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Stavi I.,Dead Sea and Arava Science Center | Silver M.,Arava Drainage Authority | Avni Y.,Geological Survey of Israel
Catena | Year: 2014

In the hyper-arid Arava Valley and eastern Negev desert of Israel, the acacia species of raddiana, tortilis, and pachyceras play a central role as keystone species. Many studies implemented during the last few decades have revealed considerable changes in acacia populations, including high mortality rates and low recruitment. The objective of this study aimed to examine the relationships between presumed water availability for acacia populations and their mortality by examining the effect on tree mortality of latitude, basin size, and microhabitat in the valley floor. A total of 1980 acacia trees in 11 wadis along the Arava and eastern Negev region were studied. The obtained results revealed a highly varied inter-wadi mortality rate, ranging between 6.7% and 72.2%. Overall, mortality within species occurred in 14.7% of Acacia pachyceras, 16.8% of Acacia tortilis, and 29.4% of Acacia raddiana. A highly negative correlation coefficient ( r= 0.55; P<. 0.0001) was found between latitude and acacia mortality. However, a low and not statistically significant correlation coefficient was found between basin size and acacia mortality (r. = 0.24; P= 0.2103). In terms of overall occurrence in microhabitat across the valley floor, 6.4% of the trees were located in main channels, 9.8% in high banks, 10.4% in bars, 19.1% in secondary channels, and 54.3% in low banks. However, the effect of microhabitat on acacia mortality rates was not statistically significant ( P= 0.2240). In addition to these, we monitored the occurrence of the hemiparasite, mistletoe ( Plicosepalus acaciae), which was observed in 8.2% of the trees. Also, the tree canopies' height and diameter were measured in order to calculate a size index for them. Values of this index were divided into four groups in order to represent the size distribution of trees. The overall occurrence of 3.6% of the smallest tree-size group is worrisome, as it presumably indicates very low recruitment rates. © 2013 Elsevier B.V.

Stavi I.,Dead Sea and Arava Science Center
International Journal of Sustainable Development and World Ecology | Year: 2013

This study reviews the potential use of biochar as soil amendment in afforestation, reforestation, agroforestry, fruit tree orchards, and bio-energy plantations. Implementing this practice could sequester large amounts of carbon (C) over the long-term, potentially offsetting anthropogenic emissions of carbon dioxide, and mitigating climate change. On a global scale, this practice could sequester between 2 and 109.2 Pg biochar-C in 1.75 billion ha of degraded and deforested lands and agroforestry systems. An additional considerable amount could be sequestered in the soil of fruit tree orchards and bio-energy plantations. The anticipated improvement in the quality of the biochar-amended soils is expected to enhance resilience to these land uses, increasing their adaptation capacity to climate change. Yet, specific questions still need to be addressed, for example, the impact of biochar on the availability of nitrogen and potassium for plants in acidic soils and under humid conditions, as well as the impact of biochar on soil and trees in alkaline soils and under Mediterranean or drier conditions. Also, a full assessment of health hazards and environmental risks related to the production of biochar and its application in soil is required. Other questions relate to the environmental and economic costs of biochar application. Therefore, life cycle assessments and economic calculations should be conducted on a site-specific basis and include the practices of feedstock collection, transportation, processing, and spreading. International actions should regulate biochar practice as an eligible means for funding under the C finance mechanism. Specifically, payments should be provided to landowners for accomplishing ecosystem services. © 2013 Copyright Taylor & Francis.

Hadas G.,Dead Sea and Arava Science Center
Journal of Arid Environments | Year: 2012

At the Ein Gedi oasis, in the Judean Desert, abundant archaeological remains of agricultural irrigation systems are found that were fed only by spring water and used to irrigate the fields that were on the agricultural terraces. The systems date to the Roman-Byzantine period (1st-6th centuries CE) and attest to the existence of a settlement in the oasis at this time. This paper presents a description of the systems and crops grown, based on archaeological surveys and excavations together with a review of historical sources that describe the social mechanisms that enabled the systems to operate. © 2011 Elsevier Ltd.

