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Indian Savannas

Indian Savannas. A.S. Raghubanshi Banaras Hindu University. Indian Savanna/Grasslands. About 400 grass species, 139 endemic Pastoral nomadism- 200 tribes (6% of India’s total population) Grasses- multiuse species (fuel, fodder, thatching material, craft, rope, medicine, essential oils, etc)

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Indian Savannas

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  1. Indian Savannas A.S. Raghubanshi Banaras Hindu University

  2. Indian Savanna/Grasslands • About 400 grass species, 139 endemic • Pastoral nomadism- 200 tribes (6% of India’s total population) • Grasses- multiuse species (fuel, fodder, thatching material, craft, rope, medicine, essential oils, etc) • Habitat for wildlife- insects, reptiles, amphibians, birds (e.g. Lesser Florican), large mammals, wild cats, blackbuck, barasingha, chinkara, wild ass, etc.

  3. Origin • Savannas of the Indian sub-continent are derived primarily from woodlands through the action of humans (Singh, 1976; Singh e t al., 1983; Gadgil and Meher-Homji, 1985) • Originated predominantly from woodland ecosystems through deforestation, shifting cultivation, and burning • Without human disturbance, almost no natural grassland • Maintained at a subclimax stage by repeated burning & grazing

  4. Distribution & Types • 8°N-30°N • Savanna types: • Sehima-Dichanthium • Dichanthium-Cenchrus-Lasiurus • Phragmites-Saccharum-Imperata • Themeda-Arundinella • Temperate Alpine

  5. Indian Savanna Types (Dabadghao and Sankarnarayan, 1973) Lasiurus sindicus (Sewan) found in western Rajasthan- wonder grass-very high protein content

  6. Sehima-Dichanthium Type • Distribution: Tropical peninsular India, central Indian Plateau, Chhota Nagpur Plateau, Arawali ranges • Topography: undulating to hilly • Rainfall: 300-6350mm • Maximum cover: 87%

  7. Sehima-Dichanthium Type • Grasses:Aristida setacea, Borthriochloa pertusa, Dichanthium annulatum, D. caricosum, Sehima nervosum • Shrubs:Carissa auriculata, Mimosa rubicaulis, Ziziphus nummularia • Trees: Acacia catechu, A. sandra, Anogessus latifolia, Dalbergia latifolia, Hardwickia binata, Tectona grandis, Terminalia tomentosa

  8. Dichanthium-Cenchrus-Lasiurus • Distribution: subtropical and semi arid regions • Topography: mainly level, occasionally broken by spurs of southern hill ranges or by sand dunes in Rajasthan • Rainfall: 100-750mm • Maximum cover: 57%

  9. Dichanthium-Cenchrus-Lasiurus • Grasses:Cenchrusciliaris, C. setigerus, Chrysopogonmonticola, Cynodondactylon, Dactylocteniumsindicum, Dichanthiumannulatum, Eleusinecompressa, Lasiurushirsutus, L. sindicus, Panicumantidotale, Sporobolusmarginatus, S. pallidus • Shrubs:Balanitesaegyptica, Calotropisprocera, Capparisdecidua, Carissa auriculata, C. opaca, Dichrostachyscinerea, Prosopis cineraria, Tamarixdioica, Zizyphusnummularia • Trees: Acacia catechu, A. leucophloea, A. senegal, Dalbergiasisoo, Prosopis cineraria, Salvadoraoleoides • Dichanthium dominant in protected areas • Cenchrusdominant with moderate grazing

  10. Phragmites-Saccharum-Imperata • Distribution: Gangetic plains, Brahmaputra valley and plains of the Punjab • Topography: level, low lying, ill drained lands • Rainfall: up to 4000mm • Maximum cover: 57%

  11. Phragmites-Saccharum-Imperata • Grasses:Bothriochloaintermedia, Desmostachyabipinnata, Imperatacylindrica, Phragmiteskarka, Saccharumarundinaceum, S. bangalense, S. sponteneum, Sporobolusarabicus, S. indicus, Vetiveriazizanioides • Shrubs:Calotropisgigantea, Clerodendronsp., Dandrocalamusstrictus, Lantana camara, Leeaindica, Vitexnegundo • Trees: Acacia arabica, Anogeissuslatifolia, Buteamonosperma, Hydrocarpuslaurifolia, Pterocarpusdalbergioides, Tectonagrandis, Terminaliaprocera, Vitexpeduncularis

  12. Themeda-Arundinella type • Distribution: northern and north-western montane tract • Topography: mountains ranging from 350-2100 m alt • Rainfall: 1000-2000mm • Maximum cover: 80%

  13. Themeda-Arundinella type • Grasses:Arundinellabengalensis, A. nepalensis, Bothriochloaintermedia, B. pertusa, Chrysopogonfulvus, C. cerrulatus, Cymbopogonjwarancusa, Eulaliopsisbinnata, Heteropogoncontortus, Panicumorientale, Themedaanathera • Shrubs:Berberislycium, Colebrookiaoppositifolia, Daphne oleoides, Desmodiumtiliaefolium, Indigoferagerardiana, I. pulchella, Myrsineafricana, Prinsepiautilis, Punicagranatum, Rhuscotinus, Woodfordiafruticosa • Trees: Benthamidiacapitata, Pinusroxburghii, Pristaciaintegerrima, Platanusorientalis, Prunusarmeniaca, Quercusleucotricchophora, Robiniapseudoacacia

  14. Temperate Alpine Type • Distribution: northern montane tract • Topography: mountains above 1500 and 2100m alt in the east and west, respectively • Rainfall: 375-3750mm • Maximum cover: 80%

