1. Hi ho, Hi ho, Off into the Grass We Go.
Samantha Lough1; Nancy Ko2; Trina Ming1; Jade Dean4; Koang KC Chea1; Darrell Patterson5; Brian Nagy4; Dr. Chrys Rodrigue4; Dr. Paul Laris4; Randy Peterson3; Kyra Engleberg4
Geosciences Diversity Enhancement Program, California State University Long Beach
1: Lakewood High School, 2: Los Alamitos High School, 3: Wilson High School, 4: California State University Long Beach, 5: Long Beach Polytechnic High School
Abstract
Introduction
Methods
Results
Acknowledgements
References
Conclusion
Discussion
I would like to thank the National Science Foundation [award #0703798] for funding
GDEP at CSULB. I would also like to thank Dr. Chrys Rodrigue, Dr. Paul Laris, and Sr.
Randolpho Peterson for providing guidance throughout the entire research process,
Brian Nagy for answering any and all technical questions, and Koang Chea, Jade
Dean, Nancy Ko, Trina Ming, and Darrell Patterson for help with collecting all the
data out in the field as well as always being there for support.
Field work: Transects were picked based off a map produced by Kyra Engleberg. The transects were
placed at an area that included a definite boundary between CSS and the annual grasslands. The
transect tape began in the transition zone and was laid out 25 meters into the CSS and then 25 meters
into the grassland (Fig. 4). At every five meters along the tape, a 1 x 1 meter quadrat was used. The
quadrat was utilized in order to identify (Figure 6 & 7) and quantify (in percent cover) certain plant
species along the transect (Fig. 2). Because of overlapping canopies, percent cover sometimes ended
up over one hundred percent. Unidentifiable species were described with much detail and a sample
was collected to be identified later. At the transition zone, five meter, and ten meter marks in grassland
as well as in CSS, soil samples were taken from the upper level and the lower levels using a soil auger (Fig.
3). In addition to the soil samples, at the same meter marks, a soil penetrometer was used to take three
soil compaction readings within the quadrat (Fig. 5).
Lab work: In the lab, all the data collected from the field was entered into a database, with fields for the
transect location, the soil compaction readings, and the plant species and percent cover. This database
was then linked in a GIS to additional spatial data, including maps of topography and disturbance. This
data set was further analyzed for patterns, then compiled into separate spreadsheets. Using Chi Square
analysis, the data was evaluated for significant differences.
Figure 1
Figure 2
Our study consists of research done within the La Jolla Valley. The purpose was
to examine whether or not certain native shrub species led the way in
advancing into the grassland. Transects were lain across stable boundaries as
well as recovering boundaries. Along the transect plant species were identified
together with their percent cover. The collection of species data was then
analyzed for patterns and specific differences. It has been found that six native
shrub species are pioneer species that aid CSS by leading the way into the
annual grassland to potentially create a suitable environment for other native
shrubs. These species include Artemesia californica, Eriogonum fasciculatum,
Baccharis pilularis, Mimulus auirantaicus, Nassella pulchra, and Melica
imperfecta.
This study found that certain native shrub species are leading the
advancement of CSS into grasslands. A chi square analysis has proven that
Artemesia californica, Eriogonum fasciculatum, Baccharis pilularis, Mimulus
auirantaicus, Nassella pulchra, and Melica imperfecta all have chi square
values less than 0.05, which indicates that they are disproportionately more
common in the recovery versus stable boundaries. This significant difference
proves that these six native species may be considered pioneer species
(Table 2).
Patterson’s and Ming’s research explored various edaphic factors that have
been proposed as influences of CSS and grassland dominance. Their work
has shown that neither carbon to nitrogen ratios nor grain size affects CSS in
any way. Chea’s research evaluated elevation, slope, and aspect and
found that only elevation and aspect were significant in differentiating
stable from recovering CSS boundaries.
Westman (1981a) discusses possible allelopathic effects emitted from the
shrubs or the dominance of herb species as factors of species distribution.
Westman (1981b) explains other factors that influence the distribution of
certain Salvia species, and their development as mono-specific stands.
Our study results support Wells’ (1962) theory that annual grasses invaded
CSS. They counter Keeley’s (1984) and Freudenberger et al’s (1987) notion
that frequent disturbances prevents CSS recovery. In our study area grazing
ended 45 years ago and there has been but a single fire in 1993 during the
study period. They also confirm the findings of Sylinski and Allen that CSS is
slow to recover in some cases and that only a few species can invade
areas dominated by exotic grasses.
This project found that specific native shrub species are more capable of
establishing in grassland territory. The following appear to be pioneer species,
Artemesia californica, Eriogonum fasciculatum, Baccharis pilularis, Mimulus
auirantaicus, Nassella pulchra, and Melica imperfecta. We conclude that
future restoration projects should prioritize the species that have
demonstrated the ability to establish in grasslands, such as those in Table 1.
Restorationists should avoid using species that have not demonstrated the
ability to colonize in grasslands regardless of whether they are found in the
proximity to the restoration site. Future research should focus on whether
these other species can establish once the pioneer species are in place.
Chea, K. 2010. Does Slope and Aspect Affect California Sage Scrub Recovery? GDEP Research Symposium (CSULB).
