scholarly journals Drought Sensitivity and Trends of Riparian Vegetation Vigor in Nevada, USA (1985–2018)

2020 ◽  
Vol 12 (9) ◽  
pp. 1362 ◽  
Author(s):  
Christine M. Albano ◽  
Kenneth C. McGwire ◽  
Mark B. Hausner ◽  
Daniel J. McEvoy ◽  
Charles G. Morton ◽  
...  
Keyword(s):  
Riparian Vegetation ◽  
Vegetation Index ◽  
Agricultural Land ◽  
Statistical Significance ◽  
Climatic Variability ◽  
Water Levels ◽  
Private Land ◽  
Riparian Areas ◽  
Vegetative Cover ◽  
Vegetation Responses

Dryland riparian areas are under increasing stress due to expanding human water demands and a warming climate. Quantifying responses of dryland riparian vegetation to these pressures is complicated by high climatic variability, which can create strong, transient changes in vegetation vigor that could mask other disturbance events. In this study, we utilize a 34-year archive of Landsat satellite data to (1) quantify the strength and timescales of vegetation responses to interannual variability in drought status and (2) isolate and remove this influence to assess resultant trends in vegetation vigor for riparian areas across the state of Nevada, the driest state in the USA. Correlations between annual late-summer Normalized Difference Vegetation Index (NDVI) and the Standardized Precipitation–Evapotranspiration Index (SPEI) were calculated across a range of time periods (varying timing and durations) for all riparian pixels within each of the 45 ecoregions, and the variability of these values across the study area is shown. We then applied a novel drought adjustment method that used the strongest SPEI–NDVI timescale relationships for each ecoregion to remove the influence of interannual drought status. Our key result is a 30 m resolution map of drought-adjusted riparian NDVI trends (1985–2018). We highlight and describe locations where impacts of invasive species biocontrol, mine water management, agriculture, changing water levels, and fire are readily visualized with our results. We found more negatively trending riparian areas in association with wide valley bottoms, low-intensity agricultural land uses, and private land ownerships and more positive trends in association with narrow drainages, public lands, and surrounding perennial water bodies (an indication of declining water levels allowing increased vegetative cover). The drought-adjusted NDVI improved the statistical significance of trend estimates, thereby improving the ability to detect such changes. Results from this study provide insight into the strength and timescales of riparian vegetation responses to drought and can provide important information for managing riparian areas within the study area. The novel approach to drought adjustment is readily transferrable to other regions.

scholarly journals Urban Fire Severity and Vegetation Dynamics in Southern California

2020 ◽  
Vol 13 (1) ◽  
pp. 19
Author(s):  
Lauren E. H. Mathews ◽  
Alicia M. Kinoshita
Keyword(s):  
Vegetation Cover ◽  
Vegetation Index ◽  
Normalized Difference Vegetation Index ◽  
Current Knowledge ◽  
Fire Severity ◽  
Satellite Image ◽  
Burn Severity ◽  
Native Vegetation ◽  
Riparian Areas ◽  
The Impact

A combination of satellite image indices and in-field observations was used to investigate the impact of fuel conditions, fire behavior, and vegetation regrowth patterns, altered by invasive riparian vegetation. Satellite image metrics, differenced normalized burn severity (dNBR) and differenced normalized difference vegetation index (dNDVI), were approximated for non-native, riparian, or upland vegetation for traditional timeframes (0-, 1-, and 3-years) after eleven urban fires across a spectrum of invasive vegetation cover. Larger burn severity and loss of green canopy (NDVI) was detected for riparian areas compared to the uplands. The presence of invasive vegetation affected the distribution of burn severity and canopy loss detected within each fire. Fires with native vegetation cover had a higher severity and resulted in larger immediate loss of canopy than fires with substantial amounts of non-native vegetation. The lower burn severity observed 1–3 years after the fires with non-native vegetation suggests a rapid regrowth of non-native grasses, resulting in a smaller measured canopy loss relative to native vegetation immediately after fire. This observed fire pattern favors the life cycle and perpetuation of many opportunistic grasses within urban riparian areas. This research builds upon our current knowledge of wildfire recovery processes and highlights the unique challenges of remotely assessing vegetation biophysical status within urban Mediterranean riverine systems.

scholarly journals Bulk Drag Predictions of Riparian Arundo donax Stands through UAV-Acquired Multispectral Images

Water ◽  
2021 ◽  
Vol 13 (10) ◽  
pp. 1333
Author(s):  
Giuseppe Francesco Cesare Lama ◽  
Mariano Crimaldi ◽  
Vittorio Pasquino ◽  
Roberta Padulano ◽  
Giovanni Battista Chirico
Keyword(s):  
Riparian Vegetation ◽  
Vegetation Index ◽  
Arundo Donax ◽  
Water Bodies ◽  
Giant Reed ◽  
Multispectral Images ◽  
Drainage Channel ◽  
Area Index ◽  
Riparian Plants ◽  
The Impact

