The Effect of Geographical and Climatic Factors on the Distribution of Phlebotomus papatasi (Diptera: Psychodidae) in Golestan Province, an Endemic Focus of Zoonotic Cutaneous Leishmaniasis in Iran, 2014

Background: Phlebotomus papatasi is known as the main vector of zoonotic cutaneous leishmaniasis. This study aimed to investigate the effect of geographical and bioclimatic factors on the Ph. papatasi distribution. Methods: A total of 34 villages were selected, and sampling was performed three times using 120 sticky traps in each selected village. All the collected species were mounted and identified their species. The densities of Ph. papatasi were measured in all the villages and entered into ArcMap as a point layer. The required bioclimatic and environmental vari- ables were extracted from the global climate database and The normalized difference vegetation index was obtained from the MODIS satellite imagery, also, all variables entered into ArcMap as raster layers, so The numerical value of each independent variable in the cell where the selected village is located in this, was extracted using spatial analyst tools and the value to point submenu. All the data were finally entered into IBM SPSS, and the relationship was exam- ined between the number of collected Ph. papatasi and the independent variables using Spearman's correlation test. Results: A total of 1773 specimens of Ph. papatasi were collected. The findings of this study showed that max temperature of warmest month, temperature annual range, temperature seasonality, mean diurnal range, precipitation seasonality, mean temperature of driest and warmest quarter were positively associated with the density of Ph. papatasi. Conclusion: Air temperature and precipitation were shown as the most significant factors in the distribution of Ph. papatasi.

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Contrasting Effects of Temperature and Precipitation on Vegetation Greenness along Elevation Gradients of the Tibetan Plateau

Remote Sensing ◽

10.3390/rs12172751 ◽

2020 ◽

Vol 12 (17) ◽

pp. 2751

Author(s):

Yan Wang ◽

Dailiang Peng ◽

Miaogen Shen ◽

Xiyan Xu ◽

Xiaohua Yang ◽

...

Keyword(s):

Tibetan Plateau ◽

Vegetation Index ◽

Normalized Difference Vegetation Index ◽

Global Climate ◽

The Tibetan Plateau ◽

Elevation Gradients ◽

Vegetation Greenness ◽

Temperature And Precipitation ◽

Variation Rate ◽

Effects Of Temperature

The Tibetan Plateau (TP) is one of the most sensitive regions to global climate warming, not only at the inter-annual time scale but also at the altitudinal scale. We aim to investigate the contrasting effects of temperature and precipitation on vegetation greenness at different altitudes across the TP. In this study, interannual and elevational characteristics of the Normalized Difference Vegetation Index (NDVI), temperature, and precipitation were examined during the growing season from 1982 to 2015. We compared the elevational movement rates of the isolines of NDVI, temperature, and precipitation, and the sensitivities of elevational NDVI changes to temperature and precipitation. The results show that from 1982 to 2015, the elevational variation rate of isolines for NDVI mismatched with that for temperature and precipitation. The elevational movements of NDVI isolines were mostly controlled by precipitation at elevations below 2400 m and by the temperature at elevations above 2400 m. Precipitation appears to plays a role similar to temperature, and even a more effective role than the temperature at low elevations, in controlling elevational vegetation greenness changes at both spatial and interannual scales in the TP. This study highlights the regulation of temperature and precipitation on vegetation ecosystems along elevation gradients over the whole TP under global warming conditions.

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Unsynchronized Driving Mechanisms of Spring and Autumn Phenology Over Northern Hemisphere Grasslands

Frontiers in Forests and Global Change ◽

10.3389/ffgc.2020.610162 ◽

2021 ◽

Vol 3 ◽

Author(s):

Nan Cong ◽

Ke Huang ◽

Yangjian Zhang

Keyword(s):

