Mediterranean Climates & Temperate Shrublands

 

Mediterranean Climates Support Temperate Shrublands

 

 

  • A shrubland is a plant community in which the shrub growth is dominant or codominant
    • A shrub is a plant with multiple woody, persistent stems and a height from 4.5 m (15 feet) to 8 m (26 feet)

       
  • Mediterranean ecosystems are found along the western margins of the continents between 30 and 40 latitude
    • Dominated by evergreen shrubs and sclerophyllous trees
  • Five regions:
    • Western North America
    • Borders of the Mediterranean Sea
    • Central Chile
    • Cape region of South Africa
    • Southwestern/southern Australia
       

 

 

 

 

  • A Mediterranean climate has
    • Hot, dry summers with at least 1 month of protracted drought
    • Cool, moist winters
  • Mediterranean climates support similar-looking plant communities
    • Xeric broadleaf evergreen shrubs
    • Dwarf trees
    • Herbaceous understory
       

 

  • Sclerophyllous vegetation has adaptations that reduce water loss during the summer period
    • Small leaves, thickened cuticles, glandular hairs, sunken stomata
  • Shrubland vegetation also shares adaptations to fire and low nutrient levels in the soil
     

 

 

 

 

Sclerophyllous leaves of some tree and shrub species inhabiting mediterranean shrublands (chaparral) of California

Chamise (Adenostomata fasciclatum)

 

 

 

Scrub oak (Quercus dumosa)

 

 

 

 

Chinquapin (Chrysolepis sempervirens)

 

 

 

 

  • The largest area of Mediterranean ecosystem forms a discontinuous belt around the Mediterranean Sea
  • Southern Africa
    • Fynbos
       

Mediterranean vegetation (fynbos)
of the Western Cape region of
South Africa

 

 

 

 

  • Southwest Australia
    • Mallee is dominated by low-growing Eucalyptus
  • North America
    • Chaparral is dominated by scrub oak and chamise

 

Chaparral shrub vegetation of
southern California

 

 

 

 

  • Central Chile
    • Matorral shrub communities dominated by evergreen shrubs with small sclerophyllous leaves
       

 

  • For the most part, Mediterranean shrublands lack an understory and ground litter and are highly inflammable
  • Many species have seeds that require the heat and scarring action of fire to induce germination
    • As chaparral grows taller and denser, a large fuel load builds up and sets the stage for fire

       
  • A similarity in habitat structure of the Mediterranean shrublands has resulted in pronounced parallel and convergent evolution among bird and some lizard species
    • This is especially pronounced in the California chaparral and Chilean mattoral
       

 

  • Shrubland soils are generally deficient in nutrients
    • Limited litter decomposition in low winter temperatures
    • Low soil moisture in summer months
  • Shrubland soils
    • Alfisols
  • Ecosystem productivity varies with annual precipitation and severity of summer drought