scholarly journals Using Time Series Optical and SAR Data to Assess the Impact of Historical Wetland Change on Current Wetland in Zhenlai County, Jilin Province, China

2021 ◽  
Vol 13 (22) ◽  
pp. 4514
Author(s):  
Sixue Shi ◽  
Yu Chang ◽  
Yuehui Li ◽  
Yuanman Hu ◽  
Miao Liu ◽  
...  

Wetlands, as the most essential ecosystem, are degraded throughout the world. Wetlands in Zhenlai county, with the Momoge National Nature Reserve, which was included on the Ramsar list, have degraded by nearly 30%. Wetland degradation is a long-term continuous process with annual or interannual changes in water area, water level, or vegetation presence and growth. Therefore, it requires sufficiently frequent and high-spatial-resolution data to represent its dynamics. This study mapped yearly land-use maps with 30-m resolution from 1985 to 2018 using Landsat data in Google Earth Engine (GEE) to explore the wetland degradation process and mapped 12-day interval land-use maps with 15-m resolution using the Sentinel-1B and Sentinel-2 data in GEE and other assistant platforms to study the characteristics of wetland dynamics in 2018. Four sets of maps were generated using Sentinel-1B (S1), Sentinel-2 (S2), the combination of Sentinel-1B and Sentinel-2 (S12), and S12 with multitemporal remote sensing (S12’). All of the classifications were performed in the Random Forest Classification (RFC) method using remote sensing indicators. The results indicate that S12’ was the most accurate. Then, the impact of the historic land-use degradation process on current wetland change dynamics was discussed. Stable, degradation, and restoration periods were identified according to the annual changes in wetlands. The degraded, stable, restored, and vulnerable zones were assessed based on the transformation characteristics among wetlands and other land-use types. The impact of historical land-use trajectories on wetland change characteristics nowadays is diverse in land-use types and distributions, and the ecological environment quality is the comprehensive result of the effect of historical land-use trajectories and the amount of rainfall and receding water from paddy fields. This study offers a new method to map high-spatiotemporal-resolution land-use (S12’) and addresses the relationship between historic wetland change characteristics and its status quo. The findings are also applicable to wetland research in other regions. This study could provide more detailed scientific guidance for wetland managers by quickly detecting wetland changes at a finer spatiotemporal resolution.

2020 ◽  
Vol 7 (1) ◽  
pp. 91
Author(s):  
Júlio Barboza Chiquetto ◽  
Maria Elisa Siqueira Silva ◽  
Rita Yuri Ynoue ◽  
Flávia Noronha Dutra Ribieiro ◽  
Débora Souza Alvim ◽  
...  

A poluição do ar é influenciada por fatores naturais e antropogênicos. Quatro pontos de monitoramento (veicular, comercial, residencial e background urbano (BGU))da poluição do ar em São Paulo foram avaliados durante 16 anos, revelando diferenças significativas devidoao uso do solo em todas as escalas temporais. Na escala diurna, as concentrações de poluentes primários são duas vezes mais altas nos pontos veicular e residencial do que no ponto BGU, onde a concentração de ozonio (O3) é 50% mais alta. Na escala sazonal, as concentrações de monóxido de carbono(CO) variaram em 80% devido ao uso do solo, e 55% pela sazonalidade.As variações sazonais ede uso do solo exercem impactos similares nas concentrações de O3 e monóxido de nitrogênio (NO). Para o material particulado grosso (MP10) e o dióxido de nitrogênio(NO2), as variações sazonais são mais intensas do que as por uso do solo. Na série temporal de 16 anos, o ponto BGU apresentou correlações mais fortes e significativas entre a média mensal de ondas longas (ROL) e o O3 (0,48) e o MP10 (0,37), comparadas ao ponto veicular (0,33 e 0,22, respectivamente). Estes resultados confirmam que o uso do solo urbano tem um papel significativo na concentração de poluentes em todas as escalas de análise, embora a sua influência se torne menos pronunciada em escalas maiores, conforme a qualidade do ar transita de um sistema antropogênico para um sistema natural. Isto poderá auxiliar decisões sobre políticas públicas em megacidades envolvendo a modificação do uso do solo.


Geologos ◽  
2019 ◽  
Vol 25 (3) ◽  
pp. 231-240 ◽  
Author(s):  
Anna Kuczyńska

Abstract The present paper discusses the results of an analysis of the impact of land use on the distribution of pharmaceuticals in groundwater samples collected during a pilot study of the contents of pharmaceuticals and hormones in ground-water taken from the national groundwater monitoring network of the Polish Geological Institute - National Research Institute. Samples were collected during monitoring campaigns from 160 groundwater monitoring sites in various land use types in 2016 and 2017. Samples were analysed for a total of 34 active substances, including natural and synthetic oestrogen hormones, cardiovascular and respiratory medications, analgesics and anti-inflammatories, antidepressants, antimicrobial drugs and anti-epileptics. Our study confirmed the presence of pharmaceuticals in 53 per cent of ground-water samples taken. Data show variations in the distribution of pharmaceuticals depending on land use type, which can thus be employed in pressure analysis and identification of sources of pollution.


