Section Summary

Research, education and dissemination are key objectives of Project Wadi Attir. This site summarizes related Ecosystem Restoration research and provides both an interactive scientific lexicon and links to a range of educational resources. An integrative academic-level research and monitoring program has been put into place to document progress in all aspects of dryland management and desertification control, including soil conservation and improvement, sustainable agricultural production methods, water use efficiency and enhanced biodiversity.

A diverse range of educational activities are underway at the project site, whereby local students participate in research and volunteer projects as part of their high school curricula. Students have been involved in planting and maintenance activities onsite from the very beginning of the project.

This page also will offer links to a growing supplementary collection of presentations and other useful resources at different levels, and in three languages, for scientific and educational use. Dissemination activities both to academic and public audiences are being conducted regularly.

Project Wadi Attir also aims to establish a network of collaborators in all aspects of sustainable dryland development, research, training, education and dissemination, both nationally and worldwide. Our team will be happy to respond to all enquiries, so please contact us using the form below.

Scientific Research

Project Wadi Attir and collaborating scientists are performing detailed scientific research and observations to document progress in project site rehabilitation. Current research subjects are the following:

  • Soil improvement by soil conservation measures, and management approaches in agroforestry sites and protected shrubland plots. Parameters assessed are soil organic matter, soil nutrient content, soil water infiltration, soil moisture, and biomass productivity, which are being recorded periodically
  • Evolution and succession patterns of plant and animal biodiversity in differently treated plots: conserved and degraded control plots, recovering shrubland plots and the riverbank, differently-treated limans and terraces, agroforestry woodlands composed of different tree species, and Acaciawoodland areas
  • The impact of various shrubs, trees, ants and other animal species on soil quality, hydrology and nutrient cycles
  • Growth success, fruiting, fodder and wood production of various dryland and multipurpose trees and shrubs planted at Project Wadi Attir
  • Selection and testing of additional, novel species or cultivars onsite, in runoff catchments or low-intensity irrigated dryland agroforestry
  • Carbon sequestration into biomass and soils in various plots, woodland and liman areas
  • Overall sustainability assessment of various technologies applied, in terms of inputs and outputs from an environmental and economic point of view

The progress reports on soil quality and biodiversity produced so far can be found below. The results of these studies will also be summarized for publication and dissemination, in order to implement the project’s ideas at a local, regional and global scale.

Future Research Collaborations

A major project objective is sharing and exchanging our research and development efforts and technologies with others, to advance the evolution of worldwide sustainable dryland development strategies. Project Wadi Attir is therefore highly interested in participating in international research consortia in any of the above subjects.

Terms, Glossary, and Resource Links

The following are some short definitions of fundamental expressions in dryland environmental science. Most expressions are linked to Wikipedia, but we recommend following up on the reference lists provided in each Wikipedia entry for deeper understanding.

Agroforestry (

Agroforestry or agro-silviculture is a land-use management system in which trees or shrubs are grown around or among crops or pastureland. It combines agricultural and forestry technologies to create more diverse, productive, profitable, healthy, and sustainable land-use systems.

Albedo (

Albedo is the fraction of solar energy (shortwave radiation) reflected from the Earth back into space. It is a measure of the reflectivity of the earth’s surface. Ice, especially with snow on top of it, has a high albedo: most sunlight hitting the Earth’s surface bounces back towards space. Water is much more absorbent and less reflective. Therefore, if there is a lot of water, more solar radiation is absorbed by the ocean then when ice dominates. Similarly, bare sand or rock has a high albedo compared to vegetated surfaces.

Biodiversity (

Biodiversity is a measure of the variety of organisms present in different ecosystems. This can refer to genetic variation, ecosystem variation, or species variation (number of species) within an area or ecosystem.

Biological Pest Control (

Biological control is a method of controlling pests (including insects, mites, weeds and plant diseases) using other living organisms. It relies on predation, parasitism, herbivory, or other natural mechanisms, but typically also involves an active human management role.

