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General Description

The Bernard Field Station is located on approximately 86 acres of Claremont Colleges land, including approximately 75 acres of the Claremont University Consortium’s North Campus Property and adjacent properties belonging to Harvey Mudd College (approximately 5 acres) and Claremont Graduate University (approximately 6 acres).

The BFS is situated on alluvial outwash from the San Gabriel Mountains (see Geology & Geography) and contains remnants of the once widespread Coastal Sage Scrub plant community, well adapted to our Mediterranean climate (see Climate). This plant community now exists only as islands in a sea of urban areas and (formerly) citrus groves, but at one time all the alluvial deposits of the Los Angeles Basin were clothed with this type of vegetation. As land was cleared for agriculture the only undisturbed areas left were in nonarable regions at the base of the mountains, especially near canyon mouths. Eventually even these previously undisturbed areas gave way to subdivisions, which have also replaced the citrus groves. The BFS contains one of the largest remaining parcels of Coastal Sage Scrub in Los Angeles County.

Some of the Coastal Sage Scrub of the BFS has been in recovery (succession) following both natural and unnatural disturbance. The area at the corner of Mills and Blaisdell (see maps) was a citrus grove, cleared in the early sixties. Commonly referred to as “the field”, it now consists mostly of annual grasses and forbs, with an increasing number of shrubs as it very slowly returns to Coastal Sage Scrub. The southwestern portion of the BFS has also suffered from disturbance. This area was crossed by several bulldozed fire roads, which have reverted to vegetation. The area least disturbed by human activity is the long, narrow, northward-reaching portion known as the “neck”. This neck primarily contains Riversidian Alluvial Fan Sage Scrub, parts of which are in late stages of succession after a fire which occurred in the mid-sixties. The vegetation here varies in intensity and composition. Disturbance is a natural part of the maintenance of the Coastal Sage Scrub community and allows the growth of a larger variety of vegetation which in turn supports more animal species. The Coastal Sage Scrub plant community harbors an abundant and moderately diverse fauna, the most conspicuous of which are arthropods and vertebrates.

The character of the vegetation occurring at the BFS changes markedly with the seasons depending on the availability of moisture, both in the soil and in the atmosphere (see Climate). In late winter and spring much of the vegetation assumes an almost succulent appearance. Many of the dominant plants have a white pubescence (a hairy covering of the leaves and stems that reduces water loss). Between succulence and pubescence, the BFS vegetation has an overall gray-green appearance in Spring. But as the summer drought begins, the soft leaves of most plants curl and wither. If the drought is severe and long-lasting, stems become bare and die back. The general appearance of the vegetation in late summer to fall is brownish-gray. Oddly, several of the shrubby composites, such as scalebroom (Lepidospartum squamatum) come into bloom at this stressful time of year.

The BFS also harbors several other habitats distinct from the sage scrub communities. Perhaps the most prominent of these is a small “lake” (known as “pHake Lake”), which was constructed in 1978 to provide a study site for aquatic biology. pHake Lake consists of a 1/2-acre marshy habitat about 6 feet deep and a 1-acre pond some 20 feet deep. Native plants and animals were introduced to the lake, and these, along with a number of volunteer species, have developed into a thriving ecosystem.

Other distinct habitats include a small area of riparian live oak forest in southern part of the neck, where native Quercus agrifolia (live oak) and Platanus racemosa (sycamore) are supported by water pooling behind a fault (see Geology & Geography). In addition two artificial vernal pools provide habitat for fairy shrimp (primarily Brachinectia lindahlii) and support developing toad tadpoles.

The most conspicuous built structure on the BFS is the old Scripps College Infirmary. Built in the pre-antibiotic era, the infirmary was sited remotely from the collge campuses to contain the spread of infectious diseases. For a time the infirmary area was used as study site and rehabilitation center for birds and mammals, particularly raptorial birds (hawks and owls) and larger mammals such as coyotes. The main Infirmary building was burned by an arsonist in 1975 and is condemned. Some the infirmary-ssociated buildings are used by the BFS, including a garage for boats and the field house, which includes an office for the BFS Director. Just east of the infirmary is a laboratory teaching pavilion with benches and running water. A small shed in the east field houses a telescope for use by astronomy classes.

Vegetation planted for the infirmary, including Umbellularia californica (California laurel) and Eucalyptus sp. near the buildings and Quercus agrifolia (live oak) and Heteromeles arbutifolia (toyon) along the drive provide additional varied habitat, as does the proximity to the Rancho Santa Ana Botanic Garden and residential subdivisions.