Part 2

• Nine biomes: Five today
• Fynbos, Grassland, Savanna
• Discuss uniqueness of Fynbos Biome
• How can we distinguish Savanna and Grassland biomes

  
• Biome 1: Desert: characteristics?
• Biome 2: Forest biome: Characteristics and conservation issues
• Classification of Terrestrial Ecosystems
• The ecoregions are categorized within 14 biomes and eight biogeographic realms to facilitate representation analyses (Olson et al. 2001).
• SA: Global map does not reflect rich biodiversity!

  
• South African Biomes
• South Africa is host to a range of biomes, which encapsulate the huge biological diversity of the country.

  
• These can be attributed to the presence of strong environmental gradients in:

  • Rainfall
  • Temperature
  • Geology
  • Soils
• Strong effect of fire &


  • Herbivory on vegetation
• How is anthropogenic impact reflected here?
• Part of the Cape Floral Kingdom
• Home to 9 000 plant species of southern Africa's (40% flora)

  
• More species than 50% are endemic to South Africa
• More than 20% of plant species are threatened by extinction
• Own Plant Kingdom: Capensis!!
• Cape has Mediterranean climate:

  • Winterwet climate, dry summers
  • Similar to Chile, California, Mediterranean, SW Australia
  • But unique vegetation with extremely high diversity
  • But growth forms (shrubby vegetation) similar to other Mediterranean regions

  
• Do not provide enough nitrogen for the protein requirements of large mammals
• Fynbos cannot therefore support herds of large mammals
• Smaller mammals are common
• Dominant taxa: Proteaceae
• Dominant taxa: Ericaceae (658 species)
• Dominant taxa: Restionaceae
• Fynbos is a 'fire-driven' ecosystem


  • Regular burns are needed:
  • to control alien invasives
  • to trigger seed germination
  • to kill off senescent (~old) individuals
  • To remove pests and diseases
• e.g. All proteas require fire for regeneration (without fire they would go extinct)
• Fire adaptations - Serotiny

  • Storing seeds in fire-proof cones, and releasing seeds only after being burned by fire
  • e.g. many proteas
• Explaining fynbos diversity


  • Adaptive radiation (rapid speciation)
  • Allopatric speciation: Allopatric speciation is the process by which new species evolve in geographic isolation from their ancestral population
• Explaining fynbos diversity


  • Spatial and temporal factors
• Habitat transformation - agriculture
• Threats: aliens
• 'Vacant tree niche'


  trees do not naturally occur in this biome
• Susceptible to the invasion of black wattle and pine
• Aliens alter natural fire frequencies, utilise water, replace indigenous species
• Threats: poor fire management
• How to manage a 'fire-driven' ecosystem?

  Balancing control vs ecology?
• Accidental fires have a negative impact
• Controlled burns should not be:

  • Too frequent
  • Too infrequent (supressed)
  • In the wrong season (e.g. spring)