(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

Major catastrophic events originating in the physical environment - events which cause abrupt structural change in communities (White 1979)


  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

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)

[ natural disturbance | human disturbance ]



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

Ecosystem health (生態系の健全性)

a metaphor used to describe the condition of an ecosystem

productivity resilience, and organization, including biodiversity

changed by disturbances, e.g., flooding, drought, biological invasion, climate change, mining, overexploitation, and landuse change
⇒ the relationship between resilience and diversity

Natural disturbance (自然撹乱)

Volcanic eruption

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)


| 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

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