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ARS Home » Pacific West Area » Albany, California » Western Regional Research Center » Invasive Species and Pollinator Health » Research » Publications at this Location » Publication #372605
Research Project: Watershed-scale Assessment of Pest Dynamics and Implications for Area-wide Management of Invasive Insects and Weeds

Location: Invasive Species and Pollinator Health

Title: Mapping waterhyacinth drift and dispersal in the Sacramento-San Joaquin Delta using GPS trackers

Author
item MISKELLA, JOHN - University Of California, Davis
item Madsen, John

Submitted to: Journal of Aquatic Plant Management
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 7/23/2020
Publication Date: 8/31/2021
Citation: Miskella, J.J., Madsen, J.D. 2021. Mapping waterhyacinth drift and dispersal in the Sacramento-San Joaquin Delta using GPS trackers. Journal of Aquatic Plant Management. 59s:41-45. https://apms.org/journal/.

Interpretive Summary: Waterhyacinth mat movement was caused by mass flow water movement, either from river flow or tidal water movement. In the Delta, plant movement was not caused by wind activity.

Technical Abstract: Waterhyacinth (Eichhornia crassipes [Mart.] Solms) is a perennial free-floating aquatic plant species native to the Amazon region. It has become invasive around the world, including in the Sacramento-San Joaquin Delta in central California. From June 2016 to February 2018, a study was undertaken to determine to what extent wind, tidal movement, and mass flow drove the dispersal of waterhyacinth mats in the Delta. GPS trackers were deployed to track the movement of waterhyacinth mats. The location, speed, and direction of movement during the time the tracker was drifting was recorded at 15-second intervals on a Trackstick GPS device. The data were tested to determine whether the size of a plant mat had a significant effect on the distance traveled, using ANOVA to detect differences (P = 0.05). Mean separations of significant effects were evaluated with Tukey’s HSD test (P = 0.05). There was no significant difference in distance between plant mats of different sizes (p = .0867). The movement of each tracker was compared to the wind and water movement during the period the tracker was deployed, using simple linear regression. The direction of water movement, influenced by both stream flow and tides, had a significant influence on the direction of waterhyacinth mats, while the wind direction did not. The direction of water movement explained a significant proportion of the variance in direction (R2 = 0.8218, p < .0001). The direction of wind movement failed to explain a significant proportion of the variance in direction (R2 = .0163, p < .2617).