vegetation density
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2022 ◽  
Author(s):  
Gary Bell ◽  
David Abraham ◽  
Gaurav Savant ◽  
Anthony G. Emiren

The Morganza Floodway and the Atchafalaya Basin, located in Louisiana west of the Mississippi River, were evaluated using a two-dimensional Adaptive Hydraulics model. Prior to this study, Phase 1 and 2 model studies were performed that indicated that the existing floodway may not be able to pass the Project Design Flood discharge of 600,000 cubic feet per second due to levee overtopping. In this study, all elevations of exterior and interior levees were updated with current crest elevations. In addition, the Phase 3 effort evaluated the sensitivity of the floodway’s flow capacity to variations in tree/vegetation density conditions. These adjustments in roughness will improve the understanding of the role of land cover characteristics in the simulated water surfaces. This study also provides a number of inundation maps corresponding to certain flows through the Morganza Control Structure.


2022 ◽  
Vol 951 (1) ◽  
pp. 012073
Author(s):  
M Trishiani ◽  
S Sugianto ◽  
T Arabia ◽  
M Rusdi

Abstract Vegetation density in Banda Aceh is an important aspect of monitoring the recovery process after being hit by a tsunami on December 26, 2004. The tsunami disaster had a tremendous impact on Banda Aceh city, both physical and non-physical damage. As a result, a lot of vegetation was swept away by the tsunami waves. After the tsunami disaster, Banda Aceh City carried out rehabilitation and reconstruction to change the land cover. The increasing population growth in the city also has affected land cover. Changes in land use not following the spatial plan of the Banda Aceh can reduce the quality of the environment, e.g., reducing the vegetation density in some areas. This paper presents the utilization of Landsat 7 and Landsat 8 images to analyze the vegetation density in Banda Aceh city before dan after the tsunami in the last 15 years. This study aims to determine the ability of satellite imagery to detect vegetation density in Banda Aceh in designated years before and after the tsunami. This study uses the Normalized Difference Vegetation Index analysis to observe the trend of vegetation density in the Banda Aceh. Results show that the vegetation density in Banda Aceh City in 2004, 2005, 2009, 2015, and 2020 was dominated by low-density classes. Still, in 2015 and 2020, there was an increase in medium and high vegetation density classes. This finding shows the pattern of the vegetation density follows the progress of the recovery after 15 years hit by a tsunami.


2021 ◽  
Vol 26 (2) ◽  
pp. 9-12
Author(s):  
Tek Bahadur Yakha ◽  
Mukesh Kumar Chalise

Higher altitudes of Api Nampa Conservation Area have become a hunting destination for the local people bringing a threat to blue sheep and other wildlife. Blue sheep has been a national concern in Nepal due to being the main prey species of snow leopard and trophy hunting. The purpose of this paper is to examine the impact of hunters in Api Nampa Conservation Area (ANCA), Darchula, Nepal. This study was carried out around Api Nampa Conservation Area in 2016. Mixed methods of questionnaires were developed to collect data, and quantitative analysis was done by applying SPSS 16. A hundred percent of hunters like to hunt in this protected area. The hunted animals were goral, blue sheep, barking deer, boar and tahr. Site-specific characteristics like vegetation density, terrain and rugged land topography often vary markedly across surveys. Due to the regular and yearly use of grazing by the livestock in the area, it becomes imperative to study their feeding habits and document their food plants. Consequently, poaching and livestock grazing are important challenges for the conservation of blue sheep. Hunting, deforestation, forest fires, grazing and shifting agriculture are identified as major threats to the wildlife of Api Nampa Conservation Area. Envisioning, critical thinking, building partnership in decision-making, awareness, and stringent action against hunting activities must be adopted early. Api Nampa Conservation Area has received little research attention from grassland ecologists and specialists in pastoral management.


Atmosphere ◽  
2021 ◽  
Vol 13 (1) ◽  
pp. 42
Author(s):  
Xiaobin Peng ◽  
Miao Yu ◽  
Haishan Chen

