Throughout my life, I’ve spent quite some time in the Rancho Pensaquitos Canyon Preserve; from summer to winter: tromping through brush at Outpost summer camp, hiking to the waterfall, and wading (and eventually jumping into) the creek when the sun gets a little too hot. But I think that this patch of wildlife jigsawed into our suburban sprawl is especially remarkable for its impressive biodiversity and the glimpse into history the landscape offers.
KPBS called San Diego the “most biodiverse place in America,” meaning that despite the way that humans have changed the landscape, there is a wide variety in all of the living organisms in the habitats and ecosystems across San Diego. Surprisingly, Canyonside Community Park, an outlet of the preserve, is part of the California Floristic Province, which is a biodiversity hotspot with at least 1,500 endemic vascular plants. An endemic species is native to and found only within a specific geographic area, and nowhere else in the world. Canyonside alone supports over 500 species of plants, five being both endemic to San Diego and classified as endangered.
Animals are just as important to biodiversity and Ebird.org lists 48 bird species found in Canyonside alone. There, the Western screech owl can be seen 166 times more frequently than the regional average. Basically, looking for owls in Westview’s backyard can give you dramatically higher chances of seeing one than in most nearby places in California. And while you’re there, Penasquitos.org lists 21 different species of animals at the park, not including the 10 different species of bats!
Beyond today’s variety of flora and fauna, the Los Penasquitos Canyon is also the namesake for the area as well.
More than 150 million years ago, the coastline was further east and the current areas of Peñasquitos Canyon, Carmel Valley, and Del Mar Mesa were underwater. But coming into the end of the Upper Jurassic period (around 164 million years ago), as water moved west to follow a receding coastline, evidence in the oldest rocks in the canyon, called the Penasquitos Formation, lends to the theory that sediments found in the canyon today were carried by a large river before they were deposited. Our canyon helps scientists understand the way water moved through our area at that time as studies carried out in the canyon indicate that the gravels and cobbles originated in an area near present day Sonora, Mexico, and the river transported them to the present location. The water and sediments that flowed through these areas created canyons or “little cliffs,” which still exist at the waterfall in Canyonside Community Park. According to Penasquitos.org, “Peñasquitos” means “little cliffs” in Spanish—therefore, “Rancho de los Penasquitos,” Ranch of the little cliffs.
And as geologic processes continue to deposit sediment into the canyon, this means that Peñasquitos Creek continues to carry sediment not only from miles away, but also from millions of years ago. If you visited Canyonside during this winter like I did, you may have noticed that with the season’s heavy rains, the banks had overflowed. When this happens, those sediments are deposited on the floodplain. So if you took this opportunity as I did to swim in the freezing creek, swimming with the literal tops of trees just below you, then you might be equally jazzed to hear that you could be swimming with remnants of sediments from Sonara, Mexico, or sediment brushed up from 150 million-year-old rock.
Between the evident biodiversity and rich history, I feel much pride for the immensely unique environment nestled in our corner of San Diego, and an appreciation for the history that we’re lucky to have so easily accessible.
If some of what I said in this article sounds absurd, that you may’ve never seen so many or such kinds of animals, or that you doubt the credibility of the rock formations, I encourage you to go out and take a look for yourself. In the words of Anthony Bourdain, “If I’m an advocate for anything, it’s to move. As far as you can, as much as you can. Across the ocean, or simply across the river.” I urge you to wade across that river (or in this case, creek), and I’m confident you’ll like the world you find yourself in.
