TOWARDS A REMOTE SENSING BASED ASSESSMENT OF LAND SUSCEPTIBILITY TO DEGRADATION: EXAMINING SEASONAL VARIATION IN LAND USE-LAND COVER FOR MODELLING LAND DEGRADATION IN A SEMI-ARID CONTEXT

Gofamodimo Mashame,Felicia Akinyemi

doi:10.5194/isprsannals-iii-8-137-2016

Gofamodimo Mashame, Felicia Akinyemi

Open Access

https://doi.org/10.5194/isprsannals-iii-8-137-2016

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Abstract

Land degradation (LD) is among the major environmental and anthropogenic problems driven by land use-land cover (LULC) and climate change worldwide. For example, poor LULC practises such as deforestation, livestock overstocking, overgrazing and arable land use intensification on steep slopes disturbs the soil structure leaving the land susceptible to water erosion, a type of physical land degradation. Land degradation related problems exist in Sub-Saharan African countries such as Botswana which is semi-arid in nature. LULC and LD linkage information is still missing in many semi-arid regions worldwide.Mapping seasonal LULC is therefore very important in understanding LULC and LD linkages. This study assesses the impact of seasonal LULC variation on LD utilizing Remote Sensing (RS) techniques for Palapye region in Central District, Botswana. LULC classes for the dry and rainy seasons were classified using LANDSAT 8 images at Level I according to the Food and Agriculture Organization (FAO) International Organization of Standardization (ISO) code 19144. Level I consists of 10 LULC classes. The seasonal variations in LULC are further related to LD susceptibility in the semi-arid context. The results suggest that about 985 km² (22%) of the study area is susceptible to LD by water, major LULC types affected include: cropland, paved/rocky material, bare land, built-up area, mining area, and water body. Land degradation by water susceptibility due to seasonal land use-land cover variations is highest in the east of the study area where there is high cropland to bare land conversion.

Highlights

Land degradation (LD) is among the major environmental and anthropogenic problems driven by change in land useland cover (LULC) and climate change worldwide especially in semi-arid regions (Li et al, 2015; Utuk and Daniel, 2015)
The results suggest that about 985 km2 (22%) of the study area is susceptible to LD by water, major LULC types affected include: cropland (5.5%), paved/rocky material (9.5%), bare land (6%), built-up area (1.6%), mining area (0.07%), and water body (0.33%)
It was found that 22% of bare land exists in semi-arid Palapye region computed from the sum of the major LULC classes: cropland (5.5%), paved/rocky material (9.5%), bare land (6%), built-up area (1.6%), mining area (0.07%), and water body (0.33%)

Summary

Introduction

Land degradation (LD) is among the major environmental and anthropogenic problems driven by change in land useland cover (LULC) and climate change worldwide especially in semi-arid regions (Li et al, 2015; Utuk and Daniel, 2015). 16-40% of the global farmlands have already been exposed to LD and 129 million hectares of forest have been lost worldwide due to the increase in human activities such as agricultural expansion (Chappell and Lavalle, 2011; Global Forest Resources Assessment, 2015). 70% of dry lands in Africa, South America and Asia are affected by LD which involves: 30% of irrigated arid lands, 47% of rain-fed cultivation and 73% of vegetation (Utuk and Daniel, 2015) and Africa has the highest net of forest loss recording 2.8 million hectares lost annually (Food and Agriculture Organization, 2015). The Global Assessment of Human Induced Soil Degradation (GLASOD) study found that 1.97 billion hectares (ha) of global agricultural lands are subjected to extreme soil loss by water (Bhattarai, 2013) and every year soil degradation increases by 5-7 million hectares worldwide (International Atomic Energy Agency, 2014)

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