The focus of wildlife management is on the preservation of biodiversity. This means keeping a variety of ecosystems intact, protecting the species that occur within them and preserving adequate population numbers to insure genetic diversity.
With the development of conservation biology in recent decades the preservation of all wildlife, from fairy shrimp to mountain lions, has put increased emphasis on the importance of habitat. Every living thing has one, a combination of physical characteristics, such as elevation or soil type, and all the other species in the area. Animals and their environs are now understood to operate as a complex, location-specific web of life.
Managing open space in ways that preserve and improve natural habitats is a balancing act. Some factors such as invasive plant species need to be removed. Others like nesting boxes or ponds can be introduced. And still other factors, such as the presence of grazing livestock, need to be carefully managed and monitored. In addition, actions that encourage the development of one species may well depress the condition of another.
Those animals that have been granted special status by the state or the U.S. government represent a preservation priority. Three species federally listed as threatened that are known to occur on Authority lands are California red-legged frog (Rana aurora draytonii), California tiger salamander (Ambystoma californiense), and bay checkerspot butterfly (Euphydryas editha bayensis). A fourth, western pond turtle (Clemmys marmorata), is recognized as a species of special concern by the state.
California Red-Legged Frog
The largest native frog in the western United States, the California red-legged frog was once king of the mountain as Mark Twain’s The Celebrated Frog of Calaveras County attests. Measuring up to five inches in length, the frogs were a food source for humans during the nineteenth century.
When the frog supply began to decline, bullfrogs were imported to fill out the menu. Unfortunately, bullfrogs put red-legged frogs on their own menu and populations of the native species declined even further. With habitat loss due to urban growth, agricultural expansion, grazing, logging and the draining of wetlands, red-legged frogs disappeared from 70% of their historic range.
Deep, still ponds fringed by dense vegetation such as cattails and willows with grasslands nearby make ideal red-legged frog habitat. Ranch ponds and pasture lands can often be adapted and protected for this use. Streams and their adjacent plant communities may also support this species.
In 1996 the California red-legged frog was listed as threatened under the Endangered Species Act. The recovery plan includes reducing threats to existing populations, restoring and creating permanently protected habitat and reestablishing frog populations in suitable areas within its historic range. The Open Space Authority is a partner in achieving all these goals.
California Tiger Salamander
A species particularly adapted to the Mediterranean climate, the California tiger salamander requires wet season and dry season environments. During the rainy part of the year these salamanders breed in seasonal ponds. As the weather warms and the ponds dry up, they seek out the burrows of small mammals such as ground squirrels. Within this underground shelter they pass the hot months in a dormant state.
The strongest pressure on the California tiger salamander has been from habitat loss and fragmentation. Its main territory occurs from sea level to 1,500 feet in valleys and foothills that now are often next to large and growing urban areas. Preserving grasslands and oak woodlands of adequate size, maintaining and developing ponds within these areas, eliminating predators and monitoring for disease are the primary strategies in a recovery effort for this species.
Bay Checkerspot Butterfly
Listed as a threatened species under the Endangered Species Act in 1987, the bay checkerspot butterfly has been in long-term decline since the early 1980s. Historically the butterfly was distributed throughout much of the San Francisco Bay area, from Twin Peaks in San Francisco to Mount Diablo in the east bay to Hollister in the south. Currently only five core areas are known to support the butterfly, four of them in Santa Clara County.
Habitat loss due to urban sprawl and the introduction of invasive species are the main causes of the butterfly’s decline. Its life cycle is dependent on several native plants that are found in serpentine grasslands, a habitat of limited distribution. The unique chemistry of serpentine soils, which are high in magnesium, cobalt, chromium and other metals and low in calcium and other nutrients, supports a community of native plants that includes the bay checkerspot’s primary food source, dwarf plantain (Plantago erecta).
The decline in serpentine grassland habitat has undermined bay checkerspot populations throughout the bay region. A recovery effort will focus on establishing permanent protection for areas of serpentine grassland, eliminating invasive grasses through managed grazing, controlled burning, mechanical removal and other means, and reintroducing butterfly populations where appropriate. Lands owned and managed by the Open Space Authority will play a key part in this process.
