Identifying and optimizing ecological spatial patterns based on the bird distribution in the Yellow River Basin, China.

In the Yellow River Basin (YRB), there exists a rich biodiversity of species that has been shaped by its unique geography, climate, and human activities. However, the high speed of economic development has resulted in the fragmentation and loss of habitats that are crucial for the survival of these species. To address this problem, constructing ecological networks has emerged as a promising approach for biodiversity preservation. In the study, we centered on the YRB and employed bird communities as an indicator species to identify ecological sources by combining bioclimatic variables and land use data with the Maximum Entropy (MaxEnt) and Integrated Valuation of Ecosystem Services and Tradeoffs (InVEST) models. We generated a resistance surface using various data such as Digital Elevation Model (DEM), the Normalized Difference Vegetation Index (NDVI), Normalized Difference Water Index (NDWI), nighttime light, road density, railway density, and waterway density. So, we then simulated ecological corridors applying the Minimum Cumulative Resistance (MCR) model and constructed a bird diversity protection network. The results we found suggested that bird hotspots were predominantly clustered upstream and downstream in the YRB. We identified 475 sources covering a total area of 65,088 km2, 681 corridors with a total length of 11,495.05 km. This network served as a critical ecological facility to sustain and protect biodiversity. The bird ecological corridors in the YRB showed that a dense east-west pattern in the central area, with a short length in the west and east and a long length in the central area. Although the central region lacked ecological sources, the east and west were still connected as a tight whole. Two scenarios showed adding ecological stepping stones had a better optimization effect than enhancing ecological connectivity.

Study of spatialtemporal changes in Chinese forest eco-space and optimization strategies for enhancing carbon sequestration capacity through ecological spatial network theory.

The conservation of forest ecosystems and the enhancement of carbon sequestration capacity play a crucial role in maintaining ecological balance and human development. However, with excessive deforestation, the flow of energy and information within the ecosystem has changed, which in turn has led to changes in the topological properties and carbon sequestration capacity of forest ecosystems. In order to better investigate the nature and carbon sequestration capacity of forest ecological space in mainland China during 2000-2018, we constructed a time-series Chinese forest ecological spatial network based on complex network theory and graph theory, combined with the modified minimal cumulative resistance model (MCR). By combining the net primary productivity (NPP) values obtained from the Boreal Ecosystem Productivity Simulator (BEPS) model of existing scholars, we further explored the relationship between topology and carbon sequestration capacity within forest ecosystems, and proposed strategies and suggestions for optimization. The results show that forest ecological sources and ecological corridors showed an increasing trend and resistance values decreased year by year during 2000-2018, especially in the western region, indicating that ecological restoration projects in western China have achieved certain effects. However, the stability of forest ecosystems has been decreasing year by year, and the forest carbon sequestration capacity in western China is also decreasing. Through correlation analysis, we found that carbon sequestration capacity showed highly significant positive correlation with closeness centrality, harmonic closeness centrality, clustering, and eigen centrality, and carbon sequestration capacity showed highly significant negative correlation with betweeness centrality. Through Principal Components Analysis (PCA), we suggest that consolidating small patches in the northeast, reducing the number of redundant ecological corridors, adding stepping stone patches to shorten the length of ecological corridors, and increasing ecological corridors in non-northeast areas are conducive to enhancing plant carbon sequestration capacity. This study provides theoretical support and ecological engineering recommendations for China to achieve its strategic goals of carbon neutrality and carbon peaking.