Blue Oak Ranch Reserve Biodiversity's News

March 07, 2014

FACTS AT A GLANCE

Administering Campus: University of California, Berkeley

Established: 2007

Location: Santa Clara County, 11.2 km (7 mi as the crow flies) east of downtown San Jose. Approximately 30 minutes drive from the closest freeway (CA-680) via the Mt Hamilton Rd. entrance.

Size: 1,319 ha (3,260 acres)

Elevations: 454- 870 m (1,489’ - 2,855’)
Mt Hamilton summit: 1,280 m (4,200’)

Average Precipitation: at Mt Hamilton, Lick Observatory 598 mm (23.54 inches)

Average Temperatures: at Mt. Hamilton, Lick Observatory
January: 2.5°C (36.5°F) to 8.8°C (48.3°F)
August: 16.6°C (62.2°F) to 25.5°C (78°F)

Facilities: none available at this time, day use only. There is a network of roads to reach most areas within the property.

Databases: ArcGIS data library, airborne and satellite imagery for Mt. Hamilton Range, Google Earth KML for boundary, species list (vertebrates and plants), bibliography, climate records for Mt. Hamilton and San Jose.

Personnel: On-site Reserve Director; Reserve Steward; UCB Faculty Director

Contact Information:
University of California
Blue Oak Ranch Reserve
23100 Alum Rock Falls Road
San Jose CA 95127-1317

INFORMATION@BLUEOAKRANCHRESERVE.ORG

The majority of Blue Oak Ranch Reserve (BORR) lies within the Upper Sonoran Life Zone. Approximately two-thirds of is drained by tributaries of Arroyo Aguague, itself a tributary of Coyote Creek (via Penitencia Creek), which flows into the southern San Francisco Bay. The streams and the 17 ponds on the ranch represent Sensitive Aquatic Resource Areas and are the habitats where most of the rare species such as the river otter, California tiger salamander, foothill yellow-legged frog and the red-legged frog are found. Riparian areas are also utilized by more than 10 species of neotropical migratory birds including flycatchers, warblers, and vireos. The bowl shaped Arroyo Aguague catchment area is characterized by steep wooded slopes and meadows, and open flats dotted with oaks and coyote brush (Baccharis pilularis). The precipitous Arroyo Hondo is heavily wooded on north and east-facing slopes, while western and southern exposures consist of open grassland or dense chaparral patches. Four species of oak dominate the landscape: blue oak (Quercus douglasii), valley oak (Quercus lobata), black oak (Quercus kellogii), and coast live oak (Quercus agrifolia). Foothill pines (Pinus sabiniana) occur only in the Arroyo Hondo and on the slopes above its confluence with North Creek. Chaparral patches occur on many south-facing and some west-facing slopes. Grasslands are mainly dominated by exotic annuals, but some native perennial grasses are present.

Habitats at Blue Oak Ranch Reserve supports around 130 species of birds, approximately 41 species of mammals, at least seven species of amphibians, more than 14 species of reptiles, around seven species of fish, and hundreds of species of invertebrates. Plant communities include blue oak woodland, valley oak woodland, black oak woodland, coast live oak woodland, riparian forest, chamise chaparral, Diablan sage scrub, nonnative annual grassland, wildflower field, and native perennial grassland. Four of these are threatened plant communities: valley oak woodlands, blue oak woodlands, wildflower field, and native perennial grasslands. Streams on the ranch support healthy stands of riparian vegetation in addition to aquatic species. They are important habitat for migratory birds, and may be migratory corridors for numerous aquatic and terrestrial animal species.

There are 73 vascular plant families at BOR. Of the 462 taxa of vascular plants on the ranch, almost 80% are native. Blue and valley oak woodlands have become quite rare in California, and few are protected from grazing and the encroachment of suburban development. Oak woodland covers a large extent of BOR, much of this is composed of blue and valley oaks. Compounding the possibly bleak future for oak woodlands is the lack of recruitment of young oaks. In the Mt. Hamilton area, valley oaks seem to be suffering most from this problem. The exact mechanism or mechanisms preventing oak regeneration is not known, but protection from pigs, cattle, and ground squirrels has been shown to increase survivorship of existing seedlings. Prescribed fire may also help by opening canopies and reducing competition between grasses and seedlings. However, fires must be carefully controlled for low heat, and conducted at frequency intervals that allow seedlings to become established. Physiological research suggests that ozone may extend stomata opening in blue oak, forcing nighttime transpiration during periods of drought and influencing shorter leaf retention. Oaks, as the most widespread and representative forest and woodland species in California, offer excellent research opportunities for climate change and pollution-effects research.

