Ellis, John Rhys (2021). A theoretical and computational study of heterogeneous spatio-temporal distributions arising from density-dependent animal movement with applications to slugs in arable fields. University of Birmingham. Ph.D.
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Ellis2021PhD.pdf
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Abstract
Understanding the dynamics of pest populations is essential for pest management in agriculture. Slugs alone can cause large amounts of economic damage if their population is not controlled, usually by the application of chemical pesticides. However, there is pressure to reduce the amount of pesticide used because of the potential effects on human health and the environment. One solution to this problem is to target the application of pesticide only on areas of high population density.
This thesis thoroughly investigates the mechanisms in individual movement that can lead to the formation of heterogeneous spatial distributions in a population. Using an individual based model, we show that when an animal's direction of movement is dependent on the population density in its immediate surroundings, the population can form several clusters of high density. We show that the characteristics of the clusters and their temporal stability are dependent on how individual animals move, with Brownian motion producing dense stable clusters and Lévy flight producing dynamic clusters that are highly volatile. We confirm the existence of density dependent movement behaviour through an analysis of spatial tracking data from a field experiment where slugs were released in either a group or individually. Differences in individual movement seen in the data are shown to produce a heterogeneous population distribution through another individual based model. Finally, we analyse data of slug trap counts and discuss methods that can be used for identifying high density patches that should be targeted by pesticide.
| Type of Work: | Thesis (Doctorates > Ph.D.) | ||||||
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| Award Type: | Doctorates > Ph.D. | ||||||
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| Licence: | All rights reserved | ||||||
| College/Faculty: | Colleges (2008 onwards) > College of Engineering & Physical Sciences | ||||||
| School or Department: | School of Mathematics | ||||||
| Funders: | Other | ||||||
| Other Funders: | School of Mathematics, University of Birmingham | ||||||
| Subjects: | Q Science > QA Mathematics | ||||||
| URI: | http://etheses.bham.ac.uk/id/eprint/11625 |
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