Stavi I.,Dead Sea and Arava Science Center | Lal R.,Ohio State University
Journal of Arid Environments | Year: 2015

Land degradation is extensive, covering approximately 23% of the globe's terrestrial area, increasing at an annual rate of 5-10 million ha, and affecting about 1.5 billion people globally. Such detrimental processes call for urgent and comprehensive action to halt land degradation. In this paper, we assess the causes and extent of land degradation around the world, followed by an outline of the various challenges in implementing a global Zero Net Land Degradation (ZNLD) policy. The concept of ZNLD proposes a scheme under which the extent of global degraded lands will decrease or at least, remain stable. To enable this type of scenario, the rate of global land degradation should not exceed that of land restoration. Restoration efforts should include not only croplands, rangelands, and woodlands, but also natural and semi-natural lands that do not generate direct economic revenues. The United Nations Convention to Combat Desertification (UNCCD) envisages achieving this target by 2030. Despite being seemingly ambitious, the target of ZNLD could be achieved if degraded lands are restored to a considerable extent and, at the same time, land-degrading management practices are replaced with ones that conserve soils. To enable effective implementation of these steps, it is necessary to formulate a ZNLD Protocol aimed at managing assessment actions and maintaining of supportive policies and regulations. Restoration projects could be financed through payments for improving ecosystem services, as well as other economic mechanisms. Achieving the target of land degradation neutrality would decrease the environmental footprint of agriculture, while supporting food security and sustaining human wellbeing. © 2014 Elsevier Ltd.

Stavi I.,Dead Sea and Arava Science Center | Lal R.,Ohio State University
Agronomy for Sustainable Development | Year: 2013

Increased atmospheric concentrations of greenhouse gases has led to global warming and associated climatic changes. The problem has been aggravated by the perception that the atmosphere is an infinite and toll-free resource. The well-known concept proposed by Garrett Hardin - "The Tragedy of the Commons" - highlights the misuse of common resources, which ultimately lead to their depletion. This article emphasizes the relevance of the same concept to the current climatic changes and highlights the impact of agriculture on the environment. The specific focus is on field crop production and livestock husbandry that have resulted in deteriorating environmental services and increased greenhouse gas emissions. Meanwhile, the total amount of energy consumed by these sectors is enormous, encompassing 11 exajoules (EJ) annually. In addition, the article highlights possible impacts of climate change on agricultural productivity. Considering the foreseen growth of the global human population, it is expected that additional pressures will aggravate natural environments. Adoption of recommended management practices is crucial to reverse the environmental footprint of agriculture and lessen its impact on climate change. Regarding croplands, these practices can include reduced tillage systems, crop residue management, improved management of nutrients and pests, cover cropping, agroforestry, biochar application as soil amendment, and utilization of precision agriculture technologies. In the livestock sector, recommended management practices include changes in animals' diet and appropriate management of manure. Adoption of these practices is also expected to decrease the on-farm and off-farm energy use. To encourage the adoption of these practices, authorities should provide the farmers with incentives, such as payments for improving environmental services. Also, international regulations must be enforced to instigate a notable shift in human diets with the goal of reducing the environmental impact of food production. Judicious implementation of related policies would be crucial for promoting the required links between agricultural production and environmental sustainability. © 2012 INRA and Springer-Verlag, France.

Stavi I.,Dead Sea and Arava Science Center | Lal R.,Ohio State University
Agronomy for Sustainable Development | Year: 2013

Expansion of agricultural land use has increased emission of greenhouse gases, exacerbating climatic changes. Most agricultural soils have lost a large portion of their antecedent soil organic carbon storage, becoming a source of atmospheric carbon-dioxide. In addition, agricultural soils can also be a major source of nitrous oxide and methane. Adoption of conservation agricultural practices may mitigate some of the adverse impacts of landuse intensification. However, optimal implementation of these practices is not feasible under all physical and biotic conditions. Of a wide range of conservation practices, the most promising options include agroforestry systems and soil application of biochar, which can efficiently sequester large amounts of carbon over the long-run. In addition, these practices also increase agronomic productivity and support a range of ecosystem services. Payments to farmers and land managers for sequestrating carbon and improving ecosystem services is an important strategy for promoting the adoption of such practices, aimed at mitigating climate change while decreasing environmental footprint of agriculture and sustaining food security. © 2012 INRA and Springer-Verlag, France.

Abu Hamed T.,Arava Institute for Environmental Studies | Abu Hamed T.,Dead Sea and Arava Science Center | Flamm H.,Arava Institute for Environmental Studies | Azraq M.,Arava Institute for Environmental Studies
Renewable and Sustainable Energy Reviews | Year: 2012

The Palestinian Territories relies on Israel for 100% of its fossil fuel imports and for 87% of its electricity imports. Total energy consumption in the Palestinian Territories is the lowest in the region and costs more than anywhere else in the Middle East. The purpose of this paper is to present the current energy situation in the Palestinian Territories, evaluate the potential of renewable energies in meeting part of the energy demand and discuss the challenges and benefits of using these types of energies. It is shown that the main renewable energy sources in the Palestinian Territories are solar, wind and biomass. Using the available renewable energy sources in the Palestinian Territories may significantly decrease the energy reliance on neighboring countries and improve the Palestinian population's access to energy. It is estimated that solar sources have the potential to account for 13% of electricity demand and wind energy for 6.6%. The conversion of animal waste into biogas has the potential to meet the needs of 20% of the rural population. The conversion of unused agricultural residue into biodiesel could replace 5% of the imported diesel. © 2011 Elsevier Ltd. All rights reserved.

