QUANTIFYING AND MAPPING SEDIMENT RETENTION ECOSYSTEM SERVICES IN A MOUNTAIN LANDSCAPE OF SOUTHERN WESTERN GHATS, INDIAShiju Chacko, C. Ravichandran, Jikku Kurian and S.M. Vairavel
Ecosystem services models that are capable of quantifying and mapping the spatial conservation prioritization through the process of simple and scientifically credible methods, in order to conserve protected area is the need of the hour. A sediment retention model based on InVEST was employed to estimate sediment retention, soil loss and sediment export in Periyar Tiger Reserve, a representative in the mountain landscape of Southern Western Ghats, Kerala, India. The analysis included vegetation classes, rainfall erosivity, soil erodibility, watershed boundary, Digital Elevation Model (DEM), biophysical parameters and empirical constants. The estimated sediment retention of PTR was 3574263.9 tonnes/year with 55.45% from Periyar river watershed and 44.55% from Pamba river watershed. Sediment export and potential soil loss were calculated as 40272.66 and 360735.81 tonnes/year respectively. A comparison of sediment retention capacity to the forest ecosystems with different vegetation indicates that there is a decreasing trend from evergreen forest, semi evergreen forest, to grassland-savanna, plantations and moist deciduous forest. It is estimated that 37% of evergreen and 24% of semi evergreen share the major portion of the total sediment retention, 61.12% of PTR. This study reveals the significance of quantifying and mapping the ecosystem services of the Tiger reserve and importance to conserve and required efficient management.