Remote sensing assessment of vegetation and moisture stress along a seasonal cattle migration corridor in central India.

Seasonal livestock migration remains an important way of using semi-arid rangelands in India, yet the ecological conditions that herds meet along their routes are rarely measured directly. This study assessed vegetation, moisture, and surface heat along a seasonal Gir cattle migration corridor in central India, running from the Goras region of Sheopur district in Madhya Pradesh to Aligarh in Uttar Pradesh. The route of a migrating herd was tracked with a GPS collar on the lead animal and buffered by 10 km to define the grazing influence zone. Within this zone, the Normalized Difference Vegetation Index (NDVI), Soil-Adjusted Vegetation Index (SAVI), Normalized Difference Moisture Index (NDMI), and Land surface temperature (LST) were computed from pre-monsoon Landsat-8 and 9 imagery at 2372 points spaced about 0.5 km apart. NDVI, NDMI, and LST were combined into a Weighted Overlay Index (WOI), with SAVI retained as a soil-corrected check on NDVI rather than as a separate input. Greenness was moderate for most of the route (mean NDVI 0.32), with high vegetation stress at 24.4% of the points. The clearer constraints were moisture and heat. About 69.3% of the route showed a moisture deficit on NDMI, and surface temperatures stayed high through the dry season (mean LST 51 °C). The composite index placed roughly 46% of the corridor in the high or very high stress classes, concentrated in the southern scrubland, while the irrigated and riverine tracts in the north formed relief zones. Because the route is an out-and-back journey, conditions followed a south-to-north gradient that agreed on both legs, and the index-based reading was confirmed against an independent land-cover product and high-resolution imagery. The findings show that the binding constraint along this corridor is dry, hot forage rather than an absence of vegetation, and that pairing GPS tracking with several satellite indices gives a route-continuous basis for corridor-sensitive grazing and welfare management.