DDD Conference

Session Descriptions

(As part of Patterns and processes in the ecology of drylands)
Conveners: Yael Lubin, Michal Segoli and Hadas Hawlena
Harsh desert conditions may have important implications for interactions between organisms in both natural and human-impacted environments. Low water and nutrient availability may intensify the impact of exploitative interactions and promote specialized mutualistic adaptations. Low productivity also increases the severity of anthropogenic effects (e.g. settlements and agricultural fields) on the surrounding natural environment, with implications for animal movement, abundance and interactions. In this session, we will focus on the uniqueness of desert environments in shaping these effects.

Conveners: Prof. Jacob Moran-Gilad and Dr. Osnat Gillor

Molecular diagnostics have become an essential component of clinical and environmental microbiology. Techniques such as qPCR or dPCR allow speedy detection and quantitation of microbial nucleic acid targets with greater than ever accuracy and sensitivity. The growing accessibility to next-generation sequencing (NGS) is further transforming health risk assessment; genomic diagnostics are being developed and implemented via metagenome DNA sequencing, allowing precise characterisation of taxonomy, virulome and resistome and high-resolution typing. Microbiome analysis is extending microbiology into the exploration of the aetiology and pathogenesis of infectious and non-infectious diseases, while shotgun metagenomics is a critical step towards culture-independent microbiology. These advances in laboratory diagnostics are expected to have a significant impact on the assessment and management of health risks to humans and the environment. Furthermore, combining these approaches with qualitative and quantitative research methods for public and eco-health holds an even greater promise for holistic research. This session will feature invited talks and selected oral presentations dedicated to translational research harnessing advanced diagnostics to manage water bodies and aims to facilitate cross-talk between the various disciplines engaged in water sciences, microbiology, computational biology, medicine, social sciences and public health. Special emphasis will be placed on the emergence and spread of antimicrobial resistance and the role of natural and human-made aqueous environments as reservoirs for the evolution, transmission and consequences of resistance.

Conveners: Francesca Cappitelli, University of Milan and
Tali Erickson-Gini, Israel Authority of Antiquities
Cultural heritage sites are often discolored and degraded by the growth and activity of microorganisms. In desert environments, microorganisms such as bacteria, fungi, algae and lichen grow on or within the stones and were linked to monuments’ aesthetic and structural damage. It was suggested that stone type, environmental conditions and preservation practices affect the microorganisms’ colonization and the biodeterioration process. In this session, archeologists and microbiologists will share information regarding the biodeterioration and preservation of cultural heritage monuments in desert environments. Recent innovations in molecular biology and biogeology will be discussed elucidating the role of microbial activity in stone biodegradation together with lessons learned in recent years regarding the conservation of desert cultural heritage sites.

Conveners: Jayne Belnap and Ali Nejidat

Assembly rules and patterns in dryland vascular plant communities: biological soil crusts can play an influential role
Jayne Belnap, U.S. Geological Survey, Southwest Biological Science Center, 2290 S. Resource Blvd., Moab, UT 84532, U.S.A
YuanMing Zhang, Key Laboratory of Biogeography and Bioresource in Arid Land, Xinjiang Institute of Ecology and Geography, Chinese Academy of Sciences (CAS), Urumqi 830011, PR China