Global Warming ◽

Northern Hemisphere ◽

Vegetation Index ◽

Normalized Difference Vegetation Index ◽

Climatic Factors ◽

Dominant Role ◽

Growing Season ◽

Growing Season Length ◽

Driving Mechanisms ◽

Temperature And Precipitation

Global warming has impacted Northern Hemisphere (NH) grassland ecosystems to a great extent. Vegetation growing season length (GSL) has been extended by concurrent advances in spring green-up and postponements in autumn dormancy. However, the driving mechanisms of phenology are unclear as limited factors have been considered so far. Therefore, it is still elusive to what extent phenological changes shaped GSL. In this study, we used remote sensing normalized difference vegetation index (NDVI) to extract spring and autumn phenology of NH grasslands, and further explored the contribution of each phenophase to GSL through the coefficient of variation (CV) and contribution coefficient (CntC). We found that 65% of NH grasslands exhibited advanced start-of-season (SOS) and circa 58% showed delayed end-of-season (EOS) in the three decades. Changes in GSL was regulated more by EOS changes than by SOS changes, as evidenced by their respective 52 vs. 48% CntC. As for the relationship between phenology and environmental elements, the causing factor analysis revealed that climatic factors (temperature, precipitation, and their interactions) played a dominant role in SOS variations, while environmental and internal factors exerted dominant effects on EOS. Also, interactions of temperature and precipitation contributed a higher variation of SOS than either of them individually. The differentiated factors controlling the two bounding ends of the growing season suggested that it is impossible for GSL to continue to extend without limits under global warming.

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Climate Dynamics of the Spatiotemporal Changes of Vegetation NDVI in Northern China from 1982 to 2015

Remote Sensing ◽

10.3390/rs13020187 ◽

2021 ◽

Vol 13 (2) ◽

pp. 187

Author(s):

Rui Sun ◽

Shaohui Chen ◽

Hongbo Su

Keyword(s):

Solar Radiation ◽

Vegetation Index ◽

Global Climate ◽

Regional Scale ◽

Northern China ◽

Climate Dynamics ◽

High Coverage ◽

Vegetation Growth ◽

Temperature And Precipitation ◽

Precipitation And Temperature

As an important part of a terrestrial ecosystem, vegetation plays an important role in the global carbon-water cycle and energy flow. Based on the Global Inventory Monitoring and Modeling System (GIMMS) third generation of Normalized Difference Vegetation Index (NDVI3g), meteorological station data, climate reanalysis data, and land cover data, this study analyzed the climate dynamics of the spatiotemporal variations of vegetation NDVI in northern China from 1982 to 2015. The results showed that growth season NDVI (NDVIgs) increased significantly at 0.006/10a (p < 0.01) in 1982–2015 on the regional scale. The period from 1982 to 2015 was divided into three periods: the NDVIgs increased by 0.026/10a (p < 0.01) in 1982–1990, decreased by −0.002/10a (p > 0.1) in 1990–2006, and then increased by 0.021/10a (p < 0.01) during 2006–2015. On the pixel scale, the increases in NDVIgs during 1982–2015, 1982–1990, 1990–2006, and 2006–2015 accounted for 74.64%, 85.34%, 48.14%, and 68.78% of the total area, respectively. In general, the dominant climate drivers of vegetation growth had gradually switched from solar radiation, temperature, and precipitation (1982–1990) to precipitation and temperature (1990–2015). For woodland, high coverage grassland, medium coverage grassland, low coverage grassland, the dominant climate drivers had changed from temperature and solar radiation, solar radiation and precipitation, precipitation and solar radiation, solar radiation to precipitation and solar radiation, precipitation, precipitation and temperature, temperature and precipitation. The areas controlled by precipitation increased significantly, mainly distributed in arid, sub-arid, and sub-humid areas. The dominant climate drivers for vegetation growth in the plateau climate zone or high-altitude area changed from solar radiation to temperature and precipitation, and then to temperature, while in cold temperate zone, changed from temperature to solar radiation. These results are helpful to understand the climate dynamics of vegetation growth, and have important guiding significance for vegetation protection and restoration in the context of global climate change.

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Temporal and Spatial Variations in NDVI and Analysis of the Driving Factors in the Desertified Areas of Northern China From 1998 to 2015

Frontiers in Environmental Science ◽

10.3389/fenvs.2021.633020 ◽

2021 ◽

Vol 9 ◽

Author(s):

Xuyang Wang ◽

Yuqiang Li ◽

XinYuan Wang ◽

Yulin Li ◽

Jie Lian ◽

...

Keyword(s):