Selected Research: As one of the newest NRS Reserves, Blue Oak Ranch Reserve is now at the beginning of its legacy for field research. While the property has never officially operated as a coordinated field study site as have the other NRS reserves, it does nonetheless have an extensive amount of information and data collected by academic scientists and land managers over the years, resulting in very complete biotic inventories, surveys of invasive species, rare and endangered species surveys and studies, soil surveys, archeological sites, mapped GIS layers, and documented history of land uses. Past and ongoing resource management activities are well documented including feral pig removal, prescribed burns, and invasive plant removal. Most of the data resources were developed and collated in collaboration with the Nature Conservancy to validate the property for its conservation values, and to establish the Conservation Easement.

Field Courses and Public Outreach: A tremendous amount of excitement is building for field use of BORR in the upcoming first year of operation. A survey of faculty at both Berkeley and Santa Cruz campuses indicates that nearly 50 faculty will be planning to bring their field course to BORR, as well as initiate research projects in the upcoming year. While the management of BORR will certainly accommodate day use visits, it will be following the development of new facilities in 2009 that the full range of use of BORR for teaching, research and public outreach will swell to its capacity.

Posted on March 07, 2014 06:44 AM by infomgr infomgr | 0 comments | Leave a comment

CULTURAL RESOURCES

A History of Blue Oak Ranch Reserve
Jeffery T. Wilcox
12/01/2000
edited by Michael Hamilton

The first recorded inhabitants of what is now the Blue Oak Ranch Reserve (BORR) were Werwersen Ohlone Indians, who were resident for at least part of the year. According to Santa Clara County Parks historian Ron Bricmont (pers. comm.), the largest settlement was to the south, in Hall's Valley. Rob Edwards (1984) reported evidence of a large village site in the flats south of where the barn now stands. There is further evidence of habitation in the middens at West Pond, the spring east of Gramps' Pond, and the confluence of Village Creek and North Creek. Bedrock mortars exist on the west side of the ranch, south of West Pond, and on the east side north of the Sawtooth.

The present-day Blue Oak Ranch Reserve occupies what was a portion of a large former Mexican land grant called Rancho Canada de Pala. The grant was approximately 16,000 acres and included the Blue Oak property, most of what is now Joseph Grant County Park, and other small holdings. (The origin of the name Canada de Pala is the subject of debate. The word pala translates as "shovel" in Spanish, but means "water, in many Native Californian dialects. Two chieftains by the name of Pala were known to early Spanish missionaries in California; the land grant may have been named for one of them.)

Jose de Jesus Bernal, a Mexican citizen, became the Rancho Canada de Pala grantee on 9 August, 1839 (Gudde, 1960) and inhabited the land for many years, building a house and raising cattle and horses. Benal maintained his title to the land right through the period when the United States wrested Califonia from Mexico in 1846. When the U.S. government passed the Federal Land Act of 1851, which required all landowners to file claims or lose their rights to land grants deeded under the former Mexican government, Bernal pursued his claim. Legal fees and court costs from fighting other settlers' claims on the land plied up, eroding Bemal's finances and plunging him into debt. As so many grantees were forced to do, he began selling parcels to pay his legal fees. A very large parcel was deeded to Benal's attorney, Frederick Hall, to pay for processing his claim. (Hall went on to acquire large holdings in Rancho Canada de Pala, and eventually built Mt. Hamilton Road.)

Benal won his claim to the property in 1868, but his holdings had shrunk considerably in the process; between 1850 and 1880 as many as six different families raised cattle and subsistence-fanned the area now known as the Blue Oak Ranch. The foundation of the Guerraz family home is still visible near the Windmill Gate. The cabin built by Amos White, who purchased land from Bernal in 1859, still stands today. Joseph D. Grant, son of a wealthy San Francisco merchant, began buying most of the land in the area, and by 1900 owned most of what had been the Rancho Canada de Pala land grant, as well as other, contiguous lands. Grant used the property for grazing cattle, recreating, and hunting game. He also offered his deer-hunting cabin (which was located near the Sawtooth above Deer Creek) and the White cabin to friends such as Leland Stanford and Herbert Hoover. (Hoover stayed in the deer-hunting cabin for more than a month after his election loss to Franklin Roosevelt [Ron Briemont, pers. comm.].)