Factors that influence plant community composition and patterns have long been sought by ecologists, and the concept of assembly rules has influenced much recent thought. The first step in plant establishment is successful seed dispersal/germination and identifying controls on this stage is critical in understanding drivers of vascular plant community structure. Most studies examine how disturbance and plant-plant/plant-animal interactions affect assembly rules. However, we suggest that in drylands, plant-biocrust-disturbance interactions determine plant community composition by controlling what seeds enter the soil bank. We compared plant and seedbanks composition on four surface types (uncrusted, cyanobacteria, lichen, and moss). We also characterized seed weight, size, or plant life form; none of these factors influenced plant community or seedbank composition on the different surfaces. We observed that the highest diversity and richness of plant species and seeds in the seed bank was found on recently disturbed areas that were either uncrusted or covered by early successional cyanobacterial crusts, whose low biomass has little influence on soil characteristics. In contrast, diversity and richness of plants and seeds in the seedbank dropped significantly in late successional lichen- or moss-covered soils, due to the lack of plant seeds with appendages. Lichens and mosses greatly stabilize and reduce permeability of soils, reducing the opportunity for seeds to be buried. However, disturbance readily resets biocrusts to an early successional state, thus providing ample opportunity for seeds to be buried. We propose that the structure, and thus function, of this dryland region is substantially influenced by the tension between the forward forcing of biocrust succession and the backward forcing of disturbance that creates a shifting mosaic of patches with different plant, biocrust, and soil characteristics through time and space and across multiple scales. Therefore, we posit that the interaction between biocrusts and disturbance is an underlying assembly rule for this, and likely most, temperate deserts.

Convener: Nurit Agam

In arid regions, crop productivity is limited by scarce rainfall, which is often supplemented by irrigation. In both rain-fed and irrigated cropping, the actual availability of water to the crops is largely dictated by the fraction of water that is lost to the atmosphere or to deep drainage. The magnitude of these fluxes is strongly affected by the sources of energy (radiation and advection). In drylands, irrigated row crops are common and are characterized by heterogeneous soil surface wetness that may lead to micro-advection, an additional complicating factor.

Monitoring and/or modeling of the various components of the water balance are necessary in order to improve the efficiency with which this scarce resource is used.

Presentations relevant to the aforementioned topics (theoretical or applied) are welcomed.

Convener: Ehud Meron

Fairy circles are circular gaps of bare soil in grasslands that form strikingly ordered patterns on large, landscape scales. They have been observed in western Namibia and recently also in northwestern Australia. Two main hypotheses have been proposed for the cause of their formation: termite colonies, which have been found in many circles, and water-vegetation interactions. This session will bring together entomologists, ecologists and physicists who will present recent empirical and model studies that shed new light on the controversial fairy-circle phenomenon. The interest in fairy circles goes beyond the mechanisms of their formation; whatever these mechanisms turn out to be, fairy circles provide excellent empirical case models to study the impact of spatial self-organization on ecological processes and ecosystem function.

Convener: Alan Grainger,

School of Geography,
University of Leeds, Leeds LS2 9JT, UK.

Reliable empirical information on the global extent and rate of change of desertification has been lacking for decades. Reasons for this include the complexity of the phenomenon, and its multiple attributes; the small scale over which many attributes vary; limitations on the resolution of satellite sensors to map these attributes; and hardware and software limitations on processing satellite and ground data on a global scale. This paper discusses the various options available for monitoring desertification reliably, all of which include multiple data sources. Until this year, the leading option was to use a combination of ground data and medium resolution satellite data, e.g. Landsats 7-8 and Sentinel 2. This year saw the publication of the first very high resolution map of tree cover in the drylands, achieved by a combination of images from very high resolution satellite sensors (e.g. GeoEye and Ikonos); lower resolution images (e.g. Landsat and MODIS), to allow for the underlying trend in rainfall variation; and ground data. These were then analysed using a Geo-Wiki crowd sourcing method to counter automatic processing constraints. This paper suggests how this second approach could be extended in future to map soil degradation as well as vegetation degradation, though ground data will be as indispensable as in the earlier medium resolution approach if reliable results are to be obtained. This raises a question about how to integrate remote sensing data with ground data collected by scientists and by lay crowd sourcing, and this paper outlines a new conceptual framework that can facilitate such integration.

Convener: Luc Gnacadja

Land degradation neutrality (SDG target 15.3) is defined as “a state whereby the amount and quality of land resources necessary to support ecosystem functions and services and enhance food security remain stable or increase within specified temporal and spatial scales and ecosystems” to address land stewardship at all levels for the sake of sustainability.