Orenstein D.E.,Technion - Israel Institute of Technology | Groner E.,Dead Sea and Arava Science Center
Ecosystem Services | Year: 2014

Integration of the ecosystem service (ES) concept into policy begins with an ES assessment, including identification, characterization and valuation of ES. While multiple disciplinary approaches should be integrated into ES assessments, non-economic social analyses have been lacking, leading to a knowledge gap regarding stakeholder perceptions of ES.We report the results of trans-border research regarding how local residents value ES in the Arabah Valley of Jordan and Israel. We queried rural and urban residents in each of the two countries. Our questions pertained to perceptions of local environmental characteristics, involvement in outdoor activities, and economic dependency on ES.Both a political border and residential characteristics can define perceptions of ES. General trends regarding perceptions of environmental characteristics were similar across the border, but Jordanians tended to rank them less positively than Israelis; likewise, urban residents tended to show less affinity to environmental characteristics than rural residents. Jordanians and Israelis reported partaking in distinctly different sets of outdoor activities. While all groups reported little economic dependence on ES, rural Israelis reported the highest dependency.We suggest that social approaches to ES assessment can complement the predominant ecological and economic approaches thereby strengthening the relevancy of ES assessments to policy-making. © 2014 Elsevier B.V.

Stavi I.,Dead Sea and Arava Science Center
Journal of Environmental Planning and Management | Year: 2012

Many of the world's rangelands are degraded due to either natural or anthropogenic causes. One of the main indicators of the degradation process is the depletion of the organic carbon stocks in the soil. The organic carbon plays a crucial role in supporting the soil microbial community, maintaining the soil structure formation and stability, and retaining water and nutrients in the uppermost soil layers. Biochar, the by-product of the pyrolysis technology for bio-energy production, has been proven to have the capability to efficiently maintain soil quality and increase vegetative production. At the same time, the inert nature of the biochar enables the long-term sequestration of carbon in soil. To date, the application of biochar has been examined almost exclusively in arable lands, but not yet in rangelands. The objective of this paper is to raise awareness of this topic in order to encourage research and development in this field. Progress in knowledge and understanding on this matter could contribute to the reclamation of degraded rangelands. At the same time, it would potentially increase their capacity for long-term sequestration of carbon to a rate of between 0.69 and 10.7 Pg. Large-scale implementation of this practice in the future should be funded through central authorities, based on payments for improvement in ecosystem services. © 2012 Copyright Taylor and Francis Group, LLC.

Kudish A.I.,Ben - Gurion University of the Negev | Kudish A.I.,Dead Sea and Arava Science Center | Evseev E.G.,Ben - Gurion University of the Negev
Renewable Energy | Year: 2011

Incident solar radiation (insolation) is attenuated by two different phenomena, (i) atmospheric scattering by air molecules, water vapor and aerosols, and (ii) atmospheric absorption by ozone, water and carbon dioxide. The degree of terrestrial solar radiation attenuation is a function of its optical path length, i.e., the distance the Sun's ray traverse through the Earth's atmosphere prior to being incident on the its surface. The attenuation by atmospheric scattering, irrespective of source, is an inverse function of the wavelength. Absorption of insolation in the atmosphere is due mainly to ozone in the ultraviolet range and water vapor in the infrared range of the solar spectrum. Ozone absorption decreases with increasing wavelength and above 350 nm there is no absorption. Thus, a priori, any changes in either the ozone layer thickness (OLT) and/or aerosol optical density (AOD) will have a greater effect on ultraviolet radiation, in general, and on UVB in particular. An empirical correlation that determines the UVB radiation intensity as a function of solar global radiation, OLT, AOD and optical path length as represented by the air mass is presented and validated by an independent database. In addition, a parameter sensitivity study was performed on the empirical correlation using two different methods. The application of the empirical correlation as a function of hour type (i.e., clear, partially cloudy and cloudy) was also investigated. © 2010 Elsevier Ltd.

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