Effects of human activity intensity on habitat quality based on nighttime light remote sensing: A case study of Northern Shaanxi, China

Human and natural factors affect habitat quality in ecologically fragile areas: evidence from Songnen Plain, China

Habitat quality (HQ) has been progressively degrading worldwide in recent decades due to rapid climate change and intensive human activities. These changes not only threaten biodiversity and ecosystem functions, but also impact socio-economic development. Therefore, a few studies have focused on the dynamics of HQ and its natural and anthropogenic drivers. However, many contributions have failed to reveal how these factors interact to impact HQ, especially in ecologically fragile areas. We estimated HQ in the Songnen Plain of Northeast China, an ecologically fragile area, from 2000 to 2020 using the InVEST model and explored the response of HQ to the interactions of natural factors (topography, climate, NDVI) and anthropogenic factors (nighttime light index, population density) influencing HQ using Structural Equation Modelling (SEM). The results showed that 1) HQ decreased constantly from 2000 to 2018, and then increased slightly from 2018 to 2020. 2) In terms of spatial distribution, HQ appeared to be highly heterogeneous with a pattern of 'high HQ in the east - low HQ in the center - high HQ in the west' at each time point. The high-HQ areas were significantly clustered in the eastern parts with dense forests, while the low-HQ areas in the central parts were dominated by a large number of man-made patches of agriculture and towns or cities. 3) The spatial patterns of HQ are mainly affected by the interactions of factors including the natural environment and human disturbance. Natural factors had a greater impact on HQ than human disturbance, and human disturbance factors had significant negative impact among all these factors at 4 time points. Furthermore, the intensity of the impact of various influencing factors on habitat quality, as well as the positive or negative effects of these drivers on habitat quality, changed over time. The most important influencing factor was temperature in 2000 and topography in 2010, 2018, and 2020. This study can provide important suggestions for future ecological protection and restoration in similar ecologically fragile areas.

Habitat degradation changes and disturbance factors in the Tibetan plateau in the 21st century

Land use changes driven by human activities significantly impact biodiversity in plateau regions. However, current research is largely confined to identifying correlations between various factors and both habitat quality and degradation, overlooking the nonlinear relationships between them. To address this gap, we applied the PLUS-INVEST model to investigate the spatial effects of land-use changes on habitat quality and degradation patterns across the Tibetan Plateau during the 21st century. By employing a geographic detector, we determined the contribution rates of disturbance factors to habitat quality and degradation, and established constraint lines and threshold ranges between these factors. The findings reveal that: (1) The PLUS model demonstrates an exceptional performance in land-use simulation, with an overall accuracy of 0.8465. (2) The high-quality habitat area exhibits a declining trend, while the habitat degradation index steadily rises from 2000 to 2100, indicating a significant loss of biodiversity within the region. Habitat quality displays a spatial distribution pattern characterized by higher values in the south and lower values in the north, with areas in proximity to road threat sources experiencing more pronounced habitat degradation. (3) NDVI emerges as the most influential factor in promoting habitat quality, while the interaction of NDVI_Temperature exerts the greatest influence on spatial heterogeneity. The distance to resident emerges as the primary disturbance factor contributing to habitat degradation, with the interaction strength of GI_Resident being the most significant contributor. (4) Threshold intervals for ANPP, NDVI, precipitation, temperature, and distance to resident of optimal habitat quality and most severe degradation. This provides a novel scientific approach for designating areas for targeted conservation and intensive management restoration.

The spatiotemporal evolution characteristics and influencing factors of habitat quality in the typical region of the Lunan Economic Belt: a case study of Donggang District, Rizhao

Habitat quality is a key indicator for evaluating the biodiversity of a region. This study aims to assess the current status and characteristic changes of habitat quality in Donggang District, Rizhao while analyzing the potential factors influencing the quality of the habitat. The study employed the Integrated Valuation of Ecosystem Services and Tradeoffs Habitat Quality (InVEST-HQ) mode to assess the spatiotemporal variations in habitat quality in the Donggang District from 2008 to 2022. GeoDetector was utilized to investigate the impact of various factors on the spatial differentiation characteristics of habitat quality. The potential correlation between economic development and habitat quality was further explored using the Spearman correlation coefficient and Grayscale Association Analysis. The results reveal that habitat quality in Donggang District is highest in the east and lowest in the west, with significant correlations to land use and vegetation coverage. The study highlights a decline in habitat quality over the period, linked to rapid economic growth and industrial expansion. These insights are crucial for balancing urban biodiversity with economic development.

