Identification of Ecological Restoration Approaches and Effects Based on the OO-CCDC Algorithm in an Ecologically Fragile Region

Abstract

A full understanding of the patterns, trends, and strategies for long-term ecosystem changes helps decision-makers evaluate the effectiveness of ecological restoration projects. This study identified the ecological restoration approaches on planted forest, natural forest, and natural grassland protection during 2000–2022 based on a developed object-oriented continuous change detection and classification (OO-CCDC) method. Taking the Loess hilly region in the southern Ningxia Hui Autonomous Region, China as a case study, we assessed the ecological effects after protecting forest or grassland automatically and continuously by highlighting the location and change time of positive or negative effects. The results showed that the accuracy of ecological restoration approaches extraction was 90.73%, and the accuracies of the ecological restoration effects were 86.1% in time and 84.4% in space. A detailed evaluation from 2000 to 2022 demonstrated that positive effects peaked in 2013 (1262.69 km2), while the highest negative effects were observed in 2017 (54.54 km2). In total, 94.39% of the planted forests, 99.56% of the natural forest protection, and 62.36% of the grassland protection were in a stable pattern, and 35.37% of the natural grassland displayed positive effects, indicating a proactive role for forest management and ecological restoration in an ecologically fragile region. The negative effects accounted for a small proportion, only 2.41% of the planted forests concentrated in Pengyang County and 2.62% of the natural grassland protection mainly distributed around the farmland in the central-eastern part of the study area. By highlighting regions with positive effects as acceptable references and regions with negative effects as essential conservation objects, this study provides valuable insights for evaluating the effectiveness of the integrated ecological restoration pattern and determining the configuration of ecological restoration measures.

Landsat series images for evaluating ecological restoration effect from multi-time scale based on an ideal reference

“…We selected the semi-arid and sub-humid loess hilly ecoregion located in southern Ningxia (105 °19′-106 °57′ E and 35 °11′-36 °31′ N) as the study area (Figure 1). Encompassing an area of 15,526 km 2 , this region, which is a part of the northwestern Loess Plateau, is one of Ningxia's three recognized ecological functional zones, characterized by high ecological vulnerability and sensitivity (Li et al, 2015;Dong et al, 2023;Wei et al, 2023). It covers the Liupan Mountain and Qingshui Valley and is characterized by elevations ranging from 1,305 m to 2,936 m above sea level (asl) (Figure 1C).…”

“…Significant progress has been made in the assessment of ecological restoration effects. However, the existing literature lacks comprehensive assessments that focus on the short-term changes and long-term trends in the ecological environment, resulting in uncertainties in the current knowledge of ecological restoration processes (Li et al, 2023;Wei et al, 2023). Further, it is difficult to provide an objective assessment of the effects of ecological restoration, owing to the non-consideration of the natural conditions (Li et al, 2017) of a region and the environmental change response at the global scale (Guo et al, 2022).…”