UBC Theses and Dissertations

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UBC Theses and Dissertations

An experimental assessment of potential freshwater diatom dispersal via waterfowl feathers Manning, Faye


Dispersal is a fundamental ecological process that can profoundly influence the diversity and functioning of ecosystems. Yet, for microorganisms, dispersal largely remains a “black box”. For freshwater diatoms waterfowl have long been considered potential dispersal vectors, but experimental assessments of this possibility are lacking. I conducted a novel experiment designed to emulate diatom transport by waterfowl feathers, and to test the individual and interactive effects of humidity and transport time on dispersal success (fully factorial design, with N = 8 replicates per treatment combination). Each replicate involved dipping a mallard breast feather in a solution inoculated with a single strain of diatoms (genus Nitzschia), then subjecting the feather to one of 4 humidity levels and one of 4 “transport” durations within a chamber through which air was passed. Finally, the feather was placed in sterile media. I equated dispersal success with evidence of diatom growth after 2 weeks. My experiment indicated strong potential for successful dispersal via feathers overall, and revealed a significant interaction between humidity and transport time: dispersal success significantly declined with increasing transport time under low to moderate humidity levels, but was consistently high under the highest humidity levels. I place these findings in the context of waterfowl dispersal distances and inter-lake distances within the major migratory flyways of North America. In the future, my experimental design should be used to explore potential colonization success of important diatom taxa and waterfowl species to narrow in on aquatic landscapes of interest. My results should also be used alongside actual relative humidity, lake, and flight data to spatially map potential diatom dispersal.

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