Master’s Thesis Abstract

FORAGING BEHAVIOR OF HALODULE WRIGHTII

by

Maureen S. Walter

Florida Intemational University, 1998

Nfianii, Florida

Professor James W. Fourqurean, Major Professor

I investigated whether the seagrass Halodule wightii exhibits nutrient foraging ability in a heterogeneous environment. In a field survey, I found that H. wightii was variable in morphology, indicating a potential for phenotypic plasticity. Moreover, one characteristic, branching frequency, was significantly correlated with phosphorus availability in a pattem consistent with foraging theory. To test for actual phenotypic plasticity in response to resource variability (foraging behavior), I grew H. wrightii experimentally under heterogeneous nutrient conditions. While nutrient concentration in the soil had no consistent effect on the branching frequency or intemode distance, the treatment contrasts showed significant morphological changes in plants growing into the high treatment area. Plant phosphorus content was related to morphological characters of H. wrightii, but these relationships were not consistent with foraging theory predictions. Despite the ability for H. wrightii to vary its morphology, I found no experimental evidence that H. wrightii exhibits foraging behavior.