Bird Migration in Israel (

At least 500 million birds pass through Israel’s skies twice a year during the migration season. In the fall, they make their way south to Africa and in the spring they return to Europe to mate and reproduce. Israel is located on a central migratory path, attracting both professional and amateur birders, photographers, and experts from all over the world.

Biosphere degradation (

Environmental degradation is the deterioration of the environment through depletion of resources such as air, water and soil; this results in the destruction of ecosystems and the extinction of wildlife.

Byzantine Empire (

The Byzantine Empire, sometimes known as the Eastern Roman Empire, was the predominantly Greek-speaking continuation of the eastern half of the Roman Empire during Late Antiquity and the Middle Ages. Its capital city was Constantinople (modern-day Istanbul).

Carbon cycle (

Carbon is the central element of life, providing the backbone of all organic and bio-molecules. The carbon cycle is the biogeochemical cycle by which carbon is exchanged between the biosphere, the earth’s crust, the oceans, and the atmosphere. The carbon cycle comprises a sequence of events that are key to making the Earth capable of sustaining life; it describes the movement of carbon from inorganic forms such as carbon dioxide or carbonates into the biosphere and back into inorganic forms by means of photosynthesis and respiration.

Carbon Sink (

A carbon sink is a natural or artificial reservoir that accumulates and stores carbon-containing compound for an extended period. The process by which carbon sinks remove carbon dioxide (CO2) from the atmosphere is known as carbon sequestration. Public awareness of the significance of CO2 sinks has grown since passage of the Kyoto Protocol, which promotes their use as a form of carbon offset. There are also different strategies used to enhance this process. The natural sinks are absorption of carbon dioxide by the oceans via physicochemical and biological processes, and photosynthesis by terrestrial plants

Deserts and Desertification (

Deserts are areas receiving low amounts of precipitation, often inaccurately equaled to areas of low productivity or low biodiversity. Often the expression is wrongly applied to all drylands, areas where evaporation significantly exceeds precipitation. However, well protected and conserved dryland areas are everything but deserted, examples being the diverse Namib and Kalahari Deserts, or the Samburu or Sonora ecosystems, areas that are climatically similar to many parts of the highly degraded Negev. The process of transforming healthy dryland ecosystems into ‘deserts’ (deserted, denuded, bare landscapes) is called desertification: the degradation of dryland ecosystems by overgrazing, deforestation and agriculture. This process has been ongoing for thousands of years, since the development and spread of civilization and agriculture.

Fig. 1: Global desertification vulnerability map (USDA) classifying the world’s dryland areas according to their degradation risk

Drylands: (

Drylands are areas receiving significantly less precipitation (P) than evaporation (PET) and are classified into the four categories shown in table 1. Drylands are erroneously called deserts, but to a large extent can be lush, dry evergreen forests or other seasonally diverse ecosystems. Examples of this are the Mediterranean Maquis or dry forest, the Sonora, the open dry African savannas such as the Samburu or the Kalahari, and other similarly diverse ecosystems.

Degradation of up to 80% of world’s drylands has led to widespread application of the word desert to refer to all dryland areas, though this name adequately applies only to essentially lifeless areas that are naturally restricted only to parts of the hyper-arid climate zone.


Ecosystem (

An ecosystem is a community of living organisms (plants, animals and microbes) interacting as a system in conjunction with the nonliving components of their environment (air, water and mineral soil), and directed by the local climate.

Endemic species (

Endemic species are unique to a defined geographic location, such as an island, nation, country or other defined zone or habitat type; organisms that are indigenous to a place are not endemic to it if they are also found elsewhere. Protection of endemic species is of specific concern, as they are often found only in small areas and in small numbers. The opposite of endemism is cosmopolitan distribution. Wadi Attir holds a number of species endemic to this specific area of the Northeastern Negev as detailed in the file ‘Plant Biodiversity’.

