California ground squirrel behavior and ecology

Monterey Bay

The environment has clearly been impacted by human habitation. We recognize the damaging effects of much of modern life, but there has been a human impact on the environment extending back much further in history. The concentration of the human population into certain areas had an effect on the ecology of those areas on several levels, from the amount of food the population required to the effect of smoke from fires, waste disposal, clearing of ground for housing or agriculture, conflicts with other species in the area, and so on. The Monterey Bay region has long attracted human populations and has shown the effects of the human presence for centuries. The effect can be seen continuing today, indeed being accelerated today as the human footprint has expanded greatly in the area. Governments in the region have taken steps to protect the environment, notably by the creation of the Monterey Bay National Marine Sanctuary, one of the largest protected marine areas in the world.. Still, the region faces a number of environmental threats caused by human action. The region is also home to a number of plant and animal forms that can be endangered by changes in the ecology. The way human ecology has impacted the region over the centuries can be described, followed by some analysis of the life of the region today and the threats perceived by various observers.

Monterey Bay

Monterey is found on the Monterey Peninsula, 120 miles south of San Francisco, 60 miles south of San Jose, and 345 miles north of Los Angeles. The peninsula is bordered by Monterey Bay to the north, the Pacific Ocean to the west, and Carmel Bay to the south. The area is marked by cool, dry summers and wet winters, though the different regions of Monterey County show considerable climatic diversity. The warmest months are July through October, the rainiest November and April, and summer months are often foggy, especially early and late in the day, because of the chilly and unchanging water temperatures of the Pacific Ocean.

Today, the Monterey Bay National Marine Sanctuary (MBNMS) is a Federally protected marine area offshore of California's central coast and extending from Marin to Cambria, encompassing a shoreline length of 276 miles and 5,322 square miles of ocean. This area supports one of the world's most diverse marine ecosystems, home to numerous mammals, seabirds, fishes, invertebrates, and plants. The MBNMS was established for the purpose of resource protection, research, education, and public use and is part of a system of 13 National Marine Sanctuaries administered by the National Oceanic and Atmospheric Administration

The Central Valley of California was originally an extension of the Pacific Ocean and was open to the sea at San Francisco. The region has been filled with sediment from the western slope of the Sierra Nevada. Wrapped around the Central Valley along the coast from Santa Barbara to Monterey Bay are areas of mixed open forests of live oaks and pines. The coast from Monterey Bay northward is the home of the redwoods, the world's largest trees. This is also a protected area, though it is as well a major tourist attraction that brings many people through the Monterey Bay region.

Native American Populations

Human habitation in the region has a long history, and a number of California Indian tribes are associated with the region, among them the Bear River, Mattale, Lassick, Nogatl, Wintun, Yana, Yahi, Maidu, Wintun, Sinkyone, Wailaki, Kato, Yuki, Pomo, Lake Miwok, Wappo, Coast Miwok, Interior Miwok, Wappo, Coast Miwok, Interior Miwok, Monache, Yokuts, Costanoan, Esselen, Salinan and Tubatulabal tribes. These tribes had an abundance of corn and salmon for their diet as well as such game as deer, elk, antelope, and rabbit, all in the region north of Monterey Bay. A common feature of the tribes in this area was the use of the semi-subterranean roundhouse where elaborate Kuksu dances were held and are held to this day. These are rituals intended to assure the renewal of the world's natural foods both plant and animal.

Like everywhere else, in California, villages were fiercely independent and governed internally, the abundant food supply allowed for the establishment of villages of up to 1000 individuals, including craft specialists who produced specific objects and goods for a living. In smaller communities, each family produced all that was necessary for survival. In this region as in other parts of California, the tribal villages were fiercely independent and governed internally. They also had an abundant food supply, which allowed for the establishment of villages of up to one thousand individuals. In smaller communities, each family produced all that was necessary for survival, while in the larger communities, craft specialists would produce certain objects and goods needed by the village. Such large populations would have had some impact on the local ecology, though the abundance of food was such that the human population would not have depleted resources to any great degree beyond clearing areas for villages.

The human imprint would increase considerably with the coming of European settlers. The Spanish entry into California created tension with the Indian population and led to numerous Indian revolts. The Spanish responded with the mission system, organized by Junipero Serra and military authorities under Gaspar de Portola. As one writer notes,

Despite romantic portraits of California missions they were essentially coercive religious, labor camps organized primarily to benefit the colonizers. The overall plan was to first militarily intimidate the local Indians with armed Spanish soldiers who always accompanied the Franciscans in their missionary efforts. At the same time the newcomers introduced domestic stock animals that gobbled up native foods and undermined the free or "genitle" tribes efforts to remain economically independent. A well established pattern of bribes, intimidation and the expected onslaught of European diseases insured experienced missionaries that eventually desperate parents of sick and dying children and many elders would prompt frightened Indian families to seek assistance from the newcomers who seemed to be immune to the horrible diseases that overwhelmed Indians.