The terrestrial ecosystem plays a vital role in regulating the exchange of carbon between land and atmosphere. This study investigates how terrestrial vegetation coverage and carbon fluxes change in a world stabilizing at 1.5 °C and 2 °C warmer than pre-industrial level. Model results derived from 20 Earth System Models (ESMs) under low, middle, and high greenhouse emission scenarios from CMIP5 and CMIP6 are employed to supply the projected results. Although the ESMs show a large spread of uncertainties, the ensemble means of global LAI are projected to increase by 0.04 ± 0.02 and 0.08 ± 0.04 in the 1.5 and 2.0 °C warming worlds, respectively. Vegetation density is projected to decrease only in the Brazilian Highlands due to the decrease of precipitation there. The high latitudes in Eurasia are projected to have stronger increase of LAI in the 2.0 °C warming world compared to that in 1.5 °C warming level caused by the increase of tree coverage. The largest zonal LAI is projected around 70° N while the largest zonal NPP is projected around 60° N and equator. The zonally inhomogeneous increase of vegetation density and productivity relates to the zonally inhomogeneous increase of temperature, which in turn could amplify the latitudinal gradient of temperature with additional warming. Most of the ESMs show uniform increases of global averaged NPP by 10.68 ± 8.60 and 15.42 ± 10.90 PgC year−1 under 1.5 °C and 2.0 °C warming levels, respectively, except in some sparse vegetation areas. The ensemble averaged NEE is projected to increase by 3.80 ± 7.72 and 4.83 ± 10.13 PgC year−1 in the two warming worlds. The terrestrial ecosystem over most of the world could be a stronger carbon sink than at present. However, some dry areas in Amazon and Central Africa may convert to carbon sources in a world with additional 0.5 °C warming. The start of the growing season in the northern high latitudes is projected to advance by less than one month earlier. Five out of 10 CMIP6 ESMs, which use the Land Use Harmonization Project (LUH2) dataset or a prescribed potential vegetation distribution to constrain the future change of vegetation types, do not reduce the model uncertainties in projected LAI and terrestrial carbon fluxes. This may suggest the challenge in optimizing the carbon fluxes modeling in the future.


2021 ◽  
Vol 9 (3) ◽  
pp. 346
Author(s):  
Syarifuddin Kadir ◽  
Ichsan Ridwan ◽  
Wahyuni Ilham ◽  
Nurlina Nurlina

A Watershed is an ecosystem whose first component consists of natural resources vegetation, land, water, and human resources. Tabunio watershed covering an area of 62,558.56 hectares consists of 10 sub-watersheds. The Normalized Difference Vegetation Index (NDVI) is used in vegetation density analysis. Vulnerability of environmental damage is the condition of a region that has the potential for environmental damage due to human activities and or activities that have the potential to cause environmental impacts.The purpose of vegetation density analysis is carried out for the evaluation of environmental vulnerability dynamics in Tabunio watershed, i.e: 1). Knowing changes in land cover; 2. Knowing the classification of vegetation density; 3. Determine efforts to increase vegetation density. The benefits of this analysis are to obtain directives that can have a positive impact on the control of flood suppliers' vulnerability and environmental vulnerability by determining forest and land rehabilitation techniques.Based on the results of mapping and analysis obtained: 1) changes in land cover in 2005-2020 are dominant in forest land cover, open land, settlements, plantations, swamp farming, shrubs, and mining; 2) Vegetation density in the upstream sub-watershed is dominated by the classification of dense and very tight vegetation density; 3) The green revolution of the upstream watershed is dominated for ecological purposes with dense and very close vegetation, the central part of the watershed is dominated for ecological, economic and social with tight vegetation, downstream green revolution watershed dominated for economic and social interests with dense and sparse vegetation


2021 ◽  
Vol 9 (2) ◽  
pp. 13-24
Author(s):  
Binod Baniya ◽  
Narayan Prasad Gaire ◽  
Qua-anan Techato ◽  
Yubraj Dhakal ◽  
Yam Prasad Dhital

Identification of high altitudinal vegetation dynamics using remote sensing is important because of the complex topography and environment in the Himalayas. Langtang National Park is the first Himalayan park in Nepal representing the best area to study vegetation change in the central Himalaya region because of the high altitudinal gradient and relatively less disturbed region. This study aimed at mapping vegetation in Langtang National Park and its treeline ecotone using Moderate Resolution Imaging Spectroradiometer (MODIS), Normalized Difference Vegetation Index (NDVI). Two treeline sites with an altitude of 3927 and 3802 meters above sea level (masl) were selected, and species density was measured during the field survey. The linear slope for each pixel and the Mann Kendall test to measure significant trends were used. The results showed that NDVI has significantly increased at the rate of 0.002yr-1 in Langtang National Park and 0.003yr-1 in treeline ecotone during 2000-2017. The average 68.73% equivalents to 1463 km2 of Langtang National Park are covered by vegetation. At the same time, 16.45% equivalents to 350.43 km2 are greening, and 0.25%, i.e., 5.43 km2 are found browning. In treeline ecotone, the vegetation is mostly occupied by grasses, shrublands and small trees where the NDVI was found from 0.1 to 0.5. The relative changes of NDVI in barren lands are negative and vegetative lands above 0.5 NDVI are positive between 2000 and 2017. The dominant treeline vegetation were Abies spectabilis, Rhododendron campanulatum, Betula utilis and Sorbus microphyla, with the vegetation density of 839.28 and 775 individuals per hectare in sites A and B, respectively. The higher average NDVI values, significantly increased NDVI, and higher density of vegetation in both A and B sites indicate that the vegetation in treeline ecotone is obtaining a good environment in the Himalayas of Nepal.


