Nearly one-third of the world's total land area is arid or semi-arid. Many developing countries are situated in dry regions where the needs of the rapidly increasing population have often led to misuse of the land. In recent years the consequences of such misuse have been compounded by drought. Desert ecosystems are so delicately balanced that once disturbed they may require a lengthy period of time to recover. In order to improve our understanding of the structure and function of arid and semi-arid areas, and in view of the ongoing threat of desertification, the Hebrew University of Jerusalem, together with the Minerva Gesellschaft of the Federal Republic of Germany, established the Arid Ecosystems Research Center (AERC) in 1987. The purpose was to encourage long-term interdisciplinary scientific cooperation for research to be carried out at field stations in the Negev desert and vicinity.
Due to the strong interactions between abiotic (climatology, hydrology, pedology, geomorphology) and biotic aspects (botany, microbiology, physiology, zoology), the AERC adopted a multidisciplinary research approach to integrate them as well as investigate feedback mechanisms. Initially four experimental sites (Nizzana, Sede Boker, Avdat, Hatzeva) were selected in the Negev desert to serve as long-term monitoring and experimental stations. The stations were established in sandy, rocky and loess ecosystems in order to develop our overall understanding of the desert environment. The bulk of AERC research activities have focused, however, at two stations - Sede Boker and Nizzana - primarily as a result of greater interest in these two sites.
The Nizzana station (average annual rainfall about 80 mm) was established in 1988, in a sandy area composed of linear dunes having relatively well-preserved natural vegetation. Measurements have included meteorological data collection, high-density rainfall measurements, dew, soil moisture, runoff and sediment removal, dust fallout, seed germination and others.
Three additional sites were later established along a rainfall gradient north of Nizzana along the Egyptian-Israeli border.
The Sede Boker experimental station (average annual rainfall about 100 mm), originally established in 1972 by Prof. A. Yair, had been instrumented for measuring the spatial and temporal variability of rainfall, wind regime, hillslope and channel runoff, and soil erosion. It is characterized by a rocky/loess environment.
AERC research has resulted in about 200 publications and 45 graduate theses.
The abiotic variables studied have so far included:
Soils: Morphology, genesis, ecology, soil moisture, salinity, permeability, soil erosion and deposition.
Climate: Temperature, rainfall, hydrological rainfall, rainfall intensity, wind speeds and wind regime, dew deposition and evaporation, dew collecting, fog water collecting.
Hydrology: Runoff, rainfall-runoff relationships, spatial variability of runoff along slopes, water harvesting.
The biotic variables studied have so far included:
Plant ecology and physiology: Responses to the stress conditions (studied at the proteins and gene levels), seed production and dispersal, germination, establishment, survival, growth, flowering, pollination, and competition.
Biological crust: Characteristics and activities, nature of the organisms and their physiological/molecular response to hydration/dehydration cycles, the effect on runoff and erosion, recovery following disturbance.
Animal ecology and behavior: foraging strategies, habitat selection and preference, bioturbation.
Resources: The availability and predictability of resources (water, nutrients, etc.) and spatial heterogeneity of these resources.
Amit, R. and Harrison, J.B.J. (1995) Biogenic calcic horizon development under extremely arid conditions – Nizzana sand dunes. Israel. Advances in GeoEcology 28: 65-88.
Littmann,T. (1997) Atmospheric input of dust and nitrogen into the Nizzana sand dune ecosystem, northwestern Negev, Israel. J. Arid Environments, 36(3): 433-457.
Tielborger, K. (1997) The vegetation of linear desert dunes in the Northwestern Negev, Israel. Flora, 192: 261-278.
Tielborger, K. and Kadmon, R. (1997) Relationships between shrubs and annual communities in a sandy desert ecosystem: A three-year study. Plant Ecology, 130: 191-201.
Yair, A., Lavee, H. and Greitser, N. (1997) Spatial and temporal variability of water percolation and movement in a system of longitudinal dunes, western Negev, Israel. Hydrological Processes, 11: 43-58.
Berkowicz, S.M., Lavee, H. and Yair, A., eds. (1998) Geomorphic Response to Climate Change. Geomorphology (Special Volume), 23 (2-4): 369 pp.
Beyer, L., Tielborger, K., Blume, H-P., Pfisterer, U., Pingpank, K. and Podlech, D. (1998) Geoecological soil features and the vegetation pattern in an arid dune area in the Northern Negev, Israel. Zeitschrift fur Pflanzenernahrung und Bodenkunde, 161: 347-356.
