Waitakere Ranges –  Elements and Interactions Spatial Variations
Element / Interaction Model  GEOLOGICAL / GEOMORPHOLOGICAL SYSTEMS = RELIEF PEDOLOGICAL SYSTEM = SOILS CLIMATIC SYSTEM BIO...
Climate <ul><li>Climate data shows the Waitakere Ranges are slightly  cooler  and rather  wetter  than the Auckland urban ...
Why? <ul><li>Effect of Altitude:  roughly 6 0  temp decrease every 1000m increase in altitude.  </li></ul><ul><li>Waitaker...
<ul><li>Orographic Rainfall </li></ul>Moist air forced to rise  Rain shadow on leeward side  Air warms as it descends   Ai...
<ul><li>The climate of the Waitakeres is  sub-tropical .  It lies in the path of prevailing westerly winds which are moist...
Relief – Geology / Geomorphology <ul><li>Refer back to notes about the formation / evolution of the Ranges </li></ul><ul><...
Main landforms <ul><li>Prominent ridgelines (e.g. Scenic Drive Scarp) </li></ul><ul><li>Incised stream catchments and stre...
 
 
 
 
 
 
 
 
 
 
Formation of landforms <ul><li>The topography (shape) of a landscape is determined by 2 major processes  </li></ul><ul><li...
Tectonic Processes <ul><li>These are caused by movement in the earths crust and cause </li></ul><ul><li>Fold mountains  </...
Erosional Processes <ul><li>These erode (break down) the mountain landscapes, remove the rock and soil through wind, rain,...
Soils <ul><li>SOIL = the transition zone between rocks and vegetation. </li></ul><ul><li>Soils are in a constant state of ...
<ul><li>The soil of the Waitakeres is generally red-yellow podzolic.  This is highly fertile and formed from andesitic roc...
Reasons / Patterns <ul><li>High rainfall (2000mm per year) AND mild-warm temperatures  </li></ul><ul><li>= Rapid forest gr...
Kauri / Rimu Forest soils <ul><li>These trees are inefficient at cycling nutrients back to the soil.  The litter they drop...
Other patterns <ul><li>“ Gley” soils  = Waterlogged soils around stream floodplains where the soil has a very high water c...
Vegetation <ul><li>Vegetation in the Waitakere Ranges is known as “sub-tropical Rainforest”. However, there are variation ...
Forest Stratification <ul><li>The forest is made up of several “layers”.  The process by which this structure emerges over...
General Structure <ul><li>Dominated by Kauri, Rimu and Northern Rata </li></ul><ul><li>The  Emergent  layer is (or was) th...
… continued <ul><li>Lower shrub and ground level  has small ferns, grasses, mosses and lichens. </li></ul><ul><li>Clinging...
<ul><li>Due to the high rainfall and mild temperatures The Waitakere Ranges contain: </li></ul><ul><li>¼ of our flowering ...
Vegetation Patterns <ul><li>Vegetation distribution mostly influenced by micro-climates largely influenced by  relief </li...
Ridge Tops… <ul><li>Vegetation:  </li></ul><ul><li>Canopy trees (esp. Kauri and Rata), and lots of lower canopy trees – ma...
Lower Floodplains… <ul><li>Vegetation: </li></ul><ul><li>Larger percentage of ferns (ponga’s, grass skirt ponga’s, and nik...
Western flank (Tasman coast) <ul><li>Vegetation: </li></ul><ul><li>hardy low lying trees such as manuka / kanuka / cabbage...
Wildlife <ul><li>Animals are an important feature living in our native bush.  They re-distribute seeds and help the forest...
 
 
 
 
 
 
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Waitakere Ranges – Elements And Interactions, Spatial Variations

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Waitakere Ranges – Elements And Interactions, Spatial Variations

