scholarly journals Spatiotemporal Evaluation and Driving Mechanism of Land Ecological Security in Yan’an, a Typical Hill-Gully Region of China’s Loess Plateau, from 2000 to 2018

Forests ◽  
2021 ◽  
Vol 12 (12) ◽  
pp. 1754
Author(s):  
Zhaoquan He ◽  
Xue Shang ◽  
Tonghui Zhang
Keyword(s):  
Loess Plateau ◽  
Evaluation System ◽  
Vegetation Index ◽  
Regional Scale ◽  
Vegetation Coverage ◽  
Security Level ◽  
Driving Mechanism ◽  
Ecological Security ◽  
Forest Landscape Restoration ◽  
Land Ecological Security

Forest landscape restoration and ecosystem of Loess Plateau have enhanced prominently, since the policy implementation (1999) of the Grain for Green Project in China. Land ecological security (LES) performs an extremely critical function for protecting vulnerable land resources and sustaining forest ecosystem stability. Predecessors’ studies substantially concentrate on biophysical and meteorologic variables using numerous grounded methodologies, little research has been launched on systematic natural-socio-economic-ecological relationships and how these contributions and regulations for LES evaluation. Here, pressure-state-response (PSR) model was used to establish the evaluation system of LES in regional-scale, and LES was classified into five levels measured by ecological security index (S), including high (S ≥ 0.75), medium−high (0.65 ≤ S < 0.75), medium (0.55 ≤ S < 0.65), medium−low (0.45 ≤ S < 0.55), and low (S < 0.45) level, for systematically analyzing its spatiotemporal distribution characteristic and response mechanism to explanatory variables in Yan’an, northwest China, from 2000 to 2018. The results demonstrated that: (1) LES status was mainly characterized by medium−high level and medium level, and maintained profound stability. (2) zone with medium−high LES level was mainly concentrated in western and southern regions, continuously expanding to northeast regions, and possessed the largest territorial area, accounting for 37.22%–46.27% of the total area in Yan’an. (3) LES was primarily susceptible to normalized differential vegetation index, vegetation coverage, and land surface temperature with their optimal impacting thresholds of 0.20–0.64, 0.20–0.55, and 11.20–13.00 °C, respectively. (4) Normalized differential vegetation index and vegetation coverage had a significant synergistic effect upon LES based on their interactive explanation rate of 31% and had significant variation consistency (positive and negative) with LES, which were powerfully suggested to signal the intensification of the regional eco-security level in the persistent eco-greening process.

Yunnan Haba Snow Mountain Ecological Safety Evaluation Based on the Landscape Ecological Pattern

2014 ◽  
Vol 522-524 ◽  
pp. 537-540
Author(s):  
Hui Li ◽  
Fan Tao Meng ◽  
Zhi Ying Li ◽  
Cong Cong Wang ◽  
Pan Li ◽  
...  
Keyword(s):  
Coniferous Forest ◽  
Safety Evaluation ◽  
Security Level ◽  
Ecological Security ◽  
Ecological Safety ◽  
Safety Planning ◽  
Broad Leaved Forest ◽  
Land Ecological Security ◽  
Landscape Ecological ◽  
Leaved Forest

Land ecological security research has gradually become concerned field on global. Using on the Haba Snow Mountain as an example try to discuss the evaluation of ecological security based on change of the landscape ecological pattern in the paper. In GIS, RS and GPS support and accordance with the principles of landscape ecology and using new grid map method has been 1993 and 2006 Haba Snow Mountain ecological safety evaluation and space differentiation. There are temperate coniferous forest, grassland, sclerophyll broad-leaved forest, warm coniferous forest, water area, residential land, semi-humid evergreen broad-leaved forest, ice and snow land nine landscape types, and temperate coniferous forest and grassland are dominant landscape in the study area, both area has accounted about 67% of the total area. The results show that from 1993 to 2006 the whole landscape pattern has changed less in the area. Land ecological security level space differentiation is very obvious. Ecological security level high altitude area is superior to low altitude area, the core area is superior to the edge area, north area is superior to the southern area. Land ecological security in the study area whole is in good level. From 1993 to 2006 years land ecological security level has declined in the area. Research on ecological safety planning to provide basis for ecological safety planning and for similar high mountain canyon area also has reference value.

scholarly journals Does Anthropogenic Land Use Change Play a Role in Changes of Precipitation Frequency and Intensity over the Loess Plateau of China?

