scholarly journals Impact of anthropogenic activities on natural vegetation cover of Aseer Region, Saudi Arabia

2021 ◽  
Vol 13 (1) ◽  
pp. 33-50
Keyword(s):  
Saudi Arabia ◽  
Vegetation Cover ◽  
Anthropogenic Activities ◽  
Natural Vegetation

scholarly journals Consideration of NDVI thematic changes in density analysis and floristic composition of Wadi Yalamlam, Saudi Arabia

2018 ◽  
Vol 7 (4) ◽  
pp. 297-306 ◽  
Author(s):  
Amal Y. Aldhebiani ◽  
Mohamed Elhag ◽  
Ahmad K. Hegazy ◽  
Hanaa K. Galal ◽  
Norah S. Mufareh
Keyword(s):  
Saudi Arabia ◽  
Vegetation Cover ◽  
Vegetation Index ◽  
Normalized Difference Vegetation Index ◽  
Remote Sensing Data ◽  
Floristic Composition ◽  
Water Source ◽  
Shannon Index ◽  
Landsat 8 ◽  
Main Stream

Abstract. Wadi Yalamlam is known as one of the significant wadis in the west of Saudi Arabia. It is a very important water source for the western region of the country. Thus, it supplies the holy places in Mecca and the surrounding areas with drinking water. The floristic composition of Wadi Yalamlam has not been comprehensively studied. For that reason, this work aimed to assess the wadi vegetation cover, life-form presence, chorotype, diversity, and community structure using temporal remote sensing data. Temporal datasets spanning 4 years were acquired from the Landsat 8 sensor in 2013 as an early acquisition and in 2017 as a late acquisition to estimate normalized difference vegetation index (NDVI) changes. The wadi was divided into seven stands. Stands 7, 1, and 3 were the richest with the highest Shannon index values of 2.98, 2.69, and 2.64, respectively. On the other hand, stand 6 has the least plant biodiversity with a Shannon index of 1.8. The study also revealed the presence of 48 different plant species belonging to 24 families. Fabaceae (17 %) and Poaceae (13 %) were the main families that form most of the vegetation in the study area, while many families were represented by only 2 % of the vegetation of the wadi. NDVI analysis showed that the wadi suffers from various types of degradation of the vegetation cover along with the wadi main stream.

scholarly journals Methods of GI modeling of biogenic substances removal to the Gulf of Finland from forest vegetation cover

2020 ◽  
Vol 26 (2) ◽  
pp. 137-150
Author(s):  
Alexey Osipov ◽  
Georgy Osipov ◽  
Vasily Kovyazin
Keyword(s):  
Vegetation Cover ◽  
Catchment Area ◽  
Water Area ◽  
Forest Vegetation ◽  
Natural Vegetation ◽  
Water Bodies ◽  
Gulf Of Finland ◽  
Economic Activities ◽  
Biogenic Substances ◽  
The Gulf Of Finland

Biogenic pollution of water bodies and their eutrophication is one of the most serious environmental problems of our time. One of the sources of water pollution with biogenic substances is forests, which belong to the background sources of biogenic load. Currently available methods for assessing the removal of nutrients from the forest vegetation cover do not provide the desired results, which causes an urgent need for their improvement. This article describes the method developed by the authors of geoinformation modeling of removal of biogenic substances from the forest vegetation cover to water bodies, taking into account the spatial distribution of vegetation in the catchment area, its species composition and absorption of biogenic substances during their migration. The Eastern part of the Gulf of Finland was adopted as the object of testing of the developed method. this is due to the fact that eutrophication processes are actively manifested within its water area. The volume of the background biogenic load on the Gulf of Finland, formed during the decomposition of the fall of the natural vegetation cover in the catchment area, was determined based on the specific removal of biogenic substances from plant communities and their absorption during migration “plant community — water object”. The total background biogenic load on the eastern part of the Gulf of Finland, formed as a result of decomposition of natural vegetation cover, was 170.21 t/year for the northern catchment for nitrogen, 12.14 t/year for phosphorus, and 207.31 t/year for the southern catchment for nitrogen , and 15.68 t/year for phosphorus. The data obtained do not contradict the results of other authors who study the background biogenic load on the Gulf of Finland. The method can be effectively used in the development of measures to reduce the nutrient load on water bodies and planning of economic activities in catchments.

scholarly journals Dinâmica Espaço-Temporal da Paisagem Semiárida no Município de Apodi/RN e seus Condicionantes Socioeconômicos e Ambientais