Much of the land was taken from the Indians and was subject to more intense farming and the taking of other resources. The European population had a major impact on the native population as well with the introduction of diseases such as smallpox, syphilis, diphtheria, chickenpox, and measles, leading to the deaths of countless Indians around the Spanish population centers. Even before that, there had been a reduction in population caused by the unhygienic environment of the Spanish population centers, and a numb er of disease epidemics further cut into the population. As much as sixty percent of the Indian population may have died as a result of these disease epidemics. The ecological damage was considerable to the Indian population and the environment as well:

The impact of the mission system on the many coastal tribes was devastating. Missionaries required tribes to abandon their aboriginal territories and live in filthy, disease ridden and crowded labor camps. Massive herds on introduced stock animals and new seed crops soon crowded out aboriginal game animals and native plants. Feral hogs ate tons of raw acorns, depriving even the non-missionized tribes in the interior of a significant amount of aboriginal protein. Murderous waves of epidemic diseases swept over the terrified Mission Indian tribes resulting in massive suffering and death for thousands of native men, women and children.

The Mission system and the communities that grew around the missions were certainly detrimental to the ecology of the region.

Current State

The Monterey Bay region benefits from a lower population density than is found to the north near San Francisco. There are population clusters at the northern and southern ends, but generally the south Coast Ranges are virtually empty. Larger settlements can be found only along the El Camino Real. The plains around Monterey Bay and the valleys of the Salinas, Santa Maria, and Santa Ynez rivers feature lettuce, carrots, other truck crops, and dairying as significant industry, while livestock ranching dominates the countryside. Tourists flock to Hearst's Castle at San Simeon and to the chain of missions along Highway 101, but otherwise, this is largely a country through which people travel on their way to or from Los Angeles and San Francisco.

Such travel has a harmful effect on the ecology of the region by polluting the air from the thousands of automobiles traveling through the area. To address the issue, the Monterey County Board of Supervisors created the air pollution control district in 1965, and in 1968, Santa Cruz County joined Monterey County to form a two-county unified district. In 1969, the state designated the three counties of Monterey, San Benito, and Santa Cruz as the North Central Coast Air Basin, and in 1970, the federal Clean Air Act formalized the responsibility of state and local governments to manage air quality in their regions. In 1974, Monterey and Santa Cruz County Unified Air Pollution Control District merged with the San Benito County Air Pollution Control District to form the Monterey Bay Unified Air Pollution Control District. This entity follows the California Clean Air Act and the Federal Clean Air Act so that it is responsible for air monitoring, permitting, enforcement, long-range air quality planning, regulatory development, and education and public information activities with regard to air pollution.

A more recent concern has developed as the first cruise ship to enter Monterey Bay since 1966 caused environmental groups to demand increased protection for marine sanctuaries and to increase regulation of the cruise ship industry. The water around Monterey Bay has also been affected by sewage spills at local beaches, leading to viral and bacterial contamination. In 2000, four Monterey County beaches were closed because of sewage spills, and twenty-five warning advisories were issued. In 2001, there was one beach closure and eleven advisories. It has also been found that there is inadequate storm pipe maintenance in cities on the Monterey peninsula.

The California Ground Squirrel is a large animal about 383-500mm (18 inches) long, including the moderately bushy tail. The tail is longer than half the head and body length. The squirrel has a general gray-brown coloration mottled or dappled with lighter flecks on its back, and a mantle or darker gray band of color extends from the head down and over the middle of the back. The squirrel's shoulders and the sides of the head are light gray, and there are rarely any stripes. This squirrel is distinguished from other ground squirrels in California by its large size, dark mantle, and usual lack of stripes. The habitat for the California Ground Squirrel covers many plant communities in all the life zones from the coast into the mountains, from southern California to central Washington. Nine ground squirrels are native to California, and it is known that when different squirrels live in the same area, their eating preferences will vary enough to prevent active competition for the same resources. The California Ground Squirrel lives in open spaces and can commonly be found along roadsides, in fields of stubble, or I well-grazed pastures. They are found in the western half of southern California and northwestern Baja California, normally below about 7200 ft. In elevation.

Some damage has been noted for Monterey Bay's kelp forests. These forests consist of giant kelp that can soar 100 feet or more from the ocean floor and that provides habitats ranging from tiny, seafloor caves to dense golden-green canopies just below the water's surface. At each level, creatures big and small find their own niche, such as brittle stars and sculpins within the kelp's holdfast, a root-like structure that anchors the plant to rocks and boulders. In the filtered sunlight of the mid-water region, turban snails and crabs graze on the kelp's thick stipe and are, in turn, grazed upon by lingcod and schools of rockfish. Sea otters swim amid the kelp's upper fronds. These forests require a unique set of conditions to thrive, including hard, rocky seafloors, high concentrations of nutrients, moderate waves, and clear, clean ocean water. The Monterey Bay National Marine Sanctuary spans 350 miles along the central California coast and stands as one of just a few regions in the world that provides the conditions necessary to support kelp forests. Even though this is a protected area, the sanctuary today faces a number of persistent challenges, such as undersea noise from military and commercial operations and even small motorized craft like Jet Skis. These can disrupt marine mammal communication. The area is also subject to pollution from sewage leaks, spills, rain runoff, and the dredging of nearby harbors. The human threats are clearly numerous. The nature of the pollution threat is evident from a 1966 analysis of coliform bacteria off Del Monte Beach:

