The boreal chorus frog (Pseudacris maculata) is a widespread species but we know little of its ecology. I examined the nature and existence of competitive mechanisms operating between larvae of the boreal chorus frog and wood frog (Lithobates sylvaticus) from field, mesocosm and laboratory venues spanning nutrient concentrations. I assessed larval performance and diet of tadpoles at natural ponds by measuring tadpole growth and size at metamorphosis, and stable isotope ratios for carbon and nitrogen in tadpole tissue to examine if patterns were consistent with the operation of interspecific competition. In mesocosms I measured chorus frog performance in relation to wood frog presence and nutrient enrichment to confirm the occurrence of competition and examine whether nutrient conditions typical of agriculture ponds impact tadpole performance. In the field I compared larval performance and relative abundance between agricultural ponds and those in Elk Island National Park, to examine whether habitat features surrounding ponds in farmlands reduces the abundance of tadpoles and whether tadpole performance results in reduced abundances. Lastly, I examined whether chemical interference by wood frogs occurs by raising chorus frog tadpoles with caged wood frog tadpoles and/or their feces in the laboratory.
Chorus frog performance was reduced by presence and abundance of wood frog tadpoles. Resource partitioning in natural ponds and overlap in mesocosms, based on stable isotopic analysis, suggest that resource competition occurs. In mesocosms chorus frog performance was reduced by wood frog tadpoles in fertilized treatments and nutrient conditions at agricultural sites are not in themselves detrimental to these anurans. Performance of chorus frog tadpoles in agricultural ponds was unaffected, whereas wood frogs were larger at metamorphosis in crop ponds. Reduced tadpole abundances of both species at these ponds may be related to habitat features or conditions in croplands. The existence of chemical interference in the absence of physical interaction was confirmed, as chorus frogs exposed to wood frog tadpoles and/or feces had reduced growth and were smaller at metamorphosis which could reduce terrestrial survival and future reproduction. My research contributes to our knowledge on boreal chorus frog ecology and our general understanding of competition between larval anurans. / Ecology
| Identifer | oai:union.ndltd.org:LACETR/oai:collectionscanada.gc.ca:AEU.10048/1481 |
| Date | 11 1900 |
| Creators | Whiting, Arthur V. |
| Contributors | Paszkowski, Cynthia (Biological Science), Foote, Lee (Renewable Resources), Vinebrooke, Rolf (Biological Sciences), Chapman, Ross (Elk Island National Park, Parks Canada), Tierney, Keith (Biological Sciences), Rasmussen, Joseph (Biological Science, University of Lethbridge) |
| Source Sets | Library and Archives Canada ETDs Repository / Centre d'archives des thèses électroniques de Bibliothèque et Archives Canada |
| Language | English |
| Detected Language | English |
| Type | Thesis |
| Format | 3277978 bytes, application/pdf |
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