PAPOP: Palms and Parasites on Palmyra: Indirect effects of invasive Cocos nucifera trees on the abundance of trematode parasites in Clypeomorus brevis and Planaxis sulcatus at Palmyra Atoll
Abstract/Contents
- Abstract
- Spatial variation has often been observed in the pattern of parasitism in intermediate host populations but the main drivers behind that variation are still largely unknown. In this study, we examined the effect that tree community composition has on the recruitment of two species of trematodes in intermediate host snails in the lagoon sand flats of Palmyra Atoll. Previous studies have shown high correlations between the type of tree and the number of birds that may serve as the definitive hosts for these parasites nesting and roosting in an area. In recent years, Palmyra Atoll has been taken over by Cocos nucifera a species of palm tree that likely arrived in the islands naturally but has become invasive. Birds roost and perch much less frequently in the invasive Cocos trees than in native vegetation. Seabirds are thought to be the definitive hosts for the trematode parasites that are infecting the snails as their intermediate hosts. We hypothesized that the tree composition could have an effect on the parasitism rates of snails in the intertidal lagoons through the indirect vector of the seabird hosts. We collected fifty snails of each target species from multiple sites in different parts of the lagoon, along a gradient of Cocos to native tree dominance, and dissected them to look for parasites. When the data was analyzed it showed a positive correlation between parasite infection rates and abundance of Cocos, which is the exact opposite trend we expected to find. Our results suggest that abiotic factors such as restricted water flow due to impoundment play a greater role in determining the abundance and distribution of parasites than Cocos abundance. This finding questions the long held belief in parasitology that spatial heterogeneity in parasite distribution is based on the distribution of the determinant host. This study’s finding that the level of impoundment was very highly correlated with the percentage cover of Cocos also brings to light some very interesting questions for future research that could shed some light on the reasons behind the Cocos invasion at Palmyra.
Description
| Type of resource | text |
|---|---|
| Date created | June 12, 2011 |
Creators/Contributors
| Author | Hanson, Calah |
|---|---|
| Author | Peterson, Aaron |
| Author | Perkins, Sabina |
Subjects
| Subject | Stanford@SEA |
|---|---|
| Subject | S-235 |
| Subject | Hopkins Marine Station |
| Subject | Department of Biology |
| Subject | Department of Earth System Science |
| Subject | BIOHOPK 182H |
| Subject | BIOHOPK 323H |
| Subject | EARTHSYS 323 |
| Subject | ESS 323 |
| Subject | Palmyra Atoll |
| Subject | cocos nucifera |
| Subject | trematode |
| Subject | parasites |
| Subject | Clypeomorus brevis |
| Subject | Planaxis sulcatus |
| Genre | Student project report |
Bibliographic information
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Preferred citation
- Preferred Citation
- Calah Hanson, Aaron Peterson, and Sabina Perkins, 2011. PAPOP: Palms and Parasites on Palmyra: Indirect effects of invasive Cocos nucifera trees on the abundance of trematode parasites in Clypeomorus brevis and Planaxis sulcatus at Palmyra Atoll. Unpublished student research paper, S-235, Stanford@SEA, Stanford Digital Repository. https://purl.stanford.edu/tw797wb4650.
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Stanford@SEA -- Student papers
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