Understanding changes in a Tropical Delta: A multi-method narrative of landuse/landcover change in the Niger Delta

Identification of factors influencing net primary productivity of terrestrial ecosystems based on interpretable machine learning --evidence from the county-level administrative districts in China

Global climate change is rooted in the imbalance between carbon sources and sinks, and net-zero greenhouse gas emissions should focus not only on the source-side drivers but also on the sink-side influencing factors. Taking the county-level administrative districts in China as the sample, this study uses machine learning models to fit the relationship between socioeconomic development (SED) and net primary productivity (NPP) of terrestrial ecosystems. Moreover, it identifies key influencing factors and their effects based on the SHapley Additive exPlanations (SHAP) algorithm. The results show that the districts with low terrestrial NPP show the characteristics of agglomeration distribution. The eight key factors, in order, are as follows: agricultural development level, latitude, population size, longitude, animal husbandry development level, economic scale, time trend and industrialization level. In this study, via SHAP interaction plots, we found that the effects of population, economic growth, and industrialization on terrestrial NPP are regionally heterogeneous; via cluster analysis, we found the stage characteristics of the mode of SED affecting terrestrial NPP. Therefore, the conservation of terrestrial NPP needs to be combined with the stage changes of SED, as well as inter-regional differences, to develop a regionally coordinated and time-coherent ecological carbon sink conservation plan.

Ecological Impacts of Land Use Change in the Arid Tarim River Basin of China

Land use/cover change has become an indispensable part of global eco-environmental change research. The Tarim River Basin is the largest inland river basin in China. It is also one of the most ecologically fragile areas in the country, with greening and desertification processes coexisting. This paper analyzes the evolution of land-use/cover change in the Tarim River Basin over the past 30 years based on remote sensing data. The research also explores the contribution of conversion between different land types to the ecological environment by selecting methods, such as transfer matrix and ecological contribution rate. Results indicate that grassland and barren land are the main land types in the region, accounting for 72.46% and 18.87% of the basin area, respectively. From 1990 to 2019, cropland area increased from 33,585.89 km2 to 52,436.40 km2, an increase of 56.13%, while barren land areas decreased from 781,380.57 km2 to 760,783.29 km2. Most of the land-use conversion was grassland to other land types and other land types to barren land. Since 1990, the conversion of barren land to grassland and cropland in the basin has led to ecological improvement, whereas the conversion of grassland to cropland has caused deterioration, but with a generally improving trend. It is anticipated that, over the next decade, changes in land types will involve increases in grassland and woodland area, decreases in barren land and cropland, and an overall improvement in the ecological environment in the watershed. Since agriculture and animal husbandry are the main industries in the Tarim River Basin and the land-use structure is dominated by cropland and grassland, several key measures should be implemented. These include improving land use, rationalizing the use of water and soil resources, slowing down the expansion of cropland, and alleviating the contradiction between humans and land, with the ultimate aim of achieving sustainable development of the social economy and ecological environment.

Assessment of spatial and temporal ecological environment quality under land use change of urban agglomeration in the North Slope of Tianshan, China

In the current context of rapid development and urbanization, land use and land cover (LULC) types have undergone unprecedented changes, globally and nationally, leading to significant effects on the surrounding ecological environment quality (EEQ). The urban agglomeration in North Slope of Tianshan (UANST) is in the core area of the Silk Road Economic Belt of China. This area has experienced rapid development and urbanization with equally rapid LULC changes which affect the EEQ. Hence, this study quantified and assessed the spatial-temporal changes of LULC on the UANST from 2001 to 2018 based on remote sensing analysis. Combining five remote sensing ecological factors (WET, NDVI, IBI, TVDI, LST) that met the pressure-state-response(PSR) framework, the spatial-temporal distribution characteristics of EEQ were evaluated by synthesizing a new Remote Sensing Ecological Index (RSEI), with the interaction between land use change and EEQ subsequently analyzed. The results showed that LULC change dominated EEQ change on the UANST: (1) From 2001 to 2018, the temporal and spatial pattern of the landscape on the UANST has undergone tremendous changes. The main types of LULC in the UANST are Barren land and Grassland. (2) During the study period, RSEI values in the study area were all lower than 0.5 and were at the [good] levels, reaching 0.31, 0.213, 0.362, and 0346, respectively. In terms of time and space, the overall EEQ on the UANST experienced three stages of decline-rise-decrease. (3) The estimated changes in RSEI were highly related to the changes of LULC. During the period 2001 to 2018, the RSEI value of cropland showed a trend of gradual increase. However, the rest of the LULC type's RSEI values behave differently at different times. As the UANST is the core area of Xinjiang's urbanization and economic development, understanding and balancing the relationship between LULC and EEQ in the context of urbanization is of practical application in the planning and realization of sustainable ecological, environmental, urban, and social development in the UANST.

