by Doug Drynan, Vice President of Carrizo Plain Conservancy
It was a glorious fall day out in the Carrizo in mid-November as I made my way over to the Goodwin Ranch House to meet up with Bill and Camdilla.
Bill Buck is our Conservation Coordinator and Camdilla Wirth is with Sequoia Riverlands Trust (SRT) and serves as Conservation Biologist for their Carrizo Plain landholdings. Our field meeting was initiated to foster collaboration between our organizations and exchange information and ideas.
Our first target area was California Valley where a wildfire occurred on June 12 of this year. Bill was on the Carrizo Plain that day and captured some photos and video of the fire soon after it started.
The fire was quickly extinguished by CalFire, but not before it burned through several CPC and SRT parcels. Called the Bear Fire, it impacted a total of 1,410 acres in the California Valley area, southwest of the intersection of Arrow Bear Trail and Courtland Road. We were curious to see how the landscape looked months after this fire and if there was evidence of fossorial (burrowing) mammals recovery after the fire passed through and burned most of the surface vegetation.
We visited a few of the CPC-owned parcels that were adjacent to SRT lands. The blackened landscape, devoid of vegetation, revealed its secrets and we observed many small mammal burrows and trails that had previously been hidden under vegetation. Many of the burrows had large diameter openings and smooth interior walls that appeared to be created by giant kangaroo rats. This species typically has several horizontal burrows and one or two vertical shaft burrows, or “chimneys”, located more or less in the center of what is often described as a “precinct”.
In summer and fall, these precincts have distinctly clipped vegetation as a result of the kangaroo rat’s harvest. During this time, they stack cut grasses and forbs in “haystacks” to dry out the vegetation before clipping off the seed heads and taking them into their burrows where there are chambers for seed storage. The central chimney may serve to regulate temperature and humidity and keep the larder dry and free from mold.
The fire had obliterated the distinctive surface features that biologists often use to map out the distribution of the species across the landscape. However, we soon found the occasional burrow with fresh dirt kicked out of the entrance, a light brown splash on the blacked earth. It appeared that at least some of the animals had persisted post-fire and likely had enough seed stored underground to get them through to the next growing season.
Fire and its role in an ecosystem such as the desert grasslands of the Carrizo is an interesting and often controversial topic for land managers. From the historic presence of fire in this ecosystem (pre-European influence) when the area was likely dominated by sparser vegetation such as native perennial bunch grasses, to modern day fires primarily caused by people that now spread quickly by non-native annual grasses, there is much to learn and apply to land management. We discussed the possible historic role of fire in this area and if native tribes living in the region may have had an influence in using fires to their advantage.
The evidence of modern firefighting techniques was obvious on the landscape — a bulldozer scar where a control line was cut into the earth, and a bright red swath of color that was plastered to the vegetation from the remnants of a fire retardant drop. These are the results of a fire suppression system designed to protect lives and property. This is now a critical need in our modern world where we keep pressing the boundary of human development against the thin line of where we allow nature to thrive. What we strive to improve is the way we nurture and maintain those boundaries, to be resilient in the face of these events, and allow nature to quickly rebound in a way that enables plant and animal species to thrive in the current geologic epoch known informally as the Anthropocene.
At the end of our discussion, we had more questions than answers. We look forward to exploring fire as a potential management tool in the Carrizo and looking at the balance between fire frequency and intensity in maintaining ecosystem health.
Camdilla then took us on a tour of some of the northern Carrizo CPC-owned lands where SRT serves as the land manager, across from the California Valley Solar Ranch (CVSR) project site. These properties were purchased as settlement lands for the project and form a large block of more than 4,000 acres of open grassland habitat.
Back when I was a consultant and field biologist working on the CVSR project from 2010-2017, I conducted many reconnaissance surveys of this and other properties in the region that were targeted as mitigation lands for the suite of species that occurred on the project site. At the time, the Carrizo was experiencing an historic drought that ended around 2015. The giant kangaroo rat population had contracted during the drought, but then was in an early population expansion after 2016. We observed some fairly rapid population growth as the species re-occupied lands in a generally northward direction. In 2017, there was only a handful of giant kangaroo rats north of State Route 58 and none as far north as the settlement land parcels. This species is known to have boom-and-bust cycles as it takes advantage of high seed crops resulting from several years of abundant rain and high plant growth. In addition, they also need lands that are available for their expansion– that are protected from dry land farming or other ground disturbance that would impact their underground burrows or precincts.
I was thrilled and amazed to see the “bulls eye” pattern of clipped grass that generally define a giant kangaroo rat precinct when we drove through the heart of the preservation land parcels. This north and west expansion of the population on CPC-owned lands are a critical part of the establishment of a northern Carrizo population for the species. The cascading benefits of giant kangaroo rats in an ecosystem include providing subterranean refuge for a suite of other species and a prey base for predatory species such as San Joaquin kit fox, American badger, and burrowing owl.
Speaking of burrowing owls, Camdilla pointed out several artificial burrows that SRT recently installed on the CPC-owned parcels which provide release sites for a future owl re-location effort. An airfield operator has a need to relocate several pair of owls that occur adjacent to a runway where their presence is a risk to airplanes and to the owls themselves. CPC property will be a key part of the relocation strategy in providing suitable grassland habitat with a prey base of small mammals and insects on which burrowing owls depend.
It is critical to our mission to have lands protected in perpetuity for the benefit of plants and wildlife. A place where restoration and reintroduction efforts have the space to occur. Having enough land set aside for the natural ebb-and-flow of wildlife populations is paramount in providing for places where wildlife populations can retreat in hard times or expand in good.
For an overview of the northwest expansion of the giant kangaroo rat population see Camdilla’s presentation from the 2024 Carrizo Colloquium here: https://ecologistics.org/carrizo-colloquium
-Photos by Doug Drynan and Bill Buck
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