Harrison, J.B.J. and Yair, A. (1998) Late pleistocene and fluvial interactions in the development of the Nizzana dune field, Negev Desert, Israel. Sedimentology, 45: 507-518.
Bornkamm, R., Darius, F. and Prasse, R. (1999) On the life cycle of Stipagrostis scoparia hillocks. J. Arid Environments, 42: 177-186.
Jacobs, A.F.G., Heusinkveld, B.G. and Berkowicz, S. (1999) Dew deposition and drying in a desert system: A simple simulation model. J. Arid Environments, 42: 211-222.
Kadmon, R. and Tielborger, K. (1999) Testing for source-sink population dynamics: An experimental approach exemplified with desert annuals. Oikos, 86: 417-429.
Yair, A. (1999) Spatial variability in the runoff generated in small arid watersheds: Implications for water harvesting. In: Arid Lands Management, eds. T.W. Hoekstra and M. Shachak, Urbana-Chicago, University of Illinois Press, pp.212-222.
Jacobs, A.F.G., Heusinkveld, B.G. and Berkowicz, S. (2000) Force restore technique for ground surface temperature and moisture content in a dry desert system. Water Resources Research, 36: 1261-1268.
Littmann, T. and Gintz, D. (2000) Eolian transport and deposition in a partially vegetated arid longitudinal sand dune area.. Z. Geomorphologie, Supplementband, 121: 71-90.
Tielborger, K. and Kadmon, R. (2000) Temporal environmental variation tips the balance between facilitation and interference in a desert plant community. Ecology, 81: 1544-1553.
Anand, M. and Kadmon, R. (2000) Community-level analysis of spatio-temporal plant dynamics. Ecoscience, 7: 101-110.
Hassan, M., Slaymaker, O. and Berkowicz, S.M., eds. (2000) The Hydrology - Geomorphology Interface: Rainfall, Floods, Sedimentation, Land Use. Intl. Association Hydrological Sciences, Red Series, vol.261, 326 pp.
Prasse, R. and Bornkamm, R. (2000) Effect of microbiotic soil surface crusts on emergence of vascular plants. Plant Ecology, 150: 65-75.
Kidron, G.J. (2001) Runoff-induced sediment yield over dune slopes in the Negev Desert. 2: Texture, carbonate and organic matter. Earth Surf. Proc. Land., 26: 583-599.
Kidron, G.J. and Yair, A. (2001) Runoff-induced sediment yield over dune slopes in the Negev Desert. 1: Quantity and variability. Earth Surf. Proc. and Land, 26: 461-474.
Mittler, R., Merquiol, E., Hallak-Herr, E., Rachmilevitch, S., Kaplan, A. and Cohen, M. (2001) Living under a ‘dormant’ canopy: a molecular acclimation mechanism of the desert plant Retama raetam. Plant Journal, 25: 407-416.
Veste, M., Littmann, T., Friedrich, H. and Breckle, S.W. (2001) Microclimatic boundary conditions for activity of soil lichen crusts in sand dunes of the north-western Negev desert, Israel. Flora, 196: 465-474.
Veste, M., Littmann, T., Breckle, S.W. and Yair, A. (2001) The role of biological soil crusts on desert sand dunes in the northwestern Negev, Israel. In: Sustainable Land Use in Deserts, eds. S.W. Breckle, M. Veste, and W. Wucherer, Berlin, Springer, pp.357-367.
Yair, A. (2001) Effects of biological soil crusts on water redistribution in the Negev desert, Israel: A case study in longitudinal dunes. In: Biological Soil Crusts: Structure, Function and Management, eds. J. Belnap and O.L. Lange, Berlin, Springer-Verlag, pp. 303-314.
Jacobs, A.F.G., Heusinkveld, B.G. and Berkowicz, S.M. (2002) A simple model for potential dew-fall in an arid region. Atmospheric Research, 64: 285-295.
Merquiol, M., Pnueli, L., Cohen, M., Simovitch, M., Goloubinoff, P., Kaplan, A. and Mittler, R. (2002) Seasonal and diurnal variations in gene expression in the desert legume Retama Raetam. Plant Cell & Environ., 25: 1627-1638.
Pnueli, L., Hallak-Herr, E., Rozenberg, M., Cohen, M., Goloubinoff, P., Kaplan, K. and Mittler, R. (2002) Mechanisms of dormancy and drought tolerance in the desert legume Retama raetam. Plant Journal, 31: 319-330.