Erosion (

Erosion is the action of external forces such as water flow or wind causing removal of soil and rock from one location and its transport to another location. While erosion is a natural process, human activities such as biosphere degradation have increased the rate at which erosion is occurring by 10-40 times globally. Excessive erosion causes averse impacts such as decreases in agricultural productivity and ecological collapse due to the loss of nutrient-rich upper soil layers, a process that eventually results in desertification. Off-site effects may include sedimentation of waterways and eutrophication of water bodies.

Flint (

Flint is a hard form of the mineral quartz. It occurs chiefly as nodules and masses in sedimentary rocks. Inside the nodule, flint is usually dark grey, black, green, white, or brown in color, and often has a glassy or waxy appearance. A thin layer on the outside of the nodules is usually a different color, typically white and rough in texture. “Flint” refers specifically to the form which occurs in chalk or marly limestone. Flint was used in the manufacture of tools during the Stone Age as it splits into thin, sharp splinters called flakes or blades when struck by another hard object.

Food web (

A food web (or food cycle) is the interconnection of food chains, generally an image of “what-eats-what” in an ecological community. Ecologists broadly classify all life forms into one of two categories, called trophic levels: 1) the autotrophs, and 2) the heterotrophs. Autotrophs produce organic matter to grow, develop, and to reproduce from inorganic substances, including minerals and carbon dioxide, largely by photosynthesis. Heterotrophs must feed either on plants (herbivores), other animals (carnivores) or on (normally) dead organic material (decomposers). The linkages in a food web illustrate the feeding pathways, such as where heterotrophs obtain organic matter by feeding on autotrophs and other heterotrophs. The food web is a simplified illustration of the various methods of feeding that link an ecosystem into a unified system of exchange.

(See exercise examples at:

Global Warming (

Global warming and climate change refer to the observed century-scale rise in the average global temperature and its related effects. More than 90% of the additional energy stored in the climate system since 1970 has gone into ocean warming; the remainder has melted ice, and warmed the continents and atmosphere. The observed increases in global average surface temperature and atmospheric carbon dioxide have been much faster in recent decades than the natural changes of previous millennia, and levels are now higher than at any time for hundreds of thousands of years before.

Greenhouse Gases (

A greenhouse gas (sometimes abbreviated GHG) is a gas in the atmosphere that absorbs and emits radiation within the thermal infrared range. This process is the fundamental cause of the greenhouse effect. The primary greenhouse gases in the Earth’s atmosphere are water vapor, carbon dioxide, methane, nitrous oxide, and ozone. Greenhouse gases greatly affect the temperature of the Earth; without them, Earth’s surface would average about 33°C below the present average of 14°C. Human activities such as the burning of fossil fuels and deforestation have transferred large amounts of greenhouse gases into the atmosphere, causing global warming.

Habitat (

A habitat is an ecological or environmental area that is the natural environment in which an organism lives, or the physical environment that surrounds a species population. A habitat is made up of physical factors such as soil, moisture, range of temperature, and availability of light, as well as biotic factors such as the availability of food and the presence of predators.

Harvester ants (

Harvester ant is a common name for any of the species or genera of ants that collect seeds (called seed predation), which are stored in the nest in communal chambers called granaries. Seed harvesting by some desert ants is an adaptation to the lack of typical ant resources. Harvester ants increase seed dispersal, protection, and provide nutrients that increase seedling survivorship of the desert plants. In addition, ants provide soil aeration through the creation of galleries and chambers, mix deep and upper layers of soil, and incorporate organic refuse into the soil.

Infiltration (

Infiltration is the process by which water on the ground surface enters the soil. Infiltration rate in soil science is a measure of the rate at which soil is able to absorb rainfall or irrigation. It is measured in millimeters per hour. The rate decreases as the soil becomes saturated. If the precipitation rate exceeds the infiltration rate, runoff will usually occur unless there is some physical barrier. The rate of infiltration can be measured using an infiltrometer.

