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Home > People > Graduate Students > Alexander Wegmann
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Alexander Wegmann Ph.D Student Ecology Track Contact Information University of Hawai`i at Manoa Affiliations |
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Dissertation Title: The Influence of Native and Non-native Herbivores on Ecosystem Functioning: How will Palmyra Atoll's Flora Respond to the Removal of Black Rats (Rattus rattus)? Personal Statement: After graduating from Linfield College in 1998 with a B.A. in Anthropology, I worked for the U.S. Fish & Wildlife Service (USFWS) from 1999 to 2003 as a volunteer, biological science technician, and research station manager in the Northwestern Hawaiian Islands unit of the Hawaiian Islands National Wildlife Refuge (NWR). In 2003, I entered the Botany PhD program at the University of Hawaii. I spent most of 2004 and 2005 at Palmyra Atoll NWR, conducting my PhD research on the influence of native (land crabs) and introduced (black rats; Rattus rattus) seed dispersers and seed predators on forest dynamics, with an emphasis on ecosystem response to rat eradication. During my time at Palmyra Atoll NWR, I volunteered as the USFWS on-site manager. The conservation and restoration of island ecosystems is my academic and professional focus. Human alteration of the forest system at Palmyra Atoll National Wildlife Refuge (NWR) probably began with the arrival of Polynesian voyagers who likely introduced coconut palms (Cocos nucifera) to the atoll. The disturbance of Palmyra Atoll's terrestrial ecosystem accelerated during and after WWII with introductions of plants, terrestrial arthropods, and black rats (Rattus rattus). Prior to the arrival of rats, Palmyra's flora evolved with the foraging pressures of at least five native land crabs, including the world's largest terrestrial arthropod, the coconut crab (Birgus latro). It is well documented that invasive rats significantly alter island ecosystems in general, yet little is understood about the extent to which rats influence plant or land crab communities. The primary objective of my PhD research is to assess the extent to which rats and crabs influence plant recruitment at Palmyra Atoll, and to predict how the removal of rats will affect plant recruitment and thus forest dynamics and ecosystem function. This is the first study of a rat-crab-plant trophic web. To better understand how land crabs and rats influence Palmyra Atoll's forest community, I am investigating 1) seed dispersal and seed (and seedling) predation by land crabs and rats, 2) resource competition between land crabs and rats, 3) predation of land crabs by rats, and 4) ecological response to rat removal. My research suggests that rats directly influence forest composition at Palmyra Atoll NWR by limiting plant recruitment, and indirectly manipulate forest community functioning by limiting the natural herbivores - land crabs - through predation and resource competition. The results from this research have already and will continue to inform management and ecosystem restoration actions at Palmyra Atoll NWR. Awards:
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