October 1, 2017.
Because of its great beauty, Eichhornia crassipes (Water Hyacinth), originally from South America, has been introduced to 4 continents. Furthermore, because of its genetic make-up, high versatility and resiliency, this plant has become a frightening invasive, affecting boating and shipping, farming, water quality and fishermen livelihood wherever it thrives. However, Water Hyacinth (WH) is only 1 of over 84 invasives in the California Delta, which is where we focused our study. We took photographs along the Delta in treated and non-treated areas, and used an ENVI segmentation tool to find the best parameters for discriminating Water Hyacinth and Primrose. Once those parameters were found, we created a set of rules that would convey the percent cover of each invasive and dead plant material inside every photograph. This would help to determine the effectiveness of 2,4-D herbicide treatment on the invasives. The rules we created where based on the average RGB band ratios, and minimum and maximum RGB values of Water Hyacinth, Primrose, detritus, and water. We found that the herbicidal treatment was indeed effective to reduce invasive coverage, and that overall there were more Primrose than Water Hyacinth. The best segmentation parameters we found still did not accurately separate the two plant species within a given photo graph, but performed well on photographs with only one species. This ultimately affected the percent coverage found, but we conclude that the percentages are still accurate. A literature review was also conducted by compiling information from previous research articles that were written in regards to Water Hyacinth, and implications were stated to influence future research. Furthermore, a map we created of Water Hyacinth in the U.S allowed us to conclude that this invasive will most likely spread to the Central U.S region if its growth is not impeded.
NASA Ames Research Center (ARC)
This material is based upon work supported by the National Science Foundation through the Robert Noyce Teacher Scholarship Program under Grant # 1340110. Any opinions, findings, and conclusions or recommendations expressed in this material are those of the author(s) and do not necessarily reflect the views of the National Science Foundation. The research was also made possible by the California State University STEM Teacher and Researcher Program, in partnership with Chevron (www.chevron.com), the National Marine Sanctuary Foundation (www.marinesanctuary.org) and NASA Ames Research Center.