1. Dryland Ecohydrology

​

Abstract

​

Land degradation of drylands, or desertification, impacts 40% of Earth’s land surface, 40% of the global population,
and is responsible for up to 25% of global greenhouse gas emissions. In 2015, the Conference of the Parties to the
United Nations Convention on Combating Desertification agreed on a global target to reach a net-zero increase in
land degradation by 2030, posing an urgent need to identify the risks of degradation in specific landscapes, enabling
preventative responses, and to guide the design of restoration activities. Many dryland ecosystems are sustained by
runoff-runon processes that result in the transport of resources, particularly water, from bare to vegetated sites,
determining the ultimate availability of water to plants. Such transport is dependent on storm and site
characteristics, making its behavior temporally dynamic and spatially complex. In this context, predicting the likely
vulnerability of desert landscapes to degradation or the quality of proposed restoration activities from readily
observed surface features of drylands would be extremely helpful. Yet despite several previous attempts to
generalize such predictions using models of plant water availability or runoff volumes exported from drylands, the
predictions that can be made remain hampered by two factors: firstly, the models used to make predictions are not
tested against observations of site-to-site source-sink transport of water during storm events, and secondly, the
model experiments used to link dryland surface features to water redistribution rely on single realizations of
unrealistic land surfaces - meaning that uncertainty is poorly characterized, and the behavior of resulting metrics for
real landscapes is unclear. This project exploits isotopic tracer experiments to reveal patterns of connectivity and
water availability to vegetation on a well-characterized dryland hillslope at the Lehavim LTER in Israel. The patterns
will be used to test the predictions of runoff-runon models by adapting these models to predict Lagrangian transport
of water. Finally, model experiments using the tested model will draw on the emerging field of multi-point statistics
to enable realistic realizations of landscape surface features, allowing uncertainty in predicted water availability, degradation risk or restoration quality to be characterized.

​

Collaborators

​

Shmuel Assouline, Institute of Soil, Water and Environmental Sciences. Volcani Center. A.R.O., Bet Dagan, Israel.  vwshmuel@volcani.agri.gov.il

Sally Thompson, Dept. Civil and Environmental Engineering, University of California –Berkeley, U.S.A. sally.thompson@berkeley.edu

Gabriel Katul, Nicholas School of the Environment and Earth Sciences, Duke University, U.S.A. gaby@duke.edu​

Enrique R. Vivoni, School of Earth and Space Exploration & School of Sustainable Engineering and the Built Environment, Arizona State University, U.S.A. vivoni@asu.edu 

​

Key publications

​

• Sela S, Svoray T, Assouline S, 2012. Soil water content variability at the hillslope scale: Impact of surface sealing. Water Resources Research. vol. 48, pp. 1-14. W03522, doi:10.1029/2011WR011297.

• ChenI L, Sela S, Svoray T, Assouline S, 2013. The role of soil-surface sealing, microtopography and vegetation patches in rainfall-runoff processes in semiarid areas. Water Resources Research. vol. 49, pp. 5585-5599.

• Thompson, S.E., S. Assouline, L. Chen, A. Trahktenbrot, T. Svoray, and G. G. Katul, 2014. Secondary dispersal driven by overland flow in drylands: Review and mechanistic model development. Movement Ecology. Vol. 2:7  doi:10.1186/2051-3933-2-7.    

• Yizhaq, H., Sela, S. Svoray T. Assouline S. Bell, G, 2014. Effects of heterogeneous soil-water diffusivity on vegetation pattern formation. Water Resources Research. Vol. 50/7 pp. 5743–5758. DOI: 10.1002/2014WR015362.

• Sela, S., Svoray, T., Assouline, S. 2014. Temporal soil water content variability at the hillslope scale in dry environments: from single rainfall events to long term dynamics. Journal of Arid Environments, Vol. 112, pp. 64-74.

• Sela, S., Svoray, T., Assouline, S., 2014. Validation of remotely sensed soil-moisture predictions: Effect of soil surface sealing. Remote Sensing. Vol. 6(8), pp. 7469-7490. doi:10.3390/rs6087469.

• Sela, S., Svoray, T., Assouline, S.  2015. The effect of soil surface sealing on vegetation  water uptake along a dry climatic gradient. Water Resources Research, 51, doi:10.1002/2015WR017109.

• Assouline, S., Thompson, S., Chen, L., Svoray, T. Sela, S. Katul, G.G. 2015. The duality of soil crusts in desertification. J. of Geophysical Research-Biogeosciences, Vol. 120, doi: 10.1002/2015JG003185.

• Svoray, T., Assouline, S., Katul, G. G., 2015. Introduction to Special Section on Eco-hydrology of Semiarid Environments: Confronting Mathematical Models with Ecosystem Complexity. Water Resources Research, Water Resources Research 51 (11), 8677-8683.  doi:10.1002/2015WR018131.

• Chen, L., Sela, S., Svoray, T., and Assouline,S. 2016. Scale dependence of Hortonian rainfall-runoff processes in a semiarid environment. Water Resources Research, 52:51495166.