2018 ◽  
Vol 10 (11) ◽  
pp. 1818 ◽  
Author(s):  
Zhengjia Liu ◽  
Yansui Liu
Keyword(s):  
Loess Plateau ◽  
Vegetation Cover ◽  
Vegetation Index ◽  
Normalized Difference Vegetation Index ◽  
Regional Scale ◽  
Precipitation Amount ◽  
The Loess Plateau ◽  
Precipitation Frequency ◽  
Intensity Changes ◽  
Vegetation Cover Change

Human transformation of landscapes is pervasive and accelerating across the Earth. However, existing studies have not provided a comprehensive picture of how precipitation frequency and intensity respond to vegetation cover change. Therefore, this study took the Loess Plateau as a typical example, and used satellite-based Normalized Difference Vegetation Index (NDVI) data and daily gridded climatic variables to assess the responses of precipitation dynamics to human-induced vegetation cover change. Results showed that the total precipitation amount exhibited little change at the regional scale, showing an upward but statistically insignificant (p > 0.05) trend of 7.6 mm/decade in the period 1982–2015. However, the frequency of precipitation with different intensities showed large variations over most of the Loess Plateau. The number of rainy days (light, moderate, heavy, very heavy and severe precipitation) increased in response to increased vegetation cover, especially in the central-eastern Loess Plateau. Anthropogenic land cover change is largely responsible for precipitation intensity changes. Additionally, this study also observed high spatially explicit heterogeneity in different precipitation intensities in response to vegetation cover change across the Loess Plateau. These findings provide some reference information for our understanding of precipitation frequency and intensity changes in response to regional vegetation cover change in the Loess Plateau.

scholarly journals Soil Moisture Estimation for the Chinese Loess Plateau Using MODIS-derived ATI and TVDI

2020 ◽  
Vol 12 (18) ◽  
pp. 3040
Author(s):  
Lina Yuan ◽  
Long Li ◽  
Ting Zhang ◽  
Longqian Chen ◽  
Jianlin Zhao ◽  
...  
Keyword(s):  
Soil Moisture ◽  
Loess Plateau ◽  
Vegetation Index ◽  
Joint Model ◽  
Iteration Procedure ◽  
Chinese Loess Plateau ◽  
Vegetation Coverage ◽  
Chinese Loess ◽  
The Chinese Loess Plateau

Timely and effective estimation and monitoring of soil moisture (SM) provides not only an understanding of regional SM status for agricultural management or potential drought but also a basis for characterizing water and energy exchange. The apparent thermal inertia (ATI) and Temperature Vegetation Dryness Index (TVDI) are two widely used indices to reflect SM from remote sensing data. While the ATI-based model is routinely used to estimate the SM of bare soil and sparsely vegetated areas, the TVDI-based model is more suitable for areas with dense vegetation coverage. In this study, we present an iteration procedure that allows us to identify optimal Normalized Difference Vegetation Index (NDVI) thresholds for subregions and estimate their relative soil moisture (RSM) using three models (the ATI-based model, the TVDI-based model, and the ATI/TVDI joint model) from 1 January to 31 December 2017, in the Chinese Loess Plateau. The initial NDVI (NDVI0) was first introduced to obtain TVDI value and two other thresholds of NDVIATI and NDVITVDI were designed for dividing the whole area into three subregions (the ATI subregion, the TVDI subregion, and the ATI/TVDI subregion). The NDVI values corresponding to maximum R-values (correlation coefficient) between estimated RSM and in situ RSM measurements were chosen as optimal NDVI thresholds after performing as high as 48,620 iterations with 10 rounds of 10-fold cross-calibration and validation for each period. An RSM map of the whole study area was produced by merging the RSM of each of the three subregions. The spatiotemporal and comparative analysis further indicated that the ATI/TVDI joint model has higher applicability (accounting for 36/38 periods) and accuracy than the ATI-based and TVDI-based models. The highest average R-value between the estimated RSM and in situ RSM measurements was 0.73 ± 0.011 (RMSE—root mean square error, 3.43 ± 0.071% and MAE—mean absolute error, 0.05 ± 0.025) on the 137th day of 2017 (DOY—day of the year, 137). Although there is potential for improved mapping of RSM for the entire Chinese Loess Plateau, the iteration procedure of identifying optimal thresholds determination offers a promising method for achieving finer-resolution and robust RSM estimation in large heterogeneous areas.

