scholarly journals Multi-scale analysis of the characteristics of the changing landscape of the typical mountainous region of Southwest China over the past 40 years

PeerJ ◽  
2021 ◽  
Vol 9 ◽  
pp. e10923
Author(s):  
Fang Liu ◽  
Wanbin Wang ◽  
Jinliang Wang ◽  
Xingzi Zhang ◽  
Jing Ren ◽  
...  
Keyword(s):  
Landscape Ecology ◽  
Spatial Autocorrelation ◽  
Yunnan Province ◽  
Landscape Heterogeneity ◽  
River Basins ◽  
Landscape Patterns ◽  
Fragmented Landscape ◽  
Change Analysis ◽  
Spatial Changes ◽  
Temporal And Spatial

Context Yunnan Province is an important ecological security barrier in China. This study investigated the temporal and spatial changes to landscape ecology and is of great significance for guiding landscape protection and future socio-economic development. Objectives To analyze the temporal and spatial changes of the landscape patterns at the county, river basin, and provincial levels, and clarify and describe the temporal and spatial differentiation characteristics of the landscape patterns in Yunnan Province. Methods Based on landscape ecology, GIS spatial analysis, and spatio-temporal change analysis, nine landscape pattern indices, and spatial autocorrelation for different years, were calculated. Results The landscape of Yunnan Province has evolved as a whole toward isolation. The indices of separation and fragmentation changed significantly from 2010 to 2015. From 2015 to 2018 the rate of fragmentation decreased. Fragmentation in the Nu Jiang and Irrawaddy River basins was less than in other basins. The landscape patterns of the Jinsha and Pearl River basins were relatively fragmented due to human activity, socioeconomic development, and utilization. The differences between the Lancang and Red River Basins were relatively small and at an intermediate level. Conclusions Spatial autocorrelation analysis indicated that there are three areas with typical clusters, namely the Hengduan Mountains where the degree of fragmentation of the landscape was low, while landscape connectivity and aggregation were high. The subtropical region of Southern Yunnan displayed high landscape heterogeneity, a complex shape index, and high connectivity and sprawl. Central Yunnan exhibited a fragmented landscape with poor connectivity and aggregation. These three regions correspond with “the three screens and two belts” in the Main Functional Planning Area of Yunnan Province.

Biodiversity in Heterogeneous and Dynamic Landscapes

2016 ◽  
Author(s):  
Clélia Sirami
Keyword(s):  
Landscape Ecology ◽  
Spatial Heterogeneity ◽  
Environmental Changes ◽  
Landscape Heterogeneity ◽  
Landscape Patterns ◽  
Global Changes ◽  
Time Lags ◽  
Temporal Heterogeneity ◽  
Landscape Models ◽  
Spatial And Temporal Heterogeneity

Although the concept of biodiversity emerged 30 years ago, patterns and processes influencing ecological diversity have been studied for more than a century. Historically, ecological processes tended to be considered as occurring in local habitats that were spatially homogeneous and temporally at equilibrium. Initially considered as a constraint to be avoided in ecological studies, spatial heterogeneity was progressively recognized as critical for biodiversity. This resulted, in the 1970s, in the emergence of a new discipline, landscape ecology, whose major goal is to understand how spatial and temporal heterogeneity influence biodiversity. To achieve this goal, researchers came to realize that a fundamental issue revolves around how they choose to conceptualize and measure heterogeneity. Indeed, observed landscape patterns and their apparent relationship with biodiversity often depend on the scale of observation and the model used to describe the landscape. Due to the strong influence of island biogeography, landscape ecology has focused primarily on spatial heterogeneity. Several landscape models were conceptualized, allowing for the prediction and testing of distinct but complementary effects of landscape heterogeneity on species diversity. We now have ample empirical evidence that patch structure, patch context, and mosaic heterogeneity all influence biodiversity. More recently, the increasing recognition of the role of temporal scale has led to the development of new conceptual frameworks acknowledging that landscapes are not only heterogeneous but also dynamic. The current challenge remains to truly integrate both spatial and temporal heterogeneity in studies on biodiversity. This integration is even more challenging when considering that biodiversity often responds to environmental changes with considerable time lags, and multiple drivers of global changes are interacting, resulting in non-additive and sometimes antagonistic effects. Recent technological advances in remote sensing, the availability of massive amounts of data, and long-term studies represent, however, very promising avenues to improve our understanding of how spatial and temporal heterogeneity influence biodiversity.

scholarly journals Temporal and spatial changes in wall shear stress during atherosclerotic plaque progression in mice

2018 ◽  
Vol 5 (3) ◽  
pp. 171447 ◽  
Author(s):  
R. Xing ◽  
A. M. Moerman ◽  
Y. Ridwan ◽  
M. J. Daemen ◽  
A. F. W. van der Steen ◽  
...  
Keyword(s):  
Shear Stress ◽  
Wall Shear Stress ◽  
Mouse Model ◽  
Atherosclerotic Plaque ◽  
Proximal Part ◽  
Plaque Progression ◽  
Plaque Composition ◽  
Spatial Changes ◽  
Temporal And Spatial ◽  
Wall Shear