• Dubinin, V., Svoray, T., Stavi, I., Yizhaq, H., 2021. Using LANDSAT 8 and VENμS data to study the effect of geodiversity on soil moisture dynamics in a semiarid shrubland. Remote Sensing, 12, 3377; doi:10.3390/rs12203377.  

• Dubinin, V., Stavi, I., Svoray, T., Dorman, M., Yizhaq, H., 2021. Hillslope geodiversity improves the resistance of shrubs to prolonged droughts in semiarid ecosystems. Journal of Arid Environments, 188, 104462. 

• Danino, D., Svoray, T., Thompson, S., Cohen, A., Crompton, O., Volk, E., Argaman, E., Levi, A., Cohen, Y., Narkis, K.,  Assouline, S., 2021. Quantifying shallow overland flow under laboratory rainfall simulations using thermal and LiDAR imagery. Water Resources Research. 57, 3, e2020WR028857.

• Svoray, T., Sela, S., Chen, L., Assouline, S., 2021. Lateral flow and contributing area control vegetation cover in a semiarid environment. Water Resources Research [Paper #2021WR030998R], https://doi.org/10.1029/2021WR030998.

• Assouline, S., Kamai, T., Svoray, T., Narkis, K., 2023. Understanding the dynamics of evaporation from stony soils via laboratory experiments and numerical modeling. Journal of Hydrology, 622, 129708.

​

​

2. Soil Health

​

Abstract

​

Securing food production under constant rapid growth in world population leads to land degradation and triggers the “poverty trap” spiral. The Soil Health Concept endorses the need of soil to sustain biological productivity, maintain environmental quality, and promote ecosystem health. Under the current paradigm, soil health indices focus on soil productivity and do not target support and regulation ecosystem services. We assert that a shift to a paradigm that considers all three pillars of soil ecosystem services: provision, regulation and support, will contribute to minimizing land degradation that results from the pressure to increase food production. We introduce the concept of “Soil Ecosystem Sustainability Index (SESI)”, that will quantitatively relate various soil attributes to the three ecosystem services. As an indicator for soil ecosystems functionality, SESI facilitates between needs for securing food to the world’s growing population and the threat of land degradation. Our aim is to develop a SESI on a catchment scale at different climatic regions. Research activities will comprise: (i) selection of 400 points in each of 2 catchments, where selected soil ecosystem services will be monitored and a wide range of soil  physical, chemical and biological attributes be determined; (ii) characterization of the relationships between the measured soil attributes and monitored ecosystem services; (iii) aggregation of soil attributes representing the various ecosystem services to one multifactor SESI; (iv) validation of the SESI approach at 2 additional catchments in Israel and 1 in Germany. By providing a solution for the “poverty trap” in the form of the SESI, our project will be a groundbreaking contribution to global long term food security and diminishing of land degradation. It is further envisioned that our project will become the corner stone providing the necessary basis for the creation of a world map of terrestrial SESI that can be dynamically updated.

​

Collaborators

​

Peter Atkinson, University of Lancaster (Dean of Faculty of Science and Technology), United Kingdom. pma@lancaster.ac.uk

Gil Eshel, Soil Erosion Research Station, Rishon Leziyyon, Israel. eshelgil@gmail.com 

Yosef Steinberger, Soil ecology lab, Bar-Ilan University, Ramat-Gan,Israel.  steinby@mail.biu.ac.il

Guy J. Levy, Soil, Water and Environmental Sciences, Volcani Center. A.R.O., Bet Dagan, Israel. vwguy@volcani.agri.gov.il

Oshri Rinot, Soil, Water and Environmental Sciences, Volcani Center. A.R.O., Bet Dagan, Israel. oshrinot@gmail.com

​

Key publications

​

• Svoray T, Markovitch H, 2009. Catchment scale analysis of the effect of topography, tillage direction and unpaved roads on ephemeral gully incision. Earth Surface Processes and Landforms, vol. 34, pp. 1970-1984.

• Svoray T, Ben-said S, 2010. Soil loss, water ponding and sediment deposition variations as a consequence of rainfall intensity and land use: a multi-criteria analysis. Earth Surface Processes and Landforms. vol. 35, pp. 202-216.

• Storz-Peretz Y, Bowman D, Laronne JB, Svoray T, 2011. Rapid incision of a small, coarse and steep fan-delta in response to base-level fall: the case of Nahal Qedem, the Dead Sea, Israel. Earth Surface Processes and Landforms. vol. 36, pp. 467-480.

• Svoray T, Michailov E, Cohen A, Rokach L, Sturm A, 2012. Predicting gully initiation: Comparing data mining techniques, analytical hierarchy processes and the topographic threshold. Earth Surface Processes and Landforms. vol. 37, pp. 607–619.

• Svoray, T., Levi, R., Zaidenberg, R., Yaacoby, B. 2015. The effect of cultivation method on erosion in agricultural catchments: Integrating AHP in GIS environments. Earth Surface Processes and Landforms, Vol. 40, 711-725. DOI: 10.1002/esp.3661.

• Cohen, S., Willgoose, G., Svoray, T., Hancock, G., Sela, S., 2015. Sediment-transport control on Aeolian-dominated soil distribution: New insights using numerical simulations of soil-landscape evolution. Journal of Geophysical Research-Earth Surface, Vol. 120/2, 260-274.

