Ecology Borneo peat swamp forests

peat swamp forest in kalimantan

about 62% of world s tropical peat lands occur in indo-malayan region (80% in indonesia, 11% in malaysia, 6% in papua new guinea, small pockets , remnants in brunei, viet nam, philippines , thailand). unusual ecosystems, trees 70 m high - vastly different peat lands of north temperate , boreal zones (which dominated sphagnum mosses, grasses, sedges , shrubs). spongy, unstable, waterlogged, anaerobic beds of peat can 20 m deep low ph (ph 2.9 – 4) , low nutrients, , forest floor seasonally flooded. water stained dark brown tannins leach fallen leaves , peat – hence name ‘blackwater swamps’. during dry season, peat remains waterlogged , pools remain among trees.

despite extreme conditions borneo peat swamp forests have many 927 species of flowering plants , ferns recorded (in comparison, biodiversity study in pekan peat swamp forest in peninsular malaysia reported 260 plant species). patterns of forest type can seen in circles centre of swamps outer fringes made of of tree families recorded in lowland dipterocarp forests although many species found here. many trees have buttresses , stilt roots support in unstable substrate, , pneumatophores , hoop roots , knee roots facilitate gas exchange. trees have thick, root mats in upper 50 cm of peat enable oxygen , nutrient uptake.

peat swamp forest in gunung mulu national park nepenthes bicalcarata in foreground

the lowland peat swamps of borneo geologically recent (<5000 years old), low-lying coastal formations above marine muds , sands of lakeside peat forests of kalimantan 11,000 years old.

one reason low nutrient conditions streams , rivers not flow these forests (if did, nutrient rich freshwater swamps result), water flows out of them, input of nutrients rainfall, marine aerosols , dust. in order cope lack of nutrients, plants invest heavily in defences against herbivores such chemical (toxic secondary compounds) , physical defences (tough leathery leaves, spines , thorns). these defences prevent leaves decaying , build peat. although cellular contents leach out of leaves when fall, physical structure resistant both bacterial , fungal decomposition , remains intact, breaking down form peat (yule , gomez 2008). in stark contrast lowland dipterocarp forests leaf decomposition extremely rapid, resulting in fast nutrient cycling on forest floor. if non-endemic leaf species placed in peat swamp forests, break down quite quickly, after 1 year submerged in swamp, endemic species remain virtually unchanged (yule , gomez 2008). nutrients available trees ones leach leaves when fall, , these nutrients rapidly absorbed thick root mat. assumed low ph , anaerobic conditions of tropical peat swamps meant bacteria , fungi not survive, recent studies have shown diverse , abundant communities (albeit not diverse dry land tropical rainforests, or freshwater swamps) (voglmayr , yule 2006; jackson, liew , yule 2008).