CHAPTER 4: A Mediterranean Place: Plant Communities

Mediterranean Climate

- description

- global occurrence

- Med vegetation makes up ~ 2% of the world’s vegetation

- Med vegetation makes up ~ 10% of California (pre-European) vegetation

- it’s very rare!

- all over the world it is similar despite being unrelated due to

o convergent evolution

Plant Adaptations

“HARD” CHAPARRAL (CHAPARRAL)

- evergreen

- leaves thick, waxy, tough

- growth slow, persistent, year-round (but most growth occurs during winter rains)

- many subtypes

- ex: lemonade berry

“SOFT” CHAPARRAL (COASTAL SAGE SCRUB)

- drought deciduous

- leaves softer (hence the name), quickly produced, dropped up to several times per year

- seasonal growth

- many subtypes

- example: California sagebrush

SUCCULENTS

- store water in leaves, stems and roots

- ex: coastal cholla cactus, prickly pear cactus

ALL PLANTS

- often annuals with large seed banks

- roots – deep roots and shallow roots that can be turned on/off as needed (dual root system)

- leaves often fuzzy, vertically oriented, pores on the underside to minimize evaporative water loss (remember the pores you saw under the microscope in last week’s lab?)

- frequently have chemical defenses – which are often oils

- aromatic with culinary value, or toxic, also flammable!

FIRE

historically every 80-100 years

now about every 20-30 years

FIRE ADAPTATIONS:

- (re)sprouters with basal burls

- seeders with large seed banks and fire stimulated germination (dormancy an be long!)

- fire followers – annuals, transient, large seed banks, very biodiverse

PLANT COMMUNITIES

- predictable species groups

- habitat and competition affect distributions of individual species

- transitions are gradual, but consistent groupings are real

- described based on species, in order of commonness and structure

- there are many local subtypes

On Point Loma you can find 4 of these natural plant communities (see page 94), collectively known as “scrub” (“scrub” refers to plant communities dominated by shrubs)

Coastal Sage Scrub (“soft chaparral”) after dominant California sagebrush

- covered 2.5% of pre-European California, but only ¼ to 1/3 % of California now due to agricultural and urban expansion

- it is centered in the San Diego region and extends south into Baja and north to Big Sur

o description of CSS, habitat where found, typical species

Chaparral (“hard chaparral”)

o description of chaparral, habitat where found, typical species

- on Point Loma it is a subtype called “southern maritime chaparral”

- we will see another type of chaparral when we visit Torrey Pines

other plants communities found on Point Loma include two subtypes tolerant of sandy soil and salt spray

additional plant communities found in southern California will be discussed later

CHAPTER 5: Life on the “Island”: Animals

Animals covered:

NATIVE SPECIES

mammals (recap – what’s a mammal?)

desert shrew

pocket mice

CA mouse

Mexican long-tongued bat

coyote

gray fox

raccoons

striped skunks

birds

migratory vs. resident

prothonotary warblers

rose-breasted grosbeaks

raptors

· red-tailed hawk

· broad-winged hawk

· peregrine falcons (DDT story – no longer listed)

American oystercatcher

Brant’s cormorant

blue herons

black-crowned night herons

orange-crowned warbler

song sparrows

invertebrates

insects, spiders, millipedes, land snails

strap-door spider

stink beetles

glowworms (beetle larvae)

silk-spinning crickets

Jerusalem crickets (host for parasitic horsehair worm that infects large mammals)

shoulder band snails

reptiles and amphibians (what’s the difference?)

pacific tree frog

western toad

western spade foot toad

SD alligator lizard

tail loss in lizards

SD alligator lizard bites own tail to form a loop!

CA legless lizards

orange-throated whiptail

western fence lizard

side-blotched lizard

ring-necked snake

pacific rattlesnake

red diamond rattlesnake

striped racer

CA horned lizard

slender salamander

NONNATIVE SPECIES

many! birds, reptiles, insects, house cats …

Conservation issues …