Northern coastal scrub is a diverse

scrubland Shrubland, scrubland, scrub, brush, or bush is a plant community characterized by vegetation dominance (ecology), dominated by shrubs, often also including grasses, herbaceous plant, herbs, and geophytes. Shrubland may either occur naturally o ...

plant community found along the Pacific Coast from Northern

California California () is a U.S. state, state in the Western United States that lies on the West Coast of the United States, Pacific Coast. It borders Oregon to the north, Nevada and Arizona to the east, and shares Mexico–United States border, an ...

to Southern

Oregon Oregon ( , ) is a U.S. state, state in the Pacific Northwest region of the United States. It is a part of the Western U.S., with the Columbia River delineating much of Oregon's northern boundary with Washington (state), Washington, while t ...

, as well as some offshore islands. It frequently forms a landscape mosaic with coastal prairie.

Description

Northern coastal scrub is found on various rocky coastal land forms along the Pacific Coast. It is observed as either patchy ocean-side cover near coastal prairie or a dense and continuous shrub cover over perennial herbaceous plants. Northern coastal scrub will form a landscape mosaic with coastal prairie on sites with thicker, more moist soil. The conditions are harsh, with high exposure to wind and salt deposition and generally low-quality soil. The vegetation of coastal scrub communities is mostly composed of resilient short shrubs with flexible branches growing from a rigid, woody base.

Climate

Northern coastal scrub and coastal prairie generally occur where the Pacific Ocean moderates summer drought. As a result, northern coastal scrub not only traces the Pacific Coastline from central California to Southern Oregon, but extends inland, following the distribution of marine climate influence, appearing where the winds press coastal fog inland.

Salinity and species diversity

Both coastal prairies and scrubs have high species diversity. The northern coastal scrub is specifically associated with 106 rare/endangered plant taxa, with 79 of those species being endemic to California. It is noted that the closer a community is to the coast, the more diverse it is. This diversity is likely owed in a large part to the harsh conditions of the environment as they force plants to make adaptations in order to retain a viable population. The conditions also keep the species diversity high, preventing any one species from overly proliferating. Notably, salt deposition also has a significant correlation to the kind of vegetation present, as in communities with high salt deposition, such as those located on cliff bluffs, herbaceous plants tend be more prevalent than woody ones, which were only present in more dwarfed form.

Vegetation

Coastal scrub is a common plant community along the hills of the California coast. The northern coastal scrub's predominant plants are low

evergreen In botany, an evergreen is a plant which has Leaf, foliage that remains green and functional throughout the year. This contrasts with deciduous plants, which lose their foliage completely during the winter or dry season. Consisting of many diffe ...

shrubs A shrub or bush is a small to medium-sized perennial woody plant. Unlike herbaceous plants, shrubs have persistent woody stems above the ground. Shrubs can be either deciduous or evergreen. They are distinguished from trees by their multiple ...

and

herbs Herbs are a widely distributed and widespread group of plants, excluding vegetables, with savory or aromatic properties that are used for flavoring and garnish (food), garnishing food, for medicinal purposes, or for fragrances. Culinary use typi ...

. Particularly Characteristic shrubs include coyote brush ''(Baccharis pilularis)'', California yerba santa ''(Eriodictyon californicum)'', coast silk-tassel ''(Garrya elliptica)'', salal ''(Gaultheria shallon)'', and yellow bush lupine ''(Lupinus arboreus)''. Herbaceous Northern coastal scrub species include

western blue-eyed grass ''Sisyrinchium bellum'', the western blue-eyed grass or Californian blue-eyed grass, is the common blue-eyed grass of California and Oregon in and west of the Sierra Nevada, its range extending south into Baja California. In parts of its ran ...

''(Sisyrinchium bellum)'', Douglas iris ''(Iris douglasiana)'', and native grasses. However, no single species is typical of all coastal Scrub communities, as the compositions varies greatly along the coastline. As the conditions become progressively drier moving north to south, the species composition shifts from being dominated by evergreen species to drought-deciduous species. Within the northern coastal scrub communities, there are two main types: the more uncommon type occurs on exposed ocean-side areas as short patches of bush lupine and many-colored lupine. The more common type occurs in less exposed areas and is dominated by coyote bush.

Fire

Fire was a common feature of many California landscapes prior to Western settlement, whether as a result of Indigenous land management practice or natural causes such as lightning. It is difficult to determine how common fire was in northern coastal scrub as most techniques used to determine historic frequency of fire cannot be applied to scrub vegetation. While northern coastal scrub communities are able to easily establish themselves after a fire, especially after low intensity fires, it undeniably has a significant impact on the composition of these plant communities. There are certain species which sprout and spread more quickly after low intensity fires which will then dominate the landscape until other plants are able to establish themselves. In general, the resilience of Coastal scrub may cause plants to occupy areas that have been stripped by fire or landslides. Most times the original plants will eventually reoccupy the area, but this tendency has become problematic for coastal prairie. While both northern coastal scrub and coastal prairie have increasingly become more rare due to human development in past years, coastal prairie has seen a more significant decline. This decline is largely owed to a combination of fire, lack of grazing, and coastal scrub, as the former two create allow the more resilient coastal scrub to invade the grasslands without moderation.

References