• Svoray, T. Hassid, I. Atkinson, PM. Moebius-Clune, BN, van Es, HM. 2015. Mapping soil quality over large agriculturally-important areas.  Soil Science Society of America Journal, Vol. 79, 1420-1434. doi:10.2136/sssaj2014.09.0371.

• Cohen, S., Svoray, T., Sela, S., Hancock, G,. and Willgoose, g. 2017. Soilscape evolution of Aeolian- dominated hillslopes during the Holocene: Investigation of sediment transport mechanisms and climatic-anthropogenic drivers.  Earth Surface Dynamics Discus. dio:10.5149/esurf-2016-4.

• Hoober, D., Svoray, T., and Cohen, S. 2017. Using a landform evolution model to study ephemeral gullying in agricultural fields: The effects of rainfall patterns on ephemeral gully dynamics. Earth Surface Processes and Landforms. doi:10.1002/esp.4090.

• Svoray, T., 2022. A Geoinformatics Approach to Water Erosion: Soil Loss and Beyond. Springer-Nature, ISBN 978-3-030-91535-3. 

• Nahlieli, A., Svoray, T., Argaman, E., 2022. Piping formation and distribution in the semi-arid Northern Negev environment: A new conceptual model. Catena, Volume 213, 106201.  

• Vatenmacher, M., Svoray, T., Tsesarsky, M., Isaac, S., 2022. Performance-driven Vulnerability Analysis of Infrastructure Systems. International Journal of Disaster Risk Reduction. Volume 76, 15 June 2022, 103031. 

• Steinberger, Y., Stein, A., Dorman, M. et al., 2022. A sensitive soil biological indicator to changes in land-use in regions with Mediterranean climate. Scientific Reports. 12, 22216 2022. https://doi.org/10.1038/s41598-022-26240-9. 

• Nahlieli, A., Svoray, T., Argaman, E., 2023. Mapping areas prone to piping using random forest with key explanatory variables. Geoderma, https://doi.org/10.1016/j.geoderma.2023.116367. 

• Refaeli, O., Nahlieli, A., Svoray, T. 2023. Dynamics of subsurface soil erosion in a semiarid region: a time-series study of sinkhole area and morphology. Catena, Accepted. 

​

​

3. Environmental Psychology

​

Abstract

​

The role of nature in improving health and well-being has already been demonstrated. However, most of the research on the subject is derived from self-report measures. In contrast, non-intrusive methodologies such as social networks were overlooked. We aim to explore if happy facial expressions (HFE) are particularly prevalent in areas replete with natural resources such as water bodies and green areas, and with low density built areas. To fulfill this aim, we applied a novel, spatio-temporal, analysis of photos taken in the Greater Boston Area and posted on Flickr - an online location-based social network – during 2012-2015 (N = 60,013). Photos were analyzed using Microsoft Emotion API to detect facial expressions. Exposure to nature, measured either as a composite score or based on the three aforementioned aspects, was strongly associated with HFEs, even after controlling for several temporal patterns. Moreover, the positive effect of nature was particularly pronounced during warmer seasons.

​

Collaborators

​

Michael Gilead, Psychology Department, Ben-Girion University, Beer-Sheva, Israel. https://www.gileadlab.net/

Michael Dorman,  Department of Geography and Environmental ,Ben-Girion University, Beer-Sheva, Israel.  dorman@post.bgu.ac.il 

Itai Kloog, Department of Geography and Environmental ,Ben-Girion University, Beer-Sheva, Israel.  ikloog@bgu.ac.il.

Robert Gifford, Department of Psychology ,University of Victoria, Victoria, Canada.  rgifford@uvic.ca.

​

Key publications

​

• Svoray, T. M. Dorman, G. Shahar, I. Kloog 2018. Demonstrating the effect of exposure to nature on happy facial expressions via flickr data: Advantages of non-intrusive social network data analyses and geoinformatics methodologies. J. of Env. Psychology 58, 17-24. https://doi.org/10.1016/j.jenvp.2018.07.006

• Dorman, M., Svoray, T., Kloog, I., 2020. How does socio-economic and demographic dissimilarity determine physical and virtual segregation? Journal of Spatial Information Science 21, doi:10.5311/JOSIS.2020.21.587. 

• Simchon, A., Leibman, C., Svoray, T., Dorman, M., Kloog, I., Gilead, M., 2021. Beyond doubt in a dangerous world: The effect of existential threats on the expression of certainty in societal discourse. Journal of Experimental Social Psychology, In Press. 

• Svoray, T., Dorman, M., Abu-kaf, S., Shahar, G., Gifford, R., 2022. Nature and Happiness in an Individualist and a Collectivist Culture. Scientific Reports. 12, 7701. https://doi.org/10.1038/s41598-022-11619-5.

• Blushtein-Livnon, R., Svoray, T., Dorman, M., Van der Beek, K., 2023. Economic aspects of urban greenness along a dryland rainfall gradient: A time series analysis. Urban  Forestry & Urban Greening, 83, 127915.  

​

​

 

​