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Assessment of land degradation ‘on the ground’ and from ‘above’

Assessments of land degradation vary in methodology and outcome. The objective of this study is to identify the state, extent and patterns of land degradation in Eastern Africa (Ethiopia, Kenya, Malawi and Tanzania). More recently (2000s), satellite-based imagery and remote sensing have been utilized to identify the magnitude and processes of land degradation at global, regional and national levels.

This involves the use of Normalized Difference Vegetation Index (NDVI) derived from Advanced Very High Resolution Radiometer data and the use of high-quality satellite data from Moderate Resolution Imaging Spectroradiometer.

  • This study is the first in Eastern Africa to complement remote sensing with ground-level assessments in evaluating the extent of land degradation at national and regional scales.

The results based on NDVI measures show that land degradation occurred in about 51%, 41%, 23% and 22% of the terrestrial areas in Tanzania, Malawi, Ethiopia and Kenya, respectively, between the 1982 and 2016 periods. Some of the key hot spot areas include west and southern regions of Ethiopia, western part of Kenya, southern parts of Tanzania and eastern parts of Malawi.

To evaluate the accuracy of the NDVI observations, ground-truthing was carried out in Tanzania and Ethiopia through focus group discussions (FGDs). The FGDs indicate an agreement with remotely sensed information on land degradation in seven sites out of eight in Tanzania and five sites out of six in Ethiopia.

This study makes a contribution by combining remotely sensed land degradation dataset and ground-based surveys (ground-truthing) to evaluate the extent of land degradation in Eastern Africa. Eastern Africa and sub-Saharan Africa, in general, are some of the global regions which are most affected by land degradation, with significant negative impacts on human well-being and sustainable development [40]; thus, a more accurate identification of land degradation hot spots in the region could be highly useful for national policies to address land degradation.

The identification of land degradation hot spots will consequently help in uncovering the proximate and underlying causes. Appropriate mitigation actions can then be appropriately applied to curb degradation in these areas. By employing the NDVI and LUCC data and combining them with ground-truthing methods, we discuss the state, extent and patterns of land degradation in Ethiopia, Kenya, Malawi and Tanzania.

Given the significant magnitude of land degradation, appropriate action is needed to address it.

Source: Kirui, O.K., Mirzabaev, A. & von Braun, J. Assessment of land degradation ‘on the ground’ and from ‘above’. SN Appl. Sci. 3, 318 (2021). https://doi.org/10.1007/s42452-021-04314-z

This is an Open Access article, you can access it here as well: https://link.springer.com/content/pdf/10.1007/s42452-021-04314-z.pdf

 

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