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Mixed Evergreen Forest Excerpted from MDIA's book Plants of the East Bay Parks, by Glenn Keator, Ph. D. Plant Communities of Mount Diablo State Park January 1, 1999 Madrone, Arbutus menziesii Where oak canopies overlap, conditions favor a variety of other usually evergreen trees: California bay laurel, madrone, Douglas fir, tanbark oak (not a true oak but a lithocarpus), and California nutmeg. The Douglas fir and California nutmeg are not met with in our own region, while the other trees are. These mixed forests represent habitats intermediate in winter rainfall and summer drought between redwood forests, where summer fogs and heavy winter rains rule, and oak woodlands , where we've already seen the the severity of summer drought. Often there will be no absolute line and mixed-evergreen forest nudges the borders. Generally mixed-evergreen forests occur on north-facing slopes where south slopes are home to oak woodland. However, mixed evergreen forests may carpet a canyon bottom alongside the narrow riparian corridor but give way to oak woodland or chaparral on adjacent slopes. Often, too, the mixture of trees in these forests varies from locale to locale. Close to the coast, expect to see Douglas fir (Pseudotsunga menziesii ) and California nutmeg (Torreya californica ) in the forest; inland, expect to encounter canyon live oak. California black oak, California bay laurel, and madrone. The complex interactions of different trees from site to site are still not fully understood, for they also change with the age of the forest and its fire history. With the exception of a few deciduous trees -- California black and Garry oaks, California buckeye, and occasionally bigleaf maple -- mixed evergreen forests have the leathery, tough evergreen leaves so characteristic of chaparral shrubs. Unlike those, however, mixed-evergreen forest tree leaves tend to be broader and -- at least on lower branches -- horizontally oriented, for purposes of more efficient light absorption for photosynthesis. Only near the tree tops and only in some species (such as madrones) are leaves obliquely inclined, with pale undersides held skyward to reflect away intense summer sun. Although in mixed-evergreen forests as elsewhere wind pollination is used for the conifers and oaks, both madrone and bay laurel differ sharply, having insect-pollination strategies. Madrone produces abundant, nectar-rich white bells in mid-spring (bee favorites); bay laurel makes long lasting sets of small, pale yellow, saucer shaped flowers from mid-winter to early spring. Bay laurel is thus especially important in sustaining insects active at at time of year when most life is dormant. It joins ranks with the manzanitas in fulfilling this important role. As to seed dispersal, strategies resemble those of oak woodlands; again with many nutrient rich stored foods in extra large seeds. Only the madrone makes bright red-orange berries, attractive to large numbers of birds. Where Douglas fir occurs, its seeds are winged and wind distributed. This makes good sense, for Douglas fir is taller than the other trees, and winds easily reach its tall branches laden with seed cones. Not only do the roots of these trees extend outward for great distances to pick up as much of the winter rains as possible, but the competing understory plants -- shrubs, bunch grasses, bulbs, and perennial herbs -- seek water for later use. This intense competition for water means that the drier areas with least winter rainfall, where mixed-evergreen forest is marginal at best, have poorly developed understory vegetation. At the opposite pole, along the edge of redwood forests, the understory may be rich and varied. Most smaller plants are perennial; the annual life cycle is not favored by the relatively low light intensities. Many of these smaller plants extend into adjacent communities. The moisture-loving kinds extend into redwood forests and the droughty kinds -- especially the few bunchgrasses, such as melicas and California fescue --into oak woodlands. California bay laurel | Glenn-Keator Bay Laurel Trees near Juniper Campground | Dereck Love BACK TO LIST

Wildflower Mount Diablo Chaparral Blazing Star, San Luis Stickleaf, Small Flowered Stickleaf Scientific Name: Mentzelia micrantha Family: Loasaceae (Loasa Family) Blooms: May - Jun Color: Yellow-Orange Annual herb Native Jump to Blooming Now Blue / Purple Red / Pink White Yellow / Orange Invasive Plants Donna Pomeroy, iNaturalist

