Analysis of recent changes in natural habitat types in the Apuseni Mountains (Romania), using multi-temporal Landsat satellite imagery (1986–2015)

Cheţan, Marinela Adriana; Dornik, Andrei; Urdea, Petru

doi:10.1016/j.apgeog.2018.06.007

Cited by 11 publications

(6 citation statements)

References 42 publications

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“…Locations of the two study areas are shown in color composite images (R6G3B2) in Figure 3. The flooding reference images were obtained from the corresponding Landsat 8 OLI images using the modified normalized difference water index (mNDWI) [37,38]. The resolution of the flooding reference images was 30 m. The flooding fraction images were obtained by aggregating the corresponding flooding reference images.…”

Section: Study Materialsmentioning

confidence: 99%

Remote Sensing of Wetland Flooding at a Sub-Pixel Scale Based on Random Forests and Spatial Attraction Models

Chen

et al. 2019

Remote Sensing

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Wetland flooding is significant for the flora and fauna of wetlands. High temporal resolution remote sensing images are widely used for the timely mapping of wetland flooding but have a limitation of their relatively low spatial resolutions. In this study, a novel method based on random forests and spatial attraction models (RFSAM) was proposed to improve the accuracy of sub-pixel mapping of wetland flooding (SMWF) using remote sensing images. A random forests-based SMWF algorithm (RM-SMWF) was developed firstly, and a comprehensive complexity index of a mixed pixel was formulated. Then the RFSAM-SMWF method was developed. Landsat 8 Operational Land Imager (OLI) images of two wetlands of international importance included in the Ramsar List were used to evaluate RFSAM-SMWF against three other SMWF methods, and it consistently achieved more accurate sub-pixel mapping results in terms of visual and quantitative assessments in the two wetlands. The effects of the number of trees in random forests and the complexity threshold on the mapping accuracy of RFSAM-SMWF were also discussed. The results of this study improve the mapping accuracy of wetland flooding from medium-low spatial resolution remote sensing images and therefore benefit the environmental studies of wetlands.

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Section: Study Materialsmentioning

confidence: 99%

Remote Sensing of Wetland Flooding at a Sub-Pixel Scale Based on Random Forests and Spatial Attraction Models

Chen

et al. 2019

Remote Sensing

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“…Today, the automated extraction technologies of remote sensing data can precisely delineate surface covers with significant heterogeneity (Liu, et al, 2021;Yang et al, 2022). However, classifying grasslands based on plant communities remains a challenge when using spectral imagery methods (Cheţan, et al, 2018). In recent years, researchers have discerned different types of plant communities with distinct phenological features by leveraging the spectral information of annual plant growth cycles (Lewińska, 2020;Weber, 2018).…”

Section: Introductionmentioning

confidence: 99%

Landscape changes of alpine grasslands in the Zhari Namco basin of the central-southern Qiangtang Plateau

Chen,

Zhang,

et al. 2023

Preprint

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Context. The Qiangtang Plateau, with its high elevations and cold, dry climate, poses challenges for fieldwork, particularly for ecological research of alpine grassland landscapes at the plant community scale. Objectives. This study aimed to establishand map the distribution patterns of dominant communities in the alpine basin of Zhari Namco. It also investigated the evolution over the past two decades in terms of the number of grasslands, their structural changes, and the fragmentation of habitats. Methods. We quantified the habitat characteristics of dominant plant communities considering topography, hydrology, and fractional vegetation cover. Fifteen landscape indices were selected to examine the characteristics of the grassland changes. Results. The results indicated: (1) the patches of S. purpurea steppe and K. pygmaea meadow were more fragmented compared with the other types. These two types had a decisive impact on the entire grassland landscape; (2) the patch structure of both Carex swamp meadow and C. moorcroftii meadow remained stable, but displayed a different degree of habitat fragmentation as a result of grazing management; and (3) S. purpurea + C. moorcroftii steppe, located in areas with the best hydrothermal conditions, maintained a relatively stable grassland structure with a lighter degree of habitat fragmentation. It is the most suitable grassland resource for grazing in the study region. Conclusions. The present findings provide a reference for exploring the changes in the type and scale of alpine grassland plant communities. It also serves for the rational utilization of alpine grassland resources in the Qiangtang Plateau.

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“…Forest fragmentation in protected areas is a typical research issue for searching for innovative methodologies for landscape pattern analysis and mapping [60] and is a challenge in searching for new instruments for the sustainable management of biodiversity [61]. There are few contributions in this field based on landscape metrics derived from Landsat data, such as Gounaridis et al [62] in Greece or Sahana, Sajjad and Ahmed [46] in India, IRS and other medium-resolution imagery in India [63], using fractal modelling in Bhutan [64], while Cheţan et al [65] produced landscape metrics of forested landscapes in NATURA 2000 sites from the Apuseni Mountains, Romanian Carpathians.…”

Section: Introductionmentioning

confidence: 99%

Forest Habitat Fragmentation in Mountain Protected Areas Using Historical Corona KH-9 and Sentinel-2 Satellite Imagery

et al. 2022

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Forest habitat fragmentation is one of the global environmental issues of concern as a result of forest management practices and socioeconomic drivers. In this context, a constant evaluation of natural habitat conditions still remains a challenge in order to achieve a general image of the environmental state of a protected area for proper sustainable management. The purpose of our study was to evaluate the evolution of forest habitat in the last 40 years, focusing on Bucegi Natural Park, one of the most frequented protected areas in Romania, as relevant for highly human-impacted areas. Our approach integrates a historical panchromatic Corona KH-9 image from 1977 and present-day Sentinel-2 multispectral data from 2020 in order to calculate a series of spatial metrics that reveal changes in the pattern of the forest habitat and illustrate forest habitat fragmentation density. Object-based oriented analysis with supervised maximum likelihood classification was employed for the production of forest cover fragmentation maps. Ten landscape metrics were adapted to the analysis context, from patch statistics to proximity index. The results show a general growth of the forest surface but also an increase in habitat fragmentation in areas where tourism was developed. Fragmentation indices explain that larger and compact patches feature natural park protected forests after the spruce–fir secondary canopies were grown during the last 4–5 decades. The number of patches decreased to half, and their average size is double that of before. The method can be of extensive use for environmental monitoring in protected areas management and for understanding the environmental history connected to present-day problems that are to be fixed under rising human pressure.

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Analysis of recent changes in natural habitat types in the Apuseni Mountains (Romania), using multi-temporal Landsat satellite imagery (1986–2015)

Cited by 11 publications

References 42 publications

Remote Sensing of Wetland Flooding at a Sub-Pixel Scale Based on Random Forests and Spatial Attraction Models

Remote Sensing of Wetland Flooding at a Sub-Pixel Scale Based on Random Forests and Spatial Attraction Models

Landscape changes of alpine grasslands in the Zhari Namco basin of the central-southern Qiangtang Plateau

Forest Habitat Fragmentation in Mountain Protected Areas Using Historical Corona KH-9 and Sentinel-2 Satellite Imagery

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