The Mediterranean  Biome

This biome actually goes by several names.  It is found surrounding  large parts of the Mediterranean Sea and is thus sometimes called the Mediterranean Biome, others call it a Woodland Biome, while others call it a Shrub or Chaparral Biome. 

Chaparral Community near Malibu, California

Chaparral Community near Malibu, California

Climate:  

In the "modified" Whittaker diagram shown here, the woodland/shrubland biome is found from areas with just over 100mm of rain per year to around 20 mm of rain per year; average annual temperatures range from below zero to about 20 C.  Looking at the map below, however, it is hard to imagine any of those sites being as cold as this diagram would seem to indicate.  In general, this biome is found clustered around the 30 north or south latitude line.  These are the latitudes where warm, wet air rising from the equator has cooled, dropping its moisture over the equator.  The air mass then spreads out from the equator and at these latitudes falls to the ground as very dry air.  In many parts of the world this forms deserts, but in the Mediterranean Biome the presence of an adjacent body of water, often with cold waters, offsets the dryness of the falling air to some extent.  Often the precipitation that does fall is largely restricted to a few months in the relatively warm winter, and the summers may be very hot and dry.

 

 

 

 

 

 

 

World Distribution:  

As already mentioned, this biome is most frequent from 30 to 40 north or south latitude (see map).  The largest cluster is in the Mediterranean basin, but significant areas of this habitat exist also in South America, the western coast of southern Africa, California, and in the southwestern tip of Australia.

 

 

 

 

Indicator Plant Species:

Plants adapted to this biome tend to be less than a meter tall, and relatively shrubby in appearance.  They have many of the characteristics of desert plants - adaptations to help them survive the hot dry summers.  Many are annuals, flowering briefly after winter rains, then surviving the dry summer in the form of seeds.  The perennial forms tend to have evergreen leaves, but the leaves are often small.  The may be curled, with the stomata hid among numerous hairs (trichomes) on the bottom, concave side of the leaf.  Here the stomata are protected from the hot sun and the drying winds.  Many of the plants will contain numerous volatile chemicals such as turpentine; these chemicals deter herbivores (growth may be slow in such a climate and investment in chemicals to deter herbivores is more beneficial than it would be in a climate where new leaves can easily be grown).  Many of these chemicals burn fiercely and the plant communities are termed pyrogenic for their ability to burst into flame.  Needless to say many species are fire resistant, either by virtue of underground roots or thick heavy bark such as the cork trees in the Mediterranean.

Indicator Animal Species:

This biome is interesting in that, like the desert, most of the animals are small and/or nocturnal.  Large animals simply can't stand the heat of day in many of these locations, and it's hard for a large animal to burrow.

 Mediterranean Gecko - Hemidactylus turcicus

Mediterranean Gecko - Hemidactylus turcicus

 

 Left:  The Mediterranean Gecko is a nocturnal insectivore of the Mediterranean Biome.   It has been introduced to similar climactic areas around the world and is living in the southeastern United States as well.

Ecological Notes:  

 

Wildfire in Hacienda Heights, California

Wildfire in Hacienda Heights, California

Wildfire in Hacienda Heights, California

Wildfire in Hacienda Heights, California

Fire is one of the key elements of this ecosystem.  Many members of the community rely on the fire to suppress larger competitors from shading them out; usually the large competitors are not well adapted to fire conditions (the Cork Oaks in Spain are an exception, the Live Oaks of California are not).  Fire, whether caused by humans or by natural means (lightning), controls the community.  As mentioned above, many of the plant species have high concentrations of flammable materials in their leaves, so once a fire starts it quickly spreads.  The plants with the high concentrations of flammable material also usually have adaptations to deal with fire - heavy bark, root systems that can sprout new shoots quickly after a fire, seeds that can survive fires, etc.  

Wildfire in Hacienda Heights, California

Wildfire in Hacienda Heights, California

 

Threats:

 

Cork Oak, Quercus suber

Cork Oak, Quercus suber

 

Cork Oak, Quercus suber being harvested

The biggest threat to the woodland biome is development.  A warm climate situated near the coast is desirable as a living site, and many people are moving to such areas.  Los Angeles and San Francisco (see below) are both examples of expanding cities built in this biome.  As cities spread, all too often native plant and animal communities are replaced.

Ironically, it is an extractive practice that holds some promise to protect these habitats.  As mentioned above, the cork oak, Quercus suber, grows in the European and North African part of this biome (left).  These areas are also under pressure for development, but the presence of a cork plantation can provide the owner with enough economic incentive to maintain the land in cork oak - and thus protect the other plants growing in the shade of the oaks.  While the cork plantations here are certainly not virgin habitat, they are better than subdivisions!