Spatiotemporal dynamics of ecosystem supply service intensity in China: Patterns, drivers, and implications for sustainable development

With the steady development of global economy and the rapid increase of population, it is of great significance to quantify the supply capacity of ecosystem services and reveal its driving factors for sustainable development. We quantify the ecosystem supply service intensity (ESSI) using multiple sources of natural and cultural data from 2000 to 2020. We then jointly analyze this data with the information entropy of the land to obtain the temporal and spatial evolution law of ESSI under multiple scales in China. At the same time, according to the spatial distribution of ESSI in China, the concept of China's ecosystem supply service intensity development equilibrium line (ESSIL) is innovatively put forward. The results show that the spatial distribution pattern of China's ESSI is symmetrical with the ESSIL which is nearly orthogonal to Hu Huanyong line. Because of the different regional development policies, different regions with different economic levels have different driving effects on land change. Furthermore, due to the country's large size, the primary ESSI drivers vary greatly throughout its various regions. The assessment of the ESSI changes in China from multi-scale, combined with the effects of land cover change, climate and human activities, and put forward a new pattern distribution mode of ESSI in China, which provides a new perspective for formulating ecologically sustainable development strategies in large-scale areas.

The relationship between structure and ecosystem services of forest and grassland based on pattern analysis method: A case study of the Mongolian Plateau

Global warming has led to severe land desertification on the Mongolian plateau. It puts great environmental pressure on vegetation communities. This pressure leads to fragmentation of land use and landscape patterns, thus triggering changes in the spatial distribution patterns of vegetation. The spatial distribution pattern of vegetation is crucial for the performance of its ecosystem services. However, there is not enough research on the relationship between large-scale spatial distribution patterns of vegetation and ecosystem services. Therefore, this study is to construct an ecological spatial network on the Mongolian Plateau based on landscape ecology and complex network theory. Combining pattern analysis methods to analyze the network, we obtained the spatial and temporal trends of forest and grass spatial distribution patterns from 2000 to 2100, and explored the relationship between the topological properties of source patches and ecosystem services in different patterns. It was found that there are four basic patterns of spatial distribution of forest and grass in the Mongolian Plateau. The Core-Linked Ring pattern accounts for 40.74 % and exhibits the highest stability. Under the SSP5-RCP8.5 scenario, source patches are reduced by 22.76 % in 2100. Topological indicators of source patches showed significant correlations with ecosystem services. For example, the CUE of grassland patches in the Centralized Star pattern was positively correlated with betweeness centrality. The most significant improvement in WUE after optimization is 19.90 % compared to pre-optimization. The conclusion of the study shows that the spatial distribution pattern of vegetation can be used to enhance the stability of ecological spatial network and improve ecosystem services at a larger scale. It can provide a certain reference for the study of spatial patterns of vegetation distribution in arid and semi-arid areas.

Human activities are intensifying the spatial variation of landslides in the Yellow River Basin

Human activities are a triggering factor for landslides in the Yellow River Basin (YRB, China). However, the extent to which the spatial distribution of landslides is affected by human activities is unclear. We constructed a human activity intensity index (HAII) based on nighttime light data and land cover data. Regression and dominance analyses were used to compare the effects of the HAII, precipitation, distance to river, distance to fault, topographic relief and slope on the landslides spatial density (LSD). The results showed that in the YRB, the HAII, as a dominance influencing factor, had a significant positive influence on the LSD. Moreover, regional differences in the human disturbance of nature intensify the spatial variation of LSD. To quantify the intensity of human disturbance to nature, a human-nature conflict index (HNCI) is constructed by quantifying the difference between the slope distributions of artificial and natural landscapes. The results show that in the middle section of the YRB, humans are developing more steep mountainous areas, leading to more dense landslides. This study provides a reference for landslide risk management and land use planning in the YRB.

The effectiveness of natural reserves from the perspective of habitat quality in the southern section of the Hengduan Mountains, Southwestern China

Natural reserves (NRs) play key roles in habitat integrity conservation and biodiversity loss mitigation, and the assessment of the conservation effectiveness of NRs is needed to better manage them. Habitat quality (HQ) comprehensively reflects habitat integrity and biodiversity, but the conservation effectiveness of NRs from the perspective of HQ has rarely been determined at high spatial resolution. Taking the southern section of the Hengduan Mountains (SSHM) in Southwest China as an example, combining an InVEST-HQ model and spatiotemporal change detection methods, the effectiveness of NRs from the perspective of HQ at 30-m spatial resolution was assessed in this study. The effectiveness disparities of NRs across different properties (i.e., management level, conservation target, size, and establishment age) was analyzed and the human pressures on NRs was investigated. The results showed that the HQ of the NRs is good in the SSHM, with the area ratio of the Higher and Highest HQ ≥ 93%. Most of the NR area (94.11%) was effective at improving or maintaining a good HQ. With regard to NR properties, county NRs, NRs designated to conserving wild animals, middle NRs, and younger NRs were more effective, corresponding to management level, conservation target, size, and establishment age, respectively. The human footprint for an effective area is significantly lower than that for an ineffective area, consistent with higher HQ in the effective area and lower HQ in the ineffective area. These findings support the management and zoning of NRs in the SSHM to ensure their effectiveness.