Sharon, D., Margalit, A. and Berkowicz, S.M. (2002) Locally modified surface winds on linear dunes as derived from directional raingauges. Earth Surf. Proc. Landforms, 27: 867-889.
Yair, A. and Kossovsky, A. (2002) Climate and surface properties: Hydrological response of small arid and semi-arid watersheds. Geomorphology, 42: 43-57.
Yair, A. and Verrecchia, E. (2002) The role of the mineral component in surface stabilization processes of a disturbed desert sandy surface. Land Degrad. Develop., 13: 295-306.
Berkowicz, S.M., Beysens, D., Milimouk, I., Heusinkveld, B.G., Muselli, M., Wakshal, E. and Jacobs, A.F.G. (2004) Urban dew collection under semi-arid conditions: Jerusalem. Third Intl. Conf. on Fog, Fog Collection and Dew. Oct 11-15, 2004, Cape Town, South Africa, pp. E4: 1-4.
Harel, Y., Ohad, I. and Kaplan, A. (2004) Activation of photosynthesis and resistance to photoinhibition in cyanobacteria within biological desert crust. Plant Physiology, 136: 3070-3079.
Heusinkveld, B.G., Jacobs, A.F.G., Holtslag, A.A.M. and Berkowicz, S.M. (2004) Surface energy balance closure in an arid region: Role of soil heat flux. Agriculture and Forest Meteorology, 122: 21-37.
Heusinkveld, B.G., Berkowicz, S.M., Jacobs, A.F.G., Holtslag, A.A.M. & Hillen, W.C.A.M. (2006) An automated microlysimeter to study dew formation and evaporation in arid and semi-arid regions. J. Hydrometeorology, 7, 825-832.
Jacobs, A.F.G., Heusinkveld, B.G., Wichink Kruit, R.J. and Berkowicz,S.M. (2006) Contribution of dew to the water budget of a grassland area, Netherlands. Water Resour. Res., 42, W03415, doi:10.1029/2005WR004055.
Beysens, D., Muselli, M., Milimouk, I., Ohayon, O., Berkowicz,S.M., Soyeux, E., Mileta, M., Ortega, P. (2006) Application of passive radiative cooling for dew condensation. Energy, 31: 1967-1979.
Beysens,D., Milimouk,I., V. Nikolayev, Berkowicz,S.M., Muselli,M., Heusinkveld,B.G. & Jacobs, A.F.G. (2006) Comment on “The moisture from the air as water resource in arid region: hopes, doubt and facts” by Kogan & Trachtman. J. Arid Environ., 67: 343-352.
Littmann, T. and Berkowicz, S.M. (2008) The regional climatic setting. In: Arid Dune Ecosystems - The Nizzana Sands in the Negev Desert, eds. S.W. Breckle and A. Yair, Springer, Ecological Studies. Vol. 200, pp 49-63.
Veste, M., Heusinkveld, B.G., Berkowicz, S.M., Littmann, T. and Jacobs, A.F.G. (2008). Dew formation and activity of biological soil crusts. In: Arid Dune Ecosystems - The Nizzana Sands in the Negev Desert, eds. S.-W. Breckle and A. Yair, Springer, Ecological Studies, Vol. 200. pp. 305-318.
Heusinkveld, B.G., Berkowicz, S.M., Jacobs, A.F.G., Hillen, W.C.A.M. and Holtslag, A.A.M. (2008). A remote optical wetness sensor using spectral reflectance spectroscopy. Agric. Forest Meteorology, 148: 580-591.
Ohad, I., Raanan, H., Keren, N., Tchernov, D., Kaplan, A. (2010): Light-induced changes within photosystem II protects microcoleus sp. in biological desert sand crusts against excess light. PLoS ONE 5, e11000.
Berkowicz, S.M. (2010). Perspectives on the atmosphere’s role in sustaining ecosystem services. In: Achieving Environmental Security: Ecosystem Services and Human Welfare. NATO Science for Peace and Security Series - E: Human and Societal Dynamics, Vol 69. (Eds. P. H. Liotta, D. W.G. Kepner, J.M. Lancaster, D.A. Mouat), ISO Press, Amsterdam. pp. 73-85. DOI: 10.3233/978-1-60750-579-2-73.
Yair, A., Almog, R., Veste, M. (2011). Differential hydrological response of biological topsoil crusts along a rainfall gradient in a sandy arid area: Northern Negev desert, Israel. Catena, 87: 326-333.
Ohad, I., Berg, A., Berkowicz, S.M., Kaplan, A. & Keren, N. (2011). Photoinactivation of photosystem II: is there more than one way to skin a cat? Physiologia Plantarum, 142: 79–86.