Determination of the distribution of coliform bacteria in the vicinity of the outfall effluent of the Monterey Water Pollution Control Plant was made using the membrane filter technique for enumeration. The coliforms were seen to follow the onshore mass transport of water in the surface layer in response to predominately westerly winds. The extent of penetration of coliforms into the bay north of the outfall is restricted to several hundred yards, while more extensive spreading was observed towards the surf zone. No consistent pattern of variation of the coliform distribution would be related to the tidal cycle. Higher concentrations of coliform bacteria on several occasions seemed to be related to reduced periods of solar radiation.

The problem has increased since that time as the population has also increased in the area.

Intermittent problems occur from time to time and threaten the ecology of the region as well. One such incident was in 1997 when a substance in the bay disabled some 400 birds. The problem dissipated on its own in a few days and was tentatively identified as a hydrogenated vegetable oil. The source of this substance was not known. It affected the feathers of near-shore birds and made it impossible for the birds to fly. Birds also depend on their feathers for insulation, so oiled birds are vulnerable to hypothermia. The problem was worse for birds already weak from their migratory flight from the Arctic.

Land Animals

The area surrounding Monterey Bay contains a variety of wildlife in the various parks and rural regions surrounding the bay. Many of these creates have also been impacted by the population and pollution in the area.

One such animal is the California Ground Squirrel, which is diurnal and ground-dwelling. Some species of ground squirrels become torpid (metabolism slows down) when food is scarce, and most use stored fat for energy during estivation (during the summer or dry season when the animal is in a torpid state) and hibernation (during the winter when the animal is in a resting state). Ground squirrels usually breed soon after emerging from hibernation and make their nests in the ground or in rock piles. The California Ground Squirrel has a gestation of a month, usually with one litter per year and an average of seven young per litter. The diet for these animals includes a broad range of seeds, berries and leaves of grasses, forbs, and wood plants, as well as bulbs, tubers, insects, and road-killed carrion. They have internal cheek pouches and use thee for transporting food to their burrows. In areas where the number of squirrels is high, their activities, burrows, and food preferences may cause problems for ranchers and farmers. Predators can control squirrel numbers and include coyotes, foxes, wildcats, badgers, large hawks, the golden eagle, and gopher snakes.

Several problems have been cited concerning these animals. Many species of ground squirrels carry fleas, and the fleas can transmit a bacterium responsible for plague. In wild rodents, this plague is called sylvatic plague, and when it is transmitted to humans by the fleas, it causes bubonic plague and pneumonic plague. Campgrounds warn when ground squirrels have tested positive for plague. Health officials dust the openings of burrows with flea powder to reduce the flea population, and prudent behavior calls for leaving the squirrels and other wild animals alone.

The California Ground Squirrel can actually be an indicator of problems because of its being a host for the etiologic agents and vectors of many diseases. These animals serve as subjects for research into the prevalence of certain ectoparasites. The widespread distribution of California ground squirrels is considered significant because their burrows also serve as habitat for California tiger salamanders and California red-legged frogs, and both the California Ground Squirrel and the red-legged frog require animal burrows, principally ground squirrel burrows, in upland areas away from the aquatic environment of streams. Protecting this environment also helps protect the populations of these animals. Observations in Kings Canyon National Park show that there is a prevalence of the California Ground Squirrel and Belding's ground squirrel as well as four species of chipmunks. The greatest threat to these animals is considered to be water pollution, air pollution, loss of natural fire regime, and habitat fragmentation. The most serious air pollution is ozone, which is produced when pollutants from industry and automobiles are heated by sunlight. In 2001, the park recorded more days with unhealthy levels of ozone than any other national park, standing at 61 days. Ozone harms vegetation as well, and the pine trees in the area are especially susceptible so that 90% of the pines in the Giant Forest are show some ozone damage. While Sequoia trees are more resistant, some believe that ozone affects the survival of seedlings. Acid deposition is not yet a problem but could become one as the population in the region increases. Nitrogen deposition is already increasing, probably because of motor vehicles, industry, and agriculture. More nitrogen is being retained in the vegetation in the park. Another threat is from agricultural chemicals such as organo-phosphates and PCBs, which become suspended in the air as particulates and are then deposited in the park. Some scientists believe this harms the wildlife in the park. Pollution has also been contributing to a reduction in visibility. An additional problem caused by human action has been an increase in exotic flora and fauna, and some exotic plants not native to the region have been taking over local areas, destroying diversity. The area has also been plagued by exotic wildlife, such as an exotic beaver that is now resident in the park, feral cats, and feral pigs, with the latter ruining the soil.