More than half of the additional two billion people who will live on Earth by 2050 will be born in Africa. The population of sub-Sahara Africa (SSA) is predicted to grow from 900 million in 2013 to about 1.4 billion by 2030 (UN, 2013),while the region is the world’s champion in poverty, hunger and food insecurity, land degradation and agriculture vulnerability to climate change.

But Africa is also a global hotspot for success stories in land restoration with innovations mostly occurring at local level. The institutional aspects are among the major hurdles to scaling up.

The proposed session aims to involve policy-makers, on-farm land managers and scientists to discuss the following:
What triggers land improvement processes and how can these triggers be mainstreamed?
How to support farmers to make SLM decisions and secured investments, while ensuring that they receive a fair share of the benefits generated downstream by their restoration efforts?
How to overcome the institutional challenges to scaling up restoration and furthering climate change adaptation in the agricultural sector in SSA? What enabling environment for achieving LDN? What is the role of the private sector?

Convener: Wanjira Mathai

Forest landscape restoration (FLR) is transforming landscapes and people’s lives all around the world. Experience from the Tigray region of Ethiopia demonstrates the benefits that restoration can bring for biomass energy production, food and water security, climate change resilience, and poverty alleviation. In the drylands of Tigray, community members battled harsh conditions, steep slopes, and sandy soils to restore more than 1 million hectares of degraded land. Tigray is greener and more food secure than it’s been in decades; groundwater levels have been replenished, the area under irrigation has grown more than six fold, and agricultural production has expanded even in drought years. One community in Tigray has applied the income and economic benefits from restoration to bring electricity to more than 500 households.
In addition to reclaiming our natural asset base, FLR also has the potential to meet the high demand for biomass energy in drylands while improving how the energy biomass base is grown. It is important to acknowledge that it will take some time before renewable technologies, like solar thermal, photovoltaic, and biogas, and cleaner alternative traditional fuels, like LPG, become more affordable. Until then, rural populations in developing countries will continue to depend on fuelwood or charcoal as their primary sources for meeting more than 50% of household energy needs. The loss of biomass caused by fuelwood and charcoal use needs to be restored. Numerous low-cost, low-input restoration techniques such as exclosures and farmer-managed natural regeneration (FMNR) can increase biomass above and below ground. When paired with improved technologies like clean cook stoves, communities can capture significant benefits for energy security and sustainable land management.

Conveners: Ido Regev, Roiy Sayag, Yosef Ashkenazy and Hezi Yizhaq

Granular materials are ubiquitous in nature and particularly common in arid regions in the form of sand. The formation and propagation of dunes and ripples are among the phenomena governed by granular processes. Therefore, understanding the mechanics of granular materials is highly important for understanding the dynamics and evolution of arid regions. However, the physical mechanisms that govern the flow of sand and other granular materials are highly complex and not well understood. This session will focus on recent progress in both theoretical and experimental research on granular media.

Conveners: Garik Gutman and Arnon Karnieli

Desertification and land degradation represent a global challenge to billions of people on the Earth. Land-cover change is one of the most obvious and detectable indicators of land-surface characteristics and associated human-induced and natural processes. Due to evolving technology, it has become increasingly feasible to derive land-cover change information from a combination of in situ surveys and earth observation satellite data at regional, national, and global scales. Regional analyses of desertification processes are the key to the understanding of causes and impacts of degradation. To be useful for sustainable, local combating strategies, regional analyses must provide spatially explicit information at sufficient detail. NASA- and ESA-affiliated scientists have been developing appropriate information services based on satellite observations to assess and monitor desertification and degradation trends over time. A synergistic use of spectral data with moderate to high spatial resolution from more than one source is getting momentum due to successful launches under the ESA Sentinel program. Landsat and Sentinel-2 optical data are now used synergistically by many researchers, sometimes combined with Sentinel-1 radar data. Efficient and synergistic use of these sensor data increases the number of observations available for studies. The proposed session aims at bringing together experts working on arid regions who study desertification/degradation issues by applying moderate-to-high (1-30m) resolution data. New ideas on synergistic use of data from various sensors, including moderate-to-high resolution thermal IR sensors, are welcome.