Western Pond Turtle
Originally found from northern Baja California, Mexico, to Klickitat County in the state of Washington, western pond turtles are a federal species of concern and a species of special concern in California. Not being strong swimmers, these turtles prefer the quiet waters of slow-moving streams and rivers, lakes, reservoirs, drainage ditches, waste water treatment plants and, yes, even ponds.
The main threat to the western pond turtle is, once again, loss or degradation of habitat. Hatchlings are also vulnerable to predators such as raccoons, coyotes and raptors, and may be trampled by humans or cattle. Preservation and management of wetland and riparian habitats along with adequate surrounding land for nesting, basking and wintering are key to protecting this species.
A Word About Mountain Lions (Felis concolor)
Roughly half the state of California – nearly 80,000 square miles – is considered prime mountain lion habitat. The hilly and mountainous areas of Santa Clara County are included in that tally. Mountain lions are large, carnivorous mammals and require large hunting territories to maintain themselves and, in the case of females, their young.
The mountain lion population in the state is estimated to be between 4,000 and 6,000. An adult male’s range may be as much as 100 square miles; females tend to occupy smaller territories of approximately 20 to 60 square miles. In areas where competition for habitat is intense, ranges may be much smaller.
This cat, sometimes called cougar, puma, panther or catamount, is a solitary creature that prefers to hunt alone, often at night. Deer are the prey of choice for cougars, though they also hunt bighorn sheep, elk, smaller wild mammals and domestic animals.
Clearly these are two species that would both do better if kept apart. Instead, residential development in rural areas and outdoor recreation are likely to continue bringing cougars and humans together. Though lions pose a smaller risk to human safety than lightning does, it’s important for open space visitors to act in ways that minimize the chance of lion encounters.
Since research has found that solitary hikers are three times more likely to encounter a lion, hiking in groups is a reasonable precaution. Also, lions seem to be drawn to small children, so it’s important to keep them in reach at all times.
If you do see a lion, give it room. Maintain eye contact – Cougars perceive this as threatening. Try to appear large by raising your arms or holding your jacket open. Don’t run. Don’t crouch or bend over. Speak in a loud, firm voice. If the lion approaches, fight back. People have effectively defended themselves and others with sticks, rocks or whatever they could grab.
Report any mountain lion encounters on Open Space Authority lands by calling 408-224-7476.
The Tule Elk Story (Cervus elaphus nannodes)
One of the state’s greatest comeback tales is this shaggy California native’s rebound from near extinction. Tule elk are found only in California and once ranged from the foot of the Tehachapi Mountains in the south to Shasta County in the north and from the Sierra foothills to the Pacific Ocean. At their peak, there may have been 500,000 elk in the state.
The introduction of nonnative grasses took the first swipe at elk habitat in the late 1700s and early 1800s. This was followed by commercial hunting that by 1845 was exporting approximately 3,000 elk and deer hides a year from the state. But it was the discovery of gold that created a crisis. The demand for meat skyrocketed and by 1850 all the tule elk in the Sacramento Valley were gone.
To the state’s credit, protection efforts soon followed. In 1854 elk hunting was restricted to six months of the year and it was banned entirely in 1873. A careful count of surviving elk in 1895 revealed that after 22 years of protection, just 28 animals were left.
At this point Henry Miller of the Miller and Lux ranching empire stepped in and began actively protecting elk on his land. Of the more than one million acres Miller owned, a favorite place was the summer home he built at the top of Mt. Madonna. The house burned down but the site is preserved within Mt. Madonna County Park.
The animals protected by Miller formed the core of the species’ recovery. There are now approximately 3,800 elk in the state. In 1978 California Fish & Game introduced 32 animals to the Mt. Hamilton foothills. Santa Clara County now has its own population of tule elk that range freely in the eastern foothills. Protection of this species and its habitat is an OSA priority.