Activity 6

Disturbance regimes and vegetation dynamics

Fire is a significant agent of disturbance and has been described as an 'ecosystem sculptor' in that fire regime has a big influence on the types of plants that can survive in a particular region. Fire regime has an impact on structure and also productivity as when burnt, plants can be killed or have to use resources to resprout plant parts (e.g. shoots, leaves). Read Beringer, Hutley et al. (2007) a paper that examines impact of frequent fires on savanna productivity at a site near Darwin. In this study the vegetation is absorbing more CO₂ from the atmosphere than is lost via respiration and fire derived emissions – what factors at this site make it a carbon sink? Are there site characteristics, e.g. good soils, high rainfall that supports such on-going growth, despite frequent fire?

Also highlighted as a disturbance agent in the lecture material was the effects of hurricanes or cyclones on forest ecosystems, a good review is provided by Lugo et al. (2008).

These sorts of questions can be used as a basis for your presentations.

• Introduction
• Plant function and the environment
• Disturbance and vegetation dynamics
• Climate change and terrestial ecosystems

Activities

• Activity 5
• Activity 6
• Activity 7

Assessment

• Student Presentations