scholarly journals Evaluation of the Temporal and Spatial Changes of Ecological Quality in the Hami Oasis Based on RSEI

2020 ◽  
Vol 12 (18) ◽  
pp. 7716
Author(s):  
Pengwen Gao ◽  
Alimujiang Kasimu ◽  
Yongyu Zhao ◽  
Bing Lin ◽  
Jinpeng Chai ◽  
...  

Given the restrictions on special geographic locations in development processes, the measurement and analysis of the ecological quality of the Hami Oasis are of great significance for the protection of this fragile oasis. In this study, the ecological quality of the Hami Oasis was monitored by constructing a remote sensing ecological index (RSEI) for arid areas. Using the standard deviation ellipse and moving window method, the ecological status and space–time changes were explored for both their external and internal factors in the Hami Oasis. Finally, a geo-detector was employed to determine the driving factors of the ecological quality of the Hami Oasis. The results revealed that: (1) In the remote sensing ecological index constructed in the Hami Oasis, the main influencing factors were dryness and wetness. The average value of the ecological quality of the oasis was less than 0.5, and the ecological quality level was relatively poor. Among the five grades of ecological quality in the Hami Oasis, the poor grade and the good grade showed the largest changes, decreasing by 200 and increasing by 300, respectively, which were mainly concentrated in the periphery of the oasis. (2) The improved ecological quality of the Hami Oasis was mainly manifested in the expansion of the artificial oasis, while the deteriorated area was manifested as an increase in the built-up area. Moreover, the ecological quality of the Hami Oasis presented a ringlike nesting distribution pattern from the internal built-up area to the artificial oasis periphery. (3) The external expansion direction of the ecological quality of the Hami Oasis featured southeast–northwest expansion, which was consistent with the direction of the rivers and traffic roads. The transformation between different ecological qualities in the oasis and the expansion of the built-up area were the reasons for the fragmentation of the Hami Oasis’ landscape. (4) Compared to a single factor, the dual-factor for the ecological quality of the Hami Oasis had stronger explanatory power. Moreover, changes in land use types caused changes in the ecological quality of the Hami Oasis. During the study period, we found that human activities had a more significant impact than natural factors on the development of the Hami Oasis. (5) The Moran’s I Index increased from 0.835268 in 2000 to 0.923976 in 2018, and the p values in the study area all reached a 0.05 significant level. At the same time, the areas with p values above the 0.01 and 0.001 significant levels have also increased significantly in the past 18 years.

Author(s):  
X. Niu ◽  
Y. Li

Abstract. Figuring out the regional ecological environment quality and ecological change is critical for ecological environment monitoring and management and urban construction planning. Based on the remote sensing ecological index (RESI), we evaluate the ecological quality and ecological change from 1999 to 2019 of Anqing city. Multi-temporal Landsat images are used to extract the four indicators of humidity, vegetation, heat and dryness, respectively. Then the RSEI is calculated by principal component analysis. The results show that the ecological quality of Anqing city declined from 1999 to 2019 and then grew slowly from 2009 to 2019. The eco-environmental quality of Anqing city dropped slightly from 1999 to 2019, and the regions with worse quality grades exceeded those becoming better. Particularly, we find that from 1999 to 2009, the area where the ecological quality became better made up 18.31% of the urban area, while the worse ecological area accounted for 29.68% of the urban area; from 2009 to 2019, the area of improved ecological environment reached 24.35%, while the area of degraded quality constituted 41.36%. Land-use changes dominated eco-environmental quality. The areas of poor eco-environmental quality expanded in residential regions and eco-environmental quality of mountainous area improved since returning cultivated land in steep hills into forest. The RSEI results are expected to provide a quantitative foundation for planning sustainable development and the rational use of resources in Anqing city.


