Arid Dune Ecosystems - The Nizzana dunes in the Negev

Arid dunes at the Nizzana research site, Negev, Israel

Sand dunes occur in many parts of the world, not only in deserts and other arid regions but also along many coastlines in humid biomes and environments.  Nowadays, active dune systems are found mainly in the arid and semi-arid regions. The sand dunes of the north-western Negev are the eastern most part of the sand field covering the northern part of the Sinai Peninsula and the northwestern Negev. he climate is determined by a sharp gradient from semi-arid in north to the arid in the south. Average annual rainfall decreases from around 170 mm at the northern edge of the sand field near Yevul to approx. 90 mm near Nizzana.The southern most experimental site Nizzana  is characterized by vegetated linear dunes with mobile crests. The Nizzana Research Site is one of the long-term research sites operated by the Arid Ecosystem Research Centre (AERC) established in 1987 by the Minerva Foundation (Germany) and the Hebrew University of Jerusalem. The Nizzana Sands site offers an excellent example of the structure and functioning of a sandy desert ecosystem and the importance of biological topsoil crusts. Detailed interdisciplinary studies were conducted in the area at different temporal and spatial scales to understanding the ecosystem processes and pattern in in this arid ecosystem.


A synthesis of the research activities are published in the Ecological Studies Series by Springer in 2008. This volume provides a synthesis of a specific sand dune ecosystem, the Nizzana site in the Negev Desert. Describing its climate and geophysical/geochemical properties of soils, geological history, flora and fauna, and past/present land-use patterns, it elucidates ecological and geomorphological processes and their interrelations, based on long-term monitoring, in situ experiments and satellite imagery. Particular attention is drawn to the impact of the topsoil biological crust in controlling water availability at local/regional scales. The interdisciplinary approach adopted in this case study offers a good example of a highly complex and dynamic system, which could easily be applied to other sandy ecosystems.

  • Vegetation pattern in arid sand dunes controlled by biological soil crusts along a climatic gradient in the Northern Negev desert

Vegetation cover and biomass production in drylands are largely controlled by rainfall amounts on a regional and global scale. However, soil water availability on the small-scale is influenced by hydrological processes, soil types and surface properties. In the sand dunes of the north-western Negev biological soil crusts built up by cyanobacteria, green algae, mosses and soil lichens play an important role for the ecosystem processes. They are changing the surface properties. We investigated the vegetation in response to geo-ecological parameters and biological soil crusts along a rainfall gradient from 170 mm to 78 mm. In the interdunes the vegetation cover was 26-30% and showed no significant difference along the climatic gradient. Vegetation cover on the dune crests depends on the sand mobility and decreases towards the more arid parts. The biological crusts limit infiltration and counteract on the rainfall gradient. Therefore, no differences in the vegetation cover were detected and on the mesoscale level the biomass index was negatively correlated to the annual rainfall. Sand mobility and surface stability are important parameters determining the vegetation pattern. Surface properties like crust and fine material are key factors for the hydrological processes and control water redistribution on the micro-scale and, thus, vegetation pattern.

Veste, M., Breckle, S.-W., Eggert, K., Littmann, T., Basic and Applied Dryland Research 5, 1-16, 2011. (more…)

  • Ecosystem processes and vegetation patterns in desert sand dunes: Nizzana, north-western Negev, as an example
Interdunes with playa in Nizzana

Major ecosystem processes were investigated in the sand dunes of the north-western Negev. The sand dunes of the Negev are vegetated, whereas the dunes of the Sianai are bare of vegetation due to grazing and differences in the dune morphology. Therefore, the dunes of Nizzana are an ideal study site for the the investigations of natural processes and pattern in desert sand dunes. Biological soil crusts covering the top soil and influencing sand stability and hydrological processes and they are the major source of nitrogen into the ecosystem. Spatial differences in hydrological processes are relatedto biomass. The implications for restoration and combationg desertification in sandy areas will be discussed.

Veste, M., Littmann, T., Russow, R., Breckle, S.-W., In: Gao, J., Veste, M., Sun, B., Beyschlag, W. (eds.): Rehabilitation and Stability of Ecosystems in Arid and Semi-arid Areas. Science Press, Beijing, 124-141. , 2006 (more…)

Ecosystem investigations in the Haluza dunes , Negev, Israel

  • Sensitivity of a sandy area to climate change along a rainfall gradient at a desert fringe

Global climate change has become a strongly and frequently addressed issue in the last decades. The aspect is crucial in dry-land areas, which cover approximately one third of the globe's total land area. The relationship between average annual rainfall and environmental variables has attracted the attention of many scientists. Climatologists use aridity indices to express relationships between climatic and environmental variables. These indices, based on purely climatic variables such as annual precipitation, temperature, evaporation and radiation, tend to imply that the acuteness of aridity is inversely related to annual precipitation. Although aware that soil water content depends on local soil type and precipitation regime, Walter (1939, 1960) asserted that at a larger, global scale, standing biomass is positively correlated to average annual rainfall. This approach is still followed by many researchers who assume a positive relationship between average annual rainfall and environmental variables such as water availability for plants, vegetation cover, productivity, species diversity, soil properties, human activity, and erosion rates for sub-humid to arid areas. This approach is certainly correct at the global scale, as well as for non-irrigated annual crops in dryland areas. It is, however, questionable for arid and semi-arid areas, usually regarded as highly sensitive to climate change, especially for perennial plants.

