Document Type

Research Poster

Publication Date



Baccharis salicifolia is a native riparian plant living in many places near to the Santa Monica Mountains. One of these locations is Legacy park, which has had many events effect it that has led to some very unfortunate changes. The park’s soil was tested earlier this year by a group of undergraduate students lead by Dr. Stephen Davis and was found to have a very high salinity level. The plants in the park appeared to be struggling to survive and had signs of dehydration and wilting. This led to us questioning the types of dehydration of the plants. Areas of the park that were very dry and had low access to water seemed to host Baccharis salicifolia that was much healthier than other wetter areas of the park that were tested and determined to have much higher salinity. We questioned which method of dehydration had more of a negative affect on the health of the plant. Being able to answer this question would be able to provide the people that run legacy with vital information of how to fix the struggling plants of Legacy park. To answer this question, we first had to determine what health meant in terms of this experiment. Health was ultimately decided to be the gas exchange of the plant; meaning its photosynthetic rate. A negative impact on the gas exchange would be the decrease in the plants photosynthetic rate, and the greater the decrease the lower the health. We decided that the introduction of salt to the plant would have a greater negative impact on it than the decrease in water given to it. Our next step was to create an experiment. The plants would be separated into three different groups: a control group that was given 600 milliliters of water every day, a water test group that was only given 600 milliliters of water once in every four days, and a salinity test group that was given 600 milliliters of a 25 ppt (parts per thousand) salt solution. Then we measured their gas exchange rates over the course of a month. The results of the final test would determine which of the test groups (water or salinity) would have the greatest negative impact.