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Home » Santa Clarita News » Environment » SCV Outdoor Report » SCV Outdoor Report: Edge Effect

SCV Outdoor Report: Edge Effect

By Wendy Langhans


What effect will insecticides have on this bee?

Wendy Langhans is speaking as a private citizen of Santa Clarita, not as a member of the City of Santa Clarita’s Opens Space Preservation District Financial Accountability and Audit Panel nor as a volunteer for the Mountains Recreation and Conservation Authority.


The meeting room was packed with mammals defending their territory.


Last week, I attended a meeting at City Hall on One Valley One Vision’s Draft Land Use Element. According to the city’s website, “The Draft Land Use Element reflects the City’s as well as the County’s objectives and policies for responding to planning trends and urban growth patterns in this Valley for decades to come.”


Several speakers came to the microphone to speak (growl?) about protecting their neighborhoods, including several from Placerita and Sand Canyon.  Their concerns are certainly understandable.  Land use changes have consequences that can easily “spill over” into nearby areas.


In natural areas, ecologists refer to these changes as the Edge Effect : “a general term for a variety of impacts to natural communities across a boundary with a modified landscape, such as agricultural fields or urban development.”  


A view of the wildlife crossing under the I-5, near East/Rice Canyon.

Common sense tells us that these edge effects are more pronounced when the natural area is small and narrow, like a wildlife corridor.  Consider what a housing development adjacent to a wildlife corridor could do:


• Light and noise pollution will disrupt the hunting patterns of nocturnal animals such as owls, bats, bobcats, and mountain lions.

• Introduced predators such as domestic and feral cats will prey upon small mammals and birds.

• Seeds from non-native and/or invasive landscape plants will spread into nearby areas and compete and/or hybridize with native plants.

• Insecticides and herbicides will be carried into the natural areas by the wind.

• An increase in rodents (due to increased food supply from garbage, etc.), will lead to a decline in native wildlife. In addition, pesticides will travel up the food chain and poison predators such as owls, hawks, mountain lions and coyotes.


On July 30, the LA County Regional Planning Commission will be considering the Lyon’s Canyon Project. This housing project is adjacent to Towsley Canyon, a core habitat and part of the wildlife corridor between the San Gabriel and Santa Susana Mountains.  Portions of Lyon’s Canyon have been designated by the County of Los Angeles as a “Significant Ecological Area”.


Spotted Towhees are ground nesting birds, vulnerable to predation by rodents and domestic cats.

Can you imagine the scene if that meeting room were packed with mammals from the Santa Clarita Valley defending their territory?  My how the fur would fly!

Upcoming Outdoor Events:  


Wildlands of the Santa Clara River Watershed.  Wednesday, July 23 through the end of August. Valencia Public Library.  Come to the library to see a visual and educational exhibit about our Santa Clara River Watershed and the 100 endangered, sensitive or threatened species that live in our valley.
Sponsored by South Coast Wildlands, Visual Journey’s and the Santa Clara River Trustee Council.

Free lecture on the history of Native Americans in the Santa Clarita Valley.  Saturday, July 26, 2:00 PM.  Room 318, Mentry Hall, Valencia Campus, College of the Canyons.  Dr. John Johnson, Curator of Anthropology at the Santa Barbara Museum of Natural History, will present a talk on Native Americans in the Santa Clarita Valley.  Sponsored by the Santa Clarita Valley Historical Society and the College of the Canyons.  Directions:  Park in the South Parking lot off Rockwell Canyon Road, then proceed to Mentry Hall.  For a map, click here.


Trail Maintenance Volunteers at Towsley Canyon.  Saturday, July 26th, and every Wednesday, 8:00 am.  Come join our trail maintenance volunteers for camaraderie and a heart-thumping workout.  For more information contact Steve Ioerger at or at 661-291-1565.  Sponsored by the Mountains Recreation and Conservation Authority.

You can listen to stories like this every Friday morning at 7:10 a.m. on "The Hike Report", brought to you by your hometown radio station KHTS AM 1220 and by the Mountains Recreation and Conservation Authority.


For the complete MRCA hike and activity schedule and for trail maps, click here.

SCV Outdoor Report: Edge Effect

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