USC Dana and David Dornsife College of Letters, Arts & Sciences

Many residents of Southern California are unaware of the growing threat to the California coastal sage habitat. This widespread ecosystem ranges from central to southern California. The habitat is known for its high species and soil biodiversity as it houses a wide range of organisms and diverse soil levels. This region is threatened by human and agriculture expansion and consists of diverse habitats that range from forests to woodlands to grasslands and salt marshes.  Because of this variety of habitats, the soils in these regions have to be able to support the growing habitats and ensure their survival.

The eco-region of the coastal sage habitat is home to about 200 species of butterflies, the widest range of native bees in the United States, and a wide variety of other organisms that rely on this region for their home. The California legless lizard and the rosy boa are just some of the reptiles and amphibians that belong to this certain Southern California region. The Channel Islands also take part in this eco-region, but because they are isolated, they house certain rare plant and animal species that are only native to that island.

Because of anthropogenic development, native habitats in this region are threatened. Human air pollution, specifically smog, reduces production and growth in the environment. When humans introduce outside species, such as sheep, cattle, and deer, their grazing and physical presence on the land reduces the productivity and fertility of the land. Agricultural practices do not allow for healthy regrowth of the soil and plants. Only about 15% of the coastal sage habitat is intact because of the growing expansion of agricultural lands and housing. Human invasion of this land has altered the physical makeup of the region enough to affect the organisms that live on and in the soils. Invasive plants, brought in by humans, displace native species, which change the flora and fauna of the specific eco-region.

Since humans have started to develop the land, the larger habitats are divided into smaller regions. These small habitats are more vulnerable to outside threats of animal and human predators. Humans use processes such as grazing, herbicides and burning to convert the land to their specifications. However these methods alter the soil composition, which affects the organisms that live in the soil and the organisms that rely on the soil. These unfamiliar conditions destroy the native seed beds and organisms within the soil, which negatively impacts soil productivity. Unhealthy soil leads to overall ecosystem degradation.

Because of these huge environmental impacts and risks, conservation ecology is crucial to preserve this eco-region from becoming extinct. Not only are the organisms threatened, but the diversity of the soil relies on the preservation of this coastal sage habitat. Many humans are only concerned with development and expansion, but for human society to thrive, the environment surrounding humans needs to thrive as well. With population increasing, we can’t ignore human needs, however there has to be a balance between human and environmental needs. Destroying this coastal sage habitat threatens the ecosystem services that communities depend on, such as water, oxygen from the wide range of trees, food, and other vital resources.  There needs to be a bigger focus on soil preservation and protection of organisms in this region because many of them are so rare and specific to this coastal sage region. Without this eco-region, a whole group of organisms would become extinct. We might not even know the benefits of all of these organisms, and to destroy them in order to expand our agricultural land, would be a huge loss to this treasured habitat in Southern California.

Links:

http://www.eoearth.org/article/California_coastal_sage_and_chaparral

http://www.laspilitas.com/nature-of-california/communities/coastal-sage-scrub

http://audubon2.org/watchlist/viewSpecies.jsp?id=57

http://www.ncbi.nlm.nih.gov/pubmed/10801992

http://www.treesearch.fs.fed.us/pubs/27020

http://www.jstor.org/pss/3235887

Chantal Morgan and Alanna Waldman are undergraduates in the USC Dornsife College of Letters, Arts and Sciences.