Plant litter (

Litterfall, plant litter, leaf litter, tree litter, soil litter, or duff, is dead plant material, such as leaves, bark, needles, and twigs that have fallen to the ground. This detritus, or dead organic material, and its constituent nutrients are added to the top layer of soil, commonly known as the litter layer or O horizon (“O” for “organic”). Litter has occupied the attention of ecologists at length because it is an instrumental factor in ecosystem dynamics, it is indicative of ecological productivity, and it may be useful in predicting regional nutrient cycling and soil fertility.

LCA (Life Cycle Assessment

Life-cycle Assessment is a technique used to assess environmental impacts associated with all the stages of a product’s life from cradle to grave (i.e., from raw material extraction through materials processing, manufacture, distribution, use, repair and maintenance, and disposal or recycling). LCAs can help avoid a narrow outlook on environmental concerns by:

  • Compiling an inventory of relevant energy and material inputs and environmental releases;
  • Evaluating the potential impacts associated with identified inputs and releases;
  • Interpreting the results to help make a more informed decision;

Liman (

A Liman (derived from Greek) in Israel is the name for an artificial earthen construction used to collect floodwater by damming a desert wadi or gully (not to be confused with Liman (landform)). The runoff water is slowed down by the dam, thus flooding a small area and allowing the water to infiltrate into the soil. This way, a small grove of trees can be sustained in the desert. Limans were built in order to fight desertification without depleting groundwater resources, which are becoming increasingly rare in arid ecosystems.[2] Remaining soil humidity can be found in dry riverbeds (wadis) after rains occur, but these wadis are prone to flash floods. The result is massive soil erosion and the destruction of infrastructure. Also, the infiltration is insufficient because of the water’s velocity, even though the runoff would be able to allow for the growth of trees in appropriate places.[3] The aim of building limans is to stop flash floods and to increase water infiltration, thus sustaining the growth of drought-hardy tree species and vegetation underneath them.

Loess (

Loess is an aeolian sediment formed by the accumulation of wind-blown silt, typically in the 20–50 micrometer size range, made up of roughly 20% (or less) clay, with the remainder equal parts sand and silt that are loosely cemented by calcium carbonate. It is usually homogeneous, highly porous, and traversed by vertical capillaries that permit the sediment to fracture and form vertical bluffs.

Nitrogen cycle (

The nitrogen cycle is the process by which nitrogen is converted between its various chemical forms, which can be carried out through both biological and physical processes. Important processes in the nitrogen cycle include fixation, ammonification, nitrification, and denitrification. The majority of Earth’s atmosphere (78%) is nitrogen. However, atmospheric nitrogen has limited availability for biological use, leading to a scarcity of usable nitrogen in many types of ecosystems. The nitrogen cycle is of particular interest to ecologists because nitrogen availability can affect the rate of key ecosystem processes, including primary production and decomposition. Human activities such as fossil fuel combustion, use of artificial nitrogen fertilizers, and the release of nitrogen in wastewater have dramatically altered the global nitrogen cycle.

Nitrogen fixation (

Nitrogen fixation is the process in which nitrogen (N2) from the atmosphere is converted into ammonium (NH4+). Atmospheric nitrogen or molecular nitrogen (N2) is relatively inert: it does not easily react with other chemicals to form new compounds. Nitrogen fixation, natural and synthetic, is essential for all forms of life because nitrogen is required to biosynthesize basic building blocks of plants, animals and other life forms. Therefore, nitrogen fixation is essential for agriculture and the manufacture of fertilizer. Nitrogen fixation occurs naturally in the air by means of lightning. Biological nitrogen fixation is done by way of nitrogenase metalo-enzymes. The only organisms that can fix nitrogen are prokaryotes called diazotrophs. Some higher plants, most prominently the legume family, have formed associations (symbiosis) with diazotrophs and are – misleadingly – called ‘nitrogen fixing plants.’

Permaculture (

Permaculture is a branch of ecological design, ecological engineering, environmental design, construction and integrated water resources management that develops regenerative and self-maintained habitat and agricultural systems modeled from natural ecosystems. The word permaculture originally referred to “permanent agriculture” but was expanded to stand also for “permanent culture,” as it was seen that social aspects were integral to a truly sustainable system as inspired by Masanobu Fukuoka’s natural farming philosophy.