  1. 1. Waitakere Ranges – Elements and Interactions Spatial Variations
  2. 2. Element / Interaction Model GEOLOGICAL / GEOMORPHOLOGICAL SYSTEMS = RELIEF PEDOLOGICAL SYSTEM = SOILS CLIMATIC SYSTEM BIOTIC SYSTEM = VEGETATION / ANIMALS
  3. 3. Climate <ul><li>Climate data shows the Waitakere Ranges are slightly cooler and rather wetter than the Auckland urban area </li></ul>Waitakere Ranges: Albert Park in Auckland City: 17 16 15 14 11 10 12 13 15 16 17 17 Temp ( C) 160 145 190 170 200 260 240 230 175 130 160 140 Rainfall (mm) Dec Nov Oct Sep Aug Jul Jun May Apr Mar Feb Jan Month 18 17 15 14 12 11 12 14 17 19 20 20 Temp ( C) 91 95 102 120 135 142 146 103 105 94 65 75 Rainfall (mm) Dec Nov Oct Sep Aug Jul Jun May Apr Mar Feb Jan Month
  4. 4. Why? <ul><li>Effect of Altitude: roughly 6 0 temp decrease every 1000m increase in altitude. </li></ul><ul><li>Waitakere’s max altitude is just over 400m ►about 3 0 decrease with altitude </li></ul><ul><li>Exposure to prevailing westerly winds: </li></ul><ul><li>Cooling effect of wind </li></ul>
  5. 5. <ul><li>Orographic Rainfall </li></ul>Moist air forced to rise Rain shadow on leeward side Air warms as it descends Air cools as it rises Condensation / Precipitation Leeward side: Warmer, Drier conditions Windward side: Cooler, Wetter conditions Evaporation
  6. 6. <ul><li>The climate of the Waitakeres is sub-tropical . It lies in the path of prevailing westerly winds which are moist from passing over the Tasman Sea. </li></ul><ul><li>The Block Mountain of the Ranges is prone to predominately westerly winds that are strong. These winds can dry out the western flank (side) of the ranges and cause erosion (aeolian) on the cliffs and ridges. </li></ul>
  7. 7. Relief – Geology / Geomorphology <ul><li>Refer back to notes about the formation / evolution of the Ranges </li></ul><ul><li>The Waitakere Ranges are located between Auckland City and the Tasman Sea. It was once a plateau and today rises over 400 metres above sea level. Its features include streams, valleys and gorges and it’s covered in sub-tropical rainforest. </li></ul>
  8. 8. Main landforms <ul><li>Prominent ridgelines (e.g. Scenic Drive Scarp) </li></ul><ul><li>Incised stream catchments and streams eg Piha Stream </li></ul><ul><li>Elevated hills and plateaus </li></ul><ul><li>Scarps and coastal cliffs </li></ul><ul><li>Peaks </li></ul><ul><li>Wetlands </li></ul><ul><li>Dune systems and sandy beaches </li></ul>
  9. 19. Formation of landforms <ul><li>The topography (shape) of a landscape is determined by 2 major processes </li></ul><ul><li>Tectonic processes (mountain building) </li></ul><ul><li>Erosion processes (removal of material from one area to another) </li></ul>
  10. 20. Tectonic Processes <ul><li>These are caused by movement in the earths crust and cause </li></ul><ul><li>Fold mountains </li></ul><ul><li>Block Mountains eg Waitakeres </li></ul><ul><li>Volcanic mountains – some Waitakere examples eg Lion Rock. Also the whole range is formed from volcanic products ie Manukau Breccia (conglomerate) </li></ul>
  11. 21. Erosional Processes <ul><li>These erode (break down) the mountain landscapes, remove the rock and soil through wind, rain, river and glacial movements. River movements carry the eroded material to lowland areas and deposit it – either on a floodplain (flat lowland area) or in the sea. </li></ul><ul><li>Fluvial – erosion by rivers </li></ul><ul><li>Aeolian – erosion by wind </li></ul><ul><li>Weathering (chemical, biological and physical) </li></ul><ul><li>Erosion / Transportation / Deposition </li></ul>
  12. 22. Soils <ul><li>SOIL = the transition zone between rocks and vegetation. </li></ul><ul><li>Soils are in a constant state of change and contains: </li></ul><ul><li>Organic matter – decomposed leaf litter, bacteria. Earthworms etc </li></ul><ul><li>Inorganic matter – weathered rock </li></ul><ul><li>Water </li></ul><ul><li>Air </li></ul>
  13. 23. <ul><li>The soil of the Waitakeres is generally red-yellow podzolic. This is highly fertile and formed from andesitic rocks (that are high in minerals) and has a high clay content. However, soil types vary, depending on where it is located. </li></ul><ul><li>Parent material = Manukau Breccia (volcanic rock – a fragmented andesite) </li></ul><ul><li>Soil type = podzol (reddish-brown in colour) </li></ul>
  14. 24. Reasons / Patterns <ul><li>High rainfall (2000mm per year) AND mild-warm temperatures </li></ul><ul><li>= Rapid forest growth </li></ul><ul><li>= decomposers (e.g. fungi) </li></ul><ul><li>= increased weathering </li></ul><ul><li>= fluvial erosion and mass-movement </li></ul><ul><li>= poor horizon development </li></ul>
  15. 25. Kauri / Rimu Forest soils <ul><li>These trees are inefficient at cycling nutrients back to the soil. The litter they drop is acidic and makes the soil infertile </li></ul><ul><li>The litter remains for a long time (slower decomposition) so the soil below is leached </li></ul><ul><li>Grey, structureless topsoil with Yellow – brown podsol subsoil (infertile) </li></ul><ul><li>Silica – rich “pan” (layer) below the topsoil makes drainage difficult (poor for farming) </li></ul>
  16. 26. Other patterns <ul><li>“ Gley” soils = Waterlogged soils around stream floodplains where the soil has a very high water content and is largely anaerobic </li></ul><ul><li>Sandy coastal soils where forest has grown over dunes or sand has blown over existing soil layers </li></ul><ul><li>Thin azonal soils on coastal cliffs / headlands </li></ul>
  17. 27. Vegetation <ul><li>Vegetation in the Waitakere Ranges is known as “sub-tropical Rainforest”. However, there are variation within the Ranges. There are </li></ul><ul><li>coastal dunes, </li></ul><ul><li>wetlands, </li></ul><ul><li>Variations in sub-tropical forest depending on elevation and flank (west, east, north facing etc). </li></ul>
  18. 28. Forest Stratification <ul><li>The forest is made up of several “layers”. The process by which this structure emerges over time is known as stratification </li></ul><ul><ul><li>Emergent layer </li></ul></ul><ul><ul><li>Canopy </li></ul></ul><ul><ul><li>Subcanopy </li></ul></ul><ul><ul><li>Shrubs </li></ul></ul><ul><ul><li>Epiphytes (grow in the canopy) </li></ul></ul><ul><ul><li>Lianas (grow up the tree trunks) </li></ul></ul><ul><ul><li>Ground layer (ferns, grasses. mosses etc) </li></ul></ul>
  19. 29. General Structure <ul><li>Dominated by Kauri, Rimu and Northern Rata </li></ul><ul><li>The Emergent layer is (or was) the Kauri </li></ul><ul><li>Other Canopy species include: </li></ul><ul><ul><li>Podocarps – Totara, Miro, Kahikatea </li></ul></ul><ul><ul><li>Broadleafs – Tawa, Rewarewa </li></ul></ul><ul><li>Middle canopy (sub-canopy). These include: </li></ul><ul><ul><li>Coprosma species, Mahoe, Ponga - Tree Ferns, </li></ul></ul><ul><ul><li>Nikau Palm, Lancewood, </li></ul></ul>
  20. 30. … continued <ul><li>Lower shrub and ground level has small ferns, grasses, mosses and lichens. </li></ul><ul><li>Clinging to these species are climbers and epiphytes . These include: </li></ul><ul><ul><li>Climbers - Supplejack, Kiekie, climbing ferns, </li></ul></ul><ul><ul><li>Epiphytes – Kahakaha, Puka </li></ul></ul>
  21. 31. <ul><li>Due to the high rainfall and mild temperatures The Waitakere Ranges contain: </li></ul><ul><li>¼ of our flowering plants </li></ul><ul><li>2/3 of our ferns </li></ul><ul><li>500 developed species </li></ul>
  22. 32. Vegetation Patterns <ul><li>Vegetation distribution mostly influenced by micro-climates largely influenced by relief </li></ul>
  23. 33. Ridge Tops… <ul><li>Vegetation: </li></ul><ul><li>Canopy trees (esp. Kauri and Rata), and lots of lower canopy trees – manuka, rata and rewarewa. </li></ul><ul><li>Ground cover consists of some ferns, grasses, and hebes. </li></ul><ul><li>Soil: </li></ul><ul><li>The Humus layer is very thin, as is the A + B soil horizons. Areas of rock exposed with mosses and ferns </li></ul>
  24. 34. Lower Floodplains… <ul><li>Vegetation: </li></ul><ul><li>Larger percentage of ferns (ponga’s, grass skirt ponga’s, and nikau palms, some tall canopy trees. It is shadier and the </li></ul><ul><li>Soil: </li></ul><ul><li>humus layer is thicker with a more developed soil horizon </li></ul>
  25. 35. Western flank (Tasman coast) <ul><li>Vegetation: </li></ul><ul><li>hardy low lying trees such as manuka / kanuka / cabbage tree / flax / etc – due to strong predominant westerly winds , </li></ul><ul><li>often funnelled through gaps in the sand dunes or up over cliffs / headlands </li></ul>
  26. 36. Wildlife <ul><li>Animals are an important feature living in our native bush. They re-distribute seeds and help the forest to grow and spread. One of the most important birds is Kereru (Native Wood Pigeon). It swallows seeds whole (really big ones too!) and poops them all over the forest. Other species include: Tui, Kaka, Silver Eye, Tomtit etc. </li></ul>

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