in Sri Lanka - Ministry of Environment

scrub jungles grow up to 3-4 m and mainly consist of deciduous or semi-deciduous speciesforming a single stratum (Figure 3).Savanna ecosystemsSavanna ecosystems of Sri Lanka are situated in the dry and intermediate zones of Sri Lankaat elevations between 300-1000 m (Gunatilleke et al., 2008). Savanna is a vegetation type inthe tropics in which grasses form a conspicuous ground cover (Archibold, 1991). According toCole (1986), tropical savannas are classified into several structural formations by consideringfeatures such as the major life form categories dominating them, the height and density oftrees, spacing between trees and the height and cover of grasses. It appears that, the savannasfound in Sri Lanka could be described as Savanna woodlands (Figures 4 & 5) as the spacingof the trees is about or a little higher than the diameters of the tree crowns with a considerableextent of tall mesophytic grass cover.Tall trees (> 8 m high) of deciduous and semi-deciduous species together with tall mesophyticgrasses (> 80 cm high) are common in Sri Lankan savanna woodlands. These occur aspatches of varying sizes of about 2-1000 ha, spreading intermittently with dry forests (G.G.C.Premalal and G.A.D. Perera, unpublished data) but depending on their floristic and some abioticfeatures, these can be assigned into two major types as upland savanna and lowland savannawoodlands. Upland savanna woodlands (Figure 5) occur at the slope of the central massifat Balangoda while the lowland savanna woodlands (Figure 6) are found at Nilgala, Nellikeleand Bibile in Monaragala district. Careya arborea, Phyllanthus emblica, Terminalia belliricaand T. chebula are prominant members of these ecosystems but towards higher elevations,Anogeissus latifolius occur more frequently than in the lowlands (G.G.C. Premalal and G.A.D.Perera, unpublished data). However, the two savanna ecosystem types, i.e. in lowland andupland savanna woodlands show differences in the vegetation structure, density of individualsand species abundance rather than the floristic composition of the woody perennials.Grassland ecosystemsGrassland ecosystems in the dry land of Sri Lanka include both edaphic climaxes anddisclimaxes of anthropogenic origin. Of these, the edaphic climaxes are mainly governed bythe depth of the soil and the soil moisture content which is an artifact of frequent or occasionalflooding, their close proximity to water bodies, rivers, abandoned irrigation tanks, and waterholes and/or due to soil characteristics such as the presence of alluvial soil.Four major grassland ecosystem types can be identified in the dry land of Sri Lanka namely,dry (Damana) grasslands, occasionally flooded dry grasslands, seasonally flooded dampgrasslands and grassland disclimaxes maintained by fire and/or grazing. Natural grasslands(edaphic climaxes) are more diverse compared to grassland disclimaxes. Moreover, thegrasslands occur at wetter conditions contain many different grass and sedge species.Damana grasslands are reported as natural edaphic climaxes formed due to edaphic featuresbut prolonged periods of drought in these areas may also contribute in the formation of thesegrasslands (Sezchowycz, 1954). The presence of saline soil with high osmotic pressure in166