What does Marietta College know about cork?  Quite a bit it seems.  When I was pressed for some more information to fill out this page, I naturally thought of the Jelinek's.  Henry and Cathy Jelinek graduated from Marietta in the late 1960's, and Henry now runs the family business - The Jelinek Cork Group, which imports and produces cork products.  More to the point, daughter Karina (Keena) graduated from Marietta in 1996 with a degree in biology.  I dropped Keena an email, and later that day she got back to me with these pictures from the company website.  If you want to learn more about the Jelineks, cork, cork products, and cork harvesting, try these websites:

   http://www.marietta.edu/~lead/center/jelinek.htm

   http://www.jelinek.cz/ow/english/Default.htm

    http://www.jelinekcork.com/what_is_cork.html

http://www.jelinek.com/articles/virginbark-a1.htm

http://www.corkhouse.com/harvest.html

 

 

Cork Oak, Quercus suber  in plantation.

Cork Oak, Quercus suber  in plantation.  The "3" means the cork was stripped in 2003; it will be harvested next in 9 years.

 

Workers stripping cork from the tree.

Worker stripping cork from the tree - note how thick the bark is.  In the natural ecosystem, it is this bark which protects the tree from  fire.

 

Workers stripping cork from the tree.

Workers stripping cork from the tree.

 

Cork Oak, Quercus suber

Cork Oak, Quercus suber

Cork Oak, Quercus suber

Cork Oak, Quercus suber

Cork Oak, Quercus suber on Cattle Ranch, Portugal

Cork Oak, Quercus suber on Cattle Ranch, Portugal

Here are some more pictures of cork trees and cork production.  Above, you can see 2 views of cork trees growing in a fairly natural setting.  When cork production can be done in this setting, a fair proportion of the ecosystem can be preserved while still extracting monetary value from the land.  To the left, cork trees are shown growing on a cattle ranch in Portugal.  While this has more of an impact on the environment, it's still better than selling the land for subdivisions.  Below, the stacked cork gives some idea of the amount of cork that can be harvested without hurting the trees.  Thanks to Keena and the Jelinek Cork Group for the photos.

 

Tree with stripped cork.

Tree with stripped cork.  The smaller branches are not stripped.

 

Tree with stripped cork.

Tree with stripped cork.

 

 

Tour:

Chaparral Community near Malibu, California

Chaparral Community near Malibu, California

Angeles National Forest

Angeles National Forest

We don't have a lot of pictures of this biome.  Despite having lived in Los Angeles, I just didn't take many pictures while I was there, and I'll have to dig through my old slides to see if there is anything worthwhile among the pictures I did take.  In the meantime....

Above is Chaparral near Malibu, a picture very similar to one in a major textbook.  This is right off highway 101 in Malibu.  You can see the shrubby nature of the vegetation.  In the background is the Pacific; sea fogs rolling in from the Pacific keep the vegetation along the coast moister than it would be further inland.  To the right, above and immediately right, are two views of the Angeles National Forest.  I like the trees in the Angeles National Forest, especially the one on the right.... Actually, in both these views you can again see the shrubby nature of the vegetation, although both pictures were taken high enough up in the San Bernardino mountains that a transition to a more coniferous forest is underway. The city of Los Angeles itself is hidden somewhere under the smog in the distance of the picture to the right.

Los Angeles, from Angeles National Forest

Los Angeles from Angeles National Forest

San Francisco - Downtown, Alcatraz, Angel Island

San Francisco

San Francisco - Golden Gate Bridge, Presidio, Marin County

San Francisco

San Francisco - downtown, Alcatraz

San Francisco

San Francisco is near the northern end of the Mediterranean Biome along the California coast.  The 2 images of the city itself don't tell you a whole lot about the biome, other than development is obviously a threat.  At the top of the image above left you can see Angel Island, which is in a semi-natural state.  Likewise, on the Marin County (far) side of the Golden Gate Bridge in the image above, you can see some natural vegetation in its natural color - brown, in this June photo.  

The photos above were taken on the western Costa Rica coast at a beach called Playa Nancite.  The habitat inland is a temperate seasonal forest, but on the hills overlooking the ocean there was a change to a different vegetation type, which, to my untrained eye, resembles Mediterranean Biome vegetation - low and shrubby.  

As mentioned earlier, Keena Jelinek (MC 1996) provided us with the pictures of the cork oaks and the woodland habitat in Portugal where they are found.  We'll end up here with some pictures of Keena and her family (minus their newest addition - congratulations!)

 After graduating, Keena worked at a software company that automated diet offices of hospitals/nursing homes, etc. Keena says: "The nutrition course I took at MC along with my volunteering at the Marietta hospital and some of the other bio. courses helped me with my experience in the nutrition field. They hired a lot of RDs so having the background definitely helped me with my job! But that's where I veered away from biology. I ended up in the computer field. I went and worked at Sun Microsystems in Colorado and got my Masters degree in technical communications. After a few years with a big company, I decided I wanted to work for a smaller company again and so that's how I ended up in the field of cork. Since Marietta, I've never really left the field of computers."  Marietta College offers a liberal education, and what that really means is that we try to teach students how to think and learn for themselves. We're proud that graduates like Keena can use their education to pursue careers even in fields removed from the majors they studied in college.

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