Convener: Orna Reisman-Berman

Afforestation in drylands is a unique novel ecosystem that aims at increasing ecosystem services on degraded lands in harsh environments. Therefore the selection of woody plant species for dryland afforestation actions must be an educated act. In the past, species were selected mainly for their drought resistance and fast-growth traits, and the selected species were mainly non-native. However, today there is a growing awareness of increasing the resemblance between the novel ecosystem and the surrounding natural ecosystem by integrating native woody species in afforestation. This session will accommodate various topics related to the function and the effects of integrating both native and non-native species in dryland afforestation, such as: novel ecosystems, assisted migration, physiology, ecology, and genetics of the tree species, as well as the management of the individual tree and the landscape.

Convener: Noam Weisbrod

Approximately 1.1 billion people in developing countries are currently living without an adequate supply of and access to potable water. In a world with slightly over 7 billion people, this is an outrageously high fraction of the global population. In order to ensure the water security of the world as a whole, it is necessary to start with these 1.1 billion impoverished people whose governments lack the funding necessary to help them. In developing countries, most of the population lives in rural areas where governmental involvement is often very limited. These communities often heavily depend on local agriculture and, in many cases, are limited to rain-fed agriculture. The outcome is that these rural communities are severely dependent on the activities of local or international NGOs (now also known as Civil Society Organizations: CSOs). This session aims to bring people together from organizations that are involved, in the past, present or future, in water-related activities in rural communities to share their ideas, methods, approaches, successes and failures. Representatives from both Israeli and international organizations are welcome, as well as scientists and officials who are interested in this topic.

Convener: Amit Gross

In the modern world, the use of natural resources and the production of domestic wastes and contaminated effluents have significantly increased, and they now pose severe health and environmental risks in many regions, specifically in arid regions. There is an urgent need to remedy already contaminated sites and to find means for minimizing these trends. A fairly new field of research, called Ecological Sanitation (ECOSAN), is a modern, usually on-site, alternative to conventional sanitation techniques. The objective is to protect human health and the environment. Unlike traditional sanitation methods, ecological sanitation processes on-site human waste (in addition to traditional waste, such as animal manure) to recover nutrients that would otherwise be discarded.

This session invites papers involving a range of on-site waste solutions, such as wetlands, biogas and other methods for small agro-waste operations, human wastes, wastewaters, greywater and more. It also seeks papers that evaluate the risks and environmental issues that are associated with such practices.

Conveners: Ido Regev, Roiy Sayag, Yosef Ashkenazy and Hezi Yizhaq

The geomorphology of arid regions is shaped by several physical processes that act at different spatial and temporal scales, such as erosion and sedimentation due to water flow, glacial movement and aeolian processes. One of the most interesting erosive forces is the transport of sand and dust by wind which creates sand dunes and ripples, and loads the atmosphere with suspended dust aerosols. This session will focus on the recent progress obtained in understanding the physical mechanisms behind these processes and patterns, and on the current open questions in the field.

Conveners: Vered Tzin, Rakefet David-Schwartz, and Shimon Rachmilevitch

Plants growing in arid areas confront a number of abiotic stress-causing factors including drought, extreme temperatures, high winds, low humidity, high radiation, salinity and specific ion toxicity. These factors become tangible both as direct physiological stresses in the plants and as indirect stress components, via alterations to the physical environment. This session will provide a platform to understand and discuss some of the dominant abiotic stress-causing factors in the context of desert agriculture and to investigate methods to contend with them sustainably.