Yair, A., Veste, M., Almog, R., Breckle, S.-W., In: Breckle, S.-W, Yair, A., Veste, M. (eds.), Arid Dune Ecosystems – The Nizzana Sands in the Negev Desert, Ecological Studies 200, Springer, Berlin Heidelberg New York, pp. 425-440, 2008. (more…)

  • Modelling spatial pattern of vegetation in desert sand dunes

A stochastic numerical approach was developed to model the actual standing biomass in the sand dunes of the northwestern Negev (Israel) and probable boundary conditions that may be responsible for the vegetation patterns investigated in detail. Our results for several variables characteristic for the prevailing climate, geomorphology, hydrology and biologicy at four measurement stations along a transect from northwest to southeast allowed for the development of a stochastic model for biomass distribution over the entire sand dune field (mesoscale) and at Nizzana experimental station (microscale). With this equation it was possible to compute and interpolate a biomass index value for each grid point on the mesoscale and micro scale. The spatial distribution of biomass is negatively linked to distance from the sea, to rainfall and relief energy. 

Littmann, T., Veste, M., Forestry Studies in China 7(4), 24-28, 2005 (more…)

  • Nitrogen input pathways into the sand dunes: biological fixation and atmospheric nitrogen deposition

In arid and semiarid regions, water availability is considered to be the controlling factor for the productivity and pattern of vegetation. The total biotic and abiotic N pool size of desert ecosystems is lower than in most other ecosystems. Several studies have found that even in arid lands, nutrients are critical for plant growth and successions. After good rainy years, nitrogen can become the limiting factor,  whereas added nitrogen increased productivity in several experiments in dry areas. The main N input pathways into the ecosystems are atmospheric deposition in wet, dry and gaseous forms, and the biological fixation of atmospheric nitrogen N2. Biological fixation is carried out by free-living bacteria, Fabaceae—Rhizobium symbiosis and associative symbiontic free-living cyanobacteria, as well as by cyanobacteria in lichens. Another N source is by non-leguminous nitrogen-fixing species; particularly shrubs and trees play a major role in these ecosystems.

In this paper, we present field measurements of biological N2 fixation (BNF) obtained by the natural 15N abundance method, and use these to estimate the annual nitrogen input by the soil crusts and R. raetam. We follow a novel approach for the natural 15N abundance technique, by using the non-N2-fixing lichens Squamarina lentigeria and S. cartilaginea (=S. crassa) as reference in order to determine N2 fixation by the biological crust in situ in the Negev desert. N input by BNF of atmospheric nitrogen is compared with atmospheric nitrogen deposition.

Russow, R., Veste, M., Breckle, S.-W., Littmann, T., Böhme, F., In: Breckle, S.-W, Yair, A., Veste, M. (eds.), Arid Dune Ecosystems – The Nizzana Sands in the Negev Desert, Ecological Studies 200, Springer, Berlin Heidelberg New York, pp. 319-336, 2008 (more…)

  • Vegetation of linear dunes of the Central Namib and their ion relation

The Namib sand dunes are an extraordinary desert ecosystem and characterized by low rainfall and high sand mobility. The dune sea is composed mostly of linear dunes running predominately in N-S direction. In the presented study the vegetation composition and distribution were investigated along a climatic W-E gradient in the surrounding area of Gobabeb. In the investigated sites 8 species could be found, including: the grasses Stipagrostis sabulicola (Poaceae) S. lutescens, S. gonathostachys, S. seelya, Centropodium glaucum (Poaceae), Cladoraphis spinosa and the succulent Trianthema hereroensis T. triquetra (Aizoaceae). The number of species and density increased towards east with increasing of sand stability. The ions content were measured in the dominant species. A high ions accumulation could be found in the succulent Trianthema hereroensis. This sodium accumulation is typical for the family of Aizoaceae.

Veste, M., Mohr, M., In: Veste, M., Wucherer; W., Homeier, J. (Hrsg.): Ökologische Forschung im globalen Kontext, Festschrift Siegmar-W. Breckle, Cuvillier Verlag, Göttingen, pp. 93-107, 2005 (more…)

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