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Title: Herbivore interactions and grassland biodiverity
Author: Allan, Eric
ISNI:       0000 0001 3414 9610
Awarding Body: Imperial College London (University of London)
Current Institution: Imperial College London
Date of Award: 2007
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The role of vertebrate herbivores in affecting plant diversity and coexistence in grasslands is well known. What is less clear is the importance of invertebrate herbivores and how different groups of herbivores might interact to affect plant communities. I will present data from a 16 year study which factorially excluded insects, molluscs and rabbits in an acid grassland in South East England. Rabbits play a keystone role in preventing tree invasion and therefore maintaining the community as a grassland. The invertebrate herbivores are also important but have contrasting effects: a specialist insect Diuraphis hold feeds on the competitive dominant Holcus mollis, reducing its competitiveness and allowing the coexistence ofother grasses and of forbs. Molluscs feed on forbs, particularly forb seedlings, and therefore reduce diversity by excluding these species. These resulted are supported by short tenn (three year) exclusions ofthese herbivores.One ofthese experiments also excluded fungi, with foliar fungicides, and it suggests that pathogenic fungi may be important in maintaining grassland diversity as well, by reducing the dominance of, in particular Festuca ruhra. The invertebrate herbivores may also interact with the fungi. As mentioned above mollusc herbivores have their greatest impact at the recruitment stage and my thesis will include data from an experiment with mollusc and rabbit exclusion as well as seed sowing and the use ofselective herbicides, to show what effect molluscs have on seedling recnntment and how this interacts with plant competition
Supervisor: Not available Sponsor: Not available
Qualification Name: Thesis (Ph.D.) Qualification Level: Doctoral
EThOS ID:  DOI: Not available