Chaparral constitutes one of California’s most common vegetation communities, making up 4.9 million hectares.
What is chaparral?
Chaparral is part of what is known as Mediterranean-type ecosystems (MTEs). These biomes are located in areas with vegetation adapted to a Mediterranean climate of hot, dry summers and cool, wet winters.
Chaparral is composed of dense, intertwining, evergreen shrubs ranging that average 1-3 meters in height. Mature chaparral is composed of one layer with no understory and can reach heights of 10 meters.
Chaparral vegetation communities tend to grow on steep slopes with coarse textured, shallow soils. The presence of chaparral species tends to indicate a relatively thin, gravelly and well-drained soil.
Chaparral plants species are mostly adapted to periods of drought and periodic wildfires that clear out vegetation to make space for new growth.
Mediterranean biomes around the world
Similar shrubland vegetation communities adapted to the Mediterranean climate are found in the Mediterranean Basin, California, central Chile, the Western Cape of South Africa, and southwestern Australia.
These shrublands are known by different names depending on the geographic region they are found in.
In the Mediterranean Basin, this vegetation is known as ‘maquis’. In Central Chile, the biome is known as ‘matorral’. ‘Fynbos’ is the name for this vegetation community in Western Cape of South Africa and ‘kwongan’ in southwestern Australia.
In California, this iconic vegetation community is known as ‘chaparral’ which comes from the Spanish word chaparro which translates to “place of the scrub oak.”
What is the difference between chaparral and coastal sage scrub?
While these two plant communities can exist in close proximity to one another and contain some overlap in plant species, chaparral and coastal sage scrub are not the same.
One difference noted by Ronald Quinn and Sterling Keeley, authors of books about chaparral in Southern California, is that Chaparral tends to be dominated by evergreen plants why Coastal Sage Scrub vegetation has more plants that are drought deciduous. This means these plants lose their leaves and shut down during the hotter, drier summer months.
Coastal Sage Scrub plants are not as rough and abrasive as chaparral vegetation. Coastal sage scrub’s nickname is “soft chaparral” in recognition of the predominance of small shrubs with soft leaves.
There also tends to be more fragrant plants in coastal sage scrub compared to chaparral. The strong fragrance of sage is a defensive adaptation to discourage animals and insects from foraging on the leaves.
The word “chaps” originates from chaparral
Chaps, the protective leather covering used by horse riders in the Southwestern and Western parts of the United States to prevent scratches while traveling through scrubs, was named after chaparral.
Where is chaparral located in California?
Chaparral is one of the most dominant vegetation ecosystems in California, especially along the coastal communities and across Southern California.
Chaparral is also the most widespread ecosystem in California.
Types of chaparral communities
There are numerous chaparral ecosystems found in California. Some occur in widespread swaths across the state and others are very regional and adapted to unique local climates and environments.
Chaparral communities are described by the most common vegetation species associations and the location and environment they grow in.
Some chaparral communities are found within the coastal fog zone where there is more year-round moisture due to low-lying stratus clouds that bring moisture. Other chaparral communities are found in drier and more rocky environments.
Common chaparral plant species include manzanita, oaks, chamise, California buckwheat, toyon, black sage, laurel sumac, and California lilacs.
Here are a few examples of chaparral communities. Keep in mind that different organizations and researchers use a variety of names to describe chaparral communities. The chaparral community names below are from Grossman et al., 1998 and correspond with the names used in the maps in this article.
California maritime chaparral
Occurring in chaparral communities closest to the California coast, California maritime chaparral is predominately made up of species of manzanita and California lilacs (Arctostaphylos and Ceanothus).
Maritime chaparral in California is found within the fog zone stretching from the south of the state to the Mendocino coast in the north and in patches in parts of coastal Oregon.
Maritime chaparral can found intertwined with other vegetation communities. For example, at Point Reyes in Northern California, maritime chaparral merges with mixed evergreen forests and is surrounded by groves of coast redwood (Sequoia sempervirens) and riparian woodlands.
