Torrey Pines State Park and Reserve:

1
Torrey Pines State Park and Reserve

• Maritime Succulent Scrub and Maritime Chaparral

2
Biological Levels of Organization
Individuals lt Population lt Community lt
Ecosystems lt Biome lt Biosphere
3
Chaparral Biome
4
Mediterranean Climate

• Mid-latitude (30 deg), coastal regions
• Sea level 5500
• Seasonal precipitation
• Precipitation 8-20, mostly in winter (Dec Mar)
• Summers are dryseasonal drought.
• frequent drought years
• Rain/precipitation highly variable from year to
  year.
• Seasonal Temperatures
• long dry summers 80-100 F
• spring, winter, fall are cool (50s-70s)
• winters moderately cold in coastal regions, but
  higher elevation can experience frost and small
  amounts of snow
• In more coastal regions
• Santa Ana winds in summer (hot and dry)
• fog, mist, marine layer in some seasons

5
Common Communities of the Mediterranean Climate
(Chaparral Biome) in CA

• Chaparral (true/hard chaparral)
• Coastal Sage scrub (soft chaparral)
• Oak woodland
• Riparian
• Grassland

6
Number of Chaparral Species

• 100 shrubs
• 40 common
• A given site will have 1-10 common shrub species.
• A very diverse community for having such a
  limited geographic distribution.

7
Adaptations for Dry Environments

• LEAF CHARACTERISTICS
• small leaves
• low surface area results in less water loss
• Thick cuticle
• thicker cuticle makes water loss difficult,
  bigger barrier to evaporation
• Oily/resinous leaves accomplish the same result
• These leaves are often shiny
• dull leaves
• reduces heat build, and thus reduce
  evaporation/water loss
• hairy leaves
• create a boundary layer of humidity, and reduce
  water loss
• stomata concentrated on underside of leaf
• shaded side of leaf reduces transpiration
• Spiny leaves

8
xerophytic leaf adaptations
9
Ecological (Adaptive) Strategies for Water
Stressed Environments

• Drought Deciduous
• Drops Leaves during extended dry season
• Evergreen
• Keeps leaves year round
• Succulents
• Stores water in thick, fleshy leaves

10
Ecological (Adaptive) Strategies for Water
Stressed Environments

• Drought Deciduous
• Plant has leaves that are dropped/lost seasonally
  with low water availability.
• These leaves lose a lot of water (poor resistance
  to water loss), but are highly photosynthetic.
• Trades short periods of high productivity that
  correspond with water availability with
  prolonged periods of water conservation but no
  productivity after leaves are lost.

11
Ecological (Adaptive) Strategies for Water
Stressed Environments

• Evergreen
• Plant has leaves all year long (although
  individual leaves are lost and replaced regularly
  throughout the year).
• Leaves are thick and high resistant to water
  loss, but perform lower levels of photosynthesis
  (at least at some temps).
• It compensates for low rates of photosynthesis by
  performing photosynthesis year round.
• Requires access to water for most of the year,
  thus these plants often have deep taproots to
  acquire water during dry season.

12
Ecological (Adaptive) Strategies for Water
Stressed Environments

• Succulents
• Store water in fleshy leaves and stems.
• Often have CAM metabolism
• A form of photosynthesis where stomata are open
  at night and CO2 is stored for day when it is
  used for photosynthesis
• This reduce water loss, because stomata are
  closed during day.
• Results in slow growth as only a small amount of
  CO2 is stored and so can only perform
  photosynthesis for a short period of each day.

13
Coastal Sagescrub

• Climate and Water Availability
• 8-10 of precipitation during winter
• prolonged dry season (summer through fall)
• However, moderate temperature reduce evaporation
  stress
• Winter growing season
• General Patterns in Plant Characteristics
• 2-4 tall, few truly woody plants (sub-shrubs)
• moderately spaced
• Shallow root systems capture rain/precipitation
  as soon as it falls.
• Mostly drought deciduous
• frost intolerant
• generally burned areas must be re-colonized
• this is done through wind dispersal

14
Coastal Sage scrub
15
Coastal Sage scrub
16
Coastal Sage scrub
17
The Chaparral Community

• Climate and Water Availability
• 10-25 of precipitation, mostly during winter,
  little as snow
• Prolonged dry season during summer
• Temperature range more extreme then coast
• Colder in winter, often hotter in summer
• Winter and spring growing season
• General Patterns in Plant Characteristics
• Shrub dominant, mostly woody
• 6-15 tall
• Closely spaced plants (often interlacing)
• Evergreen plants are dominant.
• Dual root systemsshallow and long taproot
• Frost tolerant
• Few understory plants
• Fire adapted
• Seed banks
• Re-sprouters

18
Chaparral in foreground with trees in background
(which is wetter)
19
More chaparral plants
20
Chaparral is Fire Adapted, NOT fire dependent

• Because fires are common in chaparral communities
  the plants have adaptations that allow the rapid
  regrowth/repopulation of plants.
• It is simplistic and incorrect to say it needs to
  burn. Individual plants can continue to grow
  just fine without fire
• Although some do need fire to complete life cycle
• Fires too frequently (lt15 yrs) will cause
  replacement of chaparral by non-native plants

21
Fire Strategies

• Crown sprouters
• Burls (roots) that store water and nutrients
• Somewhat protected from fire
• Give rise to new shoot systems after fires (from
  roots)
• Seed Banking
• A large number of dormant seeds in the soil
• Require fire to sprout, repopulate area post
  fire.
• Often sit dormant for decades resulting in areas
  with plants that are cohortslittle intermediate
  stages
• Fire Followers
• Increased nitrogen triggers germination (or other
  chemical triggers/changes to seed)
• Annuals will complete lifecycle year after fire
  and then sit dormant again for decades
• Important in soil stabilization

22
Chaparral and Fire

• Pre-human fire cycle is estimated to be 30-100
  years
• American Indians frequently burned chaparral to
  increase tuber herbs (for food), frequency of
  game animals, and growth of willows for basket
  weaving
• For much of the 1900s there was an active policy
  of fire suppression or prevention
• More recently (30 yrs) there is a recognition
  that burns are natural events.
• Controlled Burns

23
Chaparral one year after a fire
24
(No Transcript)
25
Torrey Pines--Maritime Shrub-dominant Communities
(uncommon communities)

• Maritime Succulent Scrub
• Exists in southernmore dryerregions
• Includes
• common coastal sagescrub plant
• increased number of evergreens
• Increased succulents
• central Baja through Laguna Beach
• most species rich of all scrub communities
• reduced fire frequency
• Maritime Chaparral
• Community of evergreen plants that includes a
  diminutive form of Chamise
• presence of some desert-typical plants
• these plants are not typical of coastal areas
• once common throughout San Diego Co. and northern
  Baja
• Intermixes with Maritime succulent scrub

26
Torrey Pines S.P.
27
(No Transcript)
28
(No Transcript)
29
(No Transcript)
30
Sagescrub v. Chaparral(physical structure and
ecological strategies)

• Coastal Sagescrub

• Chaparral

31
Human Impacts

• Much of the chaparral has been destroyed by
  urbanization and agriculture.
• Suppression of natural fire cycles (according to
  some sources)

Chaparral Sage Scrub impacts on Humans

• Fires that destroy property

32
Did You Know?Did you know that the coastal sage
scrub habitat is one of the most endangered
ecosystems in the world? Only 10-15 of the
original habitat now exists. Once the dominant
ecosystem, the coastal sage scrub community now
only exists in small remnant pockets n.p.s.
cabrillo national monument website
Due to urban development, grazing, and agriculture