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Biomes - Keynote pdf

Biomes

Biodiversity of Hawaii's Terrestrial Ecosystems

The terrestrial ecosystems in Hawaii are far more diverse than the commonly held vision of simply palm trees and sand.
The terrestrial biodiversity rivals the richness of the continents.
Hawaii's terrestrial ecosystems include:

The three most important factors control the type of ecosystem that forms:

  1. Climate
  2. Substrate
  3. Elevation

The primary climatic factor is the Northeast Trade Winds, which determine the precipitation available to each region of the islands.

Classification of Hawaii's Terrestrial Ecosystems

About 150 distinct communities of organisms have been identified in Hawaii's aquatic, subterranean, and terrestrial environments.

The classification of terrestrial ecosystems is based on

Five elevation zones:

  1. Coastal 0-30 m
  2. Lowland 30-1000m
  3. Montane 1000-2000m
  4. Subalpine 2000-3000 m
  5. Alpine >3000m

For each elevation zone three general moisture categories are recognized:

  1. Dry <120 cm/yr
  2. Mesic 120-250 cm/yr
  3. Wet >250 cm/yr

Several dominant plant and vegetative structures are recognized:

  1. Forests and woodlands
  2. Shrublands
  3. Dwarf shrublands
  4. Grasslands
  5. Herblands
  6. Deserts

A forests canopy is more dense, 60-100% cover, whereas a woodland is more open, 10-60% cover.
Shrublands are distinguished by branched shrubs >1 m in height.
Dwarf shrublands has a canopy height of 1 m or less.
Herblands are composed of small, nonwoody plants.
Deserts receive < 50 cm/yr of precipitation and are sparsely vegetated.

Terrestrial ecosystems commonly are named for their dominant species, e.g. Ohi'a rainforest.
Anthropogenic modification and the introduction of alien species resulted in the nearly complete loss of native coastal, lowland dry, and mesic ecosystems.
Whereas the native montane, subalpine, and alpine ecosystems mostly are intact.
These regions are considered windows to the past and are biological treasures to be protected.

The notes for the final exam are continued in Voyaging

 

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