2019 ◽  
Vol 12 (1) ◽  
pp. 21 ◽  
Author(s):  
Xiaole Wen ◽  
Yanli Ming ◽  
Yonggang Gao ◽  
Xinyu Hu

Islands face increasingly prominent environmental problems with rapid urbanization. Hence, timely and objective monitoring and evaluation of island ecology is of great significance. This study took the Pingtan Comprehensive Experimental Zone (PZ) in the east sea of Fujian Province of China as the research object. Based on remote sensing technology, four Landsat images from 2007 to 2017 and the remote sensing ecological index (RSEI) were used to explore the ecological status and space–time change. The results showed that from 2007 to 2011, the average RSEI decreased from 0.519 to 0.506, indicating that the ecological quality generally showed a slight downward trend, mainly due to large-scale development brought by the construction; by 2014, although the ecology of the original area improved, the overall ecology was still declining with 0.502 mean RSEI mainly because of large-scale reclamation projects; by 2017, the average RSEI rebounded to 0.523, which was attributed to the fact that ecological construction and protection were emphasized in the construction of PZ, especially in reclamation areas. In conclusion, the increase of large area bare soil will lead to the decline of regional ecology, but the implementation of scientific ecological planning is conducive to ecological restoration and construction.


Introduction. Assessment of the ecological status of lakes is important for their conservation and protection. Many lakes are intensively used in recreation in Volyn Region. The development of the resort and recreational facilities requires significant additional volumes of fresh water to maintain the depth of the reservoirs in the bathing area, certain sanitary and temperature regimes of the reservoirs. The limiting factors are the sanitary and hygienic indicators of water. First and foremost, high quality of water should be provided for the organization of contact types of recreation (bathing, diving, water skiing, etc.). The purpose of article. The purpose of the article is ecological assessment of water quality in various lakes of Volyn Region, which are most intensively used in recreation. Methods. Research methods are expeditionary, methods of mathematical statistics and environmental assessment of water quality, which were carried out in accordance with the methodology for assessing the quality of surface water in the respective categories. During the preparation of the article, materials from their own expeditionary studies of the natural-economic state of the lakes were used, as well as the results of chemical analysis of the water composition conducted by the Water and Soil Monitoring Laboratory of the Regional Water Resources Office in Volyn Region and the Complex Laboratory for Observation of the Environmental Environmental Center. Results. The analysis of the qualitative indicators of the lakes Svitiaz, Velyke Zgoranske and Somyn showed the high quality of water in the lakes. For the period of 2015–2019, water quality was classified as „good” class II, by degree of cleanliness „clean”, by category as „very good”, by degree of cleanliness „clean” on all lakes. The value of IE for the Lake Velyke Zgoranske varied in the range of 1.81–2.44, in the range of 1.66–2.07 for the Lake Svitiaz, and in the range of 2.56–2.96 for the Lake Somyn. Index І2 (ecological and sanitary indicators) has the most influence on the magnitude of the ecological index of water quality. The scientific novelty lies in establishing block and integral indexes of ecological assessment of water quality, classes and categories of water quality of the most recreationally-developed lakes of Volyn Region, as well as in assessment of the dynamics of indicators of water quality of lakes during the years of 2015–19. Practical significance is defined with the opportunity of development of a set of measures for the rational use and protection of lakes.


2021 ◽  
Vol 13 (14) ◽  
pp. 2815
Author(s):  
Xinran Nie ◽  
Zhenqi Hu ◽  
Qi Zhu ◽  
Mengying Ruan