Joseph D. Grant died in 1942 . In the years after his death, his heirs sold off about half of his land (Ron Bricmont, pers. comm.). When his last remaining heir (daughter Josephine Grant McCreary) died in 1972, she bequeathed what remained of the land to the Save the Redwoods League and the Menninger Foundation of Kansas. Santa Clara County purchased the land in 1975, and created Joseph D. Grant County Park. The park currently occupies approximately 10,000 acres, the northern boundary of which is contiguous with BORR.

From about 1940 to 1960 the lands now constituting the ranch were held by a few families engaged in livestock raising and subsistence farming. In the 1960s the lands were purchased by the MacDonald Land Company and consolidated into what is now known as the Blue Oak Ranch. MacDonald raised cattle until 1972, when the Rancho Pilon’s Ownership Group bought the land with plans to convert it to vineyards, complete with their own reservoir system and hydroelectric power plant. Rancho Pilon’s plans were dashed by the property's location on the Calaveras fault (some reservoirs had been planned to sit right on the fault), and by mitigation requirements to relocate proposed reservoirs that would have inundated archeological sites. In 1990, Rancho Pilon’s sold the land to the Blue Oak Trust.

The Blue Oak Trust entered into a conservation easement agreement in 2000, in partnership with The Nature Conservancy, California Field Office’s campaign to acquire open space for conservation in the Mount Hamilton Range. The campaign, now in its 10th year, is working towards protecting as open space up to 500,000 acres in the 1.2 million acre region surrounding Mt. Hamilton. To date they have purchased land and/or acquired the development rights for more than 100,000 acres. The conservation easement on BORR restricts new development to a 10 acre area, and permits only wilderness compatible activities on the majority of the Ranch.

On December 1, 2007 the Blue Oak Ranch trust transferred their ownership of the Ranch to the Regents of the University of California, for the purpose of creating the 36th reserve in the Universities' world renowned Natural Reserve System. The University accepted the terms of the Conservation Easement, with minor clarification, and entered into an open space agreement with the County of Santa Clara. An anonymous donor provided start up funds and a generous endowment gift that will ensure the NRS will be able to indefinitely operate Blue Oak Ranch Reserve.

Posted on March 07, 2014 06:43 AM by infomgr infomgr | 0 comments | Leave a comment

GEOLOGY AND SOILS

For studies of geophysical processes, the site offers many interesting features to geologists, geomorphologists studying hillslope processes, and hydrologists, Interestingly, the University of California established in 1887, at Berkeley and at Mt. Hamilton, the first seismographic stations in the Western Hemisphere on a permanent basis. These stations were in the charge of the Departments of Astronomy, Civil Engineering, and Geology.

The Mt. Hamilton area is a part of the Diablo Range, which extends from the Carquinez Straits south 170 miles to Coalinga. Bedrock in this range includes ancient marine sedimentary rocks and might provide interesting opportunities for paleomicrobial research.

The Arroyo Aguague fault, a branch of the Calaveras fault, runs almost directly up the Arroyo Aguague. Many minor faults branch out through the ranch, probably forming the many intermittent drainages. Due to the many faults, perennial springs are found throughout most of the property. Much of the western portion of the ranch is underlain by large chert formations, which are exposed on many parts of the ranch. Much of what underlies the ridges above the Arroyo Hondo is unstable mélange, and the area is punctuated with many young landslides. By contrast, the west side’s many slides are quite old (Earth Sciences Associates, 1979.) Blue Oak Ranch Reserve appears to be very well suited to research by geomorphologists studying hillslope processes.

Soils are of the Los Gatos-Gaviota complex, derived from hard sandstone and shale from the Franciscan formation and younger (Miocene age) marine sediments. Rock outcrops and unstable talus slopes are common.

