Kern County: California’s Biodiversity Hotspot

Let’s face it. When we think of Kern County, nature is one thing that really doesn’t come to mind. Endless rows of orchards, the strange sprawl of Bakersfield, and boring 85-mph drives along the I-5 corridor yes, but wildlife and biodiversity, not so much… Until about a month ago, I have to say that I agreed with that perception too.

Well, it turns out that Kern is one of the state’s most significant biodiversity hotspots. The county itself contains many of the diverse habitats we associate with Central and Southern California and also contains a host of unique species, with many endemics to boot. To best illustrate the biodiversity of this place, I think a bit of geography lesson is in order.

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Kern County is bounded on the west by the Temblor Range (1), which mark the Eastern edge of the Carrizo Plain National Monument. This area is geographically and biologically a part of the California Coast Range, but also displays significant influence from the desert ranges of the Mojave further South. While there is plenty of classic Chamise chaparral and oak woodland in these mountains, Ephedra is also a dominant component of the vegetation of these hills, something you may not expect. Add to that an eclectic mix of animal species such as Le Conte’s Thrashers, Canyon Mouse, Interior Sage Sparrow, Yellow-backed Spiny Lizard, Townsend’s Big-eared Bat, Cougar, and possibly even California Mountain Kingsnake and you see that this is a very unique habitat.

Just to the East lies a significant expanse of remnant Central Valley grasslands (2). Here, some of California’s most endangered mammals cling on, like Giant and Tipton Kangaroo Rats, Tulare Grasshopper Mouse, Nelson’s Antelope Squirrel, San Joaquin Kit Fox, and American Badger. Rare birds such as Mountain Plover, Ferruginous Hawk, Prairie Falcon, Mountain Bluebird, and Vesper Sparrow survive here too in some of the last pockets of their range. Further to the east is the complex of National Wildlife Refuges (Kern and Pixley) that protect  the last partially intact marshland in the Southern San Joaquin Valley. This is where Yellow-billed Cuckoo, Buena Vista Lake Shrew, and Burrowing and Short-eared Owls survive alongside some of the state’s rarest plant species.

The Southern edge of Kern is marked by the dramatic Tehachapi Mountains (3). This area holds distinct races of more common Sierra Nevada species, such as Sooty Grouse and Lodgepole Chipmunk. Mt. Pinos and Tejon Ranch in particular serve as a bridge between the montane habitats of the Sierra Nevada and the transverse ranges of Southern California. But this area also holds another extremely rare endemic – the Tehachapi White-eared Pocket Mouse. I have been lucky enough to observe this species in the wild near Cameron Canyon on Tehachapi Pass.

Further to the North lies another maze of mountain ranges that constitute the Southernmost extension of the Sierra Nevada (4). North of Lake Isabella and West of the Kern River lie the Greenhorn Mountains, an area that holds the Southernmost Giant Sequoias in California and small populations of the very rare Pacific Fisher. East of the Kern River is the Kern Plateau, a remote elevated region of the Sierra Nevada that shelters California’s Southernmost White-tailed Hares, Short-tailed Weasels, and the Sierra Nevada’s Southernmost California Spotted Owls. Even Porcupines are present in this remote mountain wilderness. To the south of Lake Isabella are the Piute and Breckenridge Mountains, a remote area where the endemic Piute Cypress is found. The Kern River itself is a marvelous hotspot for birds (some of California’s rarest, such as the Least Bell’s Vireo, occur here) while the Kelso Valley to the South is an otherworldly landscape where Joshua Trees occur among winter snows. Walker Pass is truly a meeting of East and West, where Singeleaf Pinyons and Foothill Pines grow on the same soil and Large-eared Woodrats scurry alongside the extremely localized Yellow-eared race of Great Basin Pocket Mouse.

Below the Mountains and the last region of Kern County is the Mojave Desert (5). Rare Desert Kit Foxes, Pronghorn, and American Badgers cling on here, alongside Desert Kangaroo Rat, Long-tailed Pocket Mouse, and Western Mastiff and Spotted Bats. The rarest species here is the endangered Mojave Ground Squirrel, which is still losing habitat to related species due to urbanization and solar energy development. The region’s most famous species, the Desert Tortoise, still survives in healthy numbers, at least for the time being… The Mojave is one of the most irreplaceable yet fragile parts of Kern County.

As part of my travels across California, I searched for mammals in Kern County last May. On the trip, I encountered many surprises, both positive and negative. The Tehachapis were full of life. In a couple of hours around Tehachapi Pass and Cameron Canyon, I saw 2 local Agile Kangaroo Rats, a couple of Panamint Kangaroo Rats, and 2 very rare Tehachapi Pocket Mice. I was expecting them to be near-extinct in this area following extreme drought conditions 2013-15 and decent (but not substantial enough) rainfall this winter. This is one of California’s rarest mammals and I’m probably one of only a handful of non-scientists to have seen this species.

I then visited Desert Tortoise Natural Area in Fremont Valley in the Mojave Desert. Kangaroo Rats were abundant (seems like the normally arid Mojave got decent rains). Merriam’s and Panamint Kangaroo Rats were everywhere, and I even saw a couple of the normally rare Desert Kangaroo Rats and one each Desert Kit Fox and Little Pocket Mouse. The Kit Fox in particular was a great sign, as these elusive carnivores require pristine areas of desert with abundant rodents. The next morning, I had a bit of shock however as I found that the Mojave Ground Squirrel, once common in this area, was now near-extinct following catastrophic drought conditions over the last couple of years (this translated into very little breeding). It took me 2.5 hours of hiking outside the reserve to briefly see 2 animals at a distance. The population within the reserve was apparently extinct, with no sightings by the reserve’s caretakers for months. I did however see a Desert Tortoise (apparently populations of this species were also depressed) within the reserve. Hopefully the ground squirrels are still doing ok at Little Dixie Wash near Inyokern/Indian Wells.

Hope you enjoyed a close look at one of California’s most underappreciated and little-known places. There’s always more to explore in this amazing state!