Soil Ecology and Restoration Group

PLANT COMMUNITY RESTORATION

POINT LOMA NAVAL SUBMARINE BASE

SAN DIEGO, CALIFORNIA

Introduction
The Point Loma Naval Submarine Base is located on the east side of the Point Loma peninsula in San Diego, California. Approximately 145 acres of the 295 acres occupied by the Navy is situated within the Point Loma Ecological Reserve established in 1996. Eighty-nine percent of the 295 acres on Point Loma is covered in either Diegan Coastal Sage Scrub or Southern Maritime Chaparral (Point Loma Natural Resource Management Plan 1994). These vegetation communities are rapidly disappearing due to an increase in development and the introduction of invasive exotic species such as Acacia cyclops (acacia) and Carpobrotus edulis (ice plant).

In October 1995, the Soil Ecology and Restoration Group (SERG) at San Diego State University formed a letter of agreement with the Department of the Navy to perform native plant restoration research on the Point Loma Submarine Base. From October 1995 through December 1997, experiments on surface amendments and erosion control methods were implemented over six sites encompassing 8000 m2 of Coastal Sage Scrub and Southern Maritime Chaparral. In December 1997, maintenance and monitoring of those 6 sites continued while restoration on three additional areas began. In an effort to control the invasion of exotic plant species, research in 1998 included testing the following weed control methods; mulch, newspaper, Dalen Weed-X fabric and Weedguard. To enhance species diversity on one of the ongoing restoration projects, experiments were installed to test native seed germination with the addition of straw and cocoa mulch. Monitoring on previous sites included additional soil nutrient tests on the acacia mulch, bark, coir and grass litter plots to record changes in soil nutrients over a two year period.

Results of the 1998 research will enhance and expand the previous research implemented in 1996 and 1997. Details of procedures and research conducted in 1997 may be found in the first Plant Community Restoration: Point Loma Naval Submarine Base San Diego, California annual report covering the time period June 1995 through December 1997.

Study sites
Bayview
Bayview is located east of the parking lot for building 512 and is approximately 1000 m2 in size (Figure 1). The northern half of the site is sloped 20 degrees with an east-northeast aspect while the southern portion is fairly flat. In January 1996, fifty acacia trees were removed from this site. Between February and May 1996, 453 container grown coastal sage seedlings were planted on this site.

South Tank Acacia
The South Tank Acacia site (South Tank) located on Ashburn Road adjacent to the Cabrillo Monument Drive gate, extends around the water tank just north of a dirt access road (Figure 1). South Tank is approximately 400 m² in size and 90 percent of the area is sloped approximately 8 degrees with an east-northeast aspect. The area directly adjacent to Ashburn Road has a slope of 52 degrees with a north-northeast aspect. In January 1996 twenty three acacia trees were removed along with approximately 80 percent of the ice plant. A total of 399 coastal sage seedlings were planted on the site by SERG during the winter/ spring 1996 and fall 1997.

South Tank Erosion
The South Tank Erosion site (Erosion Slope) is located north of the South Tank site and east of Cabrillo Monument Road (Figure 1). The slope runs east and west and is bordered to the east by a paved road dead-ending into a canyon. The site is approximately 400 m² on a 40 degree slope with a western aspect. The site was mechanically cleared for installation of a pipeline in 1995. Erosion control in the form of straw bale dams and coconut fiber dams were installed on the slope by SERG in January and February 1996 and 345 coastal sage seedlings were planted during the winter/spring of 1996 and fall of 1997. McClelland Road The McClelland Road site is located south of McClelland Road and is bordered to the west by Cabrillo Monument Road (Figure 1). Phase I of this site is approximately 7,300 m2 and is accessible by a dirt road. The eastern portion of the site has a 10 degree slope with an east-northeast facing slope while the western portion is flat. Restoration during Phase I, implemented in 1997, included rototilling, spraying iceplant with herbicide and planting 1,098 coastal sage seedlings on approximately 6,070 m². Phase II of this site is a 0.3 acre dirt road, sloping approximately 20 degrees, which leads east from the dirt road parallel to Cabrillo Monument Road down to the lower portion of the site. Disturbance on the site was caused by the installation of television cable wires and and construction of a service road no longer in use. Phase II began in 1998 and concentrated on closing and restoring the 1,225 m² acre road. The road was degraded by erosion gullies up to 12 cm wide and 5 meters long.

