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EVALUATION OF ENVIRONMENTAL FACTORS CONTROLLING THE DISTRIBUTION OF ZOSTERA ZAPONICA IN THE EXTREME UPPER TITAL PORTION OF YAQUINA BAY, OREGON
Citation:
Kaldy, J E. EVALUATION OF ENVIRONMENTAL FACTORS CONTROLLING THE DISTRIBUTION OF ZOSTERA ZAPONICA IN THE EXTREME UPPER TITAL PORTION OF YAQUINA BAY, OREGON. Presented at 2001 Estuarine Research Federation meeting, St. Petersburg Beach, FL, November 4-8, 2001.
Description:
The seagrass Zostera japonica was introduced to the Pacific Northwest from Asia 50 to 100 years ago. Since its introduction, Z. japonica has spread throughout the Pacific Northwest and now ranges between southern Oregon and British Columbia. Little information is available regarding the habitat requirements and factors which control the distribution of this non-native plant. In Yaquina Bay OR, Z. japonica exhibits a laterally patchy distribution with persistent beds restricted to the upper intertidal margin (between +1 and +2 m MLLW). Resistance to desiccation controls the distribution of many intertidal plants and animals. I hypothesized that point source seepage of freshwater run-off ameliorates desiccation stress and consequently controls the vertical and lateral distribution of Z. japonica patches in Yaquina Bay. This hypothesis was tested directly using field experiments (altered freshwater inputs) and laboratory exposure experiments. Field measurements of porewater salinity, nutrient concentrations and freshwater flow through the sediments measured using piezometers provide supporting data.