Canalization induced topographic, hydrologic, and land use changes in Olero Creek, Benin River owing to petroleum exploration activities

Canalization carried out during petroleum exploration is contributing to environmental changes in the Niger Delta. We carried out a study on five decades of canalization in Olero Creek, Benin River, from 1980 to 2020. The study site covered an area of 36.40 km². Satellite imageries of five epochs (1980, 1990, 2000, 2010, and 2020) and Shuttle Radar Topographic Mission (SRTM) of 2000, which provided digital elevation models (DEMs) of the study area were collected and analyzed using ERDAS IMAGINE 9.2 and ArcGIS 10.6 software. We found that the total length of dredged canal increased from 14.14 km in 1980 to 61.07 km in 2020, spoil banks doubled from 2.05 km² in 1980 to 4.13 km² in 2020, and direct wetland loss doubled from 3.76 km² in 1980 to 7.57 km² in 2020, with the largest increase occurring between 1990 and 2000. The land use/land cover, topography, and hydrology of the area also changed. Water bodies that originally accounted for 1.17% of the study area in 1980, increased to 22% in 2020, Rhizophora racemosa fringing the waterbodies increased from 11% in 1980 to 47% in 2020, and Rhizophora mangle decreased from over 55% in 1980 to about 23% in 2020. The results of digital elevation model show that the surface area is undulating with the relative topography of the study site ranging from - 5 to 40 m. We conclude that canalization during petroleum exploration was contributing to land use, topographic, and hydrologic changes in the study area.

Ecological environment assessment based on land use simulation: A case study in the Heihe River Basin

Ecological environment assessment can not only provide significant references for effective solutions to regional ecological problems, but also promote the benign interaction of socio-economic-ecological development. This study selected the Heihe River Basin (HRB) as the typical area to comprehensively evaluate the ecological environment from 2010 to 2030 based on the dynamics of land system (DLS) model, which is coupled with the biological abundance index (BAI), vegetation coverage index (VCI), water density index (WDI), land degradation index (LDI), and eco-environment quality index (EQI). The results indicate that the BAI and VCI will be high in the south and east, low in the north and west in general. Under the future baseline scenario, the changes of biological abundance, vegetation coverage, and deteriorating land in the midstream and downstream regions will may seriously hinder restoration of the ecological environment. In particular, the BAI in the midstream and downstream regions will decline more rapidly, with a rate of 10.30% and 18.59%, respectively. The water area will be scattered and less abundant overall, but the WDI in the midstream, that is up to 3.86 in 2030, will be higher than that in other regions. Results also show that the regions with high EQI are mainly located in the northeast and south region. It is predicted that the ecological fragile zones in the future will mainly distribute in the midstream and downstream regions, especially in Jiayuguan City and Jinta County. The EQI will drop by 44.28% and 11.40% during 2010-2030 without external conditions intervened. In addition, Qilian Mountain, Jiuquan City, Gaotai County, Linze County, and Shandan County will also have relatively strong recovery capacities under the influence of ecological policies. All above could provide the basis for the development of future watershed ecological environment management and protection planning.