Ecological Restoration ◽

Large Scale ◽

Vegetation Index ◽

Normalized Difference Vegetation Index ◽

Climatic Factors ◽

Northern China ◽

Gobi Desert ◽

Desert Grassland ◽

Dune Stability ◽

Mobile Dunes

China faces some of the most serious desertification in the world, leading to many problems. To solve them, large-scale ecological restoration projects were implemented. To assess their effectiveness, we analyzed normalized-difference vegetation index (NDVI) data derived from SPOT VEGETATION and gridded climate datasets from 1998 to 2015 to detect the degrees of desertification and the effects of human and climate drivers on vegetation dynamics. We found that NDVI of desertified areas generally decreased before 2000, then increased. The annual increase in NDVI was fixed dunes (0.0013) = semi-fixed dunes (0.0013) > semi-mobile dunes (0.0012) > gobi (gravel) desert (0.0011) > mobile dunes (0.0003) > saline–alkali land (0.0000). The proportions of the area of each desert type in which NDVI increased were fixed dunes (43.4%) > semi-mobile dunes (39.7%) > semi-fixed dunes (26.7%) > saline–alkali land (23.1%) > gobi desert (14.4%) > mobile dunes (12.5%). Thus, the vegetation response to the restoration efforts increased as the initial dune stability increased. The proportion of the area where desertification was dominated by temperature (1.8%) was far less than the area dominated by precipitation (14.1%). However, 67.6% of the change was driven by non-climatic factors. The effectiveness of the ecological restoration projects was significant in the Loess Plateau and in the Mu Us, Horqin, and Hulunbuir sandy lands. In contrast, there was little effect in the Badain Jaran, Ulan Buh, and Tengger deserts; in particular, vegetation cover has declined seriously in the Hunshandake Sandy Land and Alkin Desert Grassland. Thus, more or different ecological restoration must be implemented in these areas.

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THE NORMALIZED DIFFERENCE VEGETATION INDEX AS AN INDICATOR OF DYNAMICS

10.32008/geolinks2021/b2/v3/27 ◽

2021 ◽

Author(s):

Haddad Amar ◽

Beldjazia Amina ◽

Kadi Zahia ◽

Redjaimia Lilia ◽

Rached-Kanouni Malika

Keyword(s):

Vegetation Index ◽

Normalized Difference Vegetation Index ◽

Climatic Factors ◽

Mediterranean Ecosystems ◽

Point Of View ◽

Aleppo Pine ◽

Landsat 8 ◽

North East ◽

The North ◽

Pine Trees

Mediterranean ecosystems are considered particularly sensitive to climate change. Any change in climatic factors affects the structure and functioning of these ecosystems and has an influence on plant productivity. The main objective of this work is to characterize one of the Mediterranean ecosystems; the Chettaba forest massif (located in the North-East of Algeria) from a vegetation point of view and their link with monthly variations using Landsat 8 satellite images from five different dates (June 25, 2017, July 27, 2017, August 28, 2017, October 15, 2017). The comparison of NDVI values in Aleppo pine trees was performed using analysis of variance and the use of Friedman's non-parametric test. The Mann-Kendall statistical method was applied to the monthly distribution of NDVI values to detect any trends in the data over the study period. The statistical results of NDVI of Aleppo pine trees indicate that the maximum value is recorded in the month of June, while the lowest values are observed in the month of August where the species studied is exposed to periods of thermal stress.

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Revealing the Fingerprint of Climate Change in Interannual NDVI Variability among Biomes in Inner Mongolia, China

Remote Sensing ◽

10.3390/rs12081332 ◽

2020 ◽

Vol 12 (8) ◽

pp. 1332 ◽

Cited By ~ 4

Author(s):

Linghui Guo ◽

Liyuan Zuo ◽

Jiangbo Gao ◽

Yuan Jiang ◽

Yongling Zhang ◽

...

Keyword(s):

Climate Change ◽

Interannual Variability ◽

Inner Mongolia ◽

Vegetation Index ◽

Normalized Difference Vegetation Index ◽

Time Lag ◽

Growing Season ◽

Climate Fluctuations ◽

Temperature And Precipitation ◽

Lag Effect

An understanding of the response of interannual vegetation variations to climate change is critical for the future projection of ecosystem processes and developing effective coping strategies. In this study, the spatial pattern of interannual variability in the growing season normalized difference vegetation index (NDVI) for different biomes and its relationships with climate variables were investigated in Inner Mongolia during 1982–2015 by jointly using linear regression, geographical detector, and geographically weighted regression methodologies. The result showed that the greatest variability of the growing season NDVI occurred in typical steppe and desert steppe, with forest and desert most stable. The interannual variability of NDVI differed monthly among biomes, showing a time gradient of the largest variation from northeast to southwest. NDVI interannual variability was significantly related to that of the corresponding temperature and precipitation for each biome, characterized by an obvious spatial heterogeneity and time lag effect marked in the later period of the growing season. Additionally, the large slope of NDVI variation to temperature for desert implied that desert tended to amplify temperature variations, whereas other biomes displayed a capacity to buffer climate fluctuations. These findings highlight the relationships between vegetation variability and climate variability, which could be used to support the adaptive management of vegetation resources in the context of climate change.