Rugged Plants Contributed by Dan Day Reprinted by permission from the Northern California Geological Society Newsletter A Struggle to Survive on Barren Serpentine Soil January 1, 1999 Mike Woodring Ultramafic rocks are scattered throughout the California Coast Range, the Trinity Mountains, and the Sierra Nevada foothills. That serpentine is the state rock proves it has caught the eye of California geologists. However, many are perhaps unaware that serpentinites have spawned a unique flora specially adapted to survive on their nutrient-poor soils. The adaptive characteristics of one such species was explored in Cheryl Smith’s January 26, 2005, NCGS talk Geochemical Investigation of the Distribution Habitat of (McDonald’s Rock Cress) in the Six River National Forest, Del Norte County, California. Cheryl, current President of the Peninsula Geological Society, did field work in remote Del Norte county on the California-Oregon border studying the geochemical characteristics of soils supporting isolated communities of this rare endangered plant, pictured to the left. (Arabis macdonaldiana ) Botanical and ecological data on this and other hardy plants surviving on ultramafic soils are voluminous, but to date, the actual adaptive relationships between the plants and their environment are vague. California is an excellent place to study these interrelationships because of its quite varied plant life—over 5,000 plant species grow in the Golden State, more than the combined total of the central and eastern United States and adjacent parts of Canada. Additionally, 30% of California’s flora occur nowhere else in the world. By comparison, only 13% of the flora in the Northeastern U.S. are endemic, and only 1% in the British Isles. One reason for California’s prolific flora is its remarkably varied habitats. The latter provide conditions for a plant’s successful survival and reproduction. California has a multitude of climatic conditions as well as a wide variety of rock types to support its complex floral communities. Similar habitats have been grouped into landform provinces based on their comparable topographic and climatic conditions. Each province, however, often contains a diversity of unique habitats, in large part a result of California’s complex and active geological processes. Landscape evolution and the accompanying cooler, drier climate, for instance, gradually transformed some of the Tertiary sub-tropical habitats in central and southern California into semi-arid and desert communities. Lush forests were restricted to the wetter areas along the temperate northern California coast. Subsequent uplift of the Sierra Nevada range provided wet, higher elevation habitats on its western slopes and parched deserts in the rain-shadow to the east. Glacial-induced climate fluctuations yielded even more microenvironments that survived in sheltered areas until today. Other important factors influencing a plant’s survival include its ability to interact with other plant species, compete with them for nutrients, protect itself from indigenous fauna, and successfully reproduce. All of these geological changes drove evolutionary mechanisms to fill the new habitats, as existing species were forced to occupy restricted habitats called refugia. California’s tectonic activity and numerous microclimates have heavily influenced plant distribution in the state. Some restricted habitats are disappearing while others are emerging, but both support rare plant species. Isolated seasonal habitats likewise spawn unusual flora, often differing from one location to another. Unique habitats often occur as “islands” surrounded by more common vegetation. Many of these isolated ecological communities exist because of the local geology. Complex intermixtures of rock types provide very distinctive soils that are home to rare plant life. Because they lack many key elements that support the usual floral species, and are enriched in harmful elements, serpentine soils are home to a variety of uniquely adapted plants. The soils are rich in heavy metals and barren of vital elements needed to support conventional plant life. They are shallow, low in calcium, high in magnesium, and do not hold water well. Serpentine flora provide an exciting opportunity for botanists and ecologists to probe adaptive evolutionary mechanisms. The soils that develop on these ultramafic rocks contain some elements, like nickel and chrome, which are toxic to most plant species. The stresses induced by their extreme compositional characteristics have actually selected traits and mutations that allow certain hardy plants to adapt to serpentine soils. Some plants actually become tolerant to these toxic elements and are capable of assimilating large quantities without ill effects, a phenomenon known as hyperaccumulation. Mutation may play a role in this adaptive process. Cheryl’s thesis study was conducted in a