Posted on March 07, 2014 06:41 AM by infomgr infomgr | 0 comments | Leave a comment

HYDROLOGY

The boundaries of BOR completely enclose four watersheds (three
tributaries of Arroyo Aguague and one tributary of Arroyo Hondo), facilitating ecological, biogeochemical, and hydrological research at the whole-watershed scale. Approximately two-thirds of the 1,320-hectare (3,300-acre) Blue Oak Ranch is drained by tributaries of Arroyo Aguague, itself a tributary of Coyote Creek (via Penitencia Creek), which flows into the southern San Francisco Bay. The remainder of the ranch is drained by Smith Creek in the Arroyo Hondo and its tributaries. The four perennial streams and their many intermittent tributaries are lined with bay-laurel (Umbellularia californica), white alder (Alnus rhombifolia), sycamore (Platanus racemosa), big-leaf maple (Acer macrophylum), and coffeeberry (Rhamnus purshiana).

Seventeen livestock ponds are well distributed around the property; most are man-made reservoirs fed by spring seeps or runoff. Many of the smaller, shallow ponds are ephemeral in years of average rainfall. The deepest reservoirs are Big Lake (21 feet deep), Rope Swing Pond, Cabin Pond, and Gramps’ Pond. These deep ponds normally contain water year-round, and serve as reliable habitat for a host of wildlife as well as a source of emergency water for wildfire suppression.

The streams and the seventeen ponds on the ranch represent the Sensitive Aquatic Resources Areas, and harbor concentrations of many species of aquatic and semi-aquatic species.

Posted on March 07, 2014 06:40 AM by infomgr infomgr | 0 comments | Leave a comment

BIODIVERSITY

VERTEBRATES
The Blue Oak Ranch supports around 130 species of birds, approximately forty-one species of mammals, at least seven species of amphibians, more than fourteen species of reptiles, around seven species of fish, and hundreds of species of invertebrates.

Rare Species
In their report to the California Department of Fish and Game, Jennings and Hayes (1994) reviewed the status of 80 taxa of amphibians and reptiles native to California. Of the 80 species, they determined that 48 warranted listing. Five of those species are known to occur on the Blue Oak Ranch: California tiger salamander; Foothill yellow-legged frog; California red-legged frog; Western pond turtle, and California horned lizard. The latter species has only been seen occasionally (Eric Remington, pers. comm.). Habitat exists for the Alameda whipsnake along the Arroyo Hondo, but so far all specimens found on BORR have been of the chaparral whipsnake subspecies.

California tiger salamander (Ambystoma californiense)
California tiger salamanders are a state species of special concern. They have been found to breed in seven of the ranch ponds; South Pond, Steep Road Pond, Center Road Junction Pond, Barn Pond, High Pond, Lower Center Road Pond, and Windmill Pond (Larry Serpa, pers. comm.). No information exists on their population numbers or health. The adults spend most of their time in rodent burrows. They return to the ponds to breed when the breeding sites fill with the first heavy rains of the season, and are more vulnerable to predators while on the surface. Soon after the eggs are attached to submerged vegetation or twigs, the adults return to the safety of their burrows. The resulting larvae have to complete their metamorphosis to the terrestrial salamander form before the breeding sites dry up. If the ponds are permanent, introduced predators such as largemouth bass, other sunfish, trout, mosquitofish and bullfrogs can make survival difficult. On the ranch, these salamanders have not been found in any of the ponds with fish.

Foothill yellow-legged frog (Rana boylii)
This frog is a state species of special concern. Foothill yellow-legged frogs inhabit streams with relatively natural hydrological regimes. They are numerous in North Creek and Smith Creek at the bottom of the Arroyo Hondo, but have not been seen in any other streams on the ranch. The eggs are laid in the early spring after the water has begun to warm slightly, and after hatching, the tadpoles feed on diatoms that they scrape from underwater rocks. As with the California red-legged frogs, the tadpoles can complete their metamorphosis in most areas even if the water dries up later in the season.

California red-legged frog (Rana aurora draytonii)
The California red-legged frog is Federally listed as threatened. The species is most common in the Mt. Hamilton area in perennial ponds that have abundant amounts of aquatic buttercup, a plant which provides the frogs with cover and a feeding area for the tadpoles as they graze on algae. Buttercup does grow in most of the ranch ponds, but no frogs have been found on the ranch in this type of habitat. These frogs are also found in stream pools with relatively slow moving water. One was spotted in High Pond in spring, 1999, but it didn’t stay long. Another was seen in a pool just downstream of the road in Deer Creek on August 7, 2000. Red-legged frogs usually can’t persist in ponds with non-native bullfrogs, bass, or other introduced fish predators. They can be successful in ponds that dry up periodically, or even dry up every year, as long as the water stays long enough for the tadpoles to complete metamorphosis.