Drahorad, S.L., Felix-Henningsen, P. (2012): An electronic micropenetrometer (EMP) for field measurements of biological soil crust stability. J. Plant Nutr. Soil Sci., 175: 519–520.
Fischer, T., Yair, A., Veste, M., Geppert, H. (2013). Hydraulic properties of biological soil crusts on sand dunes studied by 13C-CP/MAS-NMR: A comparison between an arid and a temperate site. Catena, 110: 155-160.
Drahorad, S.L., Felix-Henningsen, P. (2013): Application of an electronic micropenetrometer to assess mechanical stability of biological soil crusts. J. Plant Nutr. Soil Sci., 176(6): 904-909.
Drahorad, S.L., Felix-Henningsen, P., Eckhardt, K.-U., Leinweber, P. (2013): Spatial carbon and nitrogen distribution and organic matter characteristics of biological soil crusts in the Negev desert (Israel) along a rainfall gradient. J. Arid Environ., 94: 18–26.
Treves, H., Raanan, H., Finkel, O., Berkowicz, S.M., Keren, N., Kaplan, A. (2013). A newly isolated Chlorella sp. from desert sand crusts exhibits a unique resistance to excess light intensity. FEMS Microbiology Ecology, 86: 373-380 DOI: 10.1111/1574-6941.12162.
Felde, V.J.M.N.L., Peth, S., Uteau-Puschmann, D., Drahorad, S., Felix-Henningsen, P. (2014): Soil microstructure as an under-explored feature of biological soil crust hydrological properties: case study from the NW Negev Desert. Biodivers. Conserv., 23: 1687–1708.
Raanan, H., Treves, H., Ohad, I., Berkowicz, S.M., Hagemann, M., Keren, N., Heusinkveld, B.G., Kaplan, A. (2015). Simulated soil crust conditions in a chamber system provide new insights on cyanobacterial acclimation to desiccation. Environ. Microbiol., 18: 414-426. DOI: 10.1111/1462-2920.12998.
Raanan, H., Eshkol, G., Horn, R., Felde, VJMNL, Treves, H., Hagemann, M., Peth, S. Drahorad, S., Berkowicz, S.M., Felix-Henningsen, P., Kaplan, A. (2015). 3D structure and cyanobacterial activity within a desert biological soil crust. Environ. Microbiol., 18: 372-383. doi:10.1111/1462-2920.12859.
Haimovich-Dayan, M., Lieman-Hurwitz, J., Orf, I., Hagemann, M., Kaplan, A. (2015): Does 2-phosphoglycolate serve as an internal signal molecule of inorganic carbon deprivation in the cyanobacterium Synechocystis sp. PCC 6803? Environ. Microbiol., 17: 1794–1804.
Hagemann, M., Henneberg,M., Felde, V.J.M.N.L., Drahorad, S.L., Berkowicz, S.M., Felix-Henningsen, P., Kaplan, A. (2015). Cyanobacterial diversity in biological soil crusts along a precipitation gradient, northwest Negev desert, Israel. Microbial Ecology, 70: 219-230.
Bar-Eyal, Leeat; Eisenberg, Ido; Faust, Adam; et al. (2015). An easily reversible structural change underlies mechanisms enabling desert crust cyanobacteria to survive desiccation. Biochimica et Biophysica Acta-Bioenergetics 10: 1267-1273.
Keck, H., Felde, V.J.M.N.L., Drahorad, S.L., Felix-Henningsen, P. (2016): Biological soil crusts cause subcritical water repellency in a sand dune ecosystem located along a rainfall gradient in the NW Negev desert, Israel. J. Hydrol. Hydromech. DOI: 10.1515/johh-2016-0001.
Treves, H., Raanan, H., Kedem, H., Murik, O., Keren, N., Zer, H., Berkowicz, S.M., Giordano, M., Norici, A., Shotland, Y., Ohad, I., Kaplan, A. (2016): The mechanisms whereby the green alga Chlorella ohadii, isolated from desert soil crust, exhibits unparalleled photodamage resistance. New Phytol. DOI: 10.1111/nph.13870.
Kaplan, A., Raanan, H., Oren, N., Treves, H., Keren, N., Ohad, I., Berkowicz, S.M., Hagemann, M., Koch, M., Shotland, Y. (2016). Towards clarifying what distinguishes cyanobacteria able to resurrect after desiccation from those that cannot: The photosynthetic aspect. BBA – Bioenergetics (in press).