Estimating the main hydrodynamic features of real vegetated water bodies is crucial to assure a balance between their hydraulic conveyance and environmental quality. Riparian vegetation stands have a high impact on vegetated channels. The present work has the aim to integrate riparian vegetation’s reflectance indices and hydrodynamics of real vegetated water flows to assess the impact of riparian vegetation morphometry on bulk drag coefficients distribution along an abandoned vegetated drainage channel fully covered by 9–10 m high Arundo donax (commonly known as giant reed) stands, starting from flow average velocities measurements at 30 cross-sections identified along the channel. A map of riparian vegetation cover was obtained through digital processing of Unnamed Aerial Vehicle (UAV)-acquired multispectral images, which represent a fast way to observe riparian plants’ traits in hardly accessible areas such as vegetated water bodies in natural conditions. In this study, the portion of riparian plants effectively interacting with flow was expressed in terms of ground-based Leaf Area Index measurements (LAI), which easily related to UAV-based Normalized Difference Vegetation Index (NDVI). The comparative analysis between Arundo donax stands NDVI and LAI map enabled the analysis of the impact of UAV-acquired multispectral imagery on bulk drag predictions along the vegetated drainage channel.

scholarly journals Sentinel-2 Based Temporal Detection of Agricultural Land Use Anomalies in Support of Common Agricultural Policy Monitoring

2018 ◽  
Vol 7 (10) ◽  
pp. 405 ◽  
Author(s):  
Urška Kanjir ◽  
Nataša Đurić ◽  
Tatjana Veljanovski
Keyword(s):  
Land Use ◽  
Time Series ◽  
Agricultural Policy ◽  
Common Agricultural Policy ◽  
Vegetation Index ◽  
Normalized Difference Vegetation Index ◽  
Agricultural Land ◽  
Agricultural Land Use ◽  
Land Use Control ◽  
Sentinel 2

The European Common Agricultural Policy (CAP) post-2020 timeframe reform will reshape the agriculture land use control procedures from a selected risk fields-based approach into an all-inclusive one. The reform fosters the use of Sentinel data with the objective of enabling greater transparency and comparability of CAP results in different Member States. In this paper, we investigate the analysis of a time series approach using Sentinel-2 images and the suitability of the BFAST (Breaks for Additive Season and Trend) Monitor method to detect changes that correspond to land use anomaly observations in the assessment of agricultural parcel management activities. We focus on identifying certain signs of ineligible (inconsistent) use in permanent meadows and crop fields in one growing season, and in particular those that can be associated with time-defined greenness (vegetation vigor). Depending on the requirements of the BFAST Monitor method and currently time-limited Sentinel-2 dataset for the reliable anomaly study, we introduce customized procedures to support and verify the BFAST Monitor anomaly detection results using the analysis of NDVI (Normalized Difference Vegetation Index) object-based temporal profiles and time-series standard deviation output, where geographical objects of interest are parcels of particular land use. The validation of land use candidate anomalies in view of land use ineligibilities was performed with the information on declared land annual use and field controls, as obtained in the framework of subsidy granting in Slovenia. The results confirm that the proposed combined approach proves efficient to deal with short time series and yields high accuracy rates in monitoring agricultural parcel greenness. As such it can already be introduced to help the process of agricultural land use control within certain CAP activities in the preparation and adaptation phase.

scholarly journals Assessing the hydrological impacts of agricultural changes upstream of the Tunisian World Heritage sea-connected Ichkeul Lake

2015 ◽  
Vol 365 ◽  
pp. 61-65 ◽  
Author(s):  
J. Aouissi ◽  
Z. L. Chabaane ◽  
S. Benabdallah ◽  
C. Cudennec
Keyword(s):  
Agricultural Land ◽  
World Heritage ◽  
Water Levels ◽  
World Heritage Site ◽  
Landsat Images ◽  
Heritage Site ◽  
Unesco World Heritage Site ◽  
Ichkeul Lake ◽  
The Impact

Abstract. The impact of changes in agricultural land use and practices as a controlling driver of hydrologic response and as a source of diffuse pollution, are studied in the Joumine River basin, discharging into the Ichkeul Lake, northern Tunisia, a UNESCO World Heritage site since 1979. The lake is characterized by a very specific hydrological functioning based on a seasonal alternation of water levels and salinity through its link to the Mediterranean Sea. Three Landsat images, in situ surveys and SWAT modelling were used to simulate and assess streamflows and nitrate loads under retrospective land uses.