Conveners: Uri Yermiyahu, Ran Erel

Plant nutritional needs in dry areas are often dictated by interactions with abiotic stress-causing conditions. Mechanisms for understanding plant responses to nutrition-stress interactions may be physical, chemical and/or biological, thus requiring interdisciplinary consideration. In this session, we will discuss common stresses occurring in drylands and deserts, including drought, salinity, heat, and radiation, and their effects on and interactions with plant nutrition. Topics will include root function, water and nutrient uptake, crop physiology and crop and product health.

Convener: David Mutekanga

Most rural areas in Africa and other parts of the world face challenges of desertification; however unless they have other natural resources, they are usually ignored. Still they have many traditional and non-traditional methods of combating desertification.

This session will look at different practices and theories regarding how desertification is being combated in rural areas of the world. The focus will include developing countries, especially in Asia and Africa, with lessons to be learned from developed economies. Analytical and comparative papers will be appreciated.

Convener: Arnon Karnieli

Environmental problems of drylands such as desertification processes, land degradation and rehabilitation, land cover and land use change, climatic change, droughts, early warning, and more, are characterized by both spatial and temporal dimensions. Therefore, remote sensing techniques, based on long-term monitoring and repetitive data, over vast expanses of unsettled regions, are applicative and powerful tools for research and implementation in these areas.
Special sessions on REMOTE SENSING – TOOLS AND IMPLICATIONS IN DRYLAND will take place as part of the conference to promote scientific exchange between experts who work on remote sensing and geoinformation issues of the above drylands-related aspects with special intention to restoration actions and processes.

Convener: Gilboa Arye

Soil organic carbon accounts for over 50% of soil organic matter and is commonly considered as a key indicator for soil quality with regard to its agricultural and environmental function. With increased organic matter content, aggregation stability and soil structure are improved and consequently, water retention, infiltration rate and resistance to soil erosion. The lack of or low organic matter content in agricultural dryland soils is, traditionally, compensated for by the addition of organic matter from different sources. The use of marginal irrigation water, such as treated wastewater in dryland agriculture, continuously provides inputs of dissolved and particulate organic matter to the soil.
The proposed session will address issues that are related to the role and function of soil organic matter from different origins in agricultural dryland soils. In this context, particular attention will be paid to the following topics: surface activity, aggregate stability, soil erosion, soil amendment, and carbon sequestration.

Convener: Ehud Meron

There is increasing evidence that spatial self-organization induced by water-vegetation feedbacks plays an important role in shaping dryland landscapes. Model studies have provided much insight into the mechanisms by which positive feedbacks can render uniform vegetation unstable and lead to the formation of vegetation patterns. Yet, the mechanisms at work in specific systems and the interplay between different mechanisms have remained largely unexplored. This session will bring together experts in modeling and in model analysis, as well as field and remote sensing experts, to present recent progress in understanding vegetation pattern formation and the implications it bears on ecosystem processes and function.

(as part of Soil-plant-atmosphere interactions in drylands)
Conveners: Naftali Lazarovitch and Golan Bel

Approximately 40% of the earth’s terrestrial surface comprises drylands, making a better understanding of the soil-plant-atmosphere interactions in these regions crucial for correct modeling of ecosystem and climate dynamics. In particular, soil models are crucial for capturing long-term memory effects in climate fluctuations due to the soil and vegetation large storage capacity and relatively slow dynamics. Often, there is a gap, in the complexity and spatio-temporal scales, between local models of soil-water flow and the land component of global climate models. This gap in scales also exists in measurements. Large scale measurements are usually derived from infrequent satellite imagery, while local measurements, used to develop and validate soil models, are captured locally and often continuously.