Over the last few years, under the combined effects of climate change and human factors, the ecological environment of coal mining areas has undergone tremendous changes. Therefore, the rapid and accurate quantitative assessments of the temporal and spatial evolution of the ecological environment quality is of great significance for the ecological restoration and development planning of coal mining areas. This study applied the ecological environment index after topographic correction to improve the remote sensing ecological index (RSEI). Based on a series of Landsat images, the ecological environment quality of Yangquan Coal Mine in Shanxi Province from 1987 to 2020 was monitored and evaluated by an improved remote sensing ecological index. The results show that after topographic correction, the topographic effect of the remote sensing ecological index was greatly reduced, and its practicability was improved. From 1987 to 2020, the ecological environment quality of Yangquan Coal Mine was improved, and the mean of the RSEI increased from 0.4294 to 0.6379. The ecological environment quality of the six coal mines in the study area was improved. Among the six coal gangue dumps, the ecological environmental quality of D1, D2, D3, and D4 has improved, and the ecological environment quality of D5 and D6 worsened. The percentages of improved, unchanged, and degraded ecological environment quality in the entire coal mining area were 77.08%, 0.99%, and 21.93%, respectively. The global Moran’s index was between 0.7929 and 0.9057, and it was shown that there was a strong positive correlation between the ecological environmental qualities of the study area, and that its spatial distribution was clustered rather than random. The LISA cluster map showed that the aggregation and dispersion degree of ecological environment quality was mainly high–high clustering and low–low clustering over the whole stage. During the study period, temperature and precipitation had limited impacts on the ecological environment quality of Yangquan Coal Mine, while the coal mining activities and urbanization construction seriously affected the local ecological environment quality and the implementation of ecological restoration policies, regulations, and measures was the main reason for the improvement of the ecological environment quality.


2020 ◽  
Vol 12 (15) ◽  
pp. 2462
Author(s):  
Weihua Liao ◽  
Weiguo Jiang

The eco-environment is dynamic and shows a continuous process of long-term change. It is helpful for policymakers to know the status of the regional eco-environment through accurate evaluations of the history and current situation of the regional eco-environment. The remote sensing ecological index (RSEI) model of China was established in this study by using four indexes: wetness, greenness, dryness, and heat. Knowledge granulation of the RSEIs were carried out, and a method to determine the weights of the knowledge granulation entropy of the indexes based on their characteristics was proposed. This study used Moderate Resolution Image Spectroradiometer (MODIS) data from the Google Cloud Computing Platform to study and calculate the eco-environmental quality of China from 2000–2017. The overall eco-environmental quality in China tended to improve from 2000–2017, although there were large areas of ecological degradation from 2009–2014. The eco-environment of eastern China was better than that of western China. Most of the national ecological areas were third-level ecological areas, which had moderate environmental quality. Dryness was the most important factor affecting the quality of the eco-environment, followed by greenness, which reflected the increasing environmental damage caused by human activities in China in recent years.


Author(s):  
X. Wang ◽  
C. Liu ◽  
Q. Fu ◽  
B. Yin

In order to monitor the change of regional ecological environment quality, this paper use MODIS and DMSP / OLS remote sensing data, from the production capacity, external disturbance changes and human socio-economic development of the three main factors affecting the quality of ecosystems, select the net primary productivity, vegetation index and light index, using the principal component analysis method to automatically determine the weight coefficient, construction of the formation of enhanced remote sensing ecological index, and the ecological environment quality of Hainan Island from 2001 to 2013 was monitored and analyzed. The enhanced remote sensing ecological index combines the effects of the natural environment and human activities on ecosystems, and according to the contribution of each principal component automatically determine the weight coefficient, avoid the design of the weight of the parameters caused by the calculation of the human error, which provides a new method for the operational operation of regional macro ecological environment quality monitoring. During the period from 2001 to 2013, the ecological environment quality of Hainan Island showed the characteristics of decend first and then rise, the ecological environment in 2005 was affected by severe natural disasters, and the quality of ecological environment dropped sharply. Compared with 2001, in 2013 about 20000 square kilometers regional ecological environmental quality has improved, about 8760 square kilometers regional ecological environment quality is relatively stable, about 5272 square kilometers regional ecological environment quality has decreased. On the whole, the quality of ecological environment in the study area is good, the frequent occurrence of natural disasters, on the quality of the ecological environment to a certain extent.


Author(s):  
Ergün Taşkın ◽  
İbrahim Tan ◽  
Orkide Minareci ◽  
Ersin Minareci ◽  
Hakan Atabay ◽  
...  