very remote part of the Six River National Forest in Del Norte County. Her field area was located on the Josephine ophiolite atop serpentine and ultramafic rocks. The area is isolated and inhabited by a very private rural population, wary of strangers. Cheryl needed to exercise caution as she hiked the backcountry with her trusty dog in search of Arabis macdonaldiana colonies. Serpentine chaparral interspersed with evergreen woodlands dominate the rugged landscape. The tiny magenta flowers hug the ground and are unobtrusive except in localized colonies where they form thick carpets. Cheryl sampled the soils around the plants, being careful not to disturb them. The samples were used to determine the soil mineralogy and its elemental composition. Another element in high concentration at the plant sites is barium. Adaptation to the toxic influences of barium may be a key factor for flora that exist on serpentine soils. Toxins and growth inhibitors drive natural selection by favoring certain mutations. Some of these selective processes may involve changes in only a single gene. Cheryl’s studies, though not conclusive, have provided trace element data that can be used to further characterize the environmental effects surrounding Arabis macdonaldiana . Audience discussion following the talk mentioned the pioneering work of California botanist Arthur Kruckeberg on serpentine flora. He summarized his studies in his 1984 publication California Serpentines: Flora, Vegetation, Geology, Soils, and Management Problems . This treatise, and additional research being conducted at the U.C. Davis McLaughlin Reserve in the California Coast Range north of the Napa Valley, have made significant contributions to understanding the mechanisms that control the state’s diverse vegetation. Kruckeberg echoes many of the reasons mentioned above that make serpentine soils so infertile: their high magnesium, nickel, and chromium contents, low levels of soluble calcium and nitrogen, and poor water retention. Included in the “serpentine” category are soils derived from partially serpentinized peridotite (an ultramafic rock), gabbro (the plutonic equivalent of basalt), and basalt greenstones (metabasalts of ophiolitic origin). All these soil derivatives share similar soil characteristics with the serpentinites and also support unusual plant life. Kruckeberg described plant responses to serpentine soils as avoidance, indifference, and endemism. Indigenous taxa that cannot survive on serpentine substrates are the avoiders; the flora that can endure both serpentine and nonserpentine soils are indifferent; and the endemic species are restricted to serpentine soils. It is the latter (endemic) species that have caught the eye of evolutionary biologists. Theories regarding the origin of the endemics are twofold. One champions the paleoendemic hypothesis, which propose that ancestral species occupied several habitats until climate changes caused extinction of the nonserpentine populations. The other is the neoendemic theory, which suggests the “insular” taxa with extremely limited ranges evolved from ancestors living on adjacent nonserpentine soils. Botanists have shown that the endemics will grow on nonserpentine soils if carefully nurtured, and that they will flourish there if cultivated alone. This would imply that competition with other species on the nonserpentine substrates forced them to occupy the more harsh conditions of the serpentine soils. The degree of plant endemism is also variable, from 100% serpentine restriction to only partial restriction, depending on the local geology. Reduced restriction is exhibited by “indicator” taxa, which are serpentine-restricted in only part of their ranges. Kruckeberg estimated an approximately equal count of serpentine endemic and serpentine indicator species, totaling over 425 taxa. He also noted that the Northern Coast Range serpentinites are particularly rich in plant life. Continuing serpentine flora research is being conducted at the McLaughlin Reserve, and is methodically revealing the survival strategies of these unusual plants. The NCGS gratefully acknowledges Cheryl Smith for sharing her research on the major and trace element geochemistry of serpentine soils and its potential impact on the endangered plant Arabis macdonaldiana (McDonald’s rock cress). The botanical research surrounding this and other endemic serpentine soil inhabitants is making major contributions to evolutionary biology. However, the soil mineralogy and elemental chemistry, as pointed out by Cheryl, needs further clarification to identify its specific role in the survival of these hardy plants. Note: The biological commentary on serpentine floral species and their evolutionary development was taken from the McLaughlin Reserve website, and from a short article called Why Rare Species? authored by Susan Cochrane and posted on the Ceres website. BACK TO LIST

