Biology Lab #12: Chaparral Biome and Species of Irvine Park

Ecological Observation and at Irvine Park

• Methodology of Biological Study: Biologists study organisms through two primary methods:

  • Laboratory Study: Studying organisms in a controlled environment to make discoveries.

  • Field Study (Natural Habitats): Observing how individuals interact with both living (biotic) organisms and the nonliving (abiotic) environment in their native settings.

• Irvine Park Overview:

  • Location: Situated on the northwest foothills of the Santa Ana Mountains.

  • History: Established in 1897.

  • Size: Comprises a total of $475\,\text{acres}$.

  • Land Use: Parts are developed for recreational use, while other sections remain in their native state, representing the chaparral biome.

The Chaparral Biome

• Definition of Biome: Biomes are geographic areas defined primarily by temperature and precipitation. Similar types of flora and fauna are found in areas with similar climates.

• Regional Characteristics: Orange County and coastal Southern California are characterized by:

  • Mild, wet winters.

  • Hot, dry summers.

  • The climate results from cold ocean currents located near the coast.

• Biological Composition: Includes evergreen shrubs, such as oaks, and species adapted to frequent fire events.

Adaptations to Environmental Challenges

• Climate Adaptations: Survival in hot, dry summers is a significant challenge.

  • Plant Adaptations: Some plants exhibit drought deciduousness by shedding leaves in summer. This minimizes leaf surface area to reduce water loss, allowing the plant to remain alive despite appearing dead.

  • Animal Adaptations: Many species utilize nocturnal activity patterns to remain active at night when temperatures are cooler.

• Fire Adaptations: Fire is an essential force for maintaining biodiversity in chaparrals, grasslands, and savannas.

  • Natural Causes: Historically caused by lightning.

  • Reproductive Dependency: Certain plants produce seeds that will only germinate after exposure to hot fires. Without fire, these species cannot reproduce and may be outcompeted or disappear.

Spatial Distribution of Organisms

• Water Availability: Distribution varies based on proximity to water sources.

  • Santiago Creek: A local creek that carries water only during and after rain events. Tree species composition changes significantly based on distance from the creek bed.

• Slope Aspect and Insulation:

  • South-facing Slopes (Northern Hemisphere): Receive more direct sunlight. Consequently, they are warmer and drier. Cacti are commonly observed here.

  • North-facing Slopes (Northern Hemisphere): Drier and cooler due to less direct sunlight.

  • Geographic Note: This distinction between north and south slopes exists only outside the tropics. In the Southern Hemisphere, the situation is reversed.

Native and Non-native Species Dynamics

• Native (Indigenous) Species: Species that have lived and evolved in a specific location for long periods.

• Non-native (Exotic/Invasive) Species: Species that arrived in an area relatively recently.

  • Introduction Mechanisms: Intentional (ornamental plants) or accidental (seeds sticking to hiker shoes).

  • Competitive Advantage: Non-native species often leave their natural enemies (predators/competitors) behind in their original habitats, allowing them to out-compete native species for resources.

Fauna of Irvine Park

• Detection: Many animals are elusive, but their presence is confirmed through footprints, scat, and calls.

• Key Bird Species: Crow, raven, acorn woodpecker, starling, scrub jay, turkey vulture, red-tailed hawk.

• Key Mammal Species: Cottontail rabbit, coyote, ground squirrel, packrat, opossum, red fox, bobcat.

• Key Reptile Species: Various lizards, gopher snakes, garter snakes, rattlesnake.

• Arthropods: Wide variety of insects and spiders.

Botanical Survey: Trees and Large Shrubs

• California Sycamore ($Platanus\,racemosa$):

  • Height: Ranges from $30\,\text{ft}$ to $90\,\text{ft}$.

  • Morphology: Broad palmate leaves; bark that peels away to reveal a mottled patchwork of colors.

  • Reproduction: Separate male and female flowers.

  • Habitat: Moist soils that rarely dry out.

  • Uses: Ornamental and shade usage.

• Coast Live Oak / Encina ($Quercus\,agrifolia$):

  • Height: $10\,\text{m}$ to $25\,\text{m}$.

  • Morphology: Evergreen with a broad crown; cupped, oval, toothed leaves ($2\,cm$ to $6\,cm$ long).

  • Reproduction: Monoecious (separate male and female flowers on one tree); wind-pollinated; produces nuts (acorns) $2\,cm$ to $4\,cm$ long. Flowers bloom February–April; fruit matures August–October.

  • Symbiosis: Obligate association with mycorrhizal soil fungi for nutrients and moisture.

  • Uses: Erosion control; food for birds, mammals, and deer; historical food source for Native Americans; wood used for high-quality charcoal.

• Toyon ($Heteromeles\,arbutifolia$):

  • Height: Up to $10\,m$.

  • Morphology: Evergreen shrub; gray bark; oval leaves with spiny margins; small white flowers in large clusters; red or yellow fruit.

  • Uses: Native American food source; food for birds and small mammals.

• Laurel Sumac ($Malosma\,laurina$):

  • Height: $3\,m$ to $5\,m$.

  • Morphology: Large evergreen shrub/small tree; leathery oval leaves; reddish leaf veins and petioles; fragrant white flower clusters.

