Longcore, Travis. 1997. Western Tanager 63(8):1-2.

The Endangered Delhi Sand Dunes

Sometimes one finds the unique and wonderful in the least expected places. Such is the case with the Delhi sand dunes. Picture yourself driving west on Interstate 10 from Los Angeles. Remember the flag on the remains of a mountain to the south as you drive through Rialto and Colton? That pile of granite is the remains of Slover Mountain, which has been mined for limestone by California Portland Cement for over 100 years. Just to the south, past the rail yard and the giant trucks hauling Slover Mountain away bit by bit, and surrounded by junkyards and tank farms, is the largest remaining expanse of the only inland sand dune system in the Los Angeles basin, the Delhi sand dunes.

The dunes were created as the Santa Ana winds blew down over the Cajon pass and picked up the sand in Lytle Creek and other smaller tributaries and deposited it over approximately 35,000 acres. The dunes extended from the creeks to the Santa Ana River and Jurupa Hills to the south and extended across the Ontario plain into Loma Linda.

An appreciation of the dunes is an acquired taste. One has to block out the distractions that surround the approximately 250 acre fragment, ignore the landfill and water treatment plant operating to the south, ignore the house-sized dump trucks of limestone, and ignore the junkyard. Then, one starts to notice the Western Meadowlarks singing and the extravagant flowering of the spring annuals. One sees the Burrowing Owls near their nest not twenty yards from the thundering trucks. The place really is alive. If you are so lucky as to accompany a mammalogist, the nighttime reveals a diverse and thriving small mammal population. Harvest mice and wood mice abound, but also the Los Angeles pocket mouse, a tiny buff-colored creature who fits easily in the palm of your hand, cheeks stuffed with the oatmeal from the live trap. The coastal race of the pocket mouse is already listed as endangered and the Los Angeles pocket mouse is equally imperiled.

The vegetation is sparse and open sand blow-outs are common. After the winter rains the annual wildflowers carpet the dunes with the yellow and blue of goldfields, primrose, phacelias and woolly-stars. Later, the shrubby wild buckwheat blooms and comes alive with butterflies, including the flashy Bernardino blue and an undescribed subspecies of Mormon metalmark. An occasional grizzled old Cholla or Ceanothus or buckthorn are the larger shrubs scattered across the more pristine areas. As the summer progresses the spring annuals die out but the straight stalks and yellow flowers of telegraph weed shoot up to add color. Pringle's monardella, a wildflower once restricted to the dunes, has gone extinct.

Perhaps the most famous resident of the Delhi sands comes out in the heat of summer. Cruising the buckwheat flowers for nectar in July and August is the Delhi sands flower-loving fly. This large fly, which can hover like a hummingbird as it nectars with its long proboscis, is found only on the Delhi sands. Another race formerly found on the El Segundo dunes is now extinct. Adults emerge from underground, where they lived their larval stage and pupated, to mate and lay eggs in the sweltering dog days of summer. Like all of the residents of the Delhi sands, the fly has suffered an enormous loss of habitat as European settlers first developed the sands for citrus and grape agriculture, then later urban pressures converted much of the land to industrial and residential use. Only 2% of the historic extent of the sands remains as open land, and less than that is undisturbed. Having been faced with such loss in habitat and population size, and with remaining portions of the dunes subject to imminent development, the Delhi sands flower-loving fly was listed in 1993 as an endangered species.

Needless to say, a fly does not make a charismatic endangered species. To the contrary, it has become a cause célèbre for forces who would weaken or dismantle the Endangered Species Act. But what seems to be lost in the polemical discussions about "Flies Over People" is that through protection of the fly, it may be possible to save the remaining portion of the Delhi sands and the life that they support. As an indicator of ecological health, the fly is no more or less important than the Meadowlarks or the Burrowing Owls, both of which have also witnessed declines as their habitats have been developed for urban uses. Without the fly, these species would be incrementally diminished as the Delhi sands are destroyed. It is for this reason that conservation biologists refer to species like the fly as "umbrella species" as they protect other species under their habitat umbrella.

Unfortunately, the fly's umbrella may be closing under political pressure. Only about 7.5 acres of the 250 acre contiguous fragment of the Delhi sands is protected. Other scattered, isolated fragments free from future development pressure amount to under 20 acres The city of Colton, within whose boundaries the largest contiguous remnant of the Delhi sands is found, proposes to develop -- of all things -- a paper recycling complex on about 150 acres of the remaining Delhi sands, fragmenting the remaining areas from one another. The City has offered to protect 85 acres in exchange for this habitat destruction. Whether this proposal is successful or not the development pressures will remain and grow because of the perception that it is "just a fly" that lives on the Delhi sands. But the Delhi sands are home to much more than flies. As UCLA lecturer Dr. Rudi Mattoni put it in a newspaper account of the fly controversy, "It's the habitat, stupid!"

There are some rays of hope. The volunteer group Rhapsody in Green has been restoring a four-acre Southern California Edison right-of-way under the direction of Dr. Mattoni. Their efforts include volunteers from Los Angeles as well as many local families, and energetic high schoolers. The project serves both to restore the habitat and to educate about its unique fauna. Hopefully, government agencies and elected officials will work toward saving and restoring the remaining Delhis sands, rather than presiding over the destruction of this unique and wonderful habitat.