scholarly journals Ecological Security Evaluation and Spatial-temporal Evolution Characteristics of Natural Resources Based on Wind-Driven Optimization Algorithm------A case study of Guangdong-Hong Kong-Macao Greater Bay Area

2021 ◽  
Author(s):  
Xiaoling Ke ◽  
wei shi ◽  
Chang Yang ◽  
Haixiang Guo ◽  
Amal Mougharbel
Keyword(s):  
Hong Kong ◽  
Natural Resources ◽  
Optimization Algorithm ◽  
Evaluation System ◽  
Sustainable Urban Development ◽  
Security Evaluation ◽  
Security Level ◽  
Ecological Security ◽  
Bay Area ◽  
The Impact

As a complex system, the urban natural resources system comprises water, land, forest, and air resources. Natural resources are the essential elements of economic and social development and the source of sustainable urban development. However, there are few articles which regard different natural resources as a comprehensive system to evaluate. This study aimed to reveal the patterns of natural resources and highlight the impact of natural resource subsystem. Firstly, this study establishes the ecological security evaluation system of natural resources based on the “Driving Force-Pressure-State-Response” model. Secondly, we use the Wind-Driven Optimization algorithm to optimize the Projection Pursuit model to calculate the value of ecological security level and the comprehensive value of ecological security in Guangdong-Hong Kong-Macao Greater Bay Area (2013-2018). The temporal characteristics and spatial layout of natural resources ecological security, the impact of mechanism of water, land, forest, and air resources subsystems on natural resources ecological security were assessed. The results shows that the ecological security level of natural resources in nine cities of Guangdong-Hong Kong-Macao Greater Bay Area is on the rise as a whole from 2013 to 2018. However, the ecological security level in the central region of the Greater Bay Area is low, which is directly related to the severe environmental pollution of its water and air resources. The results are basically consistent with the actual situation, which can provide a reference for the ecological security evaluation of natural resources in other urban agglomerations.

scholarly journals An analysis of the interaction between industrial structure protection, ecological resources and environmental pollution externalities based on PSR model

2021 ◽  
Author(s):  
dechun Wang
Keyword(s):  
Distribution Pattern ◽  
Yangtze River ◽  
Yangtze River Basin ◽  
Vegetation Coverage ◽  
Security Level ◽  
Ecological Security ◽  
The Yangtze River ◽  
Ecological Resources ◽  
Landscape Ecological ◽  
Landscape Ecological Security

Abstract Taking the middle and lower reaches of the Yangtze River Basin in Hubei Province as the research area, based on the "pressure state response" framework model, the evaluation index system of landscape ecological security in the basin is constructed, and its spatiotemporal change process and characteristics are discussed. The results show that the comprehensive index of landscape ecological security in the middle and lower reaches of the Yangtze River is gradually rising, and the area above the middle and high security level accounts for 52% of the total area of the study area. The high safety areas in the basin are mainly concentrated in the areas with good vegetation coverage, such as natural reserves and forestry development areas, whose distribution pattern is opposite to the risk distribution pattern of geomorphic disasters such as landslides, debris flows and soil erosion.