Evolution characteristics and multi-scenario prediction of habitat quality in Yulin City based on PLUS and InVEST models

As a major energy city in China, Yulin City has faced huge challenges to the ecological environment with its rapid economic development and rapid urbanization. Therefore, it is of great significance to study the impact of land use changes on habitat quality. Based on three periods of land use data in Yulin City in 1995, 2005 and 2015, the PLUS model was used to simulate the land use changes in 2015. The measured kappa coefficient was 0.8859, which met the simulation accuracy requirements. By setting development zone boundaries and adjusting parameters, three progressive scenarios are designed to predict the spatial distribution of land use in Yulin City in 2035. The InVEST model was used to analyze the spatiotemporal evolution of Yulin City's habitat quality in the past 20 years and evaluate the distribution of Yulin City's habitat quality under three scenarios after 20 years. The results are as follows: (1) During the study period, construction land in Yulin City expanded rapidly, with an area increase of 380.87 km2 in 20 years, and ecological land gradually shrank. (2) The land use simulation results of Yulin City under various scenarios in 2035 show that future land use changes in Yulin City will mainly be concentrated in the central and western regions. (3) During the study period, the habitat quality of Yulin City was at a medium level and the overall habitat quality showed a downward trend. Spatially, the degree of habitat quality degradation in Yulin City showed a characteristic of gradually decreasing from West to East. (4) By 2035, under the scenario of suitable urban economic development, Yulin City's habitat quality has been improved to a certain extent, which not only protects ecological security but also meets the demand for construction land for urban development. The results of this study help the government better understand the evolution of land use and habitat quality in Yulin City in the past 20 years, and provide theoretical support and reference for the formulation of Yulin City's ecological environment protection policies and the implementation of ecological protection work under the current land spatial planning.

Wetland habitats supporting waterbird diversity: Conservation perspective on biodiversity-ecosystem functioning relationship

Wetlands, as core habitats for supporting waterbird diversity, provide a variety of ecosystem services through diverse ecosystem functioning. Wetland degradation and wetland-habitat loss undermine the relationship between biodiversity-ecosystem functioning (BEF), affecting the diversity of habitats and waterbirds. The conservation of waterbird diversity is closely linked to the proper functioning of wetland ecosystems (nutrient cycling, energy storage, and productivity). Waterbirds have complex habitat preferences and sensitivities, which affect biotic interactions. By highlighting the importance of temporal and spatial scales guided by BEF, a habitat-waterbird conservation framework is presented (BEF relationships are described at three levels: habitat, primary producers, and waterbird diversity). We present a novel perspective on habitat conservation for waterbirds by incorporating research on the effects of biodiversity and ecosystem functioning to address the crucial challenges in global waterbird diversity loss, ecosystem degradation, and habitat conservation. Last, it is imperative to prioritize strategies of habitat protection with the incorporation of BEF for future waterbird conservation.

Exploring evolution characteristics of eco-environment quality in the Yangtze River Basin based on remote sensing ecological index

As an important ecological-economic development area in China, scientific understanding of the spatial and temporal changes in eco-environment quality (EEQ) and its drivers in the Yangtze River Basin (YRB) is crucial for the effective implementation of ecological protection projects in the YRB. To address the lack of large-scale EEQ assessment in the YRB, this paper uses the Google Earth Engine (GEE) platform and the Remote Sensing Ecological Index (RSEI) to investigate the spatial and temporal characteristics of EEQ in the YRB from 2000 to 2020, and to analyze the impact of various factors on the EEQ of the YRB. This study showed that: (1) The overall EEQ of YRB was at the 'good' grade over the past 20 years, showing an increasing trend, with the value changing from 0.70 to 0.77. (2) The YRB's EEQ has positive spatial aggregation characteristics, with the northern part of the Jialing River basin and the Han River basin exhibiting a high-high aggregation type and the upper reaches exhibiting a low-low aggregation type. (3) In the past 20 years, the human activities had a greater impact on the EEQ of the YRB; moreover, all factors had a greater impact on the EEQ than a single factor. The interaction between the biological abundance index and population density had the most effect, with a q-value of 0.737 in 2020.

