###### Abstract  
Ecological degradation caused by rapid urbanisation has presented great challenges in southern China. Fractional vegetation cover (FVC) has long been the most common and sensitive index to describe vegetation growth and to monitor vegetation degradation. However, most of the studies have failed to adequately explore the complexity of the relationship between fractional vegetation cover (FVC) and impact factors. In this research, we first constructed a Semi-parametric Geographically Weighted Regression (SGWR) model to analyse both the stationary and nonstationary spatial relationships between FVC and driving factors in Guangdong province in southern China on a county level. Then, climate, topographic, land cover, and socio-economic factors were introduced into the model to distinguish impacts on FVC from 2000-2015. Results suggest that the positive and negative effects of rainfall and elevation coefficients alternated, and local urban land and population estimates indicated a negative association between FVC and the modelled factors in each period. The SGWR FVC make significantly improves performance of the geographically weighted regression and ordinary least squares models, with adjusted R\({}^{2}\) higher than 0.78. The findings of this research demonstrated that, although urbanisation in the Pearl River Delta in Guangdong has encroached on the regional vegetation cover, the total vegetation area remained unchanged with the implementation of protection policies and regulations. fractional vegetation cover; geographically weighted regression; multi-driving factors; Google Earth Engine; Guangdong +
Footnote †: journal: 12  
0000-0002-4500-0002-9999-22000/0000-00002-9999-22000/00000-00002-9999-22000/0000000-00000-00000-00000-00000-000000-000000-000000-000000-000000-00  
Most research on regional vegetation coverage change and driving factors focuses on the impact of climate factors, which are closely related to vegetation cover [8; 9; 10]. Of these, rainfall and temperature are important factors affecting vegetation growth in East Africa [11; 12]. Topographic (e.g., elevation and slope) and climate factors are the most basic natural factors in the region and the primary influence on FVC change in China [13; 14]. Additionally, FVC is associated with land use and cover (LCC) factors (e.g., deforestation and urban expansion) [15; 16]. Socio-economic factors significantly impact FVC and primarily include the destruction of the regional ecological environment and deforestation caused by population growth and economic poverty, and the increase of FVC because of the Grain for Green policy [17; 18]. To better understand the regional FVC with different factors, bivariate-partial correlation analysis and piecewise linear regression were applied to the exploring the relationship between FVC with various climatic and human-induced factors [19]. Formal analytic framework can be used to quantify the contributions of climatic factors and human activities in driving FVC [20]. However, the principal drivers of FVC in Guangdong remain undetermined. Since the 1990s, a range of laws and regulations, such as the New Law of Land Administration (1998) and The Regulations on Protection of Basic Farmland (1998) have been proposed and implemented to reinforce vegetation protection and management [21; 22]. Several major ecological afforestation construction projects, such as the \"Grain for Green\" program in 1999, were initiated [23; 24]. Additionally, the policy of strengthening environmental protection, promoting cleaner production, and reducing consumption in Guangdong province has been further emphasised with the construction of a forest ecological barrier system for urban green space system in the Pearl River Delta [25]. Thus, the regional ecological environment affected by vegetation cover dynamics and driving factors has become a major concern of the Chinese government.