2021 ◽  
Vol 14 (1) ◽  
pp. 101
Author(s):  
Miguel Ibañez-Álvarez ◽  
Pol Farràs Santasusana ◽  
Juan Antonio Calleja ◽  
Carlos Rouco ◽  
Matthew Brolly ◽  
...  

Invasive rodents have a detrimental impact on terrestrial ecosystem functioning, this is often exacerbated on small islands. Rat eradication campaigns are often used to deal with this environmental perturbation given their classification as invasive species. Studies assessing the effects of rodent control at ecosystem scale are scarce and thus little is known about the subsequent functional response of vegetation subsequent to rat control. In this work, we use remote sensing to assess the effects of black rat (Rattus rattus) eradication on Mediterranean vegetation productivity in the Sa Dragonera Islet, Mallorca (Spain). Rats feed on seeds, sprouts, and leaves of woody vegetation and hence we expect primary production to increase nine years after the rodenticide campaign. The Break Detection approach for additive season and trend (BFAST method) was adopted to examine changes in vegetation density before and after the eradication campaign in Sa Dragonera Islet (Balearic Islands), using a temporal series of monthly NDVI data extracted from Landsat imagery. The same temporal trends were examined for a control zone where no rat eradication took place, in order to control for weather-driven changes. The results of this study revealed changes across the 21-year monthly NDVI time series. However, the dates, magnitude, and trend of these changes could not be explicitly attributed to the action of rats, when compared to the historical changes on the islet and the changes found to co-occur within the control zone. These finding could, perhaps, be explained by the high resilience of Mediterranean shrubs to browsing including that of rat invasion. However, the results from the study appear to show that rat damage on specific plant species, with little contribution to global NDVI values, would be overshadowed by the effects of broader environmental factors in this remote sensing approach. The results suggest that the current passive restoration scheme imposed following eradication is not sufficient for effective ecosystem restoration.


Author(s):  
İ. Avcı ◽  
E. Farzaliyev ◽  
E. Kabullar

Abstract. A large share of the earth's surface is observed with remote sensing technology. Thanks to the data obtained from this process, information about the observed lands is obtained. In this study, NDVI (normalized difference), which is developed by applying mathematical operations on the reflection values of plants at different wavelengths from remote sensing technology and different application areas of this technology, electromagnetic rays, and spectral reflection values, and which is used as a method that provides a value expressing vegetation density. Vegetation index) method, NDVI value, and plant groups analyzed according to this value, sample MATLAB applications related to the NDVI method are mentioned. -Green-Blue) image of visible red and infrared regions, histogram graph showing the relationships between the intensities of values in NIR (near-infrared) and Red (visible Red) bands, NDVI image, and threshold function at the end. The NDVI image was obtained by using the direction (to detect areas that may have vegetation) is shown.


2021 ◽  
Vol 2021 ◽  
pp. 1-10
Author(s):  
Deasy Arisanty ◽  
Muhammad Muhaimin ◽  
Dedi Rosadi ◽  
Aswin Nur Saputra ◽  
Karunia Puji Hastuti ◽  
...  

Forest and land fires occur every year in Indonesia. Efforts to handle forest and land fires have not been optimal because fires occur in too many places with unclear patterns and densities. The study analyzed the spatiotemporal patterns of burned areas and fire density in fire-prone areas in Indonesia. Data of burned areas were taken from http://sipongi.menlhk.go.id/. The website collected its data from NOAA (National Oceanic and Atmospheric Administration) images. Data were analyzed using the hot spot analysis to determine the spatiotemporal patterns of the burned areas and the kernel density analysis to examine the density of land fires. Findings showed that the spatiotemporal pattern from 2016 to 2019 formed a hot spot value in the peatland area with a confidence level of 90–99%, meaning that land fires were clustered in that area. In addition, the highest density of land fires also occurred in the peatland areas. Clustered burned areas with high fire density were found in areas with low–medium vegetation density—they were the peatland areas. The peatland areas must become the priority to prevent and handle forest and land fires to reduce fire risks.


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