Date of Award


Document Type


Degree Name

Master of Science in Earth and Environmental Sciences


Geological Sciences

First Reader/Committee Chair

Joan Fryxell


A site within San Timoteo Canyon was revisited, 13-14 years after treatment, to look at long-term effects of Arundo donax removal. The data obtained were used to determine whether A. donax had re-invaded, other non-native species had established the area, or if native species were able to grow in place of the removed A. donax. The previous removals included a combination of grinding large patches of A. donax and then foliar spraying, foliar spraying of uncut plants, and direct spraying of hand cut stems, depending upon the location and size of the plant. The effects of the A. donax removals within San Timoteo Canyon were analyzed in relation to new percent cover of the plant species, other more recent removals, and areas that did no experience removal procedures. The project included the use of data provided by the Inland Empire Resource Conservation District (IERCD) as well as the collection of data from randomized plots to generate plant species percent cover. Plant percent cover data analyzed for this paper had been collected from eight 15 by 15 foot randomly selected plots within an overall project site of 42.3 acres. Additional sites were used to investigate what can happen if A. donax is not removed from an area into which it has been introduced., the short-term effects of A. donax removal methods, and the role the ever-changing characteristics of riparian areas can play in their own restoration. These additional sites included aerial photographs supplied by IERCD of an ecologically similar area, a plot with a more recent A. donax removal date, as well as photographs and data of a site subject to natural recovery. Based on these comparisons it is concluded that the treatment methods used led to a lessened presence of A. donax, and that other invasive species did not grow in its place. Further, as the removal procedures within the project area occurred approximately 13 to 14 years prior, it can be concluded that there is no regrowth of A. donax and that many native species have been able to re-inhabit those areas previously infested by A. donax. The treatment methods used were successful without the need to continually disrupt the habitat and allowed for the habitat to recover naturally once the invasive species had been removed.