VIRTUAL STUDENT SCHOLARS SYMPOSIUM 2020 PRESENTATIONS

Ecology and Evolutionary Biology - Poster Presentations

High School Division

Undergraduate Division

Vascular Plant Analysis of Ecosystems on the Rouge River Floodplain of the University of Michigan-Dearborn
Griffin S Bray, University of Michigan-Dearborn

The 12.25 hectares (30.3 acres) of the Rouge River floodplain on the University of Michigan–Dearborn campus consist of a variety of natural landforms with unique communities of woody and herbaceous plants. This study aimed to inventory these communities and compare the community structures of the ecosystems. We identified 4,246 individuals representing 39 species of subcanopy (9.1-20 cm diameter) and canopy (>20 cm diameter) trees distributed in various patterns throughout the floodplain ecosystems. Black Maple (Acer nigrum) constituted 51% of the stems followed by Silver Maple (A. saccharinum; 9%). By contrast, Black Maple and Silver Maple constituted 25% and 15% of the relative dominance, respectively. We identified seven ecosystems on the floodplain, namely, levee, bottom, backswamp, former levee, terrace, deposition bar, and annual flood area. From multiple 200-square meter quadrats in each ecosystem, we recorded the woody stems in three categories: undergrowth (1.5-9.0 cm diameter), subcanopy, and canopy. Groundcover species were sampled in ten randomly-chosen one-square meter plots in each quadrat to determine percent coverage. We identified a 119 groundcover species with varying patterns of distribution. Comparison of woody species present in each of the ecosystems with the Cosine Similarity Coefficient showed 0%-30% similarity between any two ecosystems, while a Jaccard Similarity Coefficient comparison of groundcover species between ecosystems showed 0%-40% similarity. These data indicate that the floodplain is a biodiverse and heterogeneous environment.

Rainfall and Puberty Status Predict Energy Balance in Amboseli Baboons
Georgia K Young, Duke University

Social-living primates experience changes in their physical and social environments throughout their lives. Sometimes-extreme environmental changes lead to fluctuations in food availability and influence the nature of social interactions, changing primates’ energy intake and expenditure on daily and life-long bases. Growth and development before and during puberty creates additional energy demands. Balancing energetic demands of environmental fluctuations and growth with energy available for intake is essential for survival. Using triiodythyronine (T3) concentrations in baboons as a measure of energy balance, this paper seeks to quantify energetic balance from infancy to adolescence, and to analyze which environmental factors best predict T3 concentrations. First, I characterize longitudinal patterns of variation in T3 concentrations both in males and in females. Second, results from model selection show the strong predictive negative effect of sexual maturation and positive effect of cumulative rainfall on T3 concentrations.
My results present patterning of T3 concentrations throughout infancy and adolescence and demonstrate how environmental factors and the important transition to adolescence affect the energetic balance necessary for survival. These findings provide a jumping off point for comparison of longitudinal patterning of hormone concentrations during development and open the door for further explorations of energetic balance during puberty.

VIRTUAL STUDENT SCHOLARS SYMPOSIUM 2020 PRESENTATIONS

Ecology and Evolutionary Biology - Poster Presentations

High School Division

Undergraduate Division

Graduate Division

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