2021 ◽  
Vol 14 (4) ◽  
pp. 2446-2464
Author(s):  
Murianny Katamara Silva de Oliveira ◽  
Eveline Almeida Ferreira ◽  
Nadjacleia Vilar Almeida ◽  
Eulene Francisco da Silva ◽  
Aline Almeida Vasconcelos
Keyword(s):  
Vegetation Cover ◽  
Structural Changes ◽  
Temporal Dynamics ◽  
Agrarian Reform ◽  
Anthropogenic Activities ◽  
Standardized Precipitation Index ◽  
Environmental Drivers ◽  
Precipitation Data ◽  
Dense Vegetation ◽  
Spatio Temporal

Apodi, like many municipalities in the Northeast, underwent structural changes conducted by two main drivers: alternation of socioeconomic models and seasonal and prolonged periods of drought. Among the socioeconomic models, Apodi passed by large landowners, agrarian reform, expropriation of land for irrigated perimeters and installation of agribusiness companies. These conditions negatively impacted the vegetation cover, degrading the landscape and threatening the Lajedo de Soledade Archaeological Site (SALS) located in the middle of this landscape, an important cultural and environmental patrimony. In this context, the objective of this study was to analyze the spatio-temporal changes in the landscape around SALS and to infer about the influence of socioeconomic and environmental drivers. For this, a survey of the region's history, precipitation data, agricultural production of the main crops, and eight images captured by the TM and OLI sensors of the LANDSAT 5 and 8 satellites, between 1984 and 2018, were used. Precipitation data was modeled using the Standardized Precipitation Index (SPI). The images were classified using the SCP plugin (QGIS) and the quality was assessed using the Kappa Index. It was observed that there were three prolonged and extreme droughts events in the region: late 1980s and 1990s and between 2013 and 2017. The classification of the images indicated periods of dense vegetation reductions and exposed soil expansions, in the period of decay of cotton culture, and the reversal of these patterns after agrarian reform, with the establishment of family farming on an agroecological basis. This pattern was again reversed, with the lowest proportion of dense vegetation observed (5%) and and higher proportion of exposed soil (45%) observed in this landscape, during the period of installation of the irrigated perimeter for agribusiness. Thus, it was possible to infer that the alternation of socioeconomic models conditioned the spatio-temporal dynamics of the vegetation cover and was responsible for the environmental degradation conditions surrounding the SALS, these patterns being aggravated by the recurrence of periods of extreme and prolonged drought. During these periods, SALS was probably more vulnerable to the direct and indirect effects of anthropogenic activities common in this landscape.

scholarly journals Predicted thresholds for natural vegetation cover to safeguard pollinator services in agricultural landscapes

2020 ◽  
Vol 290 ◽  
pp. 106785
Author(s):  
Arnob Chatterjee ◽  
Soumik Chatterjee ◽  
Barbara Smith ◽  
James E. Cresswell ◽  
Parthiba Basu
Keyword(s):  
Vegetation Cover ◽  
Agricultural Landscapes ◽  
Natural Vegetation

scholarly journals Quantifying the Impacts of Anthropogenic Activities and Climate Variations on Vegetation Productivity Changes in China from 1985 to 2015

2020 ◽  
Vol 12 (7) ◽  
pp. 1113
Author(s):  
Shahid Naeem ◽  
Yongqiang Zhang ◽  
Jing Tian ◽  
Faisal Mueen Qamer ◽  
Aamir Latif ◽  
...  
Keyword(s):  
Climate Change ◽  
Primary Productivity ◽  
Human Activities ◽  
Vegetation Cover ◽  
Net Primary Productivity ◽  
Anthropogenic Activities ◽  
Climate Factors ◽  
Climate Variations ◽  
Base Period ◽  
Increasing Trends