Permaculture is a philosophy of working with, rather than against, nature; of protracted and thoughtful observation, rather than protracted and thoughtless labor; and of looking at plants and animals in all their functions, rather than treating any area as a single product system.

Pesticide (

A pesticide is a chemical or biological agent that deters, incapacitates, kills, or otherwise discourages pests. Target pests can include insects, plant pathogens, weeds, other animals, and microbes that destroy agricultural crops, cause nuisance, spread disease, or are disease vectors. Although pesticides have benefits, they also have serious drawbacks, such as potential toxicity to humans and other desired species, ecosystem disruption and the killing off of beneficial organisms. According to the Stockholm Convention on Persistent Organic Pollutants, 9 of the 12 most dangerous and persistent organic chemicals are organochlorine pesticides that have contributed to the near-extinction of some raptor species.

Plant nutrients (

Sixteen chemical elements are known to be important for plant growth and survival. The sixteen chemical elements are divided into non-mineral (C, O, H) and mineral elements. The 13 mineral nutrients are absorbed through plant roots, dissolved in water. The mineral nutrients are divided into two groups: macronutrients and micronutrients. Macronutrients can be broken into two more groups: primary and secondary nutrients.

The primary nutrients are nitrogen (N), phosphorus (P), and potassium (K). These major nutrients are usually limiting in soil because plants use large amounts for their growth and survival. The secondary nutrients are calcium (Ca), magnesium (Mg), and sulfur (S). There are usually enough of these nutrients in the soil so fertilization is not always needed. In desert soils with high pH, iron can often be limited and is added in various forms.

Productivity (

In ecology, productivity or production refers to the rate of generation of biomass in an ecosystem. It is usually expressed in units of mass per unit surface, for instance tons per hectare per year, but normally measured on much smaller areas. The mass unit may relate to the amount of dry matter or to the mass of carbon fixed. Productivity of autotrophs such as plants is called primary productivity, while that of heterotrophs such as animals is called secondary productivity.

Runoff (

Surface runoff (also known as overland flow) is the flow of water that occurs when excess stormwater or other sources flow over the earth’s surface. This might occur because rain arrives more quickly than it can infiltrate into the soil, causing soil to become saturated to capacity, and is thus directly correlated with soil quality. Surface runoff is a major component of the water cycle. Runoff is the primary agent in soil erosion by water and thus strongly affected by soil degradation and desertification.

Silvopasture/silvipasture (

Silvopasture (Latin, silva forest) is the practice of combining forestry and grazing of domesticated animals in a mutually beneficial way. Advantages of a properly managed silvopasture operation are enhanced soil protection and increased long-term income due to the simultaneous production of trees and grazing animals, or enhanced productivity due to mutually facilitating circumstances.

Perhaps the oldest agroforestry system used in the temperate regions of the world, silvopastoral systems are characterized by the integration of trees with forage and livestock production. Such systems have the potential to increase agricultural production sustainability in the long term.

Soil degradation (

Soil degradation is defined as a change in the soil health status resulting in a diminished capacity of the ecosystem to provide goods and services for its beneficiaries. Degraded soils have a health status that can not provide the normal goods and services expected in this ecosystem. These definitions, which largely follow the LADA definition of land degradation, are important in order to capture the complexity of the degradation processes and their subjective evaluation by different stakeholders.

Soil organic matter (

Soil organic matter (SOM) is the organic matter component of soil. SOM exerts numerous positive effects on soil’s physical and chemical properties, as well as the soil’s capacity to provide regulatory ecosystem services. SOM’s effects on soil function include improvements related to soil structure, aggregation, water retention, soil biodiversity, absorption and retention of pollutants, buffering capacity, and the cycling and storage of plant nutrients. SOM increases soil fertility by providing cation-exchange sites and acting as a reserve of plant nutrients, especially nitrogen (N), phosphorus (P), and sulfur (S), along with micronutrients. As such, there is a significant correlation between SOM content and soil fertility. SOM is also a major carbon sink by means of greenhouse gas sequestration into soil carbon (C).

