Free Flash Slideshow by cu3ox.com v1.1

Exploring the beautiful nature of California


California Nature:  Mediterranean Ecosystem


Mediterranean ecosystems are limited to five relatively small areas around the planet: the region bordering the Mediterranean Sea, central Chile, the Cape region of South Africa, southwestern and southern Australia, and California south to northern Baja California. These ecosystems largely occur along the western edges of continents between the 30° and 40° parallels in both northern and southern hemispheres.

There are several characteristics that define the Mediterranean biome. The Mediterranean climate is mild, with rainy winters and warm, dry summers moderated by cold ocean currents. Due to the limited extent and isolation (almost island-like) of each area of Mediterranean biome, there is frequently a high degree of uniqueness in the flora and fauna. Additionally, the Mediterranean regions typically exhibit high levels of biodiversity, while convergent evolution has led to similarities in the flora with evergreen shrubland dominant in each of the regions. Fire is an important natural process in most of the Mediterranean ecosystems.
Map of climate types in California The five Mediterranean-climate regions comprise only about 3% of the earth’s land area but account for 16% of the world’s plant species. In particular, the Cape Region of South Africa and Southwestern Australia show remarkable levels of species richness considering their relatively small areas. Twenty-five ecological hotspots, areas of irreplaceable biodiversity whose protection is of critical global importance, have been identified worldwide.

These designations are based on a large and unique diversity of organisms occurring nowhere else and on the extreme threat to these regions from human activities. While most of these hotspots lie in tropical forest regions of the world, the five Mediterranean-climate regions are included in this select group. Proportional to their area then, these five Mediterranean-climate regions have a greater significance in protecting global diversity than do the Amazon Basin and other tropical rainforests. Moreover, the five Mediterranean-climate regions face far greater immediate threats to their environments and biodiversity than rainforest areas.
The favorable climate of the Mediterranean regions makes these some of the most desirable areas to live. Consequently, there are multiple threats from human activities such as habitat loss and fragmentation from urbanization, agriculture, and recreation. Invasive species of plants and animals are dramatically altering ecosystems and biodiversity in all five regions, often combining with changing fire frequencies to cause vegetation alteration and type conversion. As a result, this ecosystem type  is one of the most highly altered on the planet and contains the least undisturbed area of any biome.

In the California Mediterranean region, the introduction of herbaceous exotics species, particularly annual grasses, has significantly affected vegetation dynamics and fundamentally altered the fire-ecology. Annual grasses increase the potential for fire by changing the type, distribution, and timing of available fuels. When coupled with increasing opportunities for fire starts associated with urbanization, a feedback cycle is introduced that can lower fire return intervals beyond the capacity for native species to recover. Significant species shifts and even complete loss of native vegetation can occur.
The Mediterranean ecosystem of southern California The fragmentation of natural habitat of the California Mediterranean ecosystem  jeopardizes wildlife populations and provides a point of entrance for non-native, often invasive, plant and animal species. Continued habitat loss and fragmentation threatens the long-term existence of many native species and is one of the greatest threats facing biodiversity in these regions. Larger mammals, such as mountain lions, bobcats, and badgers are particularly at risk, with populations reduced through isolation and habitat loss rendered vulnerable to extinction by chance demographic, environmental, and genetic events.

In the California Mediterranean region, many of the invasive exotic plants originate in the Mediterranean basin and northern Europe and have demonstrated superior competitive abilities in human-influenced environments. Alien species present a profound threat to the integrity of native communities through displacement of native species, degradation of wildlife habitat, and disruption of ecosystem function. 
 The Mediterranean ecosystem of southern California has been identified as one of the world's "hot spots" for biodiversity. Additionally, the southern California bight, an ecologically unique area of near-shore Pacific Ocean coastal habitat extending from Point Conception south and encompassing the San Diego area, provides conditions that promote high species richness and diversity.

The summers are so hot that there are frequent fires and dry spells. Consequently, the California Mediterranean ecosystem is dominated by fire-adapted shrubs, the most important being manzanita and chamise. Tall shrubs with leathery leaves or needles such as red shank, sage, mountain mahogany, Christmasberry, California scrub oak, and many different kinds of ceanothus are common

The animals that live in the California Mediterranean ecosystem have also adapted to the frequent fires and long dry spells, because they learned how to find water, and conserve it. These include invertebrates, birds, reptiles,and mammals such as Bewick's wren, California quail California striped racer snake, northern red diamond rattle snake, orange-throated whiptail lizard, pocket mouse, deer mouse, kangaroo rats, chipmunk, rabbit, fox, deer, coyote, lynx, and mountain lion.
 
 
Website Created by Website Creations

About us      Privacy Disclaimer      Advertisers     Contact Us     Bookstore    Sitemap     Search    Floridian Nature