scholarly journals Mapping the Spatial Distribution of Tea Plantations Using High-Spatiotemporal-Resolution Imagery in Northern Zhejiang, China

Forests ◽  
2019 ◽  
Vol 10 (10) ◽  
pp. 856 ◽  
Author(s):  
Li ◽  
Zhang ◽  
Li ◽  
Zhang
Keyword(s):  
Spatial Distribution ◽  
Vegetation Index ◽  
Regional Scale ◽  
Vegetation Coverage ◽  
Distribution Map ◽  
Spatiotemporal Resolution ◽  
Simple Method ◽  
Tea Plantation ◽  
High Spatiotemporal Resolution ◽  
Tea Plantations

Tea plantations are widely distributed in the southern provinces of China and have expanded rapidly in recent years due to their high economic value. This expansion has caused ecological problems such as soil erosion, and it is therefore urgent to clarify the spatial distribution and area of tea plantations. In this study, we developed a simple method to accurately map tea plantations based on their unique phenological characteristics observed from VENμS high-spatiotemporal-resolution multispectral imagery. The normalized difference vegetation index (NDVI) and red—green ratio index (RGRI) of time series were calculated using 40 VENμS images taken in 2018 to evaluate the phenology of tea plantations. The unique phenological period of tea plantations in northern Zhejiang is from April to May, with obvious deep pruning, which is very different from the phenological period of other vegetation. During this period, the RGRI values of tea plantations were much higher than those of other vegetation such as broadleaf forest and bamboo forest. Therefore, it is possible to identify tea plantations from the vegetation in images acquired during their phenological period. This method was applied to tea plantation mapping in northern Zhejiang. The NDVI value of the winter image was used to extract a vegetation coverage map, and spatial intersection analysis combined with maps of tea plantation phenological information was performed to obtain a tea plantation distribution map. The resulting tea plantation map had a high accuracy, with a 94% producer accuracy and 95.9% user accuracy. The method was also applied to Sentinel-2 images at the regional scale, and the obtained tea plantation distribution map had an accuracy of 88.7%, indicating the good applicability of the method.

Ecological Security Research of the Northern Slope of Qinling Mountains under the Impact of Tourism Activities

2014 ◽  
Vol 955-959 ◽  
pp. 1634-1639
Author(s):  
Shi Dong Liu ◽  
Jun Gao ◽  
Wei Tao Pan
Keyword(s):  
Evaluation System ◽  
Positive Impact ◽  
State Level ◽  
Security Evaluation ◽  
Security Level ◽  
Ecological Security ◽  
Qinling Mountains ◽  
Northern Slope ◽  
Regional Tourism ◽  
The Impact

The ecological security of the piedmont area has been a focus in the research of mountain ecosystem. However, with the development of the urbanization, the research of mountain ecological security under the impact of human activities, especially in the city which near the mountain, the research of protection and development of piedmont area seems not updated enough. Therefore, this paper selected Northern slope of Qinling Mountains in Xi’an, and made tourism activities the major driving factor for ecological security of tourism environment in piedmont area, thus establishing an ecological security evaluation system of piedmont tourism environment, based on DPSIR Model. The result showed that tourism development would enhance the ecological security level of regional tourism environment, and tourism activities would exert positive impact on regional tourism environment. The conclusions include: (1) Before 2007, the tourist environment of Huxian had been in an unsafe state, but in 2013, the ecological security level was largely raised; (2)The tourism ecological security in Chang’an is higher than that in Huxian District, and the ecological security level had already got into the safe state level

scholarly journals Land ecological security assessment for Yancheng city based on catastrophe theory

