Gohar Ghazaryan

Gohar Ghazaryan
Leibniz Centre for Agricultural Landscape Research | ZALF · Research Platform "Data Analysis & Simulation"

Dr. rer. nat.

About

34
Publications
9,785
Reads
How we measure 'reads'
A 'read' is counted each time someone views a publication summary (such as the title, abstract, and list of authors), clicks on a figure, or views or downloads the full-text. Learn more
241
Citations

Publications

Publications (34)
Article
Full-text available
Population growth and increasing demand for agricultural production continue to drive global cropland expansions. These expansions lead to the overexploitation of fragile ecosystems, propagating land degradation, and the loss of natural diversity. This study aimed to identify the factors driving land use/land cover changes (LULCCs) and subsequent c...
Article
The availability of freshwater is highly influenced by climate change, extreme climate events and by anthropogenic use. Countries where a large part of the population depends on the agricultural sector, such as South Africa, are strongly affected by changes in climate, which emphasizes that water is an essential source for food production and drink...
Conference Paper
Growing metropolitan areas have potential to affect the climate of local neighborhoods and thus become a hot topic in regional planning. The study is a contribution to the climate change related land cover simulation efforts in Germany. It investigates future land consumption rates and population growth rates keeping goal 11 of the United Nation’s...
Article
Urban sprawl is ubiquitous with a complex network of driving forces and human and natural impacts on various scales of the coupled human-environment urban system. In Germany, a land consumption of 30 ha per day is envisaged. In that regard, the effect of growing metropolitan areas on the climate of local neighborhoods becomes more and more a topic...
Preprint
Full-text available
The availability of freshwater is highly influenced by climate change, extreme climate events and by anthropogenic use. Countries where a large part of the population depends on the agricultural sector, such as South Africa, are strongly affected by changes in climate, which emphasizes that water is an essential source for food production and drink...
Article
Full-text available
The regular drought episodes in South Africa highlight the need to reduce drought risk by both policy and local community actions. Environmental and socioeconomic factors in South Africa's agricultural system have been affected by drought in the past, creating cascading pressures on the nation's agro-economic and water supply systems. Therefore, un...
Article
Full-text available
The intensification of food production systems has resulted in landscape simplification, with trees and hedges disappearing from agricultural land, principally in industrialized countries. However, more recently, the potential of agroforestry systems and small woody landscape features (SWFs), e.g., hedgerows, woodlots, and scattered groups of trees...
Article
Full-text available
Political instability and economic crises may trigger informal, unsustainable and often illegal land use, leading to land degradation. One of the most recent and striking examples of such a phenomenon within Europe is demonstrated by the Polissia region in Northern Ukraine, famous for its amber deposits. Amid severe political disturbances and subse...
Article
Full-text available
Increasing population and a severe water crisis impose growing pressure on cropping systems of Iran to increase crop production meeting the rising demand for food. Little is known on the separate contribution of trends and variability of the harvested area and yield on crop production in severely drought-prone areas such as Iran. In this study, we...
Article
Full-text available
Monitoring land degradation (LD) to improve the measurement of the sustainable development goal (SDG) 15.3.1 indicator (“proportion of land that is degraded over a total land area”) is key to ensure a more sustainable future. Current frameworks rely on default medium-resolution remote sensing datasets available to assess LD and cannot identify subt...
Article
Full-text available
By 2050, two-third of the world’s population will live in cities. In this study, we develop a framework for analyzing urban growth-related imperviousness in North Rhine-Westphalia (NRW) from the 1980s to date using Landsat data. For the baseline 2017-time step, official geodata was extracted to generate labelled data for ten classes, including thre...
Article
Full-text available
One of the major sources of uncertainty in large-scale crop modeling is the lack of information capturing the spatiotemporal variability of crop sowing dates. Remote sensing can contribute to reducing such uncertainties by providing essential spatial and temporal information to crop models and improving the accuracy of yield predictions. However, l...
Article
Full-text available
Drought is one of the extreme climatic events that has a severe impact on crop production and food supply. Our main goal is to test the suitability of remote sensing-based indices to detect drought impacts on crop production from a global to regional scale. Moderate resolution imaging spectroradiometer (MODIS) based imagery, spanning from 2001 to 2...
Article
Full-text available
Agricultural production and food security highly depend on crop growth and condition throughout the growing season. Timely and spatially explicit information on crop phenology can assist in informed decision making and agricultural land management. Remote sensing can be a powerful tool for agricultural assessment. Remotely sensed data is ideally su...
Article
Globally, drought constitutes a serious threat to food and water security. The complexity and multivariate nature of drought challenges its assessment, especially at local scales. The study aimed to assess spatiotemporal patterns of crop condition and drought impact at the spatial scale of field management units with a combined use of time-series f...
Article
Full-text available
Achieving land degradation neutrality (LDN) has been proposed to stem the loss of land resources globally. To date, LDN operationalization at country level has remained a challenge both from a policy and science perspective. Using an approach incorporating cloud‐based geospatial computing with machine learning, national level datasets of land cover...
Article
Full-text available
Abstract—Drought is one of the most severe natural disasters with a high risk for human livelihoods. Remote sensing based drought indices can identify dry periods using, e.g., precipitation or vegetation information. Besides frequency, duration, and intensity, the timing of a drought onset and duration are important variables to measure the drought...
Article
Full-text available
Invasive plant species in eastern Africa severely impede rangeland and cropland productivity with dire consequences for livelihoods of agro-pastoralist communities. We produced the first occurrence and spread map of invasive plant species (Prosopis: Prosopis juliflora and Parthenium: Parthenium hysterophorus) for western Somaliland (a region of eas...
Article
Full-text available
Droughts have significant negative impacts on livelihoods and economy of Kazakhstan. In this study, we assessed and characterized drought hazard events in Kazakhstan using satellite Remote Sensing time series for the period between 2000 and 2016. First, we calculated Vegetation Condition Index (VCI) and Standardized Enhanced Vegetation Index anomal...
Conference Paper
Climate change, food insecurity and limited land and water resources strengthen the need for operational and spatially explicit information on vegetation condition and dynamics. The detection of vegetation condition as well as multiannual and seasonal changes using satellite remote sensing, however, depends on the choice of data including length an...
Article
Full-text available
Accurate classification and mapping of crops is essential for supporting sustainable land management. Such maps can be created based on satellite remote sensing; however, the selection of input data and optimal classifier algorithm still needs to be addressed especially for areas where field data is scarce. We exploited the intra-annual variation o...
Article
Full-text available
Eastern Cape Province in South Africa has experienced extreme drought events during the last decade. In South Africa, different land management systems exist belonging to two different land tenure classes: commercial large scale farming and communal small-scale subsistence farming. Communal lands are often reported to be affected by land degradatio...
Poster
Invasive species (namely Prosopis juliflora and Parthenium hysterophorus) significantly impede rangeland and cropland productivity in Somaliland impacting the livelihoods of thousands of agro-pastoralists. Invasive species propagate well in overgrazed and poorly managed sites while their encroachment enables further land degradation processes such...
Presentation
Abstract Invasive species and deforestation are significant land degradation factors in eastern Africa that in unity severely impede rangeland and cropland productivity with dire consequences for livelihoods of agropastoralist communities. Using 250‐meter Moderate Resolution Imaging Spectroradiometer (MODIS) satellite data and trends computed from...
Article
Full-text available
Abstract: Ukraine has experienced immense environmental and institutional changes during the last three decades. We have conducted this study to analyze important land surface dynamics and to assess processes underlying the changes. This research was conducted in two consecutive steps. To analyze monotonic changes we first applied a Mann–Kendall tr...