Western pond turtle (Clemmys marmorata)
The pond turtle is a state species of special concern. It is noted as “Threatened” in “Amphibian and Reptile Species of Special Concern in California. “ Western pond turtles are found in six of the ranch ponds; Gramps Pond, Cabin Pond, Big Lake, Lower Center Road Pond, Upper Center Road Pond, Rope Swing Pond. Their population appears to be on the increase; over the last three years I have seen most age classes, from approximately three to eight inches in size. Young turtles are eaten by both bass and bullfrogs. Ponds and lakes that have these exotic predators usually have no turtles or only adult turtles. They only seem to reach high density where there are a lot of basking sites. In fall, 1999 I constructed anchored, floating rafts made of wood from the old barn and fences, and installed them in nine ponds; Gramps Pond, Cabin Pond, Big Lake, Lower Center Road Pond, Upper Center Road Pond, North Pond, South Pond, High Pond, and Rope Swing Pond. These rafts have successfully provided turtles basking sites out of the reach of terrestrial predators—specifically wild pigs. Ducks, snakes, and frogs also use the rafts. The females also need to be able to reach adjacent terrestrial habitats to construct nests for their eggs. Western pond turtles are omnivores, and feed on plants, insects, crustaceans, and carrion.

Fish
Farther downstream, the Arroyo Aguague is the focus of a Department of Fish and Game project to enhance steelhead populations. According to the The Nature Conservancy Project Ecologist, Larry Serpa (pers. comm.), a natural fish barrier exists downstream of the ranch, within the boundaries of Alum Rock Park, blocking the steelheads’ passage to ranch property. Rainbow trout do well above the waterfall barrier, though, and occasionally a few make it onto the ranch itself. Although Smith Creek at the bottom of the Arroyo Hondo is blocked by Calaveras Reservoir, it is home to at least three species of fish: rainbow trout (Oncorhynchus mykiss), California roach (Lavinia symmetricus), and Sacramento sucker (Catostomys occidentalis). There are 17 ponds and lakes on the ranch; three of them—Big Lake, Rope Swing Pond, and Cabin Pond—have been stocked with large–mouth bass (Micropterus salmoides) and another sunfish species, while West Pond has been stocked with mosquito fish (Gambusia affinis),

Mammals and Birds
Black-tailed deer are common on the ranch year-round, in all communities. They frequent meadows and ridge tops in the crepuscular hours. Coyotes are abundant. Bobcat sightings are not uncommon, particularly in winter and spring. Badger sightings are more rare. River otter tracks and scat were found along Smith Creek in the Arroyo Hondo in June 1999. The most conspicuous rodent is the California ground squirrel, especially during warm months. Several bat species, including pallid bats (Antrozus pallidus), frequent the ranch and use the roosting boxes erected for them on the south side of the White cabin.

Up to a year ago, the introduced wild boar (crossed with feral pigs) was abundant. With the construction of a perimeter hog fence and increased hunting pressure, the population has dropped dramatically. In 1997 sounders of 40 to 60 pigs were not uncommon; today, a sighting of more than two individuals together is unusual. The fox squirrel (Sciurus niger) has also invaded the ranch area, spreading from the Stanford University campus and urban San Jose parks, where it was introduced early in the 20th century (Sam Blankenship, pers. comm.).

Golden eagles, turkey vultures, and red-tailed hawks are present year–round. Cooper’s hawks, sharp-shinned hawks, and kestrels are year-round residents, and the ranch is occasionally visited by merlins and prairie falcons. The ranch is also home to band-tailed pigeons, wood ducks, an abundance of California quail, and five species of owl. Migrants include phainopepla, Lewis’ woodpecker, chipping sparrow, and grasshopper sparrow.

The three nonnative species are the ubiquitous European starling, the rock dove, and the introduced game bird, the wild turkey.

Reptiles and Amphibians
Pacific rattlesnakes abound on the Blue Oak Ranch, and I have discovered several dens. Gopher snakes are common in the meadows, and garter snakes frequent streams and ponds, particularly when prey is concentrated in shrinking summer pools. Racers and California kingsnakes are resident, but infrequent. Sharp-tailed snakes can be found under logs and planks in the winter months. California horned lizards are said to have been seen infrequently on Poverty Ridge (Eric Remington, pers. comm.). Pacific treefrogs are abundant, and numbers may burgeon it the introduced bullfrog can be diminished or eliminated from West Pond and Big Lake. Western toads are frequently seen crossing roads at night.