2015 ◽  
Vol 18 (2) ◽  
pp. 181-187 ◽  
Author(s):  
Wang Liang ◽  
Bian Zhengfu ◽  
Chen Hongquan
Keyword(s):  
Land Use ◽  
Economic Development ◽  
Catastrophe Theory ◽  
Land Application ◽  
Security Level ◽  
Ecological Security ◽  
Rapid Urbanization ◽  
State Response ◽  
Land Ecological Security ◽  
Pressure State

<p>Based on actual land use in Yancheng city, this paper establishes the ecological security of the land index system from the perspectives of economy, society and ecological environment. Using the catastrophe theory and pressure-state-response (PSR) model, the purpose of the research was to judge the degree of land ecological security in Yancheng city from 2002 to 2011 and determine the requirements to ensure the sustainable development of this region. The results showed that over the ten years, the pressure, state, response and synthetic values of the land ecological security were evaluated as safe in 2003 and 2007 and at middle level in 2002 and for 2004 to 2006 and then dropped to insecure for 2008 to 2009 and very insecure for 2011 to 2012. The ecological security level and circumstance of land use in Yancheng city has generally declined. During this period, the land use pattern of Yancheng city was under tremendous pressure from the conflict between rapid urbanization and economic development, as well as conservation and rehabilitation of the eco-environment. This research shows that conditions for the land ecosystems of Yancheng city are not optimistic and, as such, should draw the attention of responsible government departments. Future policy options should aim to mitigate these problems through the control of population growth and the improvement in quality of life, protection of wetland and forest land, application of scientific concepts of development, coordination of economic development and land utility, and strengthening the control functions of land-use planning.</p><p> </p><p><strong>Resumen</strong></p><p>De acuerdo con el uso actual del suelo en la ciudad de Yancheng, en el este de China, este artículo establece la seguridad ecológica del sistema de tierras desde las perspectivas económica, social y ecológica. A partir de la Teoría de las Catástrofes y el modelo ambiental de presión-estado-respuesta (PSR), el propósito de esta investigación fue determinar el grado de seguridad ecológica del suelo en la localidad de Yancheng entre 2002 y 2011 y determinar las condiciones para asegurar el desarrollo sustentable de la región. Los resultados muestran que sobre estos diez años los valores de presión, estado, respuesta y sintéticos fueron evaluados como seguros en 2003 y 2007, como nivel medio en 2002, entre 2004 y 2006, cayeron a inseguros en 2008 y 2009, y muy inseguros para 2011 y 2012. El nivel de seguridad y las condiciones de suelo en Yancheng se han disminuido generalmente. Durante este período, el patrón de uso de la tierra en la ciudad de Yancheng estuvo bajo una gran presión por el conflicto entre la rápida urbanización y el desarrollo económico y la conservación y la rehabilitación ecoambiental. Esta investigación muestra que las condiciones para los ecosistemas terrestres no son óptimas y que por lo tanto es necesario llamar la atención de los departamentos de Gobierno responsables. Las posibles políticas futuras deben enfocarse en mitigar estos problemas a través del control al crecimiento urbano y el mejoramiento de la calidad de vida, la protección de los humedales y los bosques, la aplicación de conceptos científicos al desarrollo, la coordinación del avance económico y el suelo, y el fortalecimiento de las funciones de control en la planeación del uso de la tierra.</p><p><strong><br /></strong></p>

scholarly journals Spatiotemporal Patterns of Terrestrial Evapotranspiration in Response to Climate and Vegetation Coverage Changes across the Chinese Loess Plateau

Water ◽  
2019 ◽  
Vol 11 (8) ◽  
pp. 1625 ◽  
Author(s):  
Han Zheng ◽  
Henry Lin ◽  
Xianjin Zhu
Keyword(s):  
Climate Variability ◽  
Interannual Variability ◽  
Loess Plateau ◽  
Vegetation Index ◽  
Growing Season ◽  
Spatiotemporal Patterns ◽  
Chinese Loess Plateau ◽  
Vegetation Coverage ◽  
Chinese Loess ◽  
The Chinese Loess Plateau

