A composite method to identify desertification ‘hotspots’ and ‘brightspots’

Abstract

Desertification has become one of the greatest environmental concerns of our planet. Implementation of the action plans for arresting land degradation and for employing rehabilitation measures over a large spatial scale is not feasible due to the amount of time, effort, and cost involved. However, if the ‘hotspots’ the ‘brightspots’, and the ‘potential areas’ are identified, the task would be relatively easy. In this paper, a method is proposed to identify the pieces of degraded land with varying severity levels (in terms of ‘hotspots’, ‘brightspots’, and ‘potential areas’), using Bowen ratio, land surface temperature (LST), Ra, and Normalized Difference Vegetation Index (NDVI). Although the zone falls in the semiarid class, the microclimate analysis of the study area revealed high aridity. The combined analysis of LST, Ra, and NDVI helped in identifying the areas susceptible to land degradation (particularly, salinization and water erosion). Analysis of the vegetation type and condition showed their variable roles towards the protection of soil from erosion, drought, and fire. Using these analyses together with the ecosystemic approach of Bowen ratio, ‘hotspots’, ‘brightspots’, and ‘potential areas’ were identified at the pixel level. For validation, Desertification Status Map was employed. The investigations revealed that around 49% of the study area falls under the category of ‘hotspots’ (with an error estimate of 13%) and another 49% as ‘brightspots’. The findings revealed that instead of targeting the entire area for implementation of the mitigation measures with the same efforts, it would be better to focus on the specific pieces of land (‘hotspots’) to optimally utilize the available resources.

Remote sensing‐based biological and nonbiological indices for evaluating desertification in Iran: Image versus field indices

“…When vegetation, which is the most important factor in preventing land from degrada- (Jafari & Hasheminasab, 2017). Similar results have also been reported in many countries such as India (Singh, 2019), in Spain (Khorchani et al, 2018), and China (Tan, Yu, Li, Tan, & Zhou, 2020) that LST can be used as an appropriate indicator for determining degradation and desertification process. Of course, when using LST it should be noted that increasing LST does not always indicate desertification.…”

“…Therefore, one of the most important stages of evaluating desertification process is identifying and selecting appropriate indices that have characteristics such as measurement capability, appropriate spatial, and temporal resolution, accessibility, low cost, and repeatability. Currently, ready‐to‐use remote sensing products have been considered by many researchers in the field of land degradation and desertification due to the above characteristics and long‐term archives (Huang et al, 2020; Jafari & Hasheminasab, 2017; Matin & Behera, 2020; Singh, 2019; Zhuang et al, 2020; Zolotokrylin, Brito‐Castillo, & Titkova, 2020). On the other hand, due to the fact that many MEDALUS indices are local, discontinuous, and expert opinion is involved in their evaluation, their use at the local, national, regional, and global levels is limited.…”

“…As shown, there was not much difference between desertification classes. Probably, one of the reasons for the high consistency of desertification maps is the selection of appropriate indices, which has also been reported in other studies (e.g.,Singh, 2019). For example, NDVI may be considered instead ofthe vegetation indicator, AI instead of the climate indicator, RUE instead of soil erosion, and management indicator.…”

From Historical Narratives to Circular Economy: De-Complexifying the “Desertification” Debate

“…Landscapes are heterogeneous, reflecting past and current land uses and disturbance regimes as well as different morphology, substrates and ecological mosaics [60]. Assuming the importance of ecological mosaics influencing desertification risk, spatial contexts should be considered in the analysis of land degradation, representing a knowledge base for design of appropriate counteracting strategies [61].…”

Towards stopping land degradation in drylands: Water‐saving techniques for cultivating biocrusts in situ

“…These factors make it a major obstacle to the sustainable development of drylands (Gisladottir & Stocking, ; Reynolds et al, ). Finding a viable approach to reverse degradation has become an urgent problem for humanity (Gisladottir & Stocking, ; Reynolds et al, ; Singh & Ajai, ).…”