Recovery and Growth of Vegetation Pre and Post Wildland Fire in the Chaparral of Southern
California
Timothy Schang and Vanessa Haber
Department of Biological Science
Saddleback College
Mission Viejo, California 92692
The chaparral of Southern California is constantly affected by wild fire with urbanization
expanding into the chaparral. Fire affects the diversity and the populations of plants by allowing
certain species of plants to germinate at higher rates than others. In this project an area of
chaparral that had burned approximately one year prior was compared to another portion in the
same area that did not burn. Data was collected using the point quarter method. Five transects in
each portion of burned and unburned area. The following plants were found in both the burned
area and unburned area were: Lotus scoparius (Deerweed), Rhus integrifolia (Lemonade Berry),
Phacelia cicutaria (Caterpillar Phacelia), Salvia mellifera (Black Sage), Toxicodendron diversilobum
(Poisonoak), and Gnaphalium canescens (Fragrant Everlasting),
Adenostoma fasciculatum
(Chamise), Malosma laurina (Laurel Sumac), Wyethia ovate (Southern Mule Ears), Eremocarpus
setigerus (Turkey Mullein), Baccharis salicifolia (Mule's Fat). The study found there was a
significant difference in plant species and their population when compared to an area that had
burned approximately one year ago to date; using the Simpsons Diversity Index (D = 0.89968).
There also was a statistical difference in IV’s of the plants found area being investigated in the
burned area compared to the species found in the unburned area (p=8.677x10-9, ANOVA).
Introduction
Pausas et al. (2009) said that wildfires have shaped plants and their defenses against fire before humans
emerged. With that said wildfires play a key role in ecosystem conservation. The effects of fires
biodiversity have not been as completely studied as many believe. Some species of plants in the Southern
California Chaparral depend on fire to increase the rate of germination in a burned area. Other plants in
the Southern California Chaparral rely on the wind or animals to bring their seeds into a burned area to
germinate. The Orange County Fire Authority Board of Directors, Freeway Complex Fire After Action
Report (2009) detailed about the fire being investigated. The fire which is being investigated is the
Freeway Complex Fire which started on November 15, 2008 and was contained on November 19, 2008.
The Fire affected the following cities of Southern California: Anaheim, Brea, Corona, Chino Hills,
Diamond Bar, and Yorba Linda. The hypothesis being tested is there will be a statistical difference in the
number of specific plant species and there Importance Value when compared to a burned and unburned
area.
Methods and Materials
The area selected to collect data was for this experiment was a location in Diamond Bar,
California along the Brea Ridge Motorway; along a 400 meter portion of the Freeway Complex Fire. The
data was collected on October 9, 2009 starting at 10:00 am till 2:00pm and October 23, 2009 at 9:30 am
till 4:30 pm. The method used to collect the data was point-quarter sampling. There were a total of ten
transect. Five at 100 meter intervals, measured with a 100 meter transect tape, which went into the burn
area. Then another five at 100 meter intervals, measured with a 100 meter transect tape, which went into
the unburned area. Each transect was 100 meter and measured with a 100 meter transect tape. Data was
then collected in 20 meter points along the transect tape. Each point represented the center of the
measurement area. Then from the center, a compass was used to define four quadrants (Northwest,
Northeast, Southwest, and Southeast). In each quadrant the closest plant’s stem or clump of stem’s to the
center of the point was measured (point to plant) and recorded using a 30 meter transect tape. The
diameter of the plant was then measured using a 30 meter transect tape. Finally the species of the plant
was recorded. This process was repeated for each transect.
All data was then transferred to MS Excel (Microsoft Corporation, Redmond, Washington). The
data was first statistically analyzed using the Simpson’s Diversity Index:
Where n equals the total number of a particular species, and N equals the total number of all species. The
value D ranges between 0 and 1; 1 represents infinite diversity and 0 represents no diversity.
The data was then manipulated algebraically to determine Importance Value (IV) as referenced
by Krebs. (2001) IV is the sum of the Relative Density, Relative Frequency, and Relative Coverage.
Then all IV were analyzed using an ANOVA: Single Factor to determine significant difference in IV.
Results
The following plants were found in both the burned area and unburned area were: Lotus
scoparius (Deerweed), Rhus integrifolia (Lemonade Berry), Phacelia cicutaria (Caterpillar Phacelia),
Salvia mellifera (Black Sage), Toxicodendron diversilobum (Poisonoak), and Gnaphalium canescens
(Fragrant Everlasting), Adenostoma fasciculatum (Chamise), Malosma laurina (Laurel Sumac), Wyethia
ovate (Southern Mule Ears), Eremocarpus setigerus (Turkey Mullein), Baccharis salicifolia (Mule's Fat).
