Responses of landscape structure to the ecological restoration programs in the farming-pastoral ecotone of Northern China.

Ecological restoration programs (ERPs) have been conducted in China since 2000 to improve ecological conditions, particularly in the farming-pastoral ecotone of Northern China. Few have studied the effects of ERPs on landscape structure. Taking West Liaohe River Basin (WLRB) as a case study, we explored how landscape dynamics were altered before and after ERPs from 1990 through 2015 by using multi-temporal Landsat TM images. We analyzed the effects of ERPs on landscape structure by exploring the relationships between landscape features and land cover change (LCC). The results indicate that dramatic changes in land cover and landscape structure occurred before and after ERPs implementation. During 2000-2015 woodlands increased with a sharper annual growth, grasslands reclamation slowed down and was restricted, whereas more croplands were converted to grasslands and woodlands. ERPs decreased landscape fragmentation and increased landscape diversity, due mostly to the portion and spatial configures of croplands, grasslands and woodlands. Landscape fragmentation was significantly correlated with mean patch size of grasslands (r = -0.677, p < 0.0001) and woodlands (r = -0.515, p < 0.0001), as well as patch number ratio of croplands to the sum of grasslands and woodlands (r = -0.414, p < 0.01). Additionally, landscape diversity had a significant negative correlation with the areal ratio of grasslands (r = -0.345, p < 0.001). Our findings indicate that the LCCs were in agreement with ERPs' key goals. The changes in landscape structure in WLRB, however, were not expected from the ERPs design. Given the importance of landscape structure in human vulnerability to environment, it seemed that EPRs from the central government should not only regulate specific land use but also focus on the health and sustainability of the landscapes. Explicit function-based local landscape management should be taken into account for the future through better design and implementations of ERPs.