The Chaparral (Mediterranean) Biome
The chaparral is the smallest of the biomes. It is found in specific areas between places with hot, dry climates and high atmospheric pressure and those with cool, wet climates and low atmospheric pressure. Most often, this biome is located between forest and grassland, or between desert and grassland biomes. According to most scientists, the chaparral exists in only five different locations throughout the world, including the Cape of Good Hope at the southern tip of South America, western North America (from south western Oregon through California), southwestern Australia, central Chile, and the coastal areas surrounding the Mediterranean Sea.
The chaparral is noted for its hot, dry summers and cool winters. Summer temperatures can reach 100º F, causing desert-like conditions. Conversely, temperatures during the winter can drop below freezing and cause hard frosts to hit the land. Most of the rainfall arrives during the late fall and early spring seasons, and reaches its peak in February. During the summer, an area of high atmospheric pressure forms and stops rain clouds from the Pacific Ocean from reaching the chaparral. Droughts and fires are prevalent as a result. This type of climate is caused by the positioning of this particular biome, which is generally around the 30º north or south latitude line. These are the latitudes where warm, wet air rising from the equator has cooled and dropped its moisture over the equator. The air mass then spreads out from the equator and falls to the ground as very dry air. In many parts of the world this forms deserts, but in the chaparral biome the presence of an adjacent body of water, often with cold currents, offsets the dryness of the falling air to some extent.
Plants in the chaparral biome must be well suited to the varying temperatures, nutrient-poor soil, and lack of moisture in the region. In response to climatic conditions, some plants are drought and fire resistant, while others become dwarfed. Most flowers bloom and most plants grow in the spring when the soil holds the largest amount of water. Later, when temperature begins to rise and the water in the soil evaporates, seeds set out by plants can start to mature. During the summer droughts, the seeds remain dormant, waiting until the rains begin until they sprout. Plants of this type are known as drought avoiders. They are adapted to conserve water and be able to survive with as little amounts as possible. Some drought avoiding plants drop their leaves when the weather gets hot to avoid excessive evaporation. Other plants have adapted to the changing temperatures of the biome in the opposite way. Drought tolerators do not begin to grow until after the rains have passed and water is set deep beneath the soil. This is effective because the ground water can be reached by shrubs’ deep growing roots during dry spells. Drought-tolerating plants also often have small, leathery leaves that help reduce water loss. One shrub of this sort, the chamiso, produces a waxy, flammable substance on its leaves when the weather gets hot. This grease is one reason why fires are a common occurrence. Though the fires char the land, they are beneficial to the flora that resides there. They improve the well being of dominant plants by getting rid of decaying matter that is often impedes their growth. In the spring season following a fire, flowers called fire-following plants, finally have enough space to spread and bloom in the burned land. After a few years, space for the flowers again becomes limited as shrubs, grasses, and trees again take over. Some of the most common plants found in chaparral regions in California include the chamiso shrub, poison oak, manzanita, sugar sumac, dwarf coniferous pines, and mountain mahogany.
In addition to plants, animals must adapt to the conditions of the chaparral. Many of the animals found here are small and/or nocturnal because most larger animals cannot stand the heat of day during the summer months. However, the California chaparral contains a very diverse animal population. The chaparral’s bird population is comprised of a large number of hawks and eagles, as well as the migratory species that reside there during certain seasons. Ground birds like the quail, wrentit, and thrasher live and nest in the thick, low growing shrubs. The top predators include a couple large cat species, like the mountain lion and bobcat, which rely on mule deer as their main source of food. They thrive in this biome because they are suited to the dry climate and they can use the dense thickets to stalk their prey. Another predator is the coyote, which travels in packs and feeds on small mammals like the brush rabbit and ground squirrel. At night, rattlesnakes hunt similar prey using their incredible sense of smell and heat sensors. Insects like Muir’s hairstreak butterflies are specially adapted to areas of nearly toxic, magnesium-rich soil (known as serpentine). Even in a seemingly undesirable climate, many different species are able to live and thrive.
In California, a main concern associated with the chaparral is the large human population that lives in and around this biome. The California coast is heavily populated, and many of the chaparral areas have been developed for cities and agriculture. Cattle have destroyed much of the remaining area through overgrazing. Brush fires are often controlled to prevent damage to houses and other property, which causes changes in the natural patterns that many species need to survive and regenerate. Fires caused by human activity can alter the natural cycle and put at risk the endangered and sensitive species that live in this biome. Also, people have brought foreign plants and animals into the ecoregion that compete with the native species for food and land. As of today, there are two National Parks surrounding Santa Barbara that are designed to help protect the important chaparral habitat. This is a step in the right direction because it indicates that people living in this area have identified-and have begun trying to reverse-the damage done to the natural habitat. In the future, it is necessary for humans to take even more active measures to protect the chaparral (as well as the other biomes) in order to maintain the planet’s rich, yet ever dwindling, biodiversity.
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