###### Abstract  
Large-scale ecosystem restoration projects (ERPs) have been implemented since the beginning of the new millennium to restore vegetation and improve the ecosystem in Southwest China. However, quantifying the effects of specific restoration activities, such as afforestation and grass planting, on vegetation recovery is difficult due to their incommensurable spatiotemporal distribution. Long-term and successive ERP-driven land use/cover changes (LUCCs) were used to recognise the spatiotemporal patterns of major restoration activities, and a contribution index was defined to assess the effects of these activities on gross primary production (GPP) dynamics in Southwest China during the period of 2001-2015. The results were as follows. (1) Afforestation and grass planting were major restoration activities that accounted for more than 54% of all LUCCs in Southwest China. Approximately 96% of restoration activities involved afforestation, and these activities were mostly distributed around Yunnan Province. (2) The Breathing Earth System Simulator (BESS) GPP performed better than the Moderate Resolution Imaging Spectroradiometer (MODIS) GPP validated by field observation data. Nevertheless, their annual GPP trends were similar and increased by 12,581 g C m\({}^{-2}\) d\({}^{-1}\) and 13,406 g C m\({}^{-2}\) d\({}^{-1}\) for MODIS and BESS GPPs, respectively. (3) Although the afforestation and grass planting areas accounted for less than 1% of the total area of Southwest China, they contributed to more than 1% of the annual GPP increase in the entire study area. Afforestation directly contributed 14.94% (BESS GPP) or 24.64% (MODIS GPP) to the annual GPP increase. Meanwhile, grass planting directly contributed only 0.41% (BESS GPP) or 0.03% (MODIS GPP) to the annual GPP increase. ecological restoration; afforestation; LUCC; gross primary production; Southwest China 2021233123  
However, new plants in ERPs may be degraded and even die due to human disturbance and extreme climate events [9; 10]. Overplanting trees may also aggravate water shortage due to excessive water consumption and reduce vegetation cover in arid and semiarid areas [11; 12]. Monitoring spatiotemporal variations in restoration activities, such as afforestation and grass planting, and vegetation growth characteristics in areas with these activities can effectively help evaluate the effectiveness of ERPs and their ecosystems [13]. Although field studies can obtain accurate spatiotemporal distributions of these restoration activities, applying this method to large areas can be difficult due to extensive human resource and economic costs. Therefore, an effective method for determining the spatiotemporal distributions of afforestation and grass planting is necessary to assess the effectiveness of ERPs. Remote sensing-based land use/cover change (LUCC) that directly reflects human-caused land use activities [14; 15] is an effective method for exploring ERP-induced vegetation dynamics on a large scale [13; 16; 17]. Restoration activities, including afforestation and grass planting, which are largely linked to LUCC patterns converted from other land uses/covers into forests and grasslands, have been used to explore vegetation recovery [18]. For example, [PERSON] et al. [19] examined dominant systematic changes in land cover to recognise fundamental processes of land transition characteristics before and after the implementation of ecological programmes in the Loess Plateau in China. [PERSON] et al. [13] developed an LUCC-based vegetation succession mapping method for evaluating the effects of restoration on karst vegetation in Southwest China. LUCC has also demonstrated that ecological restorations represent a major factor in increasing vegetation cover and greenness [8; 17]. However, the increased occurrence of extreme climate events (e.g., drought and wildfire) due to climate change and the rapid expansion of human activities, such as agricultural reclamation, have exerted a considerable negative impact on vegetation recovery [9; 10; 20; 21].