scholarly journals GIS-Based Climate Change Induced Flood Risk Mapping in Uhunmwonde Local Government Area, Edo State, Nigeria

2020 ◽  
pp. 8-23
Author(s):  
Obot Akpan Ibanga ◽  
Osaretin Friday Idehen
Keyword(s):  
Climate Change ◽  
Local Government ◽  
Flood Risk ◽  
Vegetation Index ◽  
Agricultural Land ◽  
Local Government Area ◽  
Risk Mapping ◽  
Risk Zone ◽  
Edo State ◽  
Risk Zones

Introduction: Flood is one of the climate change induced hazards occurring in most parts of the world. It exposes humanity and many socio-ecological systems to various levels of risks. In Nigeria, extreme rainfall events and poor drainage system have caused inundation of several settlements to flooding. To contain the disaster, risk mapping were among the measures recommended. Aims: The aim of this paper is to highlight flood risk zones (FRZ) in Uhunmwonde Local Government Area (LGA), Edo State, Nigeria. Methodology: Flood risk (FR) was mapped using hazards and vulnerability and implemented using geographic information system (GIS)-based multi-criteria analysis analytic hierarchy process (MCA-AHP) framework by incorporating seven environmental and two socio-economic factors. Elevation, flow accumulation, soil water index of wettest quarter, normalized difference vegetation index, rainfall of wettest quarter, runoff of wettest quarter and distance from rivers constituted the hazard component while population density and area of agricultural land use was the vulnerability layer. The climate change induced flood risk was validated using the responses of 150 residents in high, moderate and low flood risk zones. Results: The resulting flood risk map indicated that about 40.4% of Uhunmwonde LGA fell within high flood risk zone, 35.3% was categorized under moderate flood risk zone whereas low flood risk zone extended up to about 24.3% of the LGA. The high number of respondents who reported occurrence of flooding with frequency being very often and the fact that flooding was a very serious environmental threat during on-the-spot field assessment validated the generated climate change induced flood risk. Conclusion: The utilitarian capabilities of GIS-based MCA-AHP framework in integrating remotely-sensed biophysical and climate change related flood inducing indicators with socio-economic vulnerabilities to arrive at composite flood risk was demonstrated.

scholarly journals THE EXTENT OF AGRICULTURAL LAND DAMAGE IN VARIOUS TSUNAMI WAVE HEIGHT SCENARIOS: DISASTER MANAGEMENT AND MITIGATION

2018 ◽  
Vol XLII-3/W4 ◽  
pp. 51-57 ◽  
Author(s):  
S. Antoni ◽  
R. A. Bantan ◽  
H. M. Taki ◽  
W. Anurogo ◽  
M. Z. Lubis ◽  
...  
Keyword(s):  
Wave Height ◽  
Vegetation Index ◽  
Agricultural Land ◽  
Numerical Data ◽  
Earthquake Hazard ◽  
Case Scenario ◽  
Worst Case ◽  
Large Power ◽  
Aster Image ◽  
Run Up

<p><strong>Abstract.</strong> The southern coastal areas of Java are highly vulnerable areas of earthquake hazard because they located 200&amp;thinsp;km from the southern Java subduction zone. This zone is an active seismicity area, resulting in many tectonic earthquakes caused by collisions and shift between the plates. This shift when it occurs under the sea surface with a large power intensity can lead to a tsunami. This research conducted to identify the extent of agricultural land (AL) damaged by the tsunami for disaster risk management and mitigation. Numerical modelling was performed to determine the run-up height of the tsunami through numerical data. This model was designed using the worst-case scenario. The tsunami inundation model analysed from the coming wave (run-up) with a height of 30&amp;thinsp;m. This model used scenarios of tsunami run-up height in a coastline, coarse coefficient and slope. The data extracted using remote sensing (RS) data was the slope obtained from the ASTER image GDEM data, the agricultural land productivity data obtained using NDVI vegetation index transformation and field data on productivity, and tsunami hazard analysis with various altitude scenarios using run-up model impact on existing AL conditions. The elevation-data was obtained from the 15&amp;thinsp;m ASTER image data (GDEM) that was reclassified into a slope class map. The risk of destruction of AL based on wave height extracted by using RS data generated rice risk loss index of AL of 190.5071&amp;thinsp;tons for a height of 1&amp;thinsp;m, 1851.522&amp;thinsp;tons for a height of 5&amp;thinsp;m, 7402.71&amp;thinsp;tons for a height of 10&amp;thinsp;m, 10776.47&amp;thinsp;tons to a height of 15&amp;thinsp;m, 11823.9&amp;thinsp;tons for height 20&amp;thinsp;m, and 11824.27&amp;thinsp;tons to a height of 30&amp;thinsp;m.</p>

scholarly journals Relation of leaf water content with real evapotranspiration and biomass in Caatinga biome, using remote sensing data

