David StokerUndergraduate Researcher
Resource subsidies and biodiversity are important for community structure and ecosystem processes, but the pathways through which resource subsidies and biodiversity simultaneously affect ecosystem functioning are unclear. Using detritus-based streams as a model system, we examined the top-down effects of consumer diversity on decomposition in a reciprocal transplant experiment. We found that consumer biomass was consistently the primary driver of decomposition. Biomass was stimulated by specific resource subsidies, leading to direct and indirect effects of resource subsidies on ecosystem functioning. We did not find evidence that communities were adapted to locally-derived resource subsidies. In contrast, communities with dominant and productive functional traits significantly increased decomposition, suggesting that the distribution of functional traits between communities was an important component of the decomposition process. We show that biodiversity and resource subsidies affect community assemblages and ecosystem functioning through complex pathways, and that both consumer and resource diversity should be considered for decomposition. We also show that top-down diversity effects, mediated by consumers, can be equal in magnitude to the bottom-up effects of detrital resource characteristics.
Along with my personal research, I have worked as the lab manager. I maintained the lab and inventoried equipment and samples; processed and analyzed samples for stoichiometry (C:N:P) and chlorophyll a; determined ash-free dry mass of leaf litter and algae samples; analyzed leaf litter samples for proximate lignin content; identified aquatic macroinvertebrates; assisted with fieldwork through the Coweeta and Luquillo Long-Term Ecological Research programs; other duties, as assigned.
Honors & Awards:
- 2015 CURO Undergraduate Research Assistantship
- 2015 Society for Freshwater Science UndergraduateTravel Award
- 2015 Josh Laerm Memorial Outstanding Ecology Undergraduate Award
- 2014 UGA Student Employee of the Year
- 2013 Thelma Richardson and Frank Golley Undergraduate Support Award