Network

Cited By

Projects

Projects (5)
Project
In the past decades, most grassland ecosystems in Central Europe were transformed by higher fertilization rates in combination with increased frequencies of mowing or grazing. While this land-use intensification improved the delivery of the Ecosystem Service (ES) of forage, it has in many cases decreased biodiversity and the delivery of other ESs. In this context, there is an urgent need for a more mechanistic understanding of land-use effects on the biodiversity-ecosystem functioning (BEF) and the biodiversity-ecosystem service (BES) relationship. Due to inherent spatial mismatches between ecological processes and management units in coupled social-ecological systems, though, this is a challenging task. In our proposed project SEBAS, we aim at improving this mechanistic understanding by integrating site-based ecological research on the land-use intensity and six ‘essential biodiversity variables’ (EBVs) with satellite Remote Sensing of these proxies. We will specifically explore linkages between functional and structural diversity and the ecosystem service of forage production, focusing on observation units relevant for decisions-making, i.e. meadows /pastures, farms, and landscapes. We hypothesize that (i) the six EBVs as affected by different land-use intensities could be derived at multiple spatial scales using multi-modal satellite image time series data calibrated and validated with existing and newly collected data on land-use intensity and EBVs; and that (ii) land-use effects on BEF/BES relationships will vary across spatial scales, with functional and structural diversity playing a key role for the supply and temporal stability of forage production. The output of the project will be a set of spatially explicit satellite and unmanned aerial vehicle based EBVs products, as well as novel methodologies relying on a number of multi-scale and multi-modal Remote Sensing datasets (PlanetScope, RapidEye, Sentinel 1/2, Landsat and MODIS) and novel machine learning and hybrid models. Via space-for-time substitutions for climate change and land-use change, we will also address the interactive effects of these two main drivers of global change on the BEF/BES relationship. We will formalize drivers’ direct and indirect (biodiversity-mediated) effects on forage production through a social-ecological systems approach, and quantify them via structural equation models to foster a deeper understanding of ecosystem functioning and ES supply in Central European grasslands.
Project
GlobeDrought aims to develop a web-based information system for comprehensively characterizing drought events. https://bmbf-grow.de/en/joint-research-projects/globedrought The project will produce a spatially explicit description of drought risks by considering three components: drought hazard, exposure and vulnerability. It will investigate how droughts impact water resources, crop productivity, trade in food products and the need for international food aid. https://grow-globedrought.net/
Project
GlobeDrought aims to develop a web-based information system for comprehensively characterising drought events. The project will produce a spatially explicit description of drought risks by considering three components: drought hazard, exposure and vulnerability. It will investigate how droughts impact water resources, crop productivity, trade in food products and the need for international food aid. In terms of methodology, the project aims to link satellite-based remote sensing and analyses of precipitation data with hydrological modelling and yield modelling. This will produce indicators for characterising meteorological, hydrological and agricultural droughts, which in turn will make it possible to quantify drought risks. Analyses of socioeconomic data will provide the basis for quantifying exposure and vulnerability. Within the framework of a co-design process, users and stakeholders will help to shape the content and technical design of the drought information system. The global-scale analyses planned for the project will be supplemented by detailed analyses for regions heavily affected by droughts, in particular Southern Africa, Northeastern Brazil, Western India and the Missouri Basin in the United States.