Spatial patterns of long-term vegetation greening and browning are consistent across multiple scales: Implications for monitoring land degradation

Murthy, Karthik and Bagchi, Sumanta (2018) Spatial patterns of long-term vegetation greening and browning are consistent across multiple scales: Implications for monitoring land degradation. In: LAND DEGRADATION & DEVELOPMENT, 29 (8). pp. 2485-2495.

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Abstract

Understanding spatial-temporal patterns of terrestrial vegetation response to climate change (long-term greening/browning) is important for developing strategies to mitigate degradation. Semiarid rangelands are especially susceptible to degradation, which challenges wildlife conservation and human livelihoods that depend on livestock production. In the cold-arid Trans-Himalayan ecosystem (northern India), temperature is increasing, and it is also becoming progressively wetter. Yet, counter-intuitively, there are widespread concerns over degradation. We evaluated whether greening/browning patterns in long-term satellite-derived vegetation indices (normalized difference vegetation index NDVI]) are consistent across different spatial and temporal scales using 6 datasets: MODIS (250m, 500m, 1km, and 5.5km), SPOT 1km, and GIMMS 8km. Results indicate browning in the spring and greening in late summer. Location of hotspots of degradation (browning) was broadly consistent across spatial scales (10(-2)-10(2)km(2)) and were found in regions with warmer temperature and at higher elevations. Broadly, the spatial/temporal pattern of browning does not coincide strongly with location and timing of human land use via livestock grazing. This geographical and seasonal context indicates that vegetation response may be more strongly related to climate than to human land use (overgrazing). Importantly, the dynamic nature of greening/browning, across space and time, is not captured by composite annual metrics (sum-NDVI, max-NDVI, and mean-NDVI). This reiterates the importance of both intraannual and interannual assessments. Location of hotspots indicates that degradation occurs in a spatially contiguous manner, but these are not stationary and instead shift with seasons. Overall, the results show that evaluating the consistency of greening/browning trends across different spatial/temporal scales is critical for understanding and managing vegetation degradation.

Item Type:	Journal Article
Publication:	LAND DEGRADATION & DEVELOPMENT
Publisher:	WILEY
Additional Information:	Copy right for this article belong to WILEY, 111 RIVER ST, HOBOKEN 07030-5774, NJ USA
Keywords:	climate change; grazing management; restoration ecology; Sen's slope; time series analysis
Department/Centre:	Division of Biological Sciences > Centre for Ecological Sciences
Date Deposited:	27 Sep 2018 14:48
Last Modified:	27 Sep 2018 14:48
URI:	http://eprints.iisc.ac.in/id/eprint/60756

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