Non-Native/Invasive Vegetation in the Santa Monica Mountains

1. What topographical features promote the growth of invasive vegetation? Non-Native/Invasive Vegetation in the Santa Monica Mountains GIS 36 Cartography Dec. 15, 2008

2. Data Used in this Project • Datasets from National Park Service http://science.nature.gov/nrdata/quickoutput2.cfm Santa Monica Mountain Soils Santa Monica Mountain Vegetation • Datasets from California Spatial Information Library http://casil.ucdavis.edu/casil/ Roads, Cities, Counties • Data from USGS http://www.usgs.gov Ventura County Digital Elevation Model Rasters • Data from Terraserver USA http://terraserver-usa.com/ Ventura County Topographical Map

3. Santa Monica Mountain National Recreation Area Locator Map

4. Santa Monica Mountain Soil Dataset Contains about 75 soil type entries and over 700 entries in attribute table

5. Santa Monica Mountain Soil Dataset • Dataset was clipped with Ventura County layer for manageability • Attribute Table Included Area in Acres, Perimeter in Miles, and Soil Classification (which included percent slope) Example: Botella Loam, 10 to 50 percent slope • To examine significance of percent slope, a new field was added to attribute table. • Percent slope was deleted from classification field in the table and inserted in the new field as integers, e.g. 10-50.

7. Equal Interval Symbology Exercise with Soil Dateset • In symbology, quantities, graduated colors was selected, then manual classification divided into break values of 1000 acres. • A map was then generated with six 1000 acre divisions with colors ranging from yellow to brown.

8. Equal Interval Soil Symbology

9. Santa Monica Mountain Vegetation Dataset • Contains locations of about twenty vegetation categories • Consists of a layer file, a shape file and a text file (purpose of the text file?) • Layer file must be added first, then the shape file.

10. Contents of Vegetation Layer Text File • 1 coastal dune/bluff scrub • 2 coastal sage scrub • 3 coastal sage scrub-chaparral transition • 4 northern mixed chaparral • 5 red shank chaparral • 6 chamise chaparral • 7 coastal cactus scrub • 8 non-native grassland/herbaceous • 9 rock outcrops (barren inland) • 10 salt marsh • 11 valley oak • 12 coast live oak • 13 walnut • 14 riparian (Sycamore-Oak) • 15 non-native conifer/hardwood • 16 coastal strand • 17 water • 18 development • 19 agriculture

11. Santa Monica Mountain Vegetation Non-native/invasive vegetation denoted in red for emphasis

12. Invasive Vegetation/Soil Study • In the vegetation layer: symbology, categories, unique values, all values in vegetation layer were removed except non-native/invasive • In the clipped soil layer: symbology, categories, unique values for all soil categories was selected. • Non-native/invasive only vegetation layer was then examined in soil map. • At first no compelling correlations were observed. • Soils were then symbolized by percent slope - lowest (yellows) to highest (browns). • It was discovered that non-native/invasive vegetation was directly correlated with soils that had low percent slopes.

13. Santa Mountain Soils/Invasive Vegetation

14. Ventura County Soil Substrates Classified by Percent Slope

15. Invasive Vegetation Correlates With Low Percent Slope Soils

16. Georeferenced Topographic Map of Point Mugu State Park

17. Invasive Vegetation Using Digital Elevation Model Rasters

18. Western Ventura County View Using DEMS

19. Western Ventura County Using DEMS Indicating Invasives

20. Conclusions • Non-native/invasive vegetation is found throughout the Santa Monica Mountains. • The primary contributor of invasive vegetation is not soil type as originally thought but a low slope topography, usually in upper elevations.