Spatio-temporal modelling for the evaluation of an altered Indian saline Ramsar site and its drivers for ecosystem management and restoration

Abstract

Saline wetlands are keystone ecosystems in arid and semi-arid landscapes that are currently under severe threat. This study conducted spatio-temporal modelling of the largest saline Ramsar site of India, in Sambhar wetland from 1963-2059. One CORONA aerial photograph of 1963 and Landsat images of 1972, 1981, 1992, 2009, and 2019 were acquired and classified under 8 classes as Aravalli, barren land, saline soil, salt crust, saltpans, waterbody, settlement, and vegetation for spatial modelling integrated with bird census, soil-water parameters, GPS locations, and photographs. Past decadal area statistics state reduction of waterbody from 30.7 to 3.4% at constant rate (4.23%) to saline soil. Saline soil increased from 12.4 to 21.7% and saline soil converted to barren land from 45.4 to 49.6%; saltpans from 7.4 to 14% and settlement from increased 0.1 to 1.3% till 2019. Future predictions hint at a net increase of 20% by wetland, vegetation by 30%, settlement by 40%, saltpan by 10%, barren land by 5%, and net loss of 20%, each by Aravalli and salt crust. The biggest loss of 120% was seen by saline soil converted to barren land. Notably, 40% of the current wetland will be lost by 2059. Additionally, soil-water parameters result state a loss of saline character of wetland ecosystem; subsequently bird statistics indicate a shift in migratory birds disturbing the wetland food web. India has been losing a critical habitat of migratory birds, halophytes, and halophiles, along with livelihood. This study looks to bridge the missing link from local to global wetland ecological disconnect, providing thereby lake management and restoration strategies.