  • Climate Sensitivity: Frost-sensitive; plants die when temperatures drop below $26^\circ F$.

  • Uses: Indicator plant for farmers to site frost-sensitive crops.

• Blue Elderberry ($Sambucus\,nigra$):

  • Height: Up to $8\,m$.

  • Morphology: Deciduous shrub; opposite compound leaves with $3$ to $9$ leaflets (pungent smell); white flowers (June/July); deep-purple/black fruit (August/September).

  • Toxicity/Medicine: Purple/black berries are edible, but red berries are poisonous. Contains alkaloids that induce nausea/vomiting.

  • Uses: Dye for basketry; wood used for flutes and arrow shafts.

• Lemonade Berry ($Rhus\,integrifolia$):

  • Height: Up to $8\,m$.

  • Morphology: Evergreen shrub; rounded leathery leaves with toothed edges; sticky reddish hairy fruit; white or pinkish flowers.

  • Uses: Fruits used to make lemonade-like drink; landscaping.

Botanical Survey: Shrubs and Herbs

• Coastal Sagebrush ($Artemisia\,californica$):

  • Height: Up to $2.5\,m$.

  • Characteristics: Rounded shrub belonging to the sunflower family; threadlike, thin leaves with a strong scent.

  • Uses: Cooking herb.

• White Sage ($Salvia\,apiana$):

  • Height: Up to $1\,m$.

  • Characteristics: Perennial shrub from the mint family; leaves ($4\,cm$ to $8\,cm$) covered in whitish powder; white flowers with lavender spots.

  • Uses: Pinole ingredient; stems/leaves eaten; seeds used as shampoo or placed under eyelids to clean/heal eyes. Tea used to decrease sweating/secretions.

• Black Sage ($Salvia\,mellifera$):

  • Height: $1\,m$.

  • Characteristics: Evergreen shrub from the mint family; square stem; opposite leaves in pairs alternating at $90^\circ$ angles; mint smell.

  • Uses: Leaf tea; seeds as spices; leaves chewed for gas relief.

• Horehound ($Marrubium\,vulgare$):

  • Height: $30\,cm$ to $40\,cm$.

  • Characteristics: Perennial herb; square stem; circular wrinkled leaves; white flowers in whorls.

  • Uses: Dried leaves for cold/cough/sore throat tea; high doses act as a laxative.

• Buckwheat ($Eriogonum\,fasciculatum$):

  • Height: Up to $2\,m$.

  • Characteristics: Rounded shrub; leathery leaf clusters with woolly undersides; pink/white flower clusters.

  • Uses: Leaf tea for headaches/stomach aches; root tea for colds/laryngitis; nectar source for insects.

• Iceplant:

  • Status: Non-native (introduced from Africa).

  • Characteristics: Long, thin, triangular succulent leaves; dark pink or purple flowers.

  • Uses: Soil erosion control.

• Prickly Pear Cactus ($Opuntia\,littoralis$):

  • Characteristics: Succulent perennial; modified leaves for defense; flattened oval stem segments.

  • Uses: Fruit, seeds (ground for flour), and pads (cooked as vegetables) are edible.

Parasitic and Reactive Plants

• Mistletoe:

  • Type: Parasitic evergreen shrub.

  • Mechanism: Photosynthetic (green leaves) but relies on host for water and minerals via a modified root.

  • Dispersal: Birds eat the whitish berry fruit and deposit seeds via feces.

  • Uses: One family member is used as "kissing mistletoe."

• Poison Oak ($Toxicodendron\,diversilobum$):

  • Type: Woody shrub or climbing vine.

  • Identification: Three-lobed leaves; winter deciduous.

  • Toxicity: Contains urushiol oil. $70\%$ to $85\%$ of people have an allergic reaction, though typically not upon the first exposure.

• Dodder / Witches Hair ($Cuscuta\,californica$):

  • Type: Parasitic vine.

  • Mechanism: Yellow hair-like stems wrap around host to extract nutrients/water; reduced leaves.

  • Impact: Transmits diseases to the host plant.

• Wild Cucumber / Manroot ($Marah\,macrocarpus$):

  • Type: Vine with a perennial root that can weigh over $100\,kg$.

  • Fruit: Distinctive green prickly fruit that turns yellow at maturity.

  • Uses: Root processed for soap; leaves used as vegetables (bitter taste).

Review Questions

• Characteristics of Chaparral: Defined by the seasonal cycle of mild, wet winters and hot, dry summers influenced by cold coastal ocean currents.

• Fire Survival/Benefit: Mechanisms include fire-stimulated seed germination and the clearing of competitors to facilitate reproduction.

• Survival in Arid Conditions: Observed adaptations include summer leaf shedding (drought deciduousness) to prevent water loss and nocturnal activity in animals.

• Nature of Non-native Species: Defined as species introduced recently to an area, often having advantages because they arrive without the natural enemies (predators) found in their native habitats.

• Vegetation on Slopes: South-facing slopes are warmer and drier, supporting more succulents like cacti, while north-facing slopes are cooler.

• Botanical Hazards: Poison Oak ($Toxicodendron\,diversilobum$) should not be touched; the red berries of the Blue Elderberry ($Sambucus\,nigra$) should not be eaten; Prickly Pear Cactus ($Opuntia\,littoralis$) pads and fruit are edible.