Mycorrhiza ◽  
2020 ◽  
Vol 30 (6) ◽  
pp. 749-759
Author(s):  
Zerihun Belay ◽  
Mesele Negash ◽  
Janne Kaseva ◽  
Mauritz Vestberg ◽  
Helena Kahiluoto

Abstract The rapid conversion of native forests to farmland in Ethiopia, the cradle of biodiversity, threatens the diversity of the arbuscular mycorrhizal fungi (AMF) pivotal to plant nutrition and carbon sequestration. This study aimed to investigate the impact of this land-use change on the AMF species composition and diversity in southern Ethiopia. Soil samples were collected from nine plots in each of three land-use types: native forest, agroforestry, and khat monocropping. The plots of the three land-use types were located adjacent to each other for each of the nine replicates. Three 10 × 10m subplots per plot were sampled. AMF spores were extracted from the soil samples, spore densities were determined, and species composition and diversity were evaluated through morphological analysis. Both spore density and species richness were statistically significantly higher in the native forest than in the agroforestry plots with no clear difference to khat, whereas the true diversity (exponential of Shannon–Wiener diversity index) did not differ among the three land-use types due to high evenness among the species in agroforestry. In total, 37 AMF morphotypes belonging to 12 genera in Glomeromycota were found, dominated by members of the genera Acaulospora and Glomus. The highest isolation frequency index (78%) was recorded for Acaulospora koskei from native forest. Consequently, the agroforestry system did not appear to aid in preserving the AMF species richness of native forests relative to perennial monocropping, such as khat cultivation. In contrast, the native forest areas can serve as in situ genetic reserves of mycorrhizal symbionts adapted to the local vegetative, edaphic, and microbial conditions.


2019 ◽  
Author(s):  
Donia Jendoubi ◽  
Hanspeter Liniger ◽  
Chinwe Ifejika Speranza

Abstract. This study evaluated the impact of land use and landscape forms on SOC within the Wadi Beja watershed in north-western Tunisia. A soil spectral library was set to assess the variation of the SOC of 1440 soil samples from four land use types (field crops, permanent crops, forest, and grazing land), three slope categories (flat, moderate, and steep) and two aspects (north- and south-facing). For field crops, only one factor – slope – significantly affected SOC, which SOC levels in north-facing areas appear higher in flat areas (0.75 %) than in hilly areas (0.51%). However, in south-facing areas, SOC levels were also higher in flat areas (0.74 %) than in hilly areas (0.50 %). For permanent crops, which was interplanted with field crops, the slope significantly affected SOC levels where SOC levels have been improved to 0.97 % in flat north facing and 0.96 % in flat south-facing areas, which are higher than hilly south – and north-facing areas (0.79 %). In the grazing land use system, both investigated factors – aspect and slope – significantly affected the SOC levels which, SOC levels were significantly higher in flat areas (north-facing: 0.84 %, south-facing: 0.77 %), compared to hilly areas (north-facing: 0.61 %, south-facing: 0.56 %). For the forest, none of the factors had a significant effect on the SOC, which they are higher in flat areas (north-facing: 1.15 %, south-facing: 1.14 %), compared to 1.09 % in north and 1.07 % in south-facing in steep areas. This study highlights the importance of the land use and landscape forms in determining the variation in SOC levels.


Plants ◽  
2020 ◽  
Vol 9 (5) ◽  
pp. 602
Author(s):  
Ina Aneva ◽  
Petar Zhelev ◽  
Simeon Lukanov ◽  
Mariya Peneva ◽  
Kiril Vassilev ◽  
...  

Studies on the impact of agricultural practices on plant diversity provide important information for policy makers and the conservation of the environment. The aim of the present work was to evaluate wild plant diversity across the agroecosystems in two contrasting regions of Bulgaria; Pazardzhik-Plovdiv (representing agroecosystems in the lowlands) and Western Stara Planina (the Balkan Mountains, representing agroecosystems in the foothills of the mountains). This study conducted a two-year assessment of plant diversity in different types of agricultural and forest ecosystems, representing more than 30 land use types. Plant diversity, measured by species number, was affected by the land use type only in Pazardzhik-Plovdiv region. More pronounced was the effect of the groups of land use types on the diversity, measured by the mean species number per scoring plot. Climatic conditions, measured by 19 bioclimatic variables, were the most important factor affecting plant species diversity. Six bioclimatic variables had a significant effect on the plant diversity, and the effect was more pronounced when the analysis considered pooled data of the two regions. The highest plant diversity was found on grazing land with sparse tree cover, while the lowest one was in the land use types representing annual crops or fallow. The study also established a database on weed species, relevant to agriculture. A number of common weeds were found in the Pazardzhik-Plovdiv region, while the most frequent species in the Western Stara Planina region were indigenous ones. Overall, the natural flora of Western Stara Planina was more conserved; eleven orchid species with conservation significance were found in the pastures and meadows in that region. The present study is the first attempt in Bulgaria to characterize the plant diversity across diverse agroecosystems representing many different land use types and environmental conditions. The results can contribute to nature conservation, biodiversity, and the sustainable use of plant resources.