Maritime chaparral contains numerous species that are obligate seeders. This means that the vegetation, such as Bolinas Manzanita (Arctostaphylos virgata), Point Reyes ceanothus (Ceanothus gloriosus var. exaltatus), and Mason’s ceanothus (Ceanothus masonii), require scarification of the seeds from fire in order to reproduce.
California mesic chaparral
Mesic chaparral is typically found west of the coastal fog belt on slopes facing north with elevations up to 1,500 meters (4,550 feet). In Southern California, mesic chaparral is known to exist at elevations up to 1,830 meters (6,000 feet).
Also known as northern mixed chaparral, this is the dominant chaparral vegetation community in areas of Southern California like the Santa Monica Mountains.
The northern mixed chaparral association is defined as vegetation communities where Adenostoma fasciculatum (chamise) is co-dominant with typically forty percent cover with one of the following: Ceanothus (California lilacs) spp., Quercus dumosa (Coast live oak), Arctostaphylos spp. (manzanita).
Mature mesic chaparral, undisturbed by fire or other disruptions, can grow a thick canopy that prevents herbaceous plants from thriving. These shrubs can reach heights over ten meters (35 feet).
California xeric serpentine chaparral
Californias xeric serpentine chaparral thrives in areas characterized by thin, rocky, ultramafic soils such as gabbro, peridotite, and serpentinite. It also inhabits elevations that are below the snow line in winter but usually have hot, dry summers. Xeric serpentine chaparral is not found in the extremely hot southern region of California.
The vegetation composition of California xeric serpentine chaparral includes Macab’s cypress (Hesperocyparis macnabiana), leather oak (Quercus durata), various species of manzanita, as well as some species of California lilac and other oak species.
Fire cycle in chaparral ecosystems
The plants in the chaparral community are adapted to cycles of drought and wildfire.
Wildfires are a natural part of the cycle of chaparral ecosystems, although climate change is intensifying both wildfires and drought with detrimental effects.
Wildfires tends to destroy most aboveground vegetation in chaparral communities.
The post-fire vegetation succession in chaparral communities
The first stage of chaparral rejuvenation begins with a burst of herbaceous annuals and short-lived perennials. Some of these plants sprout from seeds activated by heat (scarification), while for others sprouting is triggered by chemical compounds discharged by burnt wood.
The majority of chaparral shrubs regenerate after fire by root-crown burls (lignotubers). In cases where the shrub is killed, germination by seed is a second strategy for some plant species.
After a few years, the shrub species that occupied the area pre-burn event reestablish their dominance and the herbs disappear, unable to compete with these vigorously growing shrubs for nutrients, moisture and light.
Chaparral succession is considered an autosucessional process; all species are present at the beginning of the cycle immediately following the fire event. Herbaceous species germinate from bulbs and seeds previously dormant in the soil bank.
Over time, less competitive species drop out as the post-fire crownsprouting of the chaparral shrubs crowds them out. Canopy closure of more dominant shrubs occurs after five to ten years.
Grossman, D. H., Faber-Langendoen, D., Weakley, A. S., Anderson, M., Bourgeron, P., Crawford, R., … & Sneddon, L. (1998). International classification of ecological communities: terrestrial vegetation of the United States. The Nature Conservancy, Arlington, Virginia.
Horton, J. S., & Kraebel, C. J. (1955). Development of vegetation after fire in the chamise chaparral of southern California. Ecology, 36(2), 244-262. https://doi.org/10.2307/1933230
Keeley, J. E. (1984). Factors affecting germination of chaparral seeds. Bulletin, Southern California Academy of Sciences, 83(3), 113-120. https://doi.org/10.3160/0038-3872-83.3.113
Rundel, P. W., Arroyo, M. T., Cowling, R. M., Keeley, J. E., Lamont, B. B., & Vargas, P. (2016). Mediterranean biomes: evolution of their vegetation, floras, and climate. Annual Review of Ecology, Evolution, and Systematics, 47, 383-407. https://doi.org/10.1146/annurev-ecolsys-121415-032330
Schrader-Patton, C. C., & Underwood, E. C. (2021). New biomass estimates for chaparral-dominated southern California landscapes. Remote Sensing, 13(8), 1581. https://doi.org/10.3390/rs13081581
Fonte : National Geographic