Clements, F. 1934. The Relict Method in Dynamic Ecology. Journal of Ecology 22, 1:39-68.
Freudenberger, D.O.; Fish, B.E.; Keeley, J.E. 1987. Distribution and stability of grasslands in the Los Angeles Basin. Bull.
Southern California Acad. Sci 86, 1:13-26.
Keeley, J. Postfire Recovery of California Coastal Sage Scrub. American Midland Naturalist 111, 1:15-117.
Ming, T. 2010. Does Size Matter?. GDEP Research Symposium (CSULB).
Patterson, D. 2010. Is Carbon and Nitrogen the Reason in Season?. GDEP Research Symposium (CSULB).
Wells, P. 1962. Vegetation in Relation to Geological Substratum and Fire in the San Luis Obispo Quadrangle, California.
Ecological Monographs 32, 1:79-103.
Westman, W. 1981. Diversity relations and succession in Californian coastal sage scrub. Ecology 62, 1:170-184.
Westman, W. 1981. Factors influencing the distribution of species of Californian coastal sage scrub. Ecology 62, 2:439-455.
Chart 1 shows the average percent cover of the
native plant species within the CSS, the transition
zone, and the grassland. It also breaks up the
percent cover between the transects with stable
boundaries and recovering boundaries.
Southern California is one of the world’s many biodiversity hotspots. A biodiversity
hotspot is a habitat with a significant amount of biodiversity that is threatened by
destruction. Covering a predominant portion of California is California Sage
Scrub (CSS). This environment houses the California Gnatcatcher, an endangered
bird species that lives only in CSS. CSS is threatened by two major variables,
persistent development of housing and other structures plus the invasion of exotic
grasses that were introduced in the late 18th century.
Currently there is only 10-15 % of the original CSS habitat, with much of the
remaining CSS degraded within State Parks and conservation areas. Post-
disturbance, studies have shown that CSS recovers at a slower rate than annual
grasslands. One hypothesis is that CSS thrives on areas with steeper slopes in
coarse, rocky soil whereas the grasses prefer a flat slope with a finer soil texture.
Clements (1934) discusses that the landscape used to be covered solely by native
grasslands but, Wells (1962) argues that the annual grasslands invaded land
previously dominated by CSS.
Another hypothesis concerns land disturbance, including fires, overgrazing, and
mechanical disturbance. Keeley (1984) suggests that due to too frequent fires,
the CSS is unable to recover. Freudenberger (1987) believes it to be a
combination of the frequent fires, but also overgrazing of the land. Others have
mentioned mechanical disturbance as a factor but it is usually discussed in the
context of overgrazing.
The purpose of this study was to determine the different factors that may
influence as well as limit the advancement of CSS into the areas controlled by
grasslands. In order to accomplish this, focus was placed on mapping and
comparing the changes in the boundaries between CSS and grassland during the
time period of the 1980s-2000s. We also examined whether or not certain shrub
species led the way in advancing into the grasslands. Westman (1981) studied the
factors that affected the development of mono-specific species stands. Stylinkski
and Allen !91999), who studied intensively disturbed areas, found that only two
CSS species were able to successfully colonize areas dominated by non-native
grasses. These are Eriogonum fasciculatum, and Baccharis sarothroides.
Table 1
Chart 1
Table 1 depicts the native shrub species that
were found thriving within the grassland. The
number of quadrats containing native shrubs
that appear to be advancing into the grassland
and at which meter along the transect they
were found.
Study Sites
Figure 2 Figure 3 Figure 4 Figure 5
Within Table 2, the species in the CSS, proven
to be leading the advancement into the
grasslands are shown. It is broken down to
recovering and stable transects, with the
quadrat counts for each leading species and
the sum of the remaining species as well as
their chi square values.
Native Shrub Species in the Grassland
Name Number of Shrubs Meter Location
Salvia leucophylla 2 30m, 35m
Baccharis pilularis 1 35m
Isocoma menziesii 2 30m, 50m
Hazardia squarrosa 1 45m
Eriogonum fasciculatum 4 35m, 40m, 45m, 50m
PhotocredittoJadeDean
Recovery vs. Stable: Leading Native Species
Artemisia
californica
Eriogonum
fasciculatum
Baccharis
pilularis
Mimulus
auirantaicus
Nassella
pulchra
Melica
Imperfecta
Other
Recovery 31 13 6 10 13 8 39
Stable 7 3 0 2 4 0 35
Chi
Square
Probability
0.00010 0.01242 0.01431 0.02092 0.02905 0.00468 4.74
Recovery Stable
0
20
40
60
80
100
Average % of Native Species
CSS
Transition
Grassland
Boundaries
AveragePercent
Table 2
Some Native California Plants
Scientific Name Common Name
Artemesia californica CA Sagebrush
Baccharis pilularis Coyote Bush
Encelia californica CA Bush sunflower
Eriogonum fasciculatum CA Buckwheat
Hazardia squarrosa Sawtooth Goldenbrush
Isocoma menziesii Coast Goldenbrush
Melica imperfecta Onion Grass
Mimulus auirantaicus Sticky Monkey Flower
Nassella pulchra Purple Needlegrass
Salvia leucophyila Purple Sage
Salvia mellifera Black Sage
Figure 6: CA
Buckwheat
Figure 7: CSS
Photo credit to Jade Dean