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Relationship Between the Distribution and Biodiversity of Sand Flies (Diptera: Psychodidae) With the Incidence of Zoonotic Cutaneous Leishmaniasis in Endemic Foci of Golestan Province, Iran

Journal of Medical Entomology ◽

10.1093/jme/tjaa114 ◽

2020 ◽

Vol 57 (6) ◽

pp. 1768-1774

Author(s):

Aioub Sofizadeh ◽

Kamran Akbarzadeh ◽

Ehsan Allah Kalteh ◽

Fatemeh Karimi

Keyword(s):

Cutaneous Leishmaniasis ◽

Diversity Index ◽

Wiener Index ◽

Sand Flies ◽

Phlebotomus Papatasi ◽

Light Traps ◽

Phlebotomine Sand Flies ◽

Zoonotic Cutaneous Leishmaniasis ◽

Golestan Province ◽

The Relationship

Abstract Zoonotic cutaneous leishmaniasis (ZCL) is prevalent in Golestan Province, Iran. The current study determined the relationship between the distribution and biodiversity of sand flies with cutaneous leishmaniasis at 14 villages in plain and hillsides areas. In each village from July to September 2017, 60 sticky traps and 2 CDC light traps were laid. Spearman and Mann–Whitney tests were used to determine the relationship between the incidence of ZCL and the abundance of different species of sand flies. Simpson, Shannon-Wiener, Evenness, and Margalef indices were calculated to estimate the diversity of species. A total of 5,295 phlebotomine sand flies were collected, comprising 10 species of the genus Phlebotomus (3,947 flies) and 7 species of genus Sergentomyia (1,248 flies). The abundance of sand flies and incidence of ZCL in plain areas were greater than that of hillsides areas (P = 0.013, P = 0.002). There was a significant correlation between the incidence of ZCL and the abundance of Phlebotomus papatasi (r = 0.72, P = 0.004) and P. caucasicus groups (P = 0.006; 0.022). In the Shannon-Wiener index, the rest of the biodiversity indices were reduced in higher-altitude areas. Increasing Shannon-Wiener index showed higher diversity of sand flies in higher-altitude areas. Data of the reported cases of leishmaniasis in plain areas can reveal the relationship between less diversity index (Shannon-Wiener), higher dominant diversity index (Simpson), and incidence of leishmaniasis in these areas.

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Hydrological Condition Constrains Vegetation Dynamics for Wintering Waterfowl in China’s East Dongting Lake Wetland

Sustainability ◽

10.3390/su11184936 ◽

2019 ◽

Vol 11 (18) ◽

pp. 4936 ◽

Cited By ~ 2

Author(s):

Min Wang ◽

Qing Gu ◽

Guihua Liu ◽

Jingwei Shen ◽

Xuguang Tang

Keyword(s):

Vegetation Dynamics ◽

Vegetation Index ◽

Normalized Difference Vegetation Index ◽

Temporal Dynamics ◽

Global Climate ◽

Dongting Lake ◽

Plant Resources ◽

Data Set ◽

Wintering Waterfowl ◽

The Government

As an internationally important wintering region for waterfowls on the East Asian–Australasian Flyway, the national reserve of China’s East Dongting Lake wetland is abundant in animal and plant resources during winter. The hydrological regimes, as well as vegetation dynamics, in the wetland have experienced substantial changes due to global climate change and anthropogenic disturbances, such as the construction of hydroelectric dams. However, few studies have investigated how the wetland vegetation has changed over time, particularly during the wintering season, and how this has directly affected habitat suitability for migratory waterfowl. Thus, it is necessary to monitor the spatio-temporal dynamics of vegetation in the protected wetland and explore the potential factors that alter it. In this study, the data set of time-series Moderate Resolution Imaging Spectroradiometer (MODIS) normalized difference vegetation index (NDVI) from 2000 to 2018 was used to analyze the seasonal dynamics and interannual trends of vegetation over the wintering period from October to January. The results showed that the average NDVI exhibited an overall increasing trend, with the trend rising slowly in recent years. The largest monthly mean NDVI generally occurred in November, which is pertinent to the quantity of wintering waterfowl in the East Dongting Lake wetland. Meanwhile, the mean NDVI in the wintering season is significantly correlated to temperature and water area, with apparent lagging effects. Long-term stability analysis presented a gradually decreasing pattern from the central body of water to the surrounding area. All analyses will help the government to make appropriate management strategies to protect the habitat of wintering waterfowl in the wetland.

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