Wildflower Mount Diablo San Luis Stickleaf, San Luis Blazingstar Scientific Name: Mentzelia micrantha Family: Loasaceae (Loasa Family) Blooms: Apr-Jun Color: Yellow-Orange Annual Herb Native Jump to Blooming Now Blue / Purple Red / Pink White Yellow / Orange Invasive Plants Daniel Fitzgerald Daniel Fitzgerald Daniel Fitzgerald Daniel Fitzgerald

Wildflower Mount Diablo Buck Brush Scientific Name: Ceanothus cuneatus var. cuneatus Family: Rhamnaceae (Buckthorn Family) Blooms: Feb - Apr Color: White Shrub Native A shrub commonly associated with chaparral throughout the Mount Diablo foothills. The miniature petals are spaulate in shape. Jump to Blooming Now Blue / Purple Red / Pink White Yellow / Orange Invasive Plants Mike Woodring

Wildflower Mount Diablo Tuberous Sanicle, Turkey Pea Scientific Name: Sanicula tuberosa Family: Apiaceae (Parsley-Carrot Family) Blooms: Mar - May Color: Yellow-Orange Perennial herb Native Jump to Blooming Now Blue / Purple Red / Pink White Yellow / Orange Invasive Plants Mike Woodring

Wildflower Mount Diablo Spearmint Invasive Scientific Name: Mentha spicata Family: Lamiaceae (Mint Family) Blooms: Jun - Nov Color: Blue-Purple Perennial herb Introduced Jump to Blooming Now Blue / Purple Red / Pink White Yellow / Orange Invasive Plants Steven Beatty

Wildflower Mount Diablo Notch Leaf Clover Scientific Name: Trifolium bifidum Family: Fabaceae (Pea Family) Blooms: Color: Red-Pink Annual herb Native Jump to Blooming Now Blue / Purple Red / Pink White Yellow / Orange Invasive Plants

Eurasian Collared-Dove Pigeons and Doves Eurasian Collared-Dove Streptopelia decaocto All Year Pigeons and Doves Daniel Fitzgerald A rapidly spreading species native to Eurasia this dove has a black band on its hind neck, grayish tail coverts and three-toned wing pattern in flight.

Wildflower Mount Diablo California Yampah, Kellogg’s Yampah Scientific Name: Perideridia kelloggii Family: Apiaceae (Parsley-Carrot Family) Blooms: June Color: White Perennial herb Native, endemic to California Jump to Blooming Now Blue / Purple Red / Pink White Yellow / Orange Invasive Plants

Muir's Hairstreak Callophrys muiri Lycaenidae Blues, Coppers, Hairstreaks Flies March to July Host Plant Juniper, Cypress Nectar Plant Oregon sunshine, Interior redberry, Narrow-leaved goldenbush D. L. Rawlinson Underwing

Blainville's Horned Lizard by Michael Marchiano October 1, 1998 The Coast or Blainville’s Horned Lizard (Phrynosoma blainvilli ) is considered to be an odd-looking creature by many people. Squat, flat bodied, and short-tailed with a wide head covered in spines, it causes one to consider the little lizard a miniature relic from the age of dinosaurs. In fact, its appearance gives rise to its nickname, “Horny Toad”. Growing to a length of five inches, this cryptic colored lizard depends far more on its appearance for survival than speed or agility. Its mottled coloration of large and small patches and bands on its body of various shades of brown, black, cream, and yellow allow it to blend into it environment almost to a point of invisibility. When threatened, it will first freeze and hope its camouflage will protect it. If attacked, it will run a short distance, stop suddenly, lay flat, and once again count on its coloration for protection. If grabbed, the horned lizard has a unique defense for repelling its attacker. It can actually squirt a quick stream of blood from the corner of its eyes with the hope of distracting or startling the predator and escaping. Another unique feature of this specialized lizard is its diet. Its primary food is native ants, such as species of harvester and carpenter ants. It does on occasion eat other arthropods such as beetles, crickets, and spiders, but 80-90 percent of its diet is indigenous ants. The introduction of Argentine ants (which have replaced native species) in areas once inhabited by Coast horned lizards has been one cause of their diminished numbers. These introduced ant species are not palatable to the lizard. Although three subspecies of this lizard inhabit California, from Baja up the Central Calley to the Sierra Buttes, the last vestige of these unique creatures in Contra Costa County is Mount Diablo. The overall population of the Coast horned lizard throughout California has been under threat because of habitat destruction, pesticides, agriculture, and the introduction of Argentine ants. Blainville’s horned lizards are generally seen in our coast range and the Central Valley from spring through fall, hibernating in burrows under ground in cold weather. Found in chaparral, mixed oak, and grey pine forest, sandy loam soil, and gravelly areas, these lizards need a mixture of open space and shrubbery with soil they can easily dig into as well as populations of native ants for food. They breed in spring, with the female laying a small clutch of eggs (average 8-12) in a burrow she excavates. Newborns hatch in late summer or early fall and are miniatures of their parents, about the size of a quarter. Once much more common in Contra Costa County, the population has decreased in recent years. On Mount Diablo keep your eyes open, especially on Eagle Peak, Twin Peaks, Black Point, White Canyon, Mount Olympia, and on the south side along Black Hawk Ridge. Because of its specialized diet and environmental conditions, this is a lizard that does not do well in captivity (horned lizards in North America can no longer be sold in the pet trade) so please enjoy them when you see them, but let them be. Enjoy this unique and marvelous creature along with the rest of the natural environment in Mount Diablo State Park. Blainville's Lizard changes color to blend with the soil. | Dan Sandri By Dan Sandri BACK TO LIST