Spatiotemporal evolution of habitat quality and its response to landscape patterns in karst mountainous cities: a case study of Guiyang City in China

Habitat quality heterogeneity is one of the concrete manifestations of landscape pattern changes caused by human activities, which is of great significance to improve habitat quality by optimizing landscape pattern, thus scientifically protecting biodiversity and promoting ecological civilization construction. The coupling of rapid urbanization and ecological restoration measures has had a significant influence on the habitat quality of fragile and fragmented karst mountainous cities in recent years. In this study, spatiotemporal dynamics and heterogeneity of habitat quality and the impact of landscape patterns on habitat quality are analyzed in Guiyang, a typical karst mountain city in southwest China, mainly using the key methodologies such as the Integrated Valuation of Ecosystem Services and Tradeoffs (InVEST) model, Exploratory Spatial Data Analysis (ESDA), and hierarchical partitioning (HP). We found that the habitat quality index of Guiyang City improved from 0.6643 to 0.6988 during 2000-2019; the distribution of habitat quality has significant spatiotemporal heterogeneity and spatial aggregation effect with the low values or the decreased areas concentrated in and around the built-up areas or urbanization expansion areas. Landscape composition had greater contribution than landscape configuration to habitat quality. The increased areas of natural habitat have had a positive effect on habitat quality. Moreover, each landscape configuration had a significant positive or negative correlation with the habitat quality. Therefore, implementing ecological protection and restoration measures in karst mountainous cities might be an effective strategy to improve habitat quality during rapid urbanization. Furthermore, optimizing habitat patterns, reducing the habitats loss, and protecting the natural habitat integrity are crucial to improving and maintaining biodiversity in the study area.

Comprehensive evaluation system for vegetation ecological quality: a case study of Sichuan ecological protection redline areas

Dynamic monitoring and evaluation of vegetation ecological quality (VEQ) is indispensable for ecological environment management and sustainable development. Single-indicator methods that have been widely used may cause biased results due to neglect of the variety of vegetation ecological elements. We developed the vegetation ecological quality index (VEQI) by coupling vegetation structure (vegetation cover) and function (carbon sequestration, water conservation, soil retention, and biodiversity maintenance) indicators. The changing characteristics of VEQ and the relative contribution of driving factors in the ecological protection redline areas in Sichuan Province (EPRA), China, from 2000 to 2021 were explored using VEQI, Sen's slope, Mann-Kendall test, Hurst index, and residual analysis based on the XGBoost (Extreme gradient boosting regressor). The results showed that the VEQ in the EPRA has improved over the 22-year study period, but this trend may be unsustainable in the future. Temperature was the most influential climate factor. And human activities were the dominant factor with a relative contribution of 78.57% to VEQ changes. This study provides ideas for assessing ecological restoration in other regions, and can provide guidance for ecosystem management and conservation.

Spatial pattern evolution and prediction scenario of habitat quality in typical fragile ecological region, China: A case study of the Yellow River floodplain area

The Yellow River basin is an important area for China to implement ecological protection policies. Studying the habitat quality of the Yellow River floodplain area is of great significance to the ecological security and sustainable development of the entire basin. This study primarily investigated the spatial pattern of habitat quality in the Yellow River floodplain area from 2000 to 2020, then, we also simulated changes of habitat quality in 2025-2035 and analyzed the influencing factors by coupling the PLUS (Patch-generating Land Use Simulation) model, InVEST (Integrated Valuation of Ecosystem Services and Trade-offs) model and RF (Random Forest) model. The results showed that:(1) From 2000 to 2020, cultivated land and build-up land constituted an important part of the Yellow River floodplain area, and the growth rate of build-up land was fast. (2) We also found that the ecological land (forest land, grassland, waterbody) had a higher contribution value to the habitat quality, while the build-up land had a lower contribution value to the habitat quality. (3) Overall, the habitat quality of the floodplain area showed a degradation trend from 2000 to 2020. In addition, the regions with low habitat quality accounted for the major proportion. (4) Based on the calculation results of the Random Forest (RF) model, we found that topographical relief (TR) and land use intensity (LUI) were the two most important factors affecting habitat quality of the floodplain area. (5) According to the four scenarios from 2025 to 2035, it is found that the habitat quality level would be the highest under the ecological protection scenario, while under the urban development scenario its level would be the lowest. This study attempts to combine the RF model with PLUS model to improve the objectivity and accuracy of the future prediction scenario of habitat quality, which can provide scientific reference for ecological governance and policy formulation in the Yellow River floodplain area.