Stone age (

The Stone Age is a broad prehistoric period during which stone was widely used to make implements with a sharp edge, a point, or a percussion surface. The period lasted roughly 3.4 million years, and ended between 6000 BCE and 2000 BCE with the advent of metalworking. Stone Age artifacts include tools used by modern humans and by their predecessor species in the genus Homo. Bone tools were used during this period as well but are rarely preserved in the archaeological record. The Stone Age is further subdivided by the types of stone tools in use.

The Stone Age is the first in the three-age system of archaeology, which divides human technological prehistory into three periods:


Sustainability ( :

An important goal of Project Wadi Attir is the effective application of the Five Core Principles of sustainability developed at The Sustainability Laboratory ( These principles are rooted in a perspective which defines sustainability as a particular type of dynamic equilibrium in the process of interaction between a population and the carrying capacity of its environment.

The principles are expressed in relation to five fundamental domains:

  • The Material Domain: Constitutes the basis for regulating the flow of materials and energy that underlie existence.
  • The Economic Domain: Provides a guiding framework for creating and managing wealth.
  • The Domain of Life: Provides the basis for appropriate behavior in the biosphere.
  • The Social Domain: Provides the basis for social interactions.
  • The Spiritual or Value Domain: Identifies the necessary attitudinal orientation and provides the basis for a universal code of ethics.

