Arid environments

Environmental change and human history in the Jabal Harûn area, Jordan

by Paula Kouki

Regional landform patterns in the Strzelecki Desert dunefield: dune migration and mobility at large scales

by Kathryn Fitzsimmons

Fitzsimmons, K.E. (2006) Regional landform patterns in the Strzelecki Desert dunefield: dune migration and mobility at large scales. Regolith 2006 – Consolidation and dispersion of ideas. Cooperative Research Centre for Landscape Environments and Mineral Exploration (CRC LEME), Perth, pp.95-99.

The Australian desert dunefields dominate the continent, forming a large anti-clockwise whorl across more than one... more The Australian desert dunefields dominate the continent, forming a large anti-clockwise whorl across more than one third of the country (WASSON et al. 1988). The majority of these dunes are linear bedforms, forming parallel to the resultant vector of the sand shifting winds prevailing at the time of their formation (KING
1960). Despite being the most extensive landforms on the continent, studies of regional landform patterns relating these linear dunes with other landforms have been scarce. This work aims to make use of a new geomorphic mapping system designed for aeolian environments to identify regional landform patterns in the Strzelecki Desert (Figure 1), potentially shedding further light on dunefield formation at large scales.

Aridity in the monsoon zone as indicated by desert dune formation in the Gregory Lakes basin, northwestern Australia

by Kathryn Fitzsimmons

Fitzsimmons, K.E., Miller, G.H., Spooner, N.A., Magee, J.W. (2012, in press) Aridity in the monsoon zone as indicated by desert dune formation in the Gregory Lakes basin, northwestern Australia. Australian Journal of Earth Sciences.

Desert dunes within the monsoon-fed Gregory Lakes basin form valuable archives for Quaternary paleoenvironments, in a... more Desert dunes within the monsoon-fed Gregory Lakes basin form valuable archives for Quaternary paleoenvironments, in a region where such records are scarce. Optically stimulated luminescence (OSL) chronologies from two dunes identify the timing of aeolian processes, interpreted as a complex response to aridification and increased sediment availability during lake transgressions and associated fluvial activity. The earliest aeolian deposition in our record occurred ca 91.5 ka, which postdates the last “mega-lake” phase but predates a smaller lake transgression during early MIS 3. Sand plain accretion took place around ca 47 ka during contemporaneous periodic high lake levels. This was followed by intermittent linear dune building, between ca 35 and 11.5 ka, which most likely took place during an interval of relative aridity. Close spacing of mid-Holocene ages within one dune indicates rapid sediment accumulation in a single arid event ca 5 ka. At no time in the last 50 ka have lake levels reached those of the last "mega-lake” phase prior to ca 91.5 ka, suggesting a substantially weakened present-day monsoon.

Flood Pulses and Restoration of Riparian Vegetation in the American Southwest

by Matt Chew

Ch. 2 in Middleton, Beth A., Ed. 2002. Flood Pulsing in Wetlands: Restoring the Natural Balance. John Wiley & Sons, Inc.

[From CAB Abstracts] Riparian areas in southwestern American deserts support native plant communities that are more... more [From CAB Abstracts] Riparian areas in southwestern American deserts support native plant communities that are more dense, structurally complex, productive and species-rich than those of the adjacent xeric uplands. Riparian areas attract human settlement and, as a result, riparian exotic plants have become an issue. The factors that have facilitated the influx of exotics into riparian corridors and the ways in which riparian ecosystem functions have been affected are discussed (with the impact of saltcedars (Tamarix spp.) as an example). High exotic abundance may be aided by flooding (enhancing dispersal and establishment opportunities), the introduction of grazing animals and other anthropogenic influences, e.g. road development and agriculture. Some woody exotics are now widespread and locally abundant in southwestern riparian areas, including Elaeagnus angustifolia, Ailanthus altissima, Tamarix spp. and Nicotiana glauca. There are probably over 100 naturalized exotic herbaceous species, the most successful of which are probably the grasses, e.g. Cynodon dactylon, Sorghum halepense, Polypogon monspeliensis and Bromus spp. Constructive options for restoring functionality to southwestern desert riparian ecosystems are discussed.

Market Potential for Nevada Teff Products

by Jason Entsminger

Co-authors: Kynda R. Curtis, Margret W. Cowee, Thomas R. Harris

Landowner Willingness to Sell or Lease Water Rights in the Walker River Basin.

by Jason Entsminger

Co-authors: Kynda R. Curtis and Staci Emm

Economic and Environmental Priorities of Walker River Basin Landowners.

by Jason Entsminger

Co-authors: Kynda R. Curtis and Staci Emm

Landowner Willingness to Adopt Alternative Cropping and Irrigation Strategies in the Walker River Basin.

by Jason Entsminger

Co-Authors: Kynda R. Curtis and Staci Emm

Public policy and small towns in arid South Africa: The case of Philippolis

by Jurie VAN Niekerk

Rainwater harvesting and management as an adaptive strategy to cope with the extreme climate events in the arid environment of the Arabian Peninsula.edit

by Mohammad ElNesr

Amin, M.T.; Alazba, A.A.; and ElNesr, M.N. 2011. ainwater harvesting and management as an adaptive strategy to cope with the extreme climate events in the arid environment of the Arabian Peninsula. Proc. 2nd IWA Development Congress & Exhibition 21–24 November 2011 Kuala Lumpur, MALAYSIA. Website: www.iwa2011KL.org

Water management in Saudi Arabia is facing major challenges due to the limited water resources and increasing... more Water management in Saudi Arabia is facing major challenges due to the limited water resources and increasing uncertainties caused by climate change. This paper presents an analysis of the daily, monthly and annual mean, maximum and total rainfall records of the Saudi meteorological data for nineteen cities covering the all thirteen districts for more than three decades (1980 to 2010). An increased annual total and maximum rainfall was observed for 6 cities with the decreased trends in both parameters for the same number of cities. For the reaming seven cities, however, an increased annual maximum rainfall trend was seen in opposite to the decreased annual total rainfall. This opposite rainfall trend is also seen for the 12 months of the year for the same city which signifies the variability of changing climate pattern not only in different districts but also during the year. The increased rain intensities due to climate change results in flooding of short in urban centers which are designed based on dry climates. Finally, the recommendations are made for the rooftop rainwater harvesting and management to cope with the increasing short-duration floods and to provide an additional source of drinking water. Co-operations among official efforts, local NGOs and public are suggested for better results of water supply management due to rainwater harvesting in Saudi Arabia in a changing climate associated with increased rainfall intensities.

The Gobi Region During the Younger Dryas

by Joshua Wright

with Lisa Janz, in Hunter-Gatherer Transitions Through the Younger Dryas: A global perspective. Ed. M.Eren. Left Coast Press (2012)

Shifting species interactions in terrestrial dryland ecosystems under altered water availability and climate change

by Kevin McCluney

Species interactions play key roles in linking the responses of populations, communities, and ecosystems to... more Species interactions play key roles in linking the responses of populations, communities, and ecosystems to environmental
change. For instance, species interactions are an important determinant of the complexity of changes in trophic biomass
with variation in resources. Water resources are a major driver of terrestrial ecology and climate change is expected to
greatly alter the distribution of this critical resource. While previous studies have documented strong effects of global
environmental change on species interactions in general, responses can vary from region to region. Dryland ecosystems
occupy more than one-third of the Earth’s land mass, are greatly affected by changes in water availability, and are
predicted to be hotspots of climate change. Thus, it is imperative to understand the effects of environmental change on
these globally significant ecosystems.
Here, we review studies of the responses of population-level plant-plant, plant-herbivore, and predator-prey
interactions to changes in water availability in dryland environments in order to develop new hypotheses and
predictions to guide future research. To help explain patterns of interaction outcomes, we developed a conceptual
model that views interaction outcomes as shifting between (1) competition and facilitation (plant-plant), (2) herbivory,
neutralism, or mutualism (plant-herbivore), or (3) neutralism and predation (predator-prey), as water availability crosses
physiological, behavioural, or population-density thresholds. We link our conceptual model to hypothetical scenarios
of current and future water availability to make testable predictions about the influence of changes in water availability
on species interactions. We also examine potential implications of our conceptual model for the relative importance of
top-down effects and the linearity of patterns of change in trophic biomass with changes in water availability. Finally,
we highlight key research needs and some possible broader impacts of our findings. Overall, we hope to stimulate and
guide future research that links changes in water availability to patterns of species interactions and the dynamics of
populations and communities in dryland ecosystems.

Late Pleistocene aeolian reactivation downwind of the Naracoorte East range, South Australia

by Kathryn Fitzsimmons

Fitzsimmons, K.E., Barrows, T.T. (2012) Late Pleistocene aeolian reactivation downwind of the Naracoorte East range, South Australia. Zeitschrift für Geomorphologie 56(2), 225-237.

Southeastern South Australia, straddling the coastal zone and semi-arid desert margins of the lower Murray-Darling... more Southeastern South Australia, straddling the coastal zone and semi-arid desert margins of the lower Murray-Darling Basin, provides an important record of landscape response to past environmental change during the Pleistocene. Previous research in the region has focussed either on the coastal barrier systems, which formed during interglacial periods, or the sub-parabolic and linear dune systems downwind, which generally formed under arid conditions out of phase with the strandlines. However, the geomorphologic and chronological relationship between these two systems is poorly understood. This study provides the first constraints on the initation of dune development downwind of the Naracoorte East strandline. In this preliminary study we show that aeolian deposition at Naracoorte was constrained by sediment supply from the strandline upwind, and was most likely gradual, more or less continuous, and took place under relatively arid climatic regimes. We demonstrate a genetic link between strandlines and the dune fields in the region.

Monitoring degradation in arid and semi-arid forests and woodlands: The case of the argan woodlands (Morocco)

by Yann le Polain de Waroux

This is an unformatted copy of the published version

Computing Evaporanspiraton from Weather Data Obtained from Distant, Non-Reference Weather Stations in a Hyper-Arid Region

by Mohammad ElNesr

ElNesr M. N. and Alazba A. A., 2011. Computing evaporanspiraton from weather data obtained from distant, non-reference weather stations in a hyper-arid region. Am. J. Agric. Biol. Sci.,6: 433-439.

Problem statement: Reference agro-climatic Weather Stations (WS) are rarely found in newly reclaimed areas. The usage... more Problem statement: Reference agro-climatic Weather Stations (WS) are rarely found in newly reclaimed areas. The usage of weather data from non-reference WS may lead to inaccurate estimations of Evapo Transpiration (ET), especially if the non-reference stations are distant from the reclaimed location. Approach: Weather data from four WS located at Riyadh were used to calculate ET by using Penman Monteith (PM) and Hargreaves equations. PM equation was applied with both alfalfa and grass reference crops. Calculations were done with and without temperature correction for non-reference weather stations. All calculations were compared with measured lysimeter data and corrections in Hargreaves formula were suggested. Results: (1): Weather data from non-reference WS can be used safely to calculate ET only when temperature corrections are applied. (2) Hargreaves formula underestimates ET at all locations in the study area. By applying the simple linear correction to the data, highly acceptable results are obtainned. (3) The ET ratio between alfalfa and grass in Riyadh is 1.25. Conclusion: The study concluded that temperature correction for non-reference WS is essential to ensure acceptable ET calculations. Usage of Hargreaves formula is recommended with the corrections suggested in the study due to its simplