Biological control??? My study: Study potential herbivores
Further research: Herbivor damage of these potential herbivores? More research is needed!
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Take away No connection between richness of insect herbivores to rural-urban gradient ERH is valid 27 potential herbivore species Fitness for biological control more research is needed
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