The study found there was a significant difference in plant species and their population when compared to
an area that had burned approximately one year ago to date; using the Simpsons Diversity Index (D =
0.89968). Figure-1 shows the Diversity of plant populations in the burned area compared to the unburned
area.
Figure-1: There is a significant difference in number of plant species when compared to an area that had
burned approximately one year ago to date; using the Simpsons Diversity Index (D = 0.89968)
The six species of plants that had the highest frequency were: Deerweed, Lemonade Berry,
Caterpillar Phacelia, Black Sage, Poison Oak, and Fragrant Everlasting. The mean Importance Value
(IV) for Deerweed in the burned area was 1.055 ± 0.203 (±SEM, N=5) compared to the mean IV of
Deerweed in the unburned areas was 0.035 ±0.035 (±SEM, N=5). The mean IV for Lemonade Berry in
the burned area was 0.161 ±0.068 (±SEM, N=5), compared to the mean IV of Lemonade Berry in the
unburned area was 1.204 ± 0.291 (±SEM, N=5). The mean IV of Caterpillar Phacelia found in the burned
area was 0.285 ± 0.153 (±SEM, N=5), compared to the mean IV of Caterpillar Phacelia in the unburned
area was 0.0464 ± 0.046 (±SEM, N=5). The mean IV of Black sage found in the burn area was 0.550 ±
0.155 (±SEM, N=5), compared to the mean IV of Black Sage found in the unburned area was 0.055 ±
0.034 (±SEM, N=5). The mean IV for Poison Oak in the Burned area was 0.084 ± 0.053 (±SEM, N=5),
compared to the mean IV of Poison Oak found in the unburned area was 0.245 ± 0.181 (±SEM, N=5).
The mean IV of Fragrant Everlasting found in the burned area was 0.210 ± 0.183 (±SEM, N=5),
compared to the mean IV of Fragrant Everlasting found in the unburned area was 0.710 ± 0.219 (±SEM,
N=5).
There was a statistical difference in IV’s of all the species of plants found in the burned area
compared to the same species of plants found in the unburned area (p=8.677x10-9, ANOVA). Upon
running the Bonferroni correction, the difference was between the IV of Lemonade Berry in the burned
versus the unburned area (5.24%). There was also a difference in IV of Deerweed in the burned versus
the unburned area (5.13%). Figure-2 represents the difference in IV of the six most frequently found
plants in the burned area when compared to the plants found in the unburned area.
Figure-2: Mean Importance Values (IV) with standard error of species found in a burned area compared
to species found in an unburned area (N=5).There was a statistical difference in IV’s of the all species
found in the burned area compared to the all species found in the unburned area (p=8.677x10-9, ANOVA).
Discussion
Lloret et al. (1991) researched Rhus integrifolia (Lemonade Berry) and found that the majority of
the recovery of this plant in the burned chaparral was due to Peromyscus californicus and Neotoma
fuscipes. The animals would eat the fruit of the Lemonade Berry and then while in the burned chaparral
would release the fecal waste, transporting the seeds of the Lemonade Berry into the burned area so it has
the possibility of germinating. Lemonade Berry bares its fruit in spring and well into summer. This could
account for the relatively low Importance Value of Lemonade Berry plants found in the burned area;
considering they have had one growing season to recover.
Montalvo and Ellstrand (2000) researched how to advance the growth and spread of Lotus
scoparius (Deerweed). There data suggest that success rates will be higher if genetically or
environmentally similar populations are used to supply seeds for restoration and post-fire seeding of
specific sites. With their research this may account for the Deerweed having the highest IV, when ranked,
in the burned area when compared to the rest of the species found in the Burned area.
Keeley (1991) found that heat plus charred wood had a synergistic effect on percentage of
germination of Phacelia cicutaria (Caterpillar Phacelia), over charred wood alone. Although there was
not a statistical difference in IV of Caterpillar Phacelia; this may account for why there was more
Caterpillar Phacelia found in the burned than unburned area. This was also the case with another research
project. Monroe et al. (1991) researched two shrub species native to Southern California which showed
different germination patterns in relation to fire intensity. Adenostoma had enhanced germination in the
control burn; however, as fire intensity increased, germination decreased. In contrast, while Ceanothus
was also stimulated by the heat of the control burn, it had a significantly much greater germination as fire
intensity increased in the treatment, decreasing only in the most intense treatment (controlled burn).
Acknowledgments
A special thanks to Nicole Barret who assisted in collecting data and entering data into MS Excel.
Literature Cited
Charles J. Krebs. 2001. Ecology 5th Ed. San Francisco.
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