2017 ◽  
Vol 10 (5) ◽  
pp. 1545
Author(s):  
Josiclêda Domiciano Galvíncio
Keyword(s):  
Energy Balance ◽  
Water Content ◽  
Vegetation Index ◽  
Normalized Difference Vegetation Index ◽  
Surface Energy Balance ◽  
Climatic Variability ◽  
Leaf Water ◽  
Leaf Water Content ◽  
Content Index ◽  
Caatinga Biome

R E S U M OA Caatinga é um biome que sofre com grande variabilidade climática anual e intraanual. Essa variabilidade climática faz com que o bioma em grande parte do ano sofra com grande estresse hídrico. Estudar as relações existentes entre o conteúdo de água na planta e outras variáveis do ecossistemas, tais como: biomassa e evapotranspiração pode auxiliar e prever impactos da escassez hídrica e seca climatológica sobre a produção de biomassa do bioma Caatinga. Assim, este estudo pretende analisar as relações existentes entre o conteúdo de água na folha com a biomassa e evapotranspiração em área do bioma caatinga localizado em São José do Sabugi, Paraiba, Brasil. Foi utilizado o algoritmo SEBAL-Surface Energy Balance para estimar a evapotranspiração e o foram calculados os índices de vegetação NDVI- Normalized Difference Vegetation Index, SAVI- Soil Adjusted Vegetation Index e o índice de conteúdo de água na folha LWCI- Leaf Water Content Index. Os resultados mostraram uma boa relação existente entre os índices de vegetação e o conteúdo de água na folha, sendo r=0.76 para o SAVI e 0.64 para o NDVI. Para a evapotranspiração a correlação foi de r =0.386. Conclui-se que a quantidade de água na folha está altamente correlacionada com a biomassa.Palavra chave: bioma, sazonalidade, seca, semiárido. A B S T R A C TThe Caatinga is a biome that suffers from high annual and intra-annual climatic variability. This climatic variability makes the biome in great part of the year suffer with high great water stress. To study the relationships between water content in the plant and other ecosystem variables, such as: biomass and evapotranspiration can help and predict impacts of water scarcity and climatological drought on the biomass production of the Caatinga biome. Thus, this study intends to analyze the relationship between water content in the leaf with biomass and evapotranspiration in the area of the caatinga biome located in São José do Sabugi, Paraiba, Brazil. The SEBAL-Surface Energy Balance algorithm was used to estimate the evapotranspiration and NDVI-Normalized Difference Vegetation Index, SAVI-Soil Adjusted Vegetation Index and the water content index in the LWCI- Leaf Water Content Index. were calculated. The results showed a good relationship between vegetation index and leaf water content, with r = 0.76 for SAVI and 0.64 for NDVI. For evapotranspiration the correlation was r = 0.386. It is concluded that the amount of water in the leaf is highly correlated with the biomass.Keywords: biome, seasonality, dry, semiarid

scholarly journals Assessment of Land Use and Vegetative Cover in Kano Metropolis (from 1975-2015) Employing GIS and Remote Sensing Technology

2020 ◽  
Vol 27 (2) ◽  
pp. 1-7
Author(s):  
M. Haruna ◽  
M.K. Ibrahim ◽  
U.M. Shaibu
Keyword(s):  
Remote Sensing ◽  
Land Use ◽  
Agricultural Land ◽  
Landsat 8 ◽  
Vegetative Cover ◽  
Gis And Remote Sensing ◽  
Remote Sensing Technology ◽  
Sensing Technology ◽  
Agricultural Planning ◽  
Bare Land

This study applied GIS and remote sensing technology to assess agricultural land use and vegetative cover in Kano Metropolis. It specifically examined the intensity of land use for agricultural and non agricultural purpose from 1975 – 2015. Images (1975, 1995 and 2015), landsat MSS/TM, landsat 8, scene of path 188 and 052 were downloaded for the study. Bonds for these imported scenes were processed using ENVI 5.0 version. The result indicated five classified features-settlement, farmland, water body, vegetation and bare land. The finding revealed an increase in settlement, vegetation and bare land between 1995 and 2015, however, farmland decreased in 2015. Indicatively, higher percentage of land use for non agricultural purposes was observed in recent time. Conclusively, there is need to accord surveying the rightful place and priority in agricultural planning and development if Nigeria is to be self food sufficient. Keywords: Geographic Information System, Agriculture, Remote sensing, Land use, Land cover

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