Date of Award

6-2009

Document Type

Union College Only

Degree Name

Bachelor of Science

Department

Biology

First Advisor

Steven Rice

Second Advisor

Kristina Striegnitz

Language

English

Keywords

canopy, model, light, structure, modeled

Abstract

While seemingly small and insignificant, bryophytes dominate a wide range of ecosystems such as boreal forests, rainforests, streams, wetlands, and bogs. Although rates of photosynthesis have been evaluated for a number of bryophyte species, there has been no evaluation of how variation in the three-dimensional structure of the canopy influences its function. To investigate this, I developed a 3D computer model of bryophyte canopy structure and modeled the light dynamics within the canopy. The liverwort species Bazzania trilobata was modeled due to both its ecological significance as well as its relatively simple branching structure. The model parameters were informed by measurements taken from actual B. trilobata specimens. Using the L-systems modeling approach, the model simulated a community of individual plants in order to create a holistic canopy structure. By altering structural features of individuals in the canopy, the relationship between canopy structure and function was explored. A nested radiosity algorithm previously implemented by third party open source software modeled the interactions of light within the canopy by simulating the scattering and transmission of light vertically within the canopy. The results from the model were validated against measured results of light attenuation in the canopies of living specimens of B. trilobata. The modeled canopy was found to have a much higher rate of light extinction in the canopy than the actual specimens. The source of this difference appears to be a faulty transmission function in the modeling software. However, despite a significant difference between the results from the model and the actual living specimens, the model was useful in exploring the unexpected intricacies of B. trilobata structure as well as highlighting the importance of transmission in the canopy. In the future, updates to the light modeling software may lead to a properly functioning canopy model, and eventually, the results of this research may lead to a canopy photosynthesis model to explore the connections between light intensity distribution and photosynthetic output.

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