Accurate assessment of vegetation dynamics provides important information for ecosystem management. Anthropogenic activities and climate variations are the major factors that primarily influence vegetation ecosystems. This study investigates the spatiotemporal impacts of climate factors and human activities on vegetation productivity changes in China from 1985 to 2015. Actual net primary productivity (ANPP) is used to reflect vegetation dynamics quantitatively. Climate-induced potential net primary productivity (PNPP) is used as an indicator of climate change, whereas the difference between PNPP and ANPP is considered as an indicator of human activities (HNPP). Overall, 91% of the total vegetation cover area shows declining trends for net primary productivity (NPP), while only 9% shows increasing trends before 2000 (base period). However, after 2000 (restoration period), 78.7% of the total vegetation cover area shows increasing trends, whereas 21.3% of the area shows decreasing trends. Moreover, during the base period, the quantitative contribution of climate change to NPP restoration is 0.21 grams carbon per meter square per year (gC m−2 yr−1) and to degradation is 2.41 gC m−2 yr−1, while during the restoration period, climate change contributes 0.56 and 0.29 gC m−2 yr−1 to NPP restoration and degradation, respectively. Human activities contribute 0.36 and 0.72 gC m−2 yr−1 during the base period, and 0.63 and 0.31 gC m−2 yr−1 during the restoration period to NPP restoration and degradation, respectively. The combined effects of climate and human activities restore 0.65 and 1.11 gC m−2 yr−1, and degrade 2.01 and 0.67 gC m−2 yr−1 during the base and restoration periods, respectively. Climate factors affect vegetation cover more than human activities, while precipitation is found to be more sensitive to NPP change than temperature. Unlike the base period, NPP per unit area increases with an increase in the human footprint pressure during the restoration period. Grassland has more variability than other vegetation classes, and the grassland changes are mainly observed in Tibet, Xinjiang, and Inner Mongolia regions. The results may help policy-makers by providing necessary guidelines for the management of forest, grassland, and agricultural activities.

The impact of recent land-use change in the Araucaria araucana forest in northern Patagonia

The Holocene ◽  
2020 ◽  
Vol 30 (8) ◽  
pp. 1101-1114 ◽  
Author(s):  
Ricardo Moreno-Gonzalez ◽  
Thomas Giesecke ◽  
Sonia L Fontana
Keyword(s):  
Land Use ◽  
Land Use Change ◽  
Vegetation Cover ◽  
Natural Vegetation ◽  
Northern Patagonia ◽  
Rumex Acetosella ◽  
Araucaria Araucana ◽  
The 1950S ◽  
The Impact ◽  
Nothofagus Dombeyi

Land-use change in the form of extensive Pinus plantations is currently altering the natural vegetation cover at the forest–steppe ecotone in northern Patagonia. Providing recommendations for conservation efforts, with respect to this recent and earlier land-use changes, requires a longer time perspective. Using pollen analysis, we investigated to what degree the colonization of the area by Euro-American settlers changed the forest composition and the vegetation cover, and to explore the spread of the European weed Rumex acetosella. This study is based on short sediment cores from six lakes in the Araucaria araucana forest region, across the vegetation gradient from the forest to the steppe. Results document that although Araucaria araucana has been extensively logged elsewhere, near the investigated sites, populations were rather stable and other elements of the vegetation changed little with the initiation of Euro-American settlements. A reduction of Nothofagus dombeyi-type pollen occurred at some sites presumably due to logging Nothofagus dombeyi trees, while toward the steppe, Nothofagus antarctica shrubs may have been removed for pasture. The appearance of Rumex acetosella pollen is consistent with the initiation of land use by Euro-American settlers in all cores, probably indicating the onset of animal farming. The rise of the Rumex acetosella pollen curve during the 1950s marks more recent land-use change. These observations indicate that the spread and local expansion of the weed requires disturbance. Overall, the study shows that the initial colonization of the area by Euro-American settlers had little effect on the natural vegetation structure, while developments since the 1950s are strongly altering the natural vegetation cover.

scholarly journals Characteristics of atypical Huperzia selago subsp. arctica habitats to the south of distribution area

2012 ◽  
Vol 81 (2) ◽  
pp. 87-92 ◽  
Author(s):  
Ilona Jukonienė ◽  
Rasa Dobravolskaitė ◽  
Jūratė Sendžikaitė
Keyword(s):  
Vegetation Cover ◽  
Dominant Species ◽  
Natural Vegetation ◽  
Distribution Area ◽  
The South ◽  
Campylopus Introflexus

Two localities for <em>Huperzia selago </em>subsp. <em>arctica </em>are recorded from Lithuania, to the south of its known distribution area. The habitats of this subspecies are cutover peatlands whose natural vegetation was disturbed 6-8 years ago during peat exploitation. One of the dominant species of latest vegetation cover is the invasive bryophyte <em>Campylopus introflexus</em>. Characteristics of the habitats of <em>H. selago </em>subsp. <em>arctica </em>and the frequency of this taxon in populations were analysed.

scholarly journals Natural vegetation cover on private lands: locations and risk of loss in the northwestern United States

Ecosphere ◽  
2021 ◽  
Vol 12 (10) ◽  
Author(s):  
Andrew J. Hansen ◽  
Katrina Mullan ◽  
David M. Theobald ◽  
Scott Powell ◽  
Nathaniel Robinson ◽  
...  
Keyword(s):  
United States ◽  
Vegetation Cover ◽  
Natural Vegetation ◽  
Private Lands
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