Seminars

September 29 2011

5:00 pm 154 BSRB

EcoEvoPub Series

Graduate Student Presentations

Summary

JEFF WOLF
Dept of Ecology and Evolutionary Biology, UCLA
"Unexpected variation in surface soil nutrient concentrations in a tropical forest"
Abstract: I will report on a reconnaissance of spatial variation in surface soil nutrient concentrations in the Barro Colorado Island (BCI) 50-ha Forest Dynamics Plot (FDP), Panama. A previous report (John et al., PNAS 104:864) showed that soil nutrient concentrations vary on landscape scales (0.1-1 km) by orders-of-magnitude in the BCI 50-ha FDP. Such variation was interpreted as resulting from geochemical processes. Non-random conspecific distributions on nutrient concentration gradients were interpreted as resulting from nutrient-dependent growth and/or survival. Little was known about fine-scale spatial variation in surface soil nutrient concentrations. At the beginning of the dry season in 2009, I collected soil cores (n=191) from 8 - 20 x 20 m quadrats in the BCI 50-ha FDP. I extracted and determined NO3-N, NH4-N, P, K, Ca, Mg, Mn, Zn, Fe, Al, and H+ concentrations in these soil samples. I discovered on average ≈ 2/3 X the variation in nutrient concentrations in relation to the plot-wide variation in an area < 1 % of the size. Also, I found order-of-magnitude variation in the concentrations of surface soil nutrients over distances < 10 m. I will discuss several possible explanations for fine-scale spatial variation in surface soil nutrient concentrations.

ADREA GONZALEZ-KARLSSON
Dept of Ecology and Evolutionary Biology, UCLA
"Chemical and Visual Communication in Ithomiine: Multimodal Communication in a Crowd"

Abstract: Ithomiine butterflies are Neotropical mimetic butterflies that form multispecies aggregations; butterflies use both visual and chemical cues to communicate within this complex environment. Ithomiines use exogenous plant sources to acquire pheromone precursors and these plant compounds cause the butterflies to become unpalatable to predators. My research examines the multimodal use of chemical and visual cues in intraspecific interactions (mate choice and species recognition) and interspecific interactions (species recognition, aggregation formation and plant use). I will present results from my first two field seasons, and address future research directions.

 

 

 

 

 

 



 

 

 

 

 

 

 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



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