Combining habitat area and fragmentation change for ecological disturbance assessment in Jiangsu Province, China

Evaluation for the spatiotemporal patterns of ecological vulnerability and habitat quality: implications for supporting habitat conservation and healthy sustainable development

Currently, the rapid socioeconomic development and urbanization around the world have caused the ecological environment on the earth surface to become extremely fragile and destroyed. In addition, the increasing demand of human beings for material also leads to the unsustainable development of resources and environment. However, how to achieve the win-win goal between socioeconomic development and ecological protection in the context of these impacts? It is becoming a major problem for governments and policy makers. To further reveal the contradiction between man and land, taking Wuhan metropolitan area as the study area, this study mainly proposed a framework for the comprehensive optimization of landscape pattern and ecological environment and constructed the ecological vulnerability mixed evaluation model. Then, the integrated valuation of ecosystem services and trade-offs (InVEST) model was employed to evaluate the changes in habitat quality, focusing on the analysis of the impact mechanism of the evolution of ecological environment. This study found that the hybrid model of landscape vulnerability can successfully explore the landscape ecological vulnerability of Wuhan metropolitan area from 2000 to 2020, and its spatiotemporal differentiation pattern was obvious. The InVEST model showed that the habitat quality had obvious spatial differentiation. On the whole, the overall quality of the habitat was low and the degradation degree was high. Furthermore, our study also showed that the change of landscape ecological environment was influenced by the common potential of local nature and social economy, rather than a single factor. Finally, the main purpose of this study is to help scientifically formulate habitat protection and landscape planning strategies through in-depth study of landscape ecological environment, so as to alleviate man-land contradiction and support regional sustainable development.

Vegetation cover variations associated with climate change and human activities in Nanjing metropolitan area of China

Quantify the relative effects of climate change and human activities on vegetation cover can help us understand the vegetation cover change and its drivers. Residual analysis, defined as the difference between potential normalized difference vegetation index (NDVI_pot) and observed normalized difference vegetation index (NDVI_act), was used to solve this problem. The estimation of NDVI_pot is one of the important issues faced by ecologists. Due to the strictly protection of environment and ecosystems, the ecosystems in nature reserves are rarely disturbed by human activities. Therefore, establishing NDVI_pot estimation model based on nature reserves can improve the estimation accuracy of NDVI_pot. However, the estimation of NDVI_pot based on nature reserves has not yet been reported. In this paper, the NDVI_pot estimation model was established based on nature reserves, and residual analysis was used to quantify the impact of human activities on NDVI_act. The results show that the NDVI_act in Nanjing metropolitan area (NJMA) showed a significant upward trend from 2000 to 2019, and 74.20% of NJMA showed greening trends, while 24.47% showed browning trends. The temperature and precipitation were positively correlated with normalized difference vegetation index (NDVI), and the impact of the temperature on NDVI was greater than that of precipitation. The promotion of human activities on NDVI had become more and more significant. There was 51.88% of NJMA where the human activities had a positive promotion effect on NDVI, while there was 46.29% of the regional where the human activities had a negative inhibitory effect on NDVI. The population density (POP) and gross domestic product (GDP) were mainly positively correlated with NDVI, and the impact of the POP on NDVI was greater than that of GDP. The conversion of cropland to forests and the increase of the sown area of crops also caused the NDVI to increase, while the disorderly expansion of urban land caused the NDVI to decrease.

Changes in ecological networks and eco-environmental effects on urban ecosystem in China's typical urban agglomerations