(as part of Soil-plant-atmosphere interactions in drylands)
Conveners: Naftali Lazarovitch and Golan Bel

The soil-plant-atmosphere interactions and, in particular, the exchange of water, gas and energy play crucial roles in climate and ecosystem dynamics. These interactions have inspired a great deal of scientific research, and we possess a sophisticated understanding of these processes in mesic environments. However, in arid environments, where only a small fraction of the surface is covered by vegetation, the soil-atmosphere exchanges are much less understood. Soils provide the largest terrestrial carbon store, the largest atmospheric CO2 source and the largest terrestrial N2O source. A change in land use or management can alter these soil processes such that net greenhouse gas exchange may increase or decrease. Soil properties interact in complex ways with the biological processes responsible for the production and consumption of greenhouse gases.

(As part of Patterns and processes in the ecology of drylands)
Conveners: Yael Lubin, Michal Segoli and Hadas Hawlena

Global changes in land use, in the averages and variability of temperatures, and in desertification have dramatic direct and indirect impacts on host-parasite interactions, with implications for disease risk to wild animals and people. These changes affect parasite replication and the development, survival, and mobility of vectors, as well as the geographical distributions of vectors and hosts. Changes in temperature, humidity, and habitat structure also affect the network of biotic interactions and biodiversity, which in turn influence the dynamics and evolution of host-parasite interactions. We will focus on this cascade of changes and their implications for the emergence, spread, and virulence of infectious diseases.

Convener: E. Erell and D. Pearlmutter

Rapid urbanization in dryland countries is partly the result of land degradation in rural areas. Dryland cities often suffer from water shortages and inefficient use of energy resources, subjecting their inhabitants to poor environmental conditions that are exacerbated by global climate change as well as the urban heat island. Mitigating the consequences of these processes will require a better understanding of the effects of urban form on the energy-water-land nexus. The session will provide a forum for research on issues such as water-sensitive urban design, the urban forest, pedestrian thermal comfort in outdoor spaces and the interaction between the urban microclimate and building energy consumption.

(As part of Patterns and processes in the ecology of drylands)
Conveners: Yael Lubin, Michal Segoli and Hadas Hawlena

Climatic factors and, in particular, desertification, as well as changing land use, influence individual plant traits, demography and population dynamics, and consequently, the structure of communities and patterns of diversity. This session will focus on effects of desertification, grazing and other human interventions on the performance of desert plants and subsequent changes in vegetation diversity and composition.

(as part of Viticulture in a changing climate)
Conveners: Nurit Agam, Naftali Lazarovitch and Aaron Fait

The economic value of grape as an agricultural crop relates not only to the yield but also to the quality of the berry as reflected by its chemical composition. A fundamental strategy to ameliorate fruit quality in a changing climate by optimizing viticulture practices lies in the (i) understanding of the mechanisms modulating the molecular physiology of the vine and the grape, (ii) dissecting the regulation of polyphenol and aroma potential, and the (iii) identification of candidate gene regulators of key biochemical pathways.

(as part of Viticulture in a changing climate)

Conveners: Nurit Agam, Naftali Lazarovitch and Aaron Fait

Environmental conditions optimal for quality wine-grape production are of a complex nature and are not easily defined. For example, a sufficient amount of radiation is required, but overexposure deteriorates yield quality. Similarly, a correct water balance is necessary for optimal grape development. The vast expansion of wine consumption worldwide and the increasing demand for quality wine, along with apparent signs of climate change and repeated droughts in many wine vineyard growing areas, make a better understanding of the vineyard-environment interactions necessary.

(as part of Soil-plant-atmosphere interactions in drylands)
Conveners: Naftali Lazarovitch and Golan Bel

The simultaneous movement of liquid water, water vapor, and heat in the soil plays an important role in the water and energy balance of the near surface environment of arid regions. Simulating water fluxes in unsaturated soils from complete saturation to complete dryness is challenging due to high nonlinearity and the hysteretic nature of the soil hydraulic functions. These functions describe the relation between the soil water potential, water content, and the hydraulic conductivity. Classical capillary-based functions typically hold between saturation and some residual water content. Recent models accounting for capillary and adsorptive water retention, but also for capillary and film conductivities. The success of the parameter determination of such functions depends on how well the water status is measured in extremely dry soils.

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