Monitoring of Land Use/Land Cover and Socioeconomic Changes in South China over the Last Three Decades Using Landsat and Nighttime Light Data

Sarah Hasan,Wenzhong Shi,Xiaolin Zhu,Sawaid Abbas

doi:10.3390/rs11141658

Sarah Hasan, Wenzhong Shi + Show 2 more

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https://doi.org/10.3390/rs11141658

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Journal: Remote sensing	Publication Date: Jul 11, 2019
Citations: 41	License type: CC BY 4.0

Affiliation: Hong Kong Polytechnic University

Abstract

Land use and land cover changes (LULCC) are prime variables that reflect changes in ecological systems. The Guangdong, Hong Kong, and Macau (GHKM) region located in South China has undergone rapid economic development and urbanization over the past three decades (1986–2017). Therefore, this study investigates the changes in LULC of GHKM based on multi-year Landsat and nighttime light (NTL) data. First, a supervised classification technique, i.e., support vector machine (SVM), is used to classify the Landsat images into seven thematic classes: forest, grassland, water, fishponds, built-up, bareland, and farmland. Second, the demographic activities are studied by calculating the light index, using nighttime light data. Third, several socioeconomic factors, derived from statistical yearbooks, are used to determine the impact on the LULCC in the study area. The post-classification change detection shows that the increase in the urban area, from 0.76% (1488.35 km2) in 1986 to 10.31% (20,643.28 km2) in 2017, caused GHKM to become the largest economic segment in South China. This unprecedented urbanization and industrialization resulted in a substantial reduction in both farmland (from 53.54% (105,123.93 km2) to 33.07% (64,932.19 km2)) and fishponds (from 1.25% (2463.35 km2) to 0.85% (1674.61 km2)) during 1986–2017. The most dominant conversion, however, was of farmland to built-up area. The subsequent urban growth is also reflected in the increasing light index trends revealed by NTL data. Of further interest is that the overall forest cover increased from 33.24% (65,257.55 km2) to 45.02% (88,384.19 km2) during the study period, with a significant proportion of farmland transformed into forest as a result of different afforestation programs. An analysis of the socioeconomic indicators shows that the increase in gross domestic product, total investment in real estate, and total sales of consumer goods, combined with the overall industrialization, have led to (1) urbanization on a large scale, (2) an increased light index, and (3) the reduction of farmland. The speed of development suggests that opportunistic development has taken place, which requires a pressing need to improve land policies and regulations for more sustainable urban development and protection of farmland.

Highlights

Land use and land cover changes (LULCC) have increasingly become a global challenge
The transformation between the different LULC maps reflect the direction of change, which can be best explained using a space-time change process
The results show that over the past three decades, GHKM, a large tropical and sub-tropical region in China, has undergone dramatic LULCC, mainly dominated by built-up land, farmland, and forest

Summary

Introduction

Land use and land cover changes (LULCC) have increasingly become a global challenge They are the most direct expression of the effects of human activity on the natural ecosystems [1,2,3]. It has been found that changes in land use have negative impacts on the climate, ecosystems, surface radioactivity (e.g., increased atmospheric greenhouse gasses, depletion of the ozone layer), agricultural activities, and biodiversity on both local and global scales. Such situations are more prevalent in developing countries such as China [4,6,7,8,9]

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