Exploring the changes in ecological networks (ENs), its eco-environment effects and the differences in urban agglomerations in various urbanization stages are important for achieving sustainable ecosystem management and a better layout of ecological network. In this study, China's three typical urbanization agglomerations, Beijing-Tianjin-Hebei urban agglomeration (BTH), Yangtze River Delta urban agglomeration (YRD), and Pearl River Delta urban agglomeration (PRD), were selected as the study area. Spatiotemporal changes in ENs, the changing patterns, its eco-environment effects, and impacts of rapid urbanization were analyzed by environment indices, buffer analysis, and correlation analysis. The results showed a great lost in ENs from 2000 to 2015. Four patterns were seen in changing ENs: decomposition process (DP), internal change process (ICP), polycondensation process (PP), and external change process (ECP). ICP was dominated in YRD and PRD. ECP was the main pattern in core areas of BTH. The correlation analysis with YRD as the example showed that the changes in ENs had a certain impact on the eco-environment, especially in the 10-km buffer zone. The decrease of ENs was related to the increase of developed land, and the closer to the core area, the higher the correlation coefficient was. Reduction of ENs would slow down to a certain extent, when the agglomeration is in a higher urbanization stage. Different directions of restoration and optimization of ENs were proposed for the three urban agglomerations. The study will provide support for sustainable management and restoration and optimization of ENs for China's agglomerations.

Measuring green development level at a regional scale: framework, model, and application

In this study, we propose and construct a novel model that measures regional green development level based on the "three-circle" conceptual framework for green development. Using Jiangsu Province in eastern China as a case study, the spatial-temporal characteristics and dynamics of the green development level from 2000 to 2020 were evaluated using a multi-source dataset at the grid-cell level. Our results show that (1) the analytical hierarchy process-based model proposed herein has higher reliability in terms of the development level measurement than principal component analysis and the entropy weight method. In addition, the average score of green development in the study area was approximately 0.53. Spatially, the green development level in the eastern coastal areas of the study area was found to be generally higher than in other regions, while that in southwestern regions is relatively low. In terms of sub-regions, the green development level scores of the study area have been ranked as follows: middle Jiangsu > southern Jiangsu > northern Jiangsu. (2) It was observed that the gravity center of the green development level can be divided into three stages during the study, with a whole had shifted to the north. (3) For most cities in Jiangsu, the green development level initially increased at first, then declined, and then increased again. (4) In the future, the green development level of Jiangsu Province should pay more attention to promoting regional coordinated development and relationships between society and the environment under rapid economic development.

Response of Reeves's Pheasants Distribution to Human Infrastructure in the Dabie Mountains over the Last 20 Years

Simple Summary

Human infrastructure development drives habitat loss and fragmentation worldwide. In China, rapid infrastructure development impacts the habitats of endangered species. This study assessed how the distribution of Reeves’s pheasant, an endangered species of the International Union for Conservation of Nature (IUCN) and a nationally protected species of China, was potentially affected by human infrastructure development in the Dabie Mountains, the species’ main distribution range, over the past 20 years. We found that human infrastructure became more extensively distributed throughout the study area and closer to locations where Reeves’s pheasants were detected. Our results suggest that the increased density of buildings and roads in the Dabie Mountains may have caused a negative impact on Reeves’s pheasants.

Abstract

Human infrastructure development drives habitat loss and fragmentation worldwide. In China, over the last 20 years, rapid infrastructure development impacted the habitats of endangered species. To facilitate conservation efforts, studies of how human infrastructure affects the distribution of Reeves’s pheasant (Syrmaticus reevesii), an endangered species by the International Union for Conservation of Nature (IUCN) and a nationally protected species in China, are critically needed. We assessed how the distribution of Reeves’s pheasant was impacted by human infrastructure development over the past 20 years in the Dabie Mountains, the main distribution range of the species. We surveyed Reeves’s pheasants by direct sightings and indirect evidence through line transects which were randomly distributed in the Dabie Mountains from 2001 to 2002 and 2018 to 2019. We evaluated the variation of the roads and buildings in these areas in the last 20 years, and then modeled the relationship of the distribution of this pheasant with the road and building data from 2000 and 2017. Human infrastructure became more extensively distributed throughout the Dabie Mountains during the period, with all lands within 10 km of a road or a building. The distribution of Reeves’s pheasants became closer to the buildings and roads and there was a significantly positive relationship between the occurrence of Reeves’s pheasants and the distance to the nearest buildings and roads in 2018–2019. These results suggest that the increased density of buildings and roads in the Dabie Mountains may have caused negative effects on Reeves’s pheasants.