Chaparral


Chaparral is a shrubland plant community found primarily in California, southern Oregon, and northern Baja California, part of the California floristic province. It is shaped by a Mediterranean climate and infrequent, high-intensity crown fires. Many chaparral shrubs have hard sclerophyllous evergreen leaves, as contrasted with the associated soft-leaved, drought-deciduous, scrub community of coastal sage scrub, found often on drier, southern-facing slopes.
Three other closely related chaparral shrubland systems occur in southern Arizona, western Texas, and along the eastern side of central Mexico's mountain chains, all having summer rains in contrast to the Mediterranean climate of other chaparral formations.

Etymology

The name comes from the Spanish word Quercus coccifera, which translates to "place of the scrub oak". Scrub oak in turn comes from the Basque word txapar, which has the same meaning.

Overview

In its natural state, chaparral is characterized by infrequent fires, with natural fire return intervals ranging between 30 years and over 150 years. Mature chaparral is characterized by nearly impenetrable, dense thickets. These plants are flammable during the late summer and autumn months when conditions are characteristically hot and dry. They grow as woody shrubs with thick, leathery, evergreen and often small leaves. The plants are typically drought resistant, with some exceptions. After the first rains following a fire, the landscape is dominated by small flowering herbaceous plants, known as fire followers, which die back with the summer dry period.
Similar plant communities are found in the four other Mediterranean climate regions around the world, including the Mediterranean Basin, central Chile, the South African Cape Region, and in Western and Southern Australia. According to the California Academy of Sciences, Mediterranean shrubland contains more than 20% of the world's plant diversity. Chaparral comprises 9% of California's wildland vegetation and contains 20% of its plant species.
Conservation International and other conservation organizations consider chaparral to be a biodiversity hotspot – a biological community with a large number of different species that is threatened by human activity.
Chaparral characteristically is found in areas with steep topography and shallow stony soils, while adjacent areas with clay soils, even where steep, tend to be colonized by annual plants and grasses. Some chaparral species are adapted to nutrient-poor soils developed over serpentine and other ultramafic rock, with a high ratio of magnesium and iron to calcium and potassium, that are also generally low in essential nutrients such as nitrogen.

California chaparral

California chaparral and woodlands ecoregion

The California chaparral and woodlands ecoregion, of the Mediterranean forests, woodlands, and scrub biome, has three sub-ecoregions with ecosystem–plant community subdivisions:
Some indicator plants of the California chaparral and woodlands ecoregion include:
  • Quercus species – oaks:
  • * Quercus agrifolia – coast live oak
  • * Quercus berberidifolia – scrub oak
  • * Quercus chrysolepis – canyon live oak
  • * Quercus douglasii – blue oak
  • * Quercus wislizeni – interior live oak
  • Artemisia species – sagebrush:
  • * Artemisia californica – California sagebrush, coastal sage brush
  • Arctostaphylos species – manzanitas:
  • * Arctostaphylos glauca – bigberry manzanita
  • * Arctostaphylos manzanita – common manzanita
  • Ceanothus species – California lilacs:
  • * Ceanothus cuneatus – buckbrush
  • * Ceanothus megacarpus – bigpod ceanothus
  • Rhus species – sumacs:
  • * Rhus integrifolia – lemonade berry
  • * Rhus ovata – sugar bush
  • Eriogonum species – buckwheats:
  • * Eriogonum fasciculatum – California buckwheat
  • Salvia species – sages:
  • * Salvia mellifera – Californian black sage

    California cismontane and transmontane chaparral subdivisions

Another phytogeography system uses two California chaparral and woodlands subdivisions: the cismontane chaparral and the transmontane chaparral.

