L03 Ecosystems Biomes

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L03 Ecosystems Biomes

  1. 1. Ecosystems – what types are there, and where are they located?
  2. 2. Types of Ecosystems <ul><li>estuaries </li></ul><ul><li>swamps and marshes </li></ul><ul><li>tropical rain forest </li></ul><ul><li>temperate forest </li></ul><ul><li>northern coniferous forest (taiga) </li></ul><ul><li>savanna </li></ul><ul><li>agricultural land </li></ul><ul><li>woodland and shrubland </li></ul><ul><li>temperate grassland </li></ul><ul><li>lakes and streams </li></ul><ul><li>continental shelf </li></ul><ul><li>open ocean </li></ul><ul><li>tundra (arctic and alpine) </li></ul><ul><li>desert scrub </li></ul><ul><li>extreme desert </li></ul>Miller Ch 4 Fig 4.21)
  3. 3. Biomes (Miller Ch 4 Fig 4.8); Cotgreave & Forseth Ch 2) <ul><li>large regions of the ecosphere containing ecosystems and communites which are similar in vegetation structure </li></ul><ul><li>occur in similar overall environments (climate) </li></ul><ul><li>species composition is different in the same biome in different parts of the world </li></ul>
  4. 4. BIOMES - WORLDWIDE PATTERNS OF DIVERSITY at a world scale the vegetation is clumped into a few major types called BIOMES, based on abiotic factors
  5. 5. <ul><li>BIOME boundaries tend to run east-west around the earth, and they reflect the climatic changes which occur from the POLES to the EQUATOR </li></ul><ul><li>the pattern of BIOME distribution is determined by GROSS CLIMATE and occurs over thousands of kilometres of latitude </li></ul><ul><ul><li>day-length </li></ul></ul><ul><ul><li>temperatures </li></ul></ul><ul><ul><li>rainfall distribution </li></ul></ul>
  6. 6. <ul><li>HIGH LATITUDES are characterised by TUNDRA </li></ul><ul><li>LOW TEMPERATURE </li></ul><ul><li>LOW RAINFALL </li></ul><ul><li>EXTREMES of DAY LENGTH </li></ul><ul><li>(short “growing season”) </li></ul><ul><li>and characteristic groups of plants are dominant </li></ul>SEDGES and DWARF TREES LICHENS MOSSES TUNDRA
  7. 7. <ul><li>moving towards the equator (LOW LATITUDES) the </li></ul><ul><ul><ul><ul><li>rainfall increases </li></ul></ul></ul></ul><ul><ul><ul><ul><li>temperatures rise </li></ul></ul></ul></ul><ul><ul><ul><ul><li>day length increases </li></ul></ul></ul></ul>and the vegetation which characterize the BIOMES changes high latitudes high latitudes low latitudes (equator)
  8. 8. TAIGA ( BOREAL FOREST ) BIOME large areas of boreal forest - conifer forests - only in northern hemisphere
  9. 9. TEMPERATE DECIDUOUS or EVERGREEN FOREST BIOME (eg. Eucalyptus ) evergreen deciduous
  10. 10. DESERT BIOMES occur wherever RAINFALL is low and unpredictable deserts
  11. 11. GRASSLAND BIOMES occur where rainfall is higher and reliable high but unreliable rainfalls result in SAVANNA BIOMES tropical grassland & savanna temperate grasslands
  12. 12. <ul><li>as a general rule, the diversity of species in a biome declines with increasing severity of climate </li></ul><ul><li>eg. TROPICAL BIOMES - mild climate - only 7% of land mass, but contain </li></ul><ul><ul><ul><ul><li>50% terrestrial plants </li></ul></ul></ul></ul><ul><ul><ul><ul><li>30% birds </li></ul></ul></ul></ul><ul><ul><ul><ul><li>50% vertebrates </li></ul></ul></ul></ul><ul><ul><ul><ul><li>90% insects </li></ul></ul></ul></ul>tropical biome
  13. 13. <ul><li>BUT high species diversity CAN be found in BIOMES in severe climates </li></ul><ul><ul><ul><li>eg. reptile diversity in Australian DESERT BIOME is HIGH </li></ul></ul></ul>Threats to TROPICAL BIOMES have received most attention, but BIODIVERSITY is in serious decline in most BIOMES
  14. 14. BIOME orientation can be altered by mountain ranges running north-south Rockies (USA) Andes (South America) Great Dividing Range (Australia)
  15. 15. Biome types can be altered by secondary processes such as fire, or grazing - HEATH & DRY SCLEROPHYLL (Australia), GARIQUE (Mediterranean Europe), FYNBOS (Southern Africa), CHAPARRAL (USA - California) Heath in Australia – high endemic diversity is maintained by fire
  16. 16. World-scale Plant and Animal Distributions <ul><li>species and ecosystems can be examined in terms of compositional properties as well as structural properties </li></ul><ul><li>the study of distributions shows that biomes and ecosystems with similar structures can have very different compositions , reflecting different evolutionary histories </li></ul>
  17. 17. <ul><ul><li>Lydekkers line  eastern limit of oriental elements </li></ul></ul><ul><li>Wallacaea </li></ul><ul><ul><li>zone of mixing between Australian and Oriental realms mostly in last 15 million years </li></ul></ul><ul><ul><li>Wallaces line  western limit of Australian elements </li></ul></ul>
  18. 18. Oriental and Australian avifauna in Wallacaea  ali Lombok Sumbawa flores Alor 87-13 72-28 68-32 63-37 57-43 Oriental Australian 
  19. 19. World Patterns of Plant Distribution <ul><li>distribution patterns can indicate </li></ul><ul><ul><li>environmental requirements of the taxon </li></ul></ul><ul><ul><li>dispersal ability </li></ul></ul><ul><ul><li>areas of origin or diversification </li></ul></ul><ul><ul><li>evolutionary and pre-history of the taxon </li></ul></ul>
  20. 20. Types of plant distributions <ul><li>the terms we use to describe distributions can imply processes, constraints, history </li></ul><ul><ul><li>Cosmopolitan species (e.g., Drosera spp.) </li></ul></ul><ul><ul><li>Relictual families ( Cycadaceae ) </li></ul></ul><ul><ul><li>Gondwanan families ( Restionaceae ) </li></ul></ul><ul><ul><li>sub-antarctic ( Nothofagus spp.) </li></ul></ul><ul><ul><li>disjunct species ( Eucalyptus aggregata ) </li></ul></ul><ul><ul><li>endemic genus ( Isophysis tasmanica ) </li></ul></ul>Macrozamia communis NSW
  21. 21. Regional biodiversity hotspots <ul><li>“ hotspot” - a region where high biodiversity and high endemism are found, and high threat (risk of loss) sometimes coincide </li></ul><ul><li>development of ‘hot-spot’ regional biotas </li></ul><ul><ul><li>in situ development (e.g. SW Australia, southern Africa) </li></ul></ul><ul><ul><li>survival of ancient forms (e.g. New Caledonia, Madagascar) </li></ul></ul><ul><ul><li>mixing of elements (e.g. Oriental and Australasian bird species in Wallacaea) </li></ul></ul><ul><ul><li>isolated islands </li></ul></ul>
  22. 22. Regional plant diversity for selected areas * area in thousands of square kilometres

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