Minor Sites
There are two minor sites located off Ashburn Road (Figure 1). The first site is adjacent to building 112 and approximately 200 m2 in size on a 52 degree slope facing east. The second site is approximately 200 feet to the south, adjacent to building 634, and is also 200 m2 acres in size. Erosion gullies and rills had formed on these sites due to expansion of the parking lots for buildings 112 and 634 during the previous 5 years. In September 1997, the flat area below the sites was hydroseeded with a coastal sage seed mix and a temporary sprinkler system was installed by an outside contractor. Erosion control, in the form of coconut fencing and two foot metal fences, was installed on these sites by SERG in October 1997 and a total of 258 coastal sage seedlings planted.

Ashburn Road
This site is located along the north side of Ashburn road between the Bayview site and South tank site (Figure 1). The site is naturally split into two sections by a stand of native southern maritime chaparral. The eastern portion of the site is approximately 1,000 m² with a southeast facing slope of 25 degrees while the western portion of the site is approximately 2,025m² with an east facing slope of 8 degrees. The area was covered in non native grasses, such as Bromus sp. (red brome), ice plant, Chrysanthemum coronarium (chrysanthemum) and tumbleweed.

((Figure 1))

Figure 1. Study sites located on the Naval Submarine Base on Point Loma, San Diego, California.

Site Preparation
Bayview
In December 1997, a pampas grass (Cortaderia jubata) over 6 feet tall was cut back to 3 feet and concentrated Round up Pro applied. The entire Bayview site was cleared of exotic annuals such as tocolote and red brome. A 10 m² patch of ice plant on the western portion of the site was sprayed with Round up Pro and removed from the site. One acacia tree was removed from the southwest end of the parking lot and all Foeniculum vulgare (fennel) cut down and Round up Pro applied. In January 1998, the northeast end of the site was seeded with a native coastal sage seed mixture (Table 1) and a thin layer (2 cm) of cocoa mulch applied. In March 1998 approximately 9 cubic yards of Ecomulch from A & J Ecology was applied to the entire area (4-6 cm deep) with the exception of the experimental weed control plots described in the experimental design section. The pampas grass began to resprout, so it was completely removed and the area was then treated with concentrated Round up Pro.

Table 1. Native plant species hand seeded on northeast end of Bayview site.

South Tank
This site was expanded to the north in January 1998 by removing approximately 250 m² of ice plant on the northern section of the site and 100m² on the southern end adjacent to the road. Ice plant was first sprayed with Round up Pro and then removed by hand three weeks later. The entire area was mulched in March 1998 with 6 yards of Ecomulch from A & J Ecology to a depth of 4 to 6 cm.

Erosion Slope
No additional site preparation was necessary on this slope. Biodegradable erosion control applied to the slope the previous year (Heffernan 1997) remains in good condition and continues to protect the slope from sediment loss.

McClelland Road
Phase II of this site began in March 1998 with the salvage of ten Lotus scoparius (Deerweed) and Salvia mellifera (Black sage) ranging in size from 10 cm to 35 cm tall. Salvaged plants were replanted along the edges of the road. A D4 tractor from Hawthorn rental equipment was used to level the road, moving dirt in from the sides and up from the bottom of the road. Dead brush was moved from the sides of the road into the middle of the road and crushed with the tractor to aid in erosion control and add native organic matter to the soil. The entrance to the road was closed off using branches from eucalyptus trees removed in 1997. The heavily compacted lower portion of the road was ripped with the tractor blades to ease container plant rooting. A total of 7 straw flake check dams were installed approximately every 3.5 m for erosion control. The dams were created by first digging ditches, 8-10 cm wide and 15 cm inches deep. Straw flakes were then peeled off bales and placed vertically in the ditches, back filled, and hand compacted leaving approximately 20 to 25 cm of straw above ground (Figure 2). In March 1998 a drip irrigation system was installed to seedlings planted in 1997 using ½ inch supply tubing connected to ¼ inch drip tubing and two gallon per hour drip emitters.

Figure 2. McClelland Road phase II in March 1998, immediately after planting.

Minor Sites
No additional site preparation was necessary on the minor sites.

Ashburn Road
Ashburn Road was cleared of all exotics such as ice plant, tumble weed and chrysanthemum. A total of 11 acacia trees were cut down along the northern and southern sides of Ashburn Road and remaining tree stumps treated with concentrated Round up Pro. Trees were broken down by a chipper belonging to the Submarine Base Public Works and the mulch added to a mulch pile located on the west side of the water tank adjacent to the South Tank site. Approximately 6 yards of mulch purchased from A&J Ecology was placed on the site 4 to 6 cm deep.

Experimental Design
Mulch plots
A total of 45 experimental mulch plots were set up on Bayview in February 1996 testing the effects of annual grasses and bark mulch on plant survival, soil nutrients and microbial activity. Three one meter plots were established for each of the following plant species: Artemisia californica (California sagebrush), Eriogonum fasciculatum (Flat-top buckwheat), Nassella lepida (Foothill needlegrass), Salvia mellifera (Black sage) and Encelia californica (California encelia). The bark and bare soil (control) plots were cleared of weeds and debris. Bark was then added to a depth of 6 cm to three of the plots, exotic grasses were left in place on three plots and three control plots remained bare. Soil analysis measuring total nitrogen, nitrate, ammonium, phosphate, pH, bacterial numbers and fungal hyphae were done in March 1996, October 1996 and October 1997.

The same experimental mulch plots were installed in February 1996 on the Erosion Slope with the addition of bark, coir and no addition (control). Measurements included plant survival, soil nutrients and soil microbial numbers. Plant species used on this site were Artemisia californica, Eriogonum fasciculatum, Nassella lepida, Salvia mellifera and Cneoridium dumosum (spicebush).

Experimental mulch plots were installed on the South Tank in February 1996 to test acacia mulch, bark and bare soil (control) using the same experimental design as on Bayview. Plant species used in the study were Artemisia californica, Eriogonum fasciculatum, Nassella lepida, Salvia mellifera and Encelia californica.

There were no significant changes in bacterial numbers and fungal biomass measured during the first year (March 1996 through March 1997) on all sites. Additional soil samples were taken from these plots in March 1998 and bacterial numbers and meters of fungal hyphae were measured.

Weed mats
Fourteen 4 m² plots were created on Bayview and six 4 m² plots on the Ashburn Road site in November 1997 to test Dalen commercial landscape fabric, Weedguard, newspaper, mulch and a control (no treatment). Each material was replicated 4 times for a total of 20 plots. All plots were completely cleared of existing weeds at the beginning of the study. The weed mats were cut to into 2 m squares and stapled to the ground with 6 in metal staples (Figure 3). Three layers of newspaper were soaked with water to conform to the soil surface and placed on the test plots. All mulch plots were covered with Ecomulch from A & J Ecology to a depth of approximately 5 cm. Plots were weeded in May 1998 and weeds from each plot were placed in separate paper grocery bags and allowed to dry for two weeks. The dry weight of weeds from each plot was determined and results graphed. Percent moisture of the soil was also tested to determine moisture retention benefits for native container planting. Four grams of soil were taken from each plot, dried at 80 degrees overnight, and reweighed.

Figure 3. Weed control plot (Dalen) on Ashburn Road site in November 1997.

Seeding
In March 1998, 10 circular plots with a radius of 0.75 m were established on the Erosion Slope site to determine the effect of cocoa mulch and surface applied straw on seed germination. Five plots were covered with cocoa mulch to a depth of 2 to 3 cm and 5 plots were covered with straw to the same depth. The same seed mixture used on Bayview in Table 1 was dispersed by hand on the ten plots to yield 100 live seed per m2. Seed germination was measured in May 1998 and October 1998.

Ice plant Mulch
In the Spring of 1997 ice plant on the McClelland Road site was sprayed with Roundup Pro. Forty-five container grown seedlings were planted in dead ice plant to determine its effects on plant survival and growth. Percent survival of these seedlings was measured in June, September, December 1997 and January 1999. Plant survival in the ice plant was compared to overall container plant survival on McClelland Road.

Container Planting
Bayview
An additional 52 container grown seedlings were planted on Bayview in April 1998 in the areas previously covered with ice plant and pampas grass (Table 2).

Table 2. Native plant species container planted on Bayview in Spring 1998.

South Tank
An additional 56 container grown seedlings were planted at the South Tank site in January 1998 in the areas where ice plant had been removed (Table 3).

Table 3. Native plant species container planted on South Tank in January 1998.

Erosion Slope
No additional plants were planted on this site.

McClelland Road
A total of 121 container grown seedlings were planted during Phase II of the McClelland Road site in March 1998 (Table 4). Since herbivory had been previously experienced on this site, all seedlings were covered with either treepees or tubex.

Table 4. Native plant species container planted during Phase II of the McClelland Road site in March 1998.

Minor sites
No additional planting was necessary on the Minor sites.

Ashburn Road
In December 1997, 127 container grown seedlings were planted on the lower east section of Ashburn Road and 126 seedlings planted on the upper west section for a total of 253 plants (Table 5).

Table 5. Native plant species container planted on the Ashburn Road site in December 1997.

Maintenance and Monitoring
Bayview
Seedlings planted on Bayview in 1998 and previously planted seedlings that were less than 15 cm were hand watered twice a month from June through September 1998. Weeds on Bayview were sprayed in May 1998 with Round up Pro and exotic grasses cut using a weed trimmer. Further weeding was done by hand monthly June through September 1998. Plant survival was determined in December 1997, March, June and December 1998.

South Tank
South tank was hand weeded in February, June and December 1998. Seedlings less than 15 cm were watered monthly June through September 1998. Plant survival was determined in December 1997, March, June and December 1998.

Erosion Slope
The Erosion slope was weeded in March, June and December 1998. Seedlings less than 15 cm were watered monthly June through September 1998. Plant survival was determined in December 1997, March, June and December 1998.

McClelland Road
In April 1998 the drip irrigation system on McClelland was expanded to cover Phase II seedlings by using ½ inch supply tubing connected to ¼ inch drip tubing and two gallon per hour drip emitters. The drip system was activated for approximately 45 minutes twice monthly June through September 1998. The site was hand weeded in February, June, August and October 1998. Plant survival was determined in December 1997, March, June and January 1998. Minor sites Plants on the minor site were not hand watered as foot traffic would cause additional damage to the slope. However, seedlings did receive water from the temporary mist sprinkler system at the bottom of the slope installed by a Navy contractor. The lower portions of the minor sites were weeded in May and December 1998 and survival of plants determined in December 1998.

Ashburn Road
Plants on Ashburn Road were watered twice monthly during June through September 1998. The site was sprayed with Round up Pro in May 1998 and annual exotic grasses cut using a weed trimmer. Hand weeding on the site was conducted twice a month June through September 1998 and once in December 1998. Plant survival was determined in December 1997, March, June and December 1998.

Results
Mulch plots
Bacterial numbers and fungal hyphae length under the various mulch treatments on Bayview, South Tank and the Erosion Slope were incorporated into previous results in order to determine a possible trend in changes over time. Graphs in Figure 4 depict measurements from soil samples taken in March 1996, October 1996, March 1997 and March 1998. Bacterial numbers significantly decreased on all three sites between March 1997 and March 1998; however, there were no significant differences in March 1998 between the treatments. On Bayview the fungal biomass dropped significantly under the bark and bare plots. On South Tank, the fungal biomass increased significantly under the coir and bare plots and the bark plots demonstrated little change. The fungal biomass decreased slightly under the acacia plots on the Erosion Slope and remained constant under the bark and bare plots.

Weed mats
Results of the weed control plots on Bayview and Ashburn Road were combined for analysis. All weed control methods tested were at least 29 times more effective at reducing exotic vegetation growth than the control (Figure 5). The Apex biodegradable weed mat was the most effective at preventing weed growth with only 0.41 grams (dry weight) of weed material per m² compared to the control at 17.44 grams (dry weight) of weed material per m². However, the Dalen commercial weed guard was the most durable as the other weed mats easily tore as weeds were removed.

Percent soil moisture was significantly higher under the newspaper plots at 9.9% while percent moisture was lowest under the control at 6.1% (Figure 6).

Figure 4. Bacterial numbers and fungal hyphae length in the soil on Bayview, South Tank and the Erosion Slope during the period October 1995 through March 1998.

Figure 5. Comparison of weed control methods on Bayview and Ashburn Road.

Figure 6. Comparison of percent moisture under weed control plots.

Seeding
Germination in the seed plots on the Erosion Slope was low under both the straw (0.7%) mulch and the cocoa mulch (0.4%). The cocoa mulch yielded the greatest number of seedlings; however, the straw appeared to reduce the number of exotic seedlings on the plots (Figure 7).

Figure 7. Seed Germination in seed plots on South Tank.

Ice plant mulch
A total of 37 of the 45 container grown seedlings planted in the dead ice plant on McClelland Road survived (82%) compared to overall survival of 50% container seedlings on McClelland Road. However, two years after being sprayed with Round up Pro, the ice plant continues to resprout in small patches. Exotic vegetation growth was noticeably lower under the dead ice plant in comparison to the surrounding area.

Container Plant Survival
Overall container plant survival on Bayview was 63 percent in December 1997 and 53 percent as of 31 December 1998 (Table 6). In some cases, such as Rhus integrifolia, Artemisia californica, Eriogonum fasciculatum, Euphorbia misera, Malosma laurina, Nassella lepida and Lotus scoparius, plant survival increased due to resprouting of plants previously considered dead.

Table 6. Percent survival of seedlings container planted on Bayview in 1996 and 1997 as of December 1997 and December 1998.

Overall percent survival of additional seedlings planted on Bayview in the spring of 1998 was 63 percent as of December 1998 (Table 7). Percent native plant cover on Bayview is approximately 25 percent as of October 1998 as compared to 10 percent cover in December 1997 and approximately 2 percent in February 1996 before restoration (Figure 8 ).

Table 7. Percent survival by species of seedlings container planted on Bayview in Spring 1998.

As of December 1998, overall survival of seedlings planted on South Tank in spring 1996 was 52 percent (Table 8) and survival of seedlings planted in spring 1998 was 66 percent (Table 9). Percent cover for the two year old section of South Tank was approximately 55 percent (Figure 9) while percent cover on the recently planted section was 15 percent.

Figure 8. Bayview site in February 1996 before planting and in December 1998 with approximately 25percent native plant cover

Table 8. Percent survival of container seedlings planted on South Tank in 1996 and 1997 as of December 1997 and December 1998.

Table 9. Percent survival of seedlings container planted on South Tank in Spring 1998.

Figure 9. South Tank before planting in February 1996 and in October 1998, two and one half years later.

Overall survival of container planted seedlings on the Erosion Slope was 50 percent in December 1997 and 52 percent as of December 1998 (Table 10).

Table 10. Percent survival of seedlings container planted on the Erosion Slope in 1996 and 1997 as of December 1997 and December 1998.

Overall seedling survival of phase I of McClelland Road was 50 percent as of December 1998 (Table 11) with percent cover of native vegetation ranging from 20 to 30 percent (Figure 10). Seedling survival of phase II of McClelland Road was 69 percent as of December 1998 (Table 12) and approximately 10 percent native vegetation cover.

Table 11. Percent survival of seedlings container planted on phase I of the McClelland Road site as of December 1997 and December 1998.

Figure 10. McClelland Road site in March 1997 and in October 1998, one and a half years after planting.

Table 12. Percent survival of seedlings container planted on phase II of McClelland Road site as of January 1999.

Overall survival of seedlings planted on the Minor Sites was 64 percent as of December 1998 (Table 13) with percent cover of native species approximately 15 percent.

Table 13. Percent survival of container seedlings planted on the Minor Sites as of December 1998.

Overall survival for the Ashburn Road site was 66 percent as of December 1998 (Table 14) with percent cover of native vegetation approximately 20 percent (Figure 11).

Table 14. Percent survival of seedlings container planted on Ashburn Road site as of December 1998.

Figure 11. Ashburn Road site in October 1997 before revegetation (top) and in December 1998 (bottom) one year later.

Discussion
Bacterial numbers on Bayview, South Tank and the Erosion Slope appear to have no significant changes over time. Fungal hyphae measurements were variable among sites as the hyphae decreased on Bayview, increased on South Tank and showed little change on the Erosion Slope. The increase in fungal hyphae on South Tank was likely due to the high percent cover of native plant species, since woody shrub habitats such as coastal sage scrub rend to have fungal based mineralization cycles. The study showed no consistent results among treatments most likely due to the recalcitrant mulch degrades slowly, thus two years is not enough time for the treatments to take effect.

The weed mat study demonstrated that all types of weed control methods reduce the growth of exotic plant species. Newspaper appears to be the most effective weed control material as it retains moisture better than other materials tested and provides effective protection in preventing weed growth. Adding a fourth layer of newspaper may provide additional weed suppression and make the mat more tear resistant.

Native seed germination was low under both the cocoa mulch and straw, possibly due to old seed. Native seed germination on the experimental plots on South Tank was greatest under the cocoa mulch; however, exotic seed germination was also high under the cocoa mulch. Native seed germination was lower under straw, but exotic seed germination was almost nonexistent under the straw. Cocoa mulch appears to be is more effective than straw on the slope as it remained on the plot better than the straw over time.

Seedling survival was significantly higher (82 %) with the ice plant mulch than in the surrounding area of McClelland Road (50%), however, precautions need to be taken to prevent the ice plant from resprouting and competing with native seedlings. Ice plant resprouted on some areas of the McClelland Road site, but not on others. This may have been due to a seasonal difference at the time of spraying or a difference in the frequency between initial spraying and subsequent herbicide treatments.

Overall container plant survival was variable among sites ranging from 50 percent (McClelland Road, phase I) to 69 percent (McClelland Road, phase II). Survival of individual plant species on the sites planted in 1996 (Bayview, South Tank and the Erosion Slope) increased in 1998 due to resprouts. Although container plant survival was low on Phase I of McClelland Road (50 percent), percent cover was high after two years (20 to 30 percent). Low plant survival is attributed to early loss after planting due to high herbivory in the area. This was also evident on Phase II of McClelland Road where succulent species such as Dudleya lanceolata and Ferocactus viridescens suffered from herbivory. Container plant survival on the minor sites varied along the slope. Survival and cover was highest at the bottom of the slope, most likely due to watering from the misting system at the bottom of the slope. Exotic plant species was also highest at the bottom of the slope possibly due to exotic seed such as Oxalis corniculata and Salsola tragus (tumbleweed) contaminating the hydroseed mixture used along the bottom of the slope. These exotic species were not found on the slope before hydroseeding occurred. Survival and cover on the Ashburn Road site was high as seedlings were planted in December of an El Niño year during which they received almost double the normal rainfall. Survival of Heteromeles arbutifolia was low on the Ashburn Road site as they had been grown in a commercial nursery and not hardened off before planting. Survival of Ceanothus verrucosus seedlings was low on Ashburn Road as with all sites on Point Loma.

Conclusions and Recommendations
There were no clear differences between mulch ammendments on Bayview, South Tank and the Erosion Slope. These results are likely due to the treatments dispersing from the plots over time. Future surface amendment experiments in should not be done on a slope greater than 35 degrees such as the Erosion Slope as the bark appears to move out of the plot over time. Also, long-term plots should be set up with a border in order to hold mulch in the plot and to outline the plot for long term monitoring. In addition, it is recommended that treatments be added at a minimum depth of 40 to 50 cm to make a significant difference.

Although weed mats reduced the amount of time necessary for weeding, it became apparent that this procedure is neither cost effective nor time efficient. An alternative method may be to cover an area around each seedling with a weed mat and then apply mulch to the entire site. This would reduce the amount of time required for weeding and decrease competition to native seedlings from exotic plant species. Newspaper is a cost efficient and effective means of suppressing weeds. Further studies using newspaper around seedlings should be done to test its durability and longevity. In the study done on South Tank and other studies (Heffernan, 1998), cocoa mulch has been the most effective ammendment in promoting native plant seed germination; however, the benefits also apply to exotic seed germination as well. Straw may be used to prevent exotic seed germination on sites which are container planted, but not on seeded areas as it appears to suppress native seed germination. Future studies with cocoa mulch and hydroseeding may be beneficial as cocoa mulch tends to conform to the slope after water is applied and has been successful in promoting native seed germination.

There appears to be no benefit in removing dead ice plant except for asthetics. The dead ice plant functions as a weed mat and had shown to increase container plant survival. Since ice plant has resprouted in areas where it has been removed and left in place, further documentation and studies should be done to determine why ice plant resprouts in some cases and not in others. These experiments may include varying frequency between spraying, testing foliar spraying during both the dry season and rainy season and varying concentrations of the herbicide.

Plant survival in 1998 was higher than the previous year by at least ten percent due to an El Niño year. Container seedlings were also larger and more robust after one year than plants planted in previous years. Survival of species such as Quercus dumosum, Cneoridium dumosum and Ceanothus verrucosus continues to remain low, although these species are present and seem to thrive in the undisturbed area. These plant species may be more sensitive to disturbance than other species and future studies in soil nutrients and properties should be done to determine methods to increase their survival.