Ecosystems of Sri Lanka — A/L Biology

What must I remember about Ecosystems of Sri Lanka?

• Sri Lanka, despite its compact territorial size (65,610 km²), exhibits exceptional ecosystem diversity driven by topographic elevation gradients (lowlands up to 2524 m Pidurutalagala) and monsoonal rainfall regimes (Wet, Intermediate, Dry, and Arid zones).
• Tropical Wet Lowland Evergreen Rain Forests (e.g., Sinharaja, Kanneliya): Dominated by towering Dipterocarpaceae (Dipterocarpus, Shorea); multi-tiered canopy structure, high floristic and faunal endemism (>75% endemic trees), epiphyte abundance, and torrential rainfall (>3000 mm).
• Tropical Sub-montane and Montane Forests (e.g., Knuckles, Horton Plains): Located above 1000-1500 m elevation; characterized by stunted gnarled trees (Syzygium, Rhododendron arboreum ssp. zeylanicum), dense lichen/moss epiphytic coverings ('cloud forests'), mist condensation, and high micro-endemism.
• Dry Mixed Evergreen Forests (e.g., Wilpattu, Wasgamuwa): Dominant vegetation of the dry zone; semi-deciduous canopy featuring valuable timber trees (Manilkara hexandra - Palu, Chloroxylon swietenia - Burutha, Diospyros ebenum - Kaluwara).
• Coastal and Marine Ecosystems: Mangroves (Rhizophora with stilt roots, Avicennia with pneumatophores in brackish lagoons), Salt marshes, Sand dunes, Coral reefs (Pigeon Island, Bar Reef; calcium carbonate hermatypic corals), and Seagrass beds acting as critical nursery grounds.

Test yourself (1 minute)

1. Sri Lanka Biodiversity Hotspot

   Sri Lanka, combined with the Western Ghats of India, is recognized as one of the world's 36 global biodiversity hotspots due to extreme species endemism threatened by habitat fragmentation.

2. Mangrove physiological adaptations

   Viviparous germination (seeds germinate while still attached to mother plant, e.g., Rhizophora) and negative geotropic breathing roots (pneumatophores with lenticels, e.g., Avicennia, Sonneratia) overcome anaerobic, saline coastal mud.

3. Villu ecosystems

   Unique shallow floodplain lakes in Mahaweli basin and Wilpattu, inundated during northeast monsoons, providing crucial grazing grounds for Asian elephants and aquatic avifauna.

Practise Ecosystems of Sri Lanka questions today

Source: NIE G.C.E. (A/L) Biology Syllabus & Resource Book, Unit 6

What should I study first?

What comes next?

Next in the syllabus

Where does Ecosystems of Sri Lanka fit in the syllabus?

Year 2 · Term 2