Wall shear stress (WSS) is involved in atherosclerotic plaque initiation, yet its role in plaque progression remains unclear. We aimed to study (i) the temporal and spatial changes in WSS over a growing plaque and (ii) the correlation between WSS and plaque composition, using animal-specific data in an atherosclerotic mouse model. Tapered casts were placed around the right common carotid arteries (RCCA) of ApoE −/− mice. At 5, 7 and 9 weeks after cast placement, RCCA geometry was reconstructed using contrast-enhanced micro-CT. Lumen narrowing was observed in all mice, indicating the progression of a lumen intruding plaque. Next, we determined the flow rate in the RCCA of each mouse using Doppler Ultrasound and computed WSS at all time points. Over time, as the plaque developed and further intruded into the lumen, absolute WSS significantly decreased. Finally at week 9, plaque composition was histologically characterized. The proximal part of the plaque was small and eccentric, exposed to relatively lower WSS. Close to the cast a larger and concentric plaque was present, exposed to relatively higher WSS. Lower WSS was significantly correlated to the accumulation of macrophages in the eccentric plaque. When pooling data of all animals, correlation between WSS and plaque composition was weak and no longer statistically significant. In conclusion, our data showed that in our mouse model absolute WSS strikingly decreased during disease progression, which was significantly correlated to plaque area and macrophage content. Besides, our study demonstrates the necessity to analyse individual animals and plaques when studying correlations between WSS and plaque composition.

scholarly journals Remote Sensing-Based Analysis of Urban Landscape Change in the City of Bucharest, Romania

2021 ◽  
Vol 13 (12) ◽  
pp. 2323
Author(s):  
Constantin Nistor ◽  
Marina Vîrghileanu ◽  
Irina Cârlan ◽  
Bogdan-Andrei Mihai ◽  
Liviu Toma ◽  
...  
Keyword(s):  
Policy Development ◽  
Urban Policy ◽  
Urban Landscape ◽  
Landscape Heterogeneity ◽  
Real Estate Market ◽  
Capital City ◽  
Urban Structure ◽  
Change Analysis ◽  
Complex Structural ◽  
The City

The paper investigates the urban landscape changes for the last 50 years in Bucharest, the capital city of Romania. Bucharest shows a complex structural transformation driven by the socialist urban policy, followed by an intensive real-estate market development. Our analysis is based on a diachronic set of high-resolution satellite imagery: declassified CORONA KH-4B from 1968, SPOT-1 from 1989, and multisensor stacked layers from Sentinel-1 SAR together with Sentinel-2MSI from 2018. Three different datasets of land cover/use are extracted for the reference years. Each dataset reveals its own urban structure pattern. The first one illustrates a radiography of the city in the second part of the 20th century, where rural patterns meet the modern ones, while the second one reveals the frame of a city in a full process of transformation with multiple constructions sites, based on the socialist model. The third one presents an image of a cosmopolitan city during an expansion process, with a high degree of landscape heterogeneity. All the datasets are included in a built-up change analysis in order to map and assess the spatial transformations of the city pattern over 5 decades. In order to quantify and map the changes, the Built-up Change Index (BCI) is introduced. The results highlight a particular situation linked to the policy development visions for each decade, with major changes of about 50% for different built-up classes. The GIS analysis illustrates two major landscape transformations: from the old semirural structures with houses surrounded by gardens from 1968, to a compact pattern with large districts of blocks of flats in 1989, and a contemporary city defined by an uncontrolled urban sprawl process in 2018.

The Spatial-Temporal Change Pattern of Wetland in the Middle-Lower Yangtze River: A Case Study of Wuhu, Anhui

2014 ◽  
Vol 513-517 ◽  
pp. 3228-3232 ◽  
Author(s):  
Xiao Li Tao ◽  
Yong Ping Bai
Keyword(s):  
Quantitative Methods ◽  
Temporal Change ◽  
Remote Sensing Image ◽  
Land Uses ◽  
Change Pattern ◽  
Spatial Changes ◽  
Temporal And Spatial ◽  
Gis Software ◽  
Urban Sprawling

Wetlands play a number of roles in the environment, which are also considered the most biologically diverse of all ecosystems. Utilizing RS and the GIS software, remote datum were matched and classified. By these transactions, the temporal and spatial changes of wetland landscape are explored in Wuhu, combining qualitative analysis and quantitative methods. This paper analyzed the time-spatial revolution process which indicated that, firstly the area of wetland reduced rapidly from remote sensing image in 1988, 2001 and 2005, secondly the exterior of urban changed acutely and the interior were protected well in view of spatial pattern. Moreover, driving force factors were pointed out. Human activities, especially urbanization were the main causes of wetlands degradation. Simultaneity, the development of farming, the construction of infrastructure and nature were important factors. Owing to rapid economic development and urban sprawling, wetlands are encountering threaten to be converting to other land uses. Thus, the paper provides policy advices for wetland conservation and urban planning toward sustainable development.

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