Selected Readings

  • Abu Rabia, K. Solowey, E. And Leu, S. (2009). Desert Agriculture of the Negev Bedouin: Potential for Socio-Economic Development and Ecological Rehabilitation. Management of Environmental Quality 19, No. 3, 353 – 366.
  • Boeken, B. and Shachak, M. 1994. Changes in desert plant communities in human-made patches in and their implications for the management of desertified landscapes. Ecological Applications 4: 702–716.
  • Boeken, B., Shachak, M., 1998. Colonization by annual plants of an experimentally altered desert landscape: source–sink relationships. Journal of Ecology 86 (5), 804–814.
  • Diacono, M. and Montemurro, F. 2010. Long-term effects of organic amendments on soil fertility. A review. Agronomical Sustainable Development 30: 411-422.
  • Dregne, H.E. 1978. Desertification: Man ‘s Abuse of the Land. Journal of Soil and Water Conservation 33: 11-14.
  • Fischer, R.A. and Turner, N.C. 1978. Plant productivity in the arid and semiarid zones Annual Review of Plant Physiology 29: 277-317
  • GAIA An Atlas of Planet Management, Norman Myers ed.,Anchor Books 1993;
  • Golodets, C., Boeken B. 2004. Moderate sheep grazing in semiarid shrubland alters
  • Grainger, A., Smith, M.S., Squires, V.R. and Glenn, E.P. 2000. Desertification and climate change: The case for greater convergence. Mitigation Adapt. Strategies Global Change 5: 361–377.
  • Helman, D., Lensky, I., Mor- Mussery, A., Leu, S., (2013) Creating woodland islets improve ecosystem function in long-term degraded drylands. Agricultural and Forest Meteorology 195–196 (2014) 52–60.
  • Helman, D., Mussery, A., Lensky, I. M. and Leu, S. (2014) Detecting changes in biomass productivity in a different land management regimes in drylands using satellite-derived vegetation index. Soil Use and Management, 30: 32–39. doi: 10.1111/sum.12099
  • Hussein, M.A. 2008. Costs of environmental Degradation: An analysis in the Middle East and North Africa region. Management and Environmental Quality 19: 305-317.
  • Kassas, M. 1995. Desertification: a general review. Journal of Arid Environment 30: 455-464.
  • Kéfi S, Rietkerk M, Alados CL, Pueyo Y, Papanastasis VP. ElAich A, de Ruiter PC (2007) Spatial vegetation patterns and imminent desertification in Mediterranean arid ecosystems. Nature 449: 213-217.
  • Lal, R. 2001. Potential of desertification control to sequester carbon and mitigate the greenhouse effect. Climatic Change 51: 35–72.
  • Lal, R. Soil Carbon Sequestration Impacts on Global Climate Change and Food Security. Science 304: 1623.
  • Leu S. (1990) Forests and Carbon Dioxide, Swiss Review of World Affairs No. 2 (Verlag NZZ, Zürich, Switzerland), 10-13.
  • Leu S. and A. Michaels (1990) Photosynthetic capacity to solve the carbon dioxide problem. In: Current Research in Photosynthesis III (Baltscheffsky M. ed.) Kluwer Acad. Publ., Dordrecht, The Netherlands, 811-814.
  • Leu Stefan, Mor Mussery Amir & Budovsky Arie (2014) The Effects of Long Time Conservation of Heavily Grazed Shrubland: A Case Study in the Northern Negev, Israel; Environmental Management, DOI 10.1007/s00267-014-0286-y.
  • Leu, S. (2006) Dryland Agroforestry for Biomass, Food, Carbon Sequestration and Desert Rehabilitation, in: Proceedings of the 14th European Congress on Biomass for Energy, Agriculture and Climate Protection, 341-344.
  • Leu, S. (2010). Forests and Climate: The Search for Specifics. Science, 328, 1479.
  • Mor-Mussery Amir, Leu Stefan, Arie Budovsky & Itamar Lensky (2014): Plant-Soil Interactions and Desertification: A Case Study in the Northern Negev, Israel, Arid Land Research and Management, DOI: 10.1080/15324982.2014.933455
  • Mor-Mussery, A., Leu, S., Budovsky A. (2013) Modeling the optimal grazing regime of Acacia victoriaesilvopasture in the Northern Negev, Israel Journal of Arid Environments 94, 27 – 36.
  • Mor-Mussery, A., Leu, S., Lensky, I. and Budovsky, A. 2013. The effect of planting techniques on arid ecosystems in the Northern Negev. Arid Land Research and Management 27:90-100.
  • Reid, K.D., Wilcox, B.P., Breshears, D.D. and MacDonald, L. 1999. Runoff and erosion in Pinon-Juniper woodland: influence of vegetation patches. Soil Science Society of America Journal 63: 1869-1879.
  • Ruddimann, W.F. 2003. The anthropogenic greenhouse effect era began thousands of years ago. Climatic Change 61: 261–293.
  • Safriel, U. and Adeel, Z. 2005. Dryland Systems, in: Ecosystems and Human Well-Being: Current State and Trends. Publisher: Island Press Millennium Ecosystem Assessment Series Vol. 1 (
  • Sava, R. 1994. Guide to sampling, Air, Water, Soil and vegetation for chemical analysis, Environmental protection agency, Department of pesticide regulation, Environmental Monitoring and pest management branch. California
  • Shachak, M., Boeken, B., Groner, E., Kadmon, R., Lubin, Y., Meron, E., Ne’eman, G., Perevolotsky, A., Shkedy, Y. and Ungar, E. 2008. Woody species as landscape modulators and their effect on biodiversity patterns.BioScience58: 209-221.
  • Shachak, M., Sachs, M. and Moshe, I. (1998) Ecosystem Management of Desertified Shrublands in Israel. Ecosystems 1: 475-483.
  • Sharma, K.D. 1998. The hydrological indicators of desertification. Journal of Arid Environments 39: 121-132.
  • Sparks, D.L. 1999. Environmental Soil Chemistry, Academic press, 2nd edition.
  • USDA (1999) Soil taxonomy. A basic system of soil classification for making and interpreting Soil Surveys, 2ndedition, United States Department of Agriculture Natural Resources Conservation Service, Available online at: (accessed at 12/2010).
  • Whitford, W.G. 1993. Animal feedback in desertification: an overview. Revista Chilena de Historia Natural 66:243-251. Available online at: