February 6 2014

5:00 pm 154 BSRB

EcoEvoPub Series

Graduate Student Presentations


Jonathan Chang
Department of Ecology and Evolutionary Biology

"Crowdsourced Morphometrics: Reducing Bottlenecks in Phenotypic Data Collection"

The "bioinformatics revolution" has assembled massive genomic data sets; however, our ability to collect phenotypic data at a similar scale has not kept pace. Here I present a method to distribute geometric morphometric landmarking tasks to untrained users over Amazon Mechanical Turk, an online crowdsourcing platform, and evaluate their accuracy compared to experts. Using these data, I explore how shape diversity has evolved across several families of ray-finned fishes. Compared to the traditional approach of a single trained digitizer, our method gathers crowdsourced data at low cost and competitive accuracy, with significant speed increases for larger workloads.

Jay Harvey
Department of Ecology and Evolutionary Biology

"Patterns of Consumption by Different Sizes of Herbivorous Fish in Coral and Algal Dominated Reef Zones may Enhance Reef Resilience"

Many coral reefs worldwide have undergone phase shifts to algal dominated communities as a result of various factors such as overfishing, habitat destruction, and nutrient input; as well as other factors resulting directly or indirectly from global climate change. In this study, conducted on fringing reef near Mo’orea, French Polynesia, we measured the contributions of different size classes of fish towards overall herbivory in different reef zones. We compared herbivory contributions between coral dominated habitats of different depths and two types of algal habitats: ones dominated by the macroalgae Turbinaria ornata and ones dominated by algal turfs. We found that both algal habitats supported as much herbivory as the deeper coral habitat and more herbivory than the shallower coral habitat. This indicates that the presence of algal patches following a disturbance is not enough to erode the key ecological force of herbivory on a reef; and that this reef and other patchy reefs like it will most likely recover toward a completely coral dominated community.











































































































































































































































































































































































































































































































































































































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