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(Upload on October 16 2014) [ 日本語 | English ]

Disturbance (撹乱)






Mount Usu / Sarobetsu post-mined peatland
From left: Crater basin in 1986 and 2006. Cottongrass / Daylily

索引

[ natural disturbance | human disturbance ]

Major catastrophic events originating in the physical environment - events which cause abrupt structural change in communities

(White 1979)

Problems

  1. There is a gradient from minor to major events rather than a uniquely definable set of major catastrophes for each kind of disturbance
  2. Some disturbances are initiated or promoted by the biotic component of the system

Three parameters on disturbances

3D-disturbacne

Disturbance regime = determined by the type and three parameters to characterize disturbances shown below:

Scale (size)
Frequency (interval)
Intensity (magnitude)

Grime's trianglesuccession (遷移)

Type

Natural disturbance
Human disturbance (human-induced disturbance, or anthropogenic disturbance)

Natural disturbance (自然撹乱)


Volcanic eruption
Landslide
Wildfire

Forest fire at Alaska
Sprouting Moderately-disturbed Intensitvely-disturbed
Sprouting after fire at Boston Creek (May 11 2005) Moderately disturbed site. Peat moss still remained on the forest floor. Intensively disturbed site. Peat was completely burned out by fire. Snags could not keep standing (Tsuyuzaki et al. 2014).

Human disturbance (人為撹乱)


Large-scale

| Global warming (+ ozene hole)
| ___Environmental hormone)
| Desertification → Deforestation
| Acid rain → forest ecosystem change
| Mining, e.g., coal, bauxite, and peat (Nishimura et al. 2009)
| Heat island → urban ecosystem change
| Forest cutting, including skislope establishment (Tsuyuzaki 1994)
| Reclamation for cultivation, such as meadow and paddy
| ___field (Tsuyuzaki & Kanda 1996)
| Grazing by cattle, e.g., yak (Tsuyuzaki & Tsujii 1999),
| ___and deer (Tsuyuzaki & Takahashi 2007)
| Trampling
| Clipping

Small-scale
[ occurring with various scales = biological invasion (生物学的侵入)]
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