California cismontane chaparral

Cismontane chaparral refers to the chaparral ecosystem in the Mediterranean forests, woodlands, and scrub biome in California, growing on the western sides of large mountain range systems, such as the western slopes of the Sierra Nevada in the San Joaquin Valley foothills, western slopes of the Peninsular Ranges and California Coast Ranges, and south-southwest slopes of the Transverse Ranges in the Central Coast and Southern California regions.
Cismontane chaparral plant species
In Central and Southern California chaparral forms a dominant habitat. Members of the chaparral biota native to California, all of which tend to regrow quickly after fires, include:
  • Adenostoma fasciculatum, chamise
  • Adenostoma sparsifolium, redshanks
  • Arctostaphylos spp., manzanita
  • Ceanothus spp., ceanothus
  • Cercocarpus spp., mountain mahogany
  • Cneoridium dumosum, bush rue
  • Eriogonum fasciculatum, California buckwheat
  • Garrya spp., silk-tassel bush
  • Hesperoyucca whipplei, yucca
  • Heteromeles arbutifolia, toyon
  • Acmispon glaber, deerweed
  • Malosma laurina, laurel sumac
  • Marah macrocarpus, wild cucumber
  • Mimulus aurantiacus, bush monkeyflower
  • Pickeringia montana, chaparral pea
  • Prunus ilicifolia, islay or hollyleaf cherry
  • Quercus berberidifolia, scrub oak
  • Q. dumosa, scrub oak
  • Q. wislizenii var. frutescens
  • Rhamnus californica, California coffeeberry
  • Rhus integrifolia, lemonade berry
  • Rhus ovata, sugar bush
  • Salvia apiana, Californian white sage
  • Salvia mellifera, Californian black sage
  • Xylococcus bicolor, mission manzanita
    Cismontane chaparral bird species
The complex ecology of chaparral habitats supports a very large number of animal species. The following is a short list of birds which are an integral part of the cismontane chaparral ecosystems.
Transmontane chaparral or desert chaparral—transmontane ''chaparral''—refers to the desert shrubland habitat and chaparral plant community growing in the rainshadow of these ranges. Transmontane chaparral features xeric desert climate, not Mediterranean climate habitats, and is also referred to as desert chaparral. Desert chaparral is a regional ecosystem subset of the deserts and xeric shrublands biome, with some plant species from the California chaparral and woodlands ecoregion. Unlike cismontane chaparral, which forms dense, impenetrable stands of plants, desert chaparral is often open, with only about 50% of the ground covered. Individual shrubs can reach up to in height.
Transmontane chaparral or desert chaparral is found on the eastern slopes of major mountain range systems on the western sides of the deserts of California. The mountain systems include the southeastern Transverse Ranges in the Mojave Desert north and northeast of the Los Angeles basin and Inland Empire; and the northern Peninsular Ranges, which separate the Colorado Desert from lower coastal Southern California. It is distinguished from the cismontane chaparral found on the coastal side of the mountains, which experiences higher winter rainfall. Naturally, desert chaparral experiences less winter rainfall than cismontane chaparral. Plants in this community are characterized by small, hard evergreen leaves. Desert chaparral grows above California's desert cactus scrub plant community and below the pinyon–juniper woodland. It is further distinguished from the deciduous sub-alpine scrub above the pinyon–juniper woodlands on the same side of the Peninsular ranges.
Due to the lower annual rainfall when compared to cismontane chaparral, desert chaparral is more vulnerable to biodiversity loss and the invasion of non-native weeds and grasses if disturbed by human activity and frequent fire.
Transmontane chaparral distribution
Transmontane chaparral typically grows on the lower northern slopes of the southern Transverse Ranges and on the lower eastern slopes of the Peninsular Ranges. It can also be found in higher-elevation sky islands in the interior of the deserts, such as in the upper New York Mountains within the Mojave National Preserve in the Mojave Desert.
The California transmontane chaparral is found in the rain shadow deserts of the following:
  • Sierra Nevada creating the Great Basin Desert and northern Mojave Desert
  • Transverse Ranges creating the western through eastern Mojave Desert
  • Peninsular Ranges creating the Colorado Desert and Yuha Desert.