2012 ◽  
Vol 32 ◽  
pp. 1-7 ◽  
Author(s):  
R. Benning ◽  
K. Schua ◽  
K. Schwärzel ◽  
K. H. Feger

Abstract. The aim of this study was to assess the impact of land-use on inputs of nitrogen, phosphorus, and DOC into the inflow of the Lehnmühle reservoir (drinking water supply). Land-use in the study area is dominated by forest, with smaller proportions of grassland and crops. Water quality was analyzed for the hydrological years 2010 and 2011 at the outlets of three small catchments with homogenous land-use (crops, grassland and forest) and at the outlet of the watershed. The highest nitrogen and phosphorus concentrations were observed in the streams draining the agricultural areas, and the lowest concentrations were found in the forest catchment. The DOC concentration was highest at the outlet of the watershed whereas the concentrations in the small homogeneous catchments were lower. The information collected about the land-use dependent matter exports in these study areas will be used for climate change impact modeling with the Soil and Water Assessment Tool.


2020 ◽  
Vol 9 (4) ◽  
Author(s):  
Halake Guyo Rendilicha ◽  
Patrick Home ◽  
James M. Raude ◽  
Charles M. M’Erimba ◽  
Stellamaris Muthoka

The study assessed the impact of land-use types on the groundwater quality of the mid River Njoro catchment, Kenya. Groundwater samples were collected from eight boreholes between the period of October 2017 to February 2018 and analyzed for pH, temperature, electrical conductivity, dissolved oxygen, nitrate, ammonium, and total phosphorus. These parameters were used to calculate the Groundwater Quality Index (GQI) value of the study area. The concentration maps (“primary maps I”) were constructed using Kriging interpolation of ArcGIS software from the seven groundwater quality parameters. The “primary maps I” were standardized with the KEBS and WHO standards to the “primary maps II” for ease of integration into a GIS environment. The “primary maps II” were then rated and weighted using a polynomial function to generate “rank maps” before calculating the GQI using spatial analyst tools of ArcGIS software. The land use map was prepared from a high-resolution Google earth satellite imagery of 2015. The mean GQI values for the different land use polygons were calculated and compared using GIS techniques. The GQI ranged from 68.38 to 70.92, indicating a high groundwater quality of mid River Njoro catchment. The major land-use types identified include settlement area, forest cover, agricultural land and mixed area. The agricultural land dominated the study area, followed by settlement area, forest cover and finally mixed area. The mean GQI value in each land use type varied minimally and this could be because of the diffuse nature of the land use types of the study area. Settlement area had low GQI, followed by agricultural land, mixed area and the forest cover had the highest mean GQI value, which corresponds to good quality of groundwater. Even though the variation is insignificant in this particular study, it somehow indicates the adverse effects of different land use on the quality of groundwater.


2017 ◽  
Vol 7 (1) ◽  
Author(s):  
Yuanyuan Yang ◽  
Shuwen Zhang ◽  
Yansui Liu ◽  
Xiaoshi Xing ◽  
Alex de Sherbinin

Abstract Historical land use information is essential to understanding the impact of anthropogenic modification of land use/cover on the temporal dynamics of environmental and ecological issues. However, due to a lack of spatial explicitness, complete thematic details and the conversion types for historical land use changes, the majority of historical land use reconstructions do not sufficiently meet the requirements for an adequate model. Considering these shortcomings, we explored the possibility of constructing a spatially-explicit modeling framework (HLURM: Historical Land Use Reconstruction Model). Then a three-map comparison method was adopted to validate the projected reconstruction map. The reconstruction suggested that the HLURM model performed well in the spatial reconstruction of various land-use categories, and had a higher figure of merit (48.19%) than models used in other case studies. The largest land use/cover type in the study area was determined to be grassland, followed by arable land and wetland. Using the three-map comparison, we noticed that the major discrepancies in land use changes among the three maps were as a result of inconsistencies in the classification of land-use categories during the study period, rather than as a result of the simulation model.


Urban Studies ◽  
2011 ◽  
Vol 48 (14) ◽  
pp. 3107-3124 ◽  
Author(s):  
Geoffrey Meen ◽  
Christian Nygaard

This paper considers the impact of existing land use patterns on housing supply price elasticities in local areas of England, under existing planning policies. The paper demonstrates that, despite common national planning policies, local supply responses to market pressures vary considerably, because of differences in historical land uses. The study area covers the Thames Gateway and Thames Valley, which lie to the east and west of London respectively. However, whereas the latter is one of the wealthiest areas of England, the former includes some of the highest pockets of deprivation and was a government priority area for increasing housing supply. Due to differences in historical land use and geography, the price elasticity in the least constrained area is approximately six times higher than the most constrained.


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