In the present study, the Marine Floristic Ecological Index (MARFEI) was tested to assess the impacts by using marine benthic macrophytes and pressures by using the Macroalgae-Land Uses Simplified Index (MA-LUSI) in the Marmara Sea (Turkey). Sampling of benthic macrophytes was made from 0-5 m depth at 29 different sites during the summer periods of 2017, 2018 and 2019. The study revealed good ecological status class (ESC) for 6 sites, moderate for 11 sites, poor for 8 sites and bad for 4 sites. MARFEIeqr showed a negative linear relationship with the pressure index MA-LUSI.


2021 ◽  
Vol 4 ◽  
Author(s):  
Victor Hugo Salinas Camarillo ◽  
Javier Carmona-Jiménez ◽  
Nelida Abarca ◽  
Jonas Zimmermann ◽  
Demetrio Mora

In central Mexico, streams flow from mountain protected areas at high elevations, i.e. abive 2,400 m a.s.l., being exposed to different human activities along their course. The main human threats of these aquatic ecosystems include the presence of hydraulic infrastructure (e.g. canals and dams), the construction of bridges or roads, fish farming, agriculture, livestock, unregulated tourism or irregular human settlements, resulting in nutrient enrichment, organic pollution and low hydromorphological quality. Diatoms, widely recognized as valuable indicators of environmental conditions, offer a unique opportunity to assess the ecological quality of the streams in and around this megacity, as they respond directly and sensitively to specific physical, chemical and biological changes. To conduct ecological assessment, the composition of diatom communities has traditionally been characterized by morphological methods and most recently by environmental DNA (eDNA) metabarcoding. However, the diatom communities of only a few of these streams in the Basin of Mexico have been characterized morphologically at low resolution light microscopy (LM), and no eDNA-based studies have been conducted yet. In this context, our aims are to 1) implement morphological and eDNA metabarcoding methods for the identification and quantification of epilithic diatoms and to assess their seasonal and spatial response in three peri-urban mountain streams from the Basin of Mexico, and 2) develop a metric to assess and monitor the ecological quality in these streams. For this purpose, we characterized a) the physical, environmental and hydro-morphological conditions related to ecosystem quality, and b) the diatom diversity and community structure of nine sites per stream (27 sites). The sites include headwaters, as well as middle and lower reaches with different land-use and anthropologic pressures, and were investigated over three hydrological periods, i.e. post-rainy, dry-cold and dry-warm. Species identification was first conducted under LM and scanning electron microscopy (SEM), and is currently been done by eDNA metabarcoding of the V4 region of the 18S rRNA gene and a fragment of the chloroplast marker rbcL. Our study has resulted in 520 infrageneric taxa identified by LM and SEM, the largest diversity ever found for freshwater diatoms of Mexico. From this data, we found a clear environmental gradient from almost pristine conditions towards heavily polluted states as the streams enter the city. These changes are well reflected by variations in the diatom community structure, as revealed by the Diatom Ecological Quality Index (DEQI), newly developed to evaluate the ecological quality of the streams in and around this megacity.


2015 ◽  
Vol 16 (2) ◽  
pp. 419 ◽  
Author(s):  
L. PIAZZI ◽  
P. GENNARO ◽  
E. CECCHI ◽  
F. SERENA

The ESCA (Ecological Status of Coralligenous Assemblages) index was recently developed to evaluate the ecological quality of coralligenous habitat. The study aims to improve the first index proposal through testing response to different sources of anthropogenic pressures and optimizing the sampling effort. ESCA was calculated on 14 sites and tested against a gradient of human pressures. Moreover, the main scales of spatial variability of assemblages were evaluated and values of index obtained with different sampling designs were compared. Results showed that studied sites resulted in high, good or moderate ecological status, according to an increasing gradient of the anthropization level. Values of ESCA index obtained with different methods have been compared and photographic method provides EQR values lower than destructive method. Spatial variability of assemblages was higher at large and small scales than at intermediate ones. Two locations for each study site and 20 replicated samples for each location may be consider the best sampling combination providing reliable values of ESCA index for the evaluation of ecological quality of coralligenous assemblages.


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