Stress has been identified as one of the primary factors influencing the structure of food webs, but few conclusions about the effects of stress on community dynamics have emerged. This study examined generalities that exist between salt stress and insect herbivore responses. Ambient salinity was artificially increased by adding 1.3 kg/m2 of salt to six different plant species: Avicennia germinans, Baccharis halimifolia, Batis maritima, Borrichia frutescens, Iva frutescens, and Spartina alterniflora. By performing a multiple species examination, stress responses were examined to determine if consistencies within and between plant type, ambient salinity conditions, and host plant species (among other criteria) existed, allowing for generalizations to be made about stress and herbivore interactions. Herbivore responses were determined by direct visual counts and indirect visual evidence of insects (e.g. galls, stem boring, and leaf mining). A metaanalysis was then performed on the data to determine the factors that may result in consistent responses to salt stress. No differences were found between insect feeding guilds. Herbivory increased in the presence of that added salt in high ambient salinity conditions, increased on experimental Spartina plants, and decreased on experimental Iva plants. These findings suggest that stress is generally a more important factor for plants in areas of already high ambient salinity. Results have been disparate in various studies, likely due to the difficulty in making comparisons between different field sites and experimental designs. This study addresses these issues, and ultimately finds that consistencies can be found among multiple species within communities.
| Identifer | oai:union.ndltd.org:unf.edu/oai:digitalcommons.unf.edu:etd-1446 |
| Date | 01 January 2010 |
| Creators | Foust, Christy Marie |
| Publisher | UNF Digital Commons |
| Source Sets | University of North Florida |
| Detected Language | English |
| Type | text |
| Format | application/pdf |
| Source | UNF Theses and Dissertations |
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