  15. Temperate Alpine Type • Grasses:Agropyroncanaliculatum, Agrostiscanina, Calamagrostrisepigejos, Chrysopogongryllus, Dactylisglomerata, Danthoniajacquemontii, Desmostachyabipinnata, Koeleriacristata, Phleumalpinus, Poapratensis, Stipasibirica • Shrubs:Berberisumbellata,Cotoneastermicrophylla, Spirarealindleyana, Viburnum • Trees: Cedrusdeodara, Pinusvallichiana, Quercusleucotrichophora, Rhododendron arboreum

  16. Climate Controls Distribution • Sehima-Dichanthium • Tropical, dry sub humid • Dichanthium-Cenchrus-Lasiurus • Subtropical, semi arid • Phragmites-Saccharum-Imperata • Subtropical, moist sub humid • Themeda-Arundinella • Subtropical, humid montane

  17. Open Forest 28.99 Mha (8.82%)

  18. EarthTrends 2003

  19. Geological Shifts in Forest-Savanna Boundaries • Palynological studies have shown an increase in the percentage of pollen of savanna species as early as 4000- 3500 BP, remaining almost constant up to the present (Singh et al. 1990; Caratini et al. 1991). • A recent development of the savanna, linked to a decrease in rainfall.

  20. Geological Shifts in Forest-Savanna Boundaries • In contrast, Misra (1983) suggested that forests in India are favoured by present climatic conditions • Pascal (1988) observed that plots protected from fires show increasing woody plant density • New studies using stable carbon isotope ratio analysis show that change in ecosystem dominance occurred recently (roughly 2000 BP), and that forest has invaded an area occupied previously by a C4 plant community (savanna and cultivated grassland).

  21. Deciduous Forest Fire Exploitation Savanna Woodland Scrub Woodland Further exploitation and grazing Tree removal Tree Savanna Thicket Further degradation Further degradation Shrub Savanna Scattered Shrubs Discontinuous Thicket Overexploitation and over grazing Overexploitation and over grazing Pseudosteppe

  22. Pandey & Singh 1991

  23. Land Use Change Forest Savanna

  24. Pandey & Singh 1992

  25. Pandey & Singh 1992

  26. Lele & Hegde 1997)

  27. Fine Root Production • In a tropical forest ecosystem in South India, Sundarapandian & Swamy (1996) reported a similar strongly seasonal pattern in fine-root production, with maximum production occurring during the rainy season and minimum in the dry season.

  28. Fire • The mean annual canopy and belowground biomass of a Indian dry tropical savanna increases by 40 % and 12%, respectively. • An increase in mean aboveground net production of 24 % and in belowground net production of 9 %. • Fire increases the mean concentrations of N and P by 16% and 42% in vegetation and 18% and 17% in soil, respectively.

  29. Effect of BurningSouth Indian Grasslands NPP 5294-6962 g/m2/yr

  30. Life Forms • Phanerophytes: 3-10% • Therophytes & Cryptophytes dominate • Therophytes abundant during rainy season, able to survive through seeds • Cryptophytes withstand grazing: hidden sub surface position of their perennating buds • Perennial Species: proportion increases along the gradient of increasing rainfall and grazing protection

  31. Woody plants • Mostly deciduous or nearly deciduous • The time of leaf fall appears to be related to water stress • But new leaves emerge during dry phase itself, much earlier than onset of rainy season

  32. Phenology of Woody Components Flowering Ombrothermic diagram The phenological clock of the forest is set during the interphase of winter and summer ensuring full advantage of the short rainy season that follows. fruiting leafing Fruit-fall Leaf-fall Solid symbols and curves are for initiation and open symbols and broken curves are for completion of various phenological events.

  33. Sankaran and McNaughton (1999) • In Indian savanna grasslands, resistance to compositional change was negatively correlated with diversity • More diverse communities were more stable as measured by resistance to species turnover • However, no such relationships were observed within communities • Results are best explained by the ecological history and species characteristics of communities rather than by species diversity in itself

  34. Issues • Exotic species invasions • Lantana • Parthenium • Climate Change • C3-C4 balance • Competitive ability • Defining tree-savanna boundary • PFTs? • Response to disturbance-PFTs

  35. Changes in Savanna Biomes under B2 scenario Current (%) Projected (%) Change (%) Moist savanna 32.52 0.56 -31.97 Dry savanna 33.07 4.34 -28.73

  36. Relationship of Lantana cover with Different Vegetation Parameters

  37. Indian Experimental Sites • Vindhyan Highlands- Biodiversity Park Area, Banaras Hindu University • Sariska Tiger Reserve- Rajasthan

  38. Grass • Heteropogon contortus (more palatable), Chloris dolichostachya (less unpalatable) • Questions • Do tree species’ seedlings differ in their ability to compete with palatable and unpalatable grasses for different resources? • If there are significant differences in the responsiveness of the tree species, can these be related to plant traits?

  39. Add on Experiment • How tree seedlings grow in response to a number of different grass species, representing more palatable species that dominate in moderately and undergrazed conditions and less palatable species that replace them in their local environment under heavy grazing? • Growth response of the different tree species seedlings in competition with palatable and unpalatable grass species at both Indian sites. • Heteropogoncontortus(more palatable), Chlorisdolichostachya (less unpalatable)

  40. L0 L1 Block N0 G1 N0 G2 N0 G0 N0 G1 N1 G1 N1 G0 N1 G0 N1 G2 1.6 m W1 1 m N1 G0 N1 G0 N1 G2 N1 G1 N0 G0 N0 G1 N0 G0 N0 G2 1.6 m 1 m 1.6 m 15.6 m 2 m W1 D L0 W0 N1 G1 N1 G2 N1 G1 N1 G2 N0 G1 N0 G2 N0 G2 N0 G0 1.6 m 1 m 1.6 m 2 m 10.4 m

  41. Thanks raghubansh@gmail.com

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