Home to important plant and animal species, this mountain and its spectacular views face threats from climate change, wildfires, and the border wall.

The Place:

Located just north of the U.S.-Mexico border in San Diego County, Otay Mountain is the highest summit within the San Ysidro Mountain range at 3,568 feet (1,087 meters). This rugged habitat is part of an ancient chain of volcanos creating the foundation of fertile metavolcanic soils that support numerous rare plant species and plant communities of coastal sagebrush and chaparral.

Why it matters:

Otay Mountain is a unique ecosystem and home to many sensitive plants and animals, including the largest stand of Tecate cypress trees (Hesperocyparis forbesii), which is the host plant for the imperiled Thorne’s hairstreak butterfly (Callophrys gryneus thornei), whose larvae feed on young Tecate cypress stems. Only five very small populations of the butterfly exist following the fires here in 2003 and 2007.

Photo courtesy San Diego Zoo Wildlife Alliance

A few other important plant species on the mountain include:

    • Mexican flannelbush (Fremontodendron mexicanum)
    • Otay manzanita (Arctostaphylos otayensis)
    • Otay Mountain ceanothus (Ceanothus otayensis)
    • Otay Mountain lotus (Hosakia crassifolia var. otayensis)
    • Cleveland’s bush monkeyflower (Diplacus clevelandii)
    • Southern mountain misery (Chamaebatia australis)
    • Gander’s pitcher sage (Lepechinia ganderi)
    • Chaparral pea (Pickeringia montana)

Meanwhile the mountain is also home to several species of sensitive fauna:

    • California gnatcatcher (Polioptila californica)
    • Orange-throated whiptail (Aspidoscelis hyperythrus)
    • Coast horned lizard (Phrynosoma coronatum)
    • Bighorn sheep (Ovis canadensis)
    • Mountain lion (Puma concolor)
    • Southern bald eagle (Haliaeetus leucocephalus)

The threat:

While it’s protected from development, Otay Mountain is not safe from wildfires or the impacts of the U.S.-Mexico border wall. The construction of roads and grading have negatively affected the sensitive habitat. Migrant camps can degrade habitat and increase fire risk, and the heavy border patrol presence adds to pressures on the land. So does other off-road activity, as this has become a popular OHV destination.

Photo courtesy San Diego Zoo Wildlife Alliance

Climate change also has a detrimental effect and has increased fire frequency. Fires can be particularly destructive to Tecate cypress. Although it does benefit from fire for seed germination, burned trees do not re-sprout from the roots and may take a decade to become mature enough to produce cones and longer to reach peak reproduction. An increase in fire frequency prevents the Tecate cypress from building up a healthy quantity of cones amongst its branches, limiting their ability to bounce back from back-to-back fires.

The habitats in general are prone to degradation with increased fire frequency. Fires offer more opportunity for erosion, invasive grasses to take over, and other effects.

My place in this place:

This mountain has high biodiversity, particularly for rare plant species. The Native Plant Gene Bank Collection, which I oversee, gathers rare plant seeds here for long-term conservation. We began collecting seeds from plants (rare or not) in 2006 and to date we have more than 65 collections from the area.

Photo courtesy San Diego Zoo Wildlife Alliance

I love visiting this mountain. The views as you approach the peak, which are accessible to the public via Minnewawa Truck Trail or Otay Truck Trail, are spectacular. On a clear day you can see the rural foothills east of Tijuana into Tecate, Otay Lakes to the Pacific Ocean, and suburban San Diego. The roads can be quite rugged, with steep drops into canyons. In addition to the views, these steep hillsides will be awash with color from the many plants that comprise the coastal sage scrub or chaparral bloom profusely in the spring. You’ll also observe the skeletal remains of large Tecate trees that burned during the most recent fire.

Exploration is better on foot, and there are various paths leading through the habitat.

Who’s protecting it now:

The Otay Mountain Wilderness is a designated U.S. Wilderness Area under the Wilderness Protection Act and has been managed by the Bureau of Land Management since 1998, effectively preserving 18,500 acres. California Department of Fish and Wildlife also protect 1,200 acres of the nearby Otay Mountain Ecological Reserve. There are other property boundaries that are managed by other local government or privately owned entities.

What this place needs:

The legal protections for the land are important but insufficient. Protected areas can’t safeguard against climate change and fire; nor are they very effective against border impacts. Otay Mountain needs active management and increased awareness. This ecosystem needs funding support from the federal legislature to help BLM do weed management and clean up illegal camps, make seed collections to conserve diversity, and provide a resource to reseed post-fire. Supporting government funding of our “green infrastructure” helps the land managers with these needed management actions.

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Previously in The Revelator:

Species Spotlight: Renewed Hope for the Charismatic Thick-Billed Parrot

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Stacy Anderson

serves San Diego Zoo Wildlife Alliance as a research coordinator in plant conservation. In this role she leads the efforts of the Native Plant Gene Bank to collect seed from wild plant populations as part of Alliance’s efforts to make conservation collections to support wild plant populations in San Diego County. Stacy’s current focus is participating in the California Plant Rescue Initiative, a consortium of regional botanic gardens and seed banks working in a concerted effort to conserve rare and threatened wild plant species of California.