SOUTHERN CALIFORNIA
CHAPARRAL

 The greatest threat to this ecosystem is humans, more importantly the misconceptions many of us hold about it.  Our interference as well as this lack of knowledge about the ecosystem has led to many harmful practices, most notably man-made fires, both intentional and unintentional, and clear-cutting, which have caused the population of the Southern California Chaparral to rapidly decline.  

 

Perhaps the primary and most dangerous misconception we have about Chaparral regards fire.  It is commonly believed that the Chaparral ecosystem is dependent on fire - that it needs flames in order to survive and thrive.  This is only partially true - while Chaparral evolved with the naturally occurring fire in the Mediterranean climate, it is actually very sensitive to blazes that happen in intervals of 15-20 years ("Chaparral Facts," n.d.) - any fire-return frequency higher than that has serious effects on certain keystone plants including ones that don't have the resprouting capabilities of other Chaparral plants ("Chaparral Facts", n.d.).  Before human contact with this area, fires generally burned in intervals of 30-150 years, but this has increased in frequency, and human-ignited fires now typically occur in intervals of 20-30 years ("Chaparral Facts", n.d.).  One example that depicts the devastation that human-ignited fires cause is the Cocos Fire in San Marcos.  This past May, a swarm of fires came through San Diego County and spread quickly due to a heat wave and the added effects of Santa Ana Winds.  The Cocos fire, which is now believed to have been intentionally set by a teenager, burned nearly 2,000 acres and destroyed close to 40 homes, costing the city of San Marcos over $10 million.

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

This drastic increase in the frequency of fires can be directly linked to the increase in human population that has taken place as people have come here to live in the beautiful mild climate of Southern California, which can be seen in Figure 4 (Keeley & Fotheringham, 2000).  Many people still refuse to believe that this high frequency of fire is detrimental to the ecosystem, asserting that Chaparral which doesn't burn within 50 years becomes unproductive and would eventually be taken over by foreign grasslands (Keeley, 1992).  It was found that this was actually false, and that chaparral still proves to be productive even after 100-year intervals without fire, which is shown in Table 1 (Keeley, 1992).

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

However, since this misconception is still so prevalent, many dangerous practices have arised, most notably that of prescribed fires. Since many people view chaparral as dangerous fuel for homes and other ecosystems, prescribed fires have been used in an attempt to rid the environment of this threat in a controlled manner.  However, prescribed fire itself can be dangerous, if not handled correctly, and if used in the hot, dry seasons can have devastating effects.  There have been multiple instances where these prescribed flames have escaped human control, perhaps the most notable in recent California history is the San Felipe escaped fire, which occurred in May of 2013 and burned 2,700 acres of protected land after a prescribed fire escaped human control in the San Felipe Valley Wildlife Area ("Chaparral Facts," n.d.).  If this practice is used in the cooler seasons where there is an excess of moisture in the plants, it can lead to immediate type conversion, which is exactly what happened to the Pinnacles National Park in the 1980s ("Chaparral Facts", n.d.).

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

The image above showcases the frequency and location of fires in the Santa Monica Mountains from 1925-2007 ("Santa Monica Mountains," n.d.).  As you can see, fire affects a very large area of the mountains, with many places having burned at least 3 times in the span of 82 years - an average of one fire per 27 years, a frequency which proves to be harmful for the Chaparral ecosystem.

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Another harmul human activity is the practice of clear-cutting for both development and as a way to protect ourselves and other ecosystems from the potential for fires that comes with the dry and woody Chaparral.  Because of its location and climate, the chaparral ecosystem is a highly desirable area to develop.  As a result, urban sprawl enroaches upon chaparral land, causing a loss of biodiversity within the ecosystem.  Often with urbanization comes the introduction of non-native plants for landscaping.   Introducing non-native plants and weeds into the ecosystem has caused the population of native chaparral plants to diminish on a large scale, which has in turn lead to soil erosion in some areas.  Clear-cutting is the act of cutting down and removing every tree and plant from an area.  This unsurprisingly leads to type-conversion, but also causes isolation and fragmentation of plant and animal species, and increases soil erosion (Hogan, 2014).  A new practice has been introduced for the purpose of decreasing the population of "fuel" chaparral: goats.  In the hills of Oakland, Berkeley, Monterey, and Malibu, goats have been used to safely and effectively remove the fuel-load during the 6-month fire season.  However, this practice also has its risks - unsupervised and unregulated grazing of the chaparral by livestock also has adverse affects on the ecosystem.  One astounding example is that of the Santa Cruz islands, whose population of coastal sage scrub now only covers a mere 6% of the island due to 130 years of feral sheep grazing (Hogan, 2014).