Spatiotemporal patterns of evapotranspiration (ET) and its controlling factors are important for ecosystem services and water resources management in the Chinese Loess Plateau (CLP). In this study, we assessed the spatial patterns of ET and then investigated the interannual variability of ET and its relationships with climate variability and vegetation coverage changes at the timescales of annual, active growing season, as well as different seasons across the entire CLP from 2000 to 2014. A MODIS-derived ET dataset, ground-based datasets of precipitation and atmospheric evaporative demand (AED), and a remote-sensing dataset of Normalized Difference Vegetation Index (NDVI) were comprehensively analyzed. Results showed that mean annual ET varied distinctly among different vegetation zones, generally higher in the more humid southeastern parts of the CLP. Summer ET and ET over active growing season significantly increased for more than 40% of the entire CLP area, and winter ET significantly decreased over ~70% of the entire CLP region, while annual ET, spring ET, and autumn ET remained quite stable during 2000–2014. Per-pixel interannual variability of ET was mainly positively correlated with that of precipitation and NDVI except for winter, but negatively correlated with AED trends. Our study also demonstrated that ET variation trends were exactly consistent for the entire CLP region, the areas mainly implemented with the Grain for Green (GFG) project, and other CLP areas not implemented with the GFG project during 2000–2014. Our findings suggest that the spatiotemporal patterns of CLP ET were mainly water-limited, and climate variability played an essential role in shaping the interannual variability of ET in the CLP. This study will improve our understanding on the ET variations over water-limited areas under climate and vegetation coverage changes.

Pemetaan Pulau Kecil Gelasa Kabupaten Bangka Tengah

2019 ◽  
Vol 2 (1) ◽  
pp. 11-14
Author(s):  
Wahyu Adi
Keyword(s):  
Coral Reefs ◽  
Vegetation Index ◽  
Normalized Difference Vegetation Index ◽  
Image Interpretation ◽  
Vegetation Coverage ◽  
Small Island ◽  
Shallow Waters ◽  
Small Islands ◽  
Seagrass Beds ◽  
Cover Density

Pulau Kecil Gelasa merupakan daerah yang belum banyak diteliti. Pemetaan ekosistem di pulau kecil dilakukan dengan bantuan citra Advanced Land Observing Satellite (ALOS). Penelitian terdahulu diketahui bahwa ALOS memiliki kemampuan memetakan terumbu karang dan padang lamun di perairan dangkal serta mampu memetakan kerapatan penutupan vegetasi. Metode interpretasi citra menggunakan alogaritma indeks vegetasi pada citra ALOS yaitu NDVI (Normalized Difference Vegetation Index), serta pendekatan Lyzengga untuk mengkoreksi kolom perairan. Hasil penelitian didapatkan luasan Padang Lamun di perairan dangkal 41,99 Ha, luasan Terumbu Karang 125,57 Ha. Hasil NDVI di daratan/ pulau kecil Gelasa untuk Vegetasi Rapat seluas 47,62 Ha; luasan penutupan Vegetasi Sedang 105,86 Ha; dan penutupan Vegetasi Jarang adalah 34,24 Ha.   Small Island Gelasa rarely studied. Mapping ecosystems on small islands with the image of Advanced Land Observing Satellite (ALOS). Previous research has found that ALOS has the ability to map coral reefs and seagrass beds in shallow water, and is able to map vegetation cover density. The method of image interpretation uses the vegetation index algorithm in the ALOS image, NDVI (Normalized Difference Vegetation Index), and the Lyzengga approach to correct the water column. The results of the study were obtained in the area of Seagrass Padang in the shallow waters of 41.99 ha, the area of coral reefs was 125.57 ha. NDVI results on land / small islands Gelasa for dense vegetation of 47.62 ha; area of Medium Vegetation coverage 105.86 Ha; and the coverage of Rare Vegetation is 34.24 Ha.

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