Westridge Oaks Preserve

Area: 167 acres as part of the 800-acre Westridge Valencia residential development.

Location: Santa Clarita, Los Angeles County, California

Date Acquired: 2016

Acquisition Type: CNLM does not own this Preserve, but we hold a conservation easement to permanently protect its conservation values.  Also, we have entered into a management agreement for the long-term management of the ecological features on the Preserve.

Key Habitats: Valley oak savanna; Coastal sage scrub; California annual grassland.

Species of Special Interest to CNLM:  Valley oak (Quercus lobata) and valley oak savanna, a declining vegetation type and  Southern California rufous-crowned sparrow (Aimophila ruficeps ssp. canescens).


The Preserve was established in 2002 as partial mitigation for the 800-acre Westridge Valencia residential development.  In Los Angeles County, ‘Significant Ecological Areas’ have been defined that represent rare or ecologically important remaining natural areas.  The valley oak savanna on this Preserve protects significant habitat of the same type that was impacted by the residential development.  In 2013, CNLMwas granted a conservation easement which permanently protects the conservation values on the Preserve.In the same year, CNLM entered into a management agreement in order to protect the natural ecology on the Preserve through science-based, perpetual management.

Conservation Significance

The valley oaks on the Preserve are of scientific interest and particular ecological value because they are growing near the southern extent of the species’ geographic range.  As such, they would be expected to display some genetic differentiation from other parts of the species range—evidence for which has been provided by genetic studies. In particular, the southern extent of the range may have some diversity that could be valuable in the context of rapid climate change—offering research opportunities for better understanding the species’ ability to persist in warmer/drier environments and germplasm that may be adapted to those conditions.

The coastal scrub and annual grassland provide habitat for a variety of sensitive wildlife species including the southern California rufous-crowned sparrow.

Our Work

Our current conservation strategies include (1) collecting baseline ecological information to guide future management, (2) stabilizing the valley oak population after many oaks on the Preserve died during the severe 2012-2015 drought, and (3) determining long-term management goals in the context public use and a changing climate.  Guided by the scientific data we are collecting on the Preserve, we will begin to plant locally collected acorns to replace trees that died during the drought, to ensure the oak population remains healthy.

Public Access

This Preserve is currently closed to public access.  However, in the future the Preserve will be transferred to a multi-agency management authority, and then it will become open to the public for recreational and educational activities that is consistent with preservation of the Preserve’s conservation values.  For information and inquiries, please contact Preserve Manager, Greg Warrick. Email:  gwarrick@cnlm.org


For information  about Westridge Oaks Preserve or the Center for Natural Land Management, please contact Greg Warrick, Preserve Manager at gwarrick@cnlm.org or 760.731.7790 extension 202.