Plants and Plant Communities

There are 73 vascular plant families at BORR. Of the 462 taxa of vascular plants on the ranch, almost 80% are native (Bainbridge and Kan, 1977). Four species of concern by the California Native Plant Society are :

Santa Clara thorn mint (Acanthomintha lanceolata)
Chaparral harebell (Campanula exigua)
Santa Clara red ribbons (Clarkia concinna, ssp. automixa)
Serpentine linanthus (Linanthus ambiguus)

Only the chaparral harebell is not endemic to the Diablo Range and the eastern slope of the Santa Cruz Mountains.

Plant communities of the Blue Oak Ranch include blue oak woodland, valley oak woodland, black oak woodland, coast live oak woodland, riparian forest, chamise chaparral, Diablan sage scrub, nonnative annual grassland, wildflower field, and native perennial grassland (Bainbridge and Kan, 1997). Four of these are threatened plant communities; valley oak woodlands, blue oak woodlands, wildflower field, and native perennial grasslands. Streams on the ranch support healthy stands of riparian vegetation in addition to aquatic species. They are important habitat for migratory birds, and may be migratory corridors for numerous aquatic and terrestrial animal species. The steep slopes of the Arroyo Hondo canyon provide an excellent contrast of vegetation, with the north and east-facing slopes supporting vegetation adapted to relatively cool, moist environments, and the west and south-facing slope vegetation (including chamise chaparral) adapted to hot, dry conditions.

Grasses
Patches of native grasses still occur in many places on the ranch. They are dominated by purple needle grass (Nasella pulchra), but perennial species of barley (Hordeum), bluegrass (Poa spp.), three-awn (Aristida ssp.), melic (Melica ssp.), and wildrye (Elymus and Leymus ssp.) are sometimes dominant or codominant (Bainbridge and Kan, 1997). The native grasses are most abundant on mesic north-facing slopes, in the understory of mixed evergreen woodland (Arroyo Hondo), under trees in oak savannas, and in open areas on ridge tops and slopes.

Oak Woodland
Blue and valley oak woodlands have become quite rare in California, and few are protected from grazing and the encroachment of suburban development. Oak woodland covers a large extent of BOR, much of this is composed of blue and valley oaks. Compounding the possibly bleak future for oak woodlands is the lack of recruitment of young oaks. In the Mt. Hamilton area, valley oaks seem to be suffering most from this problem. The exact mechanism or mechanisms preventing oak regeneration is not known, but protection from pigs, cattle, and ground squirrels has been shown to increase survivorship of existing seedlings. Prescribed fire may also help by opening canopies and reducing competition between grasses and seedlings. However, fires must be carefully controlled for low heat, and conducted at frequency intervals that allow seedlings to become established. Physiological research suggests that ozone may extend stomata opening in blue oak, forcing nighttime transpiration during periods of drought and influencing shorter leaf retention. Oaks, as the most widespread and representative forest and woodland species in California, offer excellent research opportunities for climate change and pollution-effects research.

Non-native Plant Infestations
Among introduced species, yellow starthistle (Centauria solstitialis) and medusahead grass (Taeniatherum caput-medusae) are highly invasive. At present, C. solstitialis occupies only about 30 acres of the ranch, but it is spreading quickly. Taeniatherum, probably introduced from bales of hay, covers most of the flat areas of the ranch.

Other introduced species of concern are Italian thistle (Carduus pycnocephalus), tocalote (Centauria melitensis), Canada thistle (Cirsium arvense), and bull thistle (Cirsium vulgare). Italian thistle in particular has become widespread in dense stands, and is a spring and summer feature under the drip lines of many oaks on the ranch.

Posted on March 07, 2014 06:38 AM by infomgr infomgr | 0 comments | Leave a comment

CLIMATE AND ATMOSPHERE

The climate of Central Coastal California is typical Mediterranean, with wet and cool winters and dry hot summers. Since BORR lies 10-50 miles (16-80 km) inland from the Pacific Ocean, and coastal ranges like the Santa Lucia Range and the Santa Cruz Mountains block Pacific incoming moisture, it receives half the precipitation seen along the coastline. Winters are mild with moderate rainfall; mean precipitation ranges from 376 mm near sea level in downtown San Jose, to 600 mm on Mount Hamilton at an elevation of 4,360’ (1,330m), but summers are very dry and hot. Areas above 2,500 feet get light to moderate snow in the winter, especially at the highest point, the 5,241 ft (1,597 m) San Benito Mountain in the remote southeastern section of the range.

Blue Oak Ranch Reserve anchors a network of sites dedicated to providing an early warning indication of climate change and understanding the resulting ecosystem and biodiversity responses to change. The region is at the intersection of the coastal-inland fog line. The extensive development of lichens dependent on fog shows dependence of a large fraction of the biodiversity dependent upon fog. This region has a greater percentage of fog than southern California, but somewhat less than regions with redwoods. Fog is dependent upon ocean temperatures, and shifting ocean temperatures, associated with El Nino-La Nina intensities feedback regulating fog. Urbanization also reduces fog through the heat island effect. Together these factors have the potential to dramatically affect coastal ecosystems, with unknown ramifications to the interior regions. California is expected to experience temperature increases, along a north-south gradient, and especially in the Sierra Nevada and Central Valley, of 2 to 4oC in winter and 2 to 8 oC in summer, depending on emissions scenario and modeling approach (Hayhoe et al., 2004). Fog formation, snow-rain transition, and temperature gradients north/south and east/west are likely interrelated processes. Monitoring stations at BORR, and other Berkeley field stations, will provide data from the western, leading edge of these responses. BORR can also provide close to coast monitoring of the land-ocean-atmosphere coupling that is a likely driver of continental climate shifts.

ATMOSPHERIC CHEMISTRY

There are approximately 100 monitoring stations for O3 and NOx in California. Monthly maximum O3 (in the vicinity of BORR) was
29.7 ppb, but only 35 km to the east, the average was 50 ppb. Current models suggest that both O3 and NOx are relatively low at
BOR (see adjacent figures), but with suburbanization of the surrounding landscape, the potential for impacts on ecosystem functioning in BORR has the same implications as for the California Central Valley and Sierra front as well as other regions of the country, such as the Great Lakes, mid-Atlantic region, southern Appalachia, and the Front Range of the Rocky Mountains.

Posted on March 07, 2014 06:36 AM by infomgr infomgr | 0 comments | Leave a comment

GEOGRAPHY

Blue Oak Ranch Reserve (BORR), is a 3,280 acre undeveloped ecological reserve perched on the west-facing slope of the Diablo Range in northern Santa Clara County, California, seven air miles east of metropolitan San Jose and five miles northwest of Mt. Hamilton. Elevations range from 1,500 feet, where the Arroyo Aguague exits the ranch, to 2,855 feet, at the top of Noah’s Ridge. The Ranch location is approximately mid-point within the Diablo Range, which is in turn a part of the Pacific Coast Ranges, bordered by the San Francisco Bay, Santa Clara Valley, Gabilan Mountains, and Salinas Valley to the west and by the Central Valley to the east. The range extends 180 miles (290 km), from Mount Diablo in the northwest to the Polonio Pass (north of the Temblor Range and the Carrizo Plain) in the southeast. The Diablo Range generally and BORR specifically supports grasslands, chaparral, and oak woodland communities typical of the broader California Floristic Province, with stands of conifers appearing above 4000 feet (outside BORR). The climate of Central Coastal California is typical Mediterranean, with wet and cool winters and dry hot summers. Since BORR lies 10-50 miles (16-80 km) inland from the Pacific Ocean, and coastal ranges like the Santa Lucia Range and the Santa Cruz Mountains block incoming moisture, it receives half the precipitation seen along the coastline. Winters are mild with moderate rainfall; mean precipitation ranges from 376 mm near sea level in downtown San Jose, to 600 mm on Mount Hamilton at an elevation of 4,360’ (1,330m), but summers are very dry and hot. Areas above 2,500 feet get light to moderate snow in the winter, especially at the highest point, the 5,241 ft (1,597 m) San Benito Mountain in the remote southeastern section of the range. For more climate information see the Climate and Weather section.

Posted on March 07, 2014 06:35 AM by infomgr infomgr | 0 comments | Leave a comment

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