Unique Landscapes of the California Deserts

By Duncan Bell

This year the Rare Plant Treasure Hunt made it to many places across our amazing California deserts updating many old rare plant occurrences and at the same time recording a great deal of new rare plant occurrences. Finding so many new rare plant occurrences is a constant reminder that our deserts are not fully explored and in a very large way are still greatly unexplored. Every day we spent in an unexplored/uncollected canyon or wash bottom we found at least one if not dozens of new rare plant populations, and it was also always a joy to find old rare plant occurrences still were they had been documented decades ago. In total we found hundreds of old and new rare plant populations.

In our explorations we came across many unique landscapes. Some of these landscapes were for the most part pristine with almost no sign of human disturbance while others had been greatly disturbed and are in need of better management and conservation planning.

Mecca Hills

The Mecca Hills was one such location where in many places the landscape appeared pristine but in sections, especially in the southeastern section of the hills, there was a great deal of illegal off road activity and garbage dumping. The Mecca Hills are a very unique landscape as it was formed by the colliding of the North American Plate and the Pacific Plate along the San Andreas Fault causing large twisted walls of sedimentary rock to form labyrinthian canyons that if not careful one can get lost in.

This unique habitat is the only place where mecca aster (Xylorhiza cognata) is found. The southeastern section of the hills had a few historic rare plant occurrences of Xylorhiza cognata but for the most part this region has seen little botanical documentation and is in need of exploration. While looking for these historic occurrences we happened upon several other rare plant populations in the area, not just of the Xylorhiza cognata but also of hairy sand verbena (Abronia villosa var. aurita). Some of these rare plant populations were mostly out of harms way and occurred in relatively inaccessible areas on the canyon walls and cliff faces, but others populations unfortunately were found in highly disturbed areas in the wash bottoms and on the canyon floors.

Jacumba Mountains

In 2012, several trips were made to the Jacumba Mountains which has a very impressive landscape were cactus and pines meet among large boulder piles. Every stop that was made and every canyon explored presented a great deal of rare plant information, some old and some new. On the upper slopes a number of locally endemic species were found while at the foot of the mountains an undescribed subspecies of Linanthus was found.

The Jacumba Mountains and surrounding area is currently feeling the strain from the massive amounts of border activity from both the U.S. and Mexico side as well as a large scale wind project currently being erected at the foot of the range.

Castle Mountains

This year the Rare Plant Treasure Hunt was able to take volunteers out to the Castle Mountains, not just in the spring but in the summer as well. If one really enjoys an area then one should experience that area during all seasons. This summer the California deserts saw a lot of monsoonal storm activity and the amount of rare plant populations found in the east Mojave following these storms was staggering. The landscape in and surrounding the Castle Mountains is beautiful and unique as there are large sections of grassland which is rather uncommon in the California deserts. The Castle Mountains also have some of the largest and thickest stands of Joshua tree woodland in California which makes for some very impressive scenery.

The Castle Mountains are managed by the BLM and it has been a concern that the area may be given over or opened up for energy development. Luckily many people see the beauty and uniqueness of this mountain range and work is currently being done to add this range to the Mojave National Preserve which would give it and its native flora and fauna the protection that it needs. With its diverse geology and unique placement in the desert the Castle Mountains have a great deal of rare plant species, some near endemic meaning they are found largely here and nowhere else. This mountain range has had some botanical exploration done but a good deal of the area has been relatively unexplored and it was great to get into some of those unexplored canyons of the area during several different seasons and collect a plethora of rare plant information to assist in the future conservation of the area. The Castle Mountains, and the other locations mentioned above, are truly special and unique places.