Ecology Lecture 9

Peat: organic matter accumulated over thousands of years storing carbon in thick layers

Tropical peat swamp forests in Southeast Asia

Only “discovered” in the 1920s-1930s. Peat formed from woody vegetation

Excessive rainfall + lack of drainage = continuous wet conditions

Ombrogenous = raised domes

• receives water only by rain

• oligotrophic (nutrient deficient)

• pH 4 or lower

• lower primary productivity

• Dome acts as a reservoir and has its own raised water table

Main drivers of formation:

• High water tables – anaerobic (low O2) soil conditions inhibit microbial decomposition

• Low nutrient environment means plants fight to survive so produce toxins in leaves which further inhibit microbial activity

• Primary productivity remains high, out weighing the low decomposition

Congo basin

High biodiversity

• 11% of plants (mostly trees) recorded from TPSF are restricted to this habitat

• Distinct species composition in different swamp areas

Key role in the water cycle

• Globally 10% of all freshwater

• Source areas of many rivers

• Important for water storage and supply

• Crucial for mitigation of droughts and floods

Critical components for peatland function

• Peat / C storage ultimately a function of decomposition rates:

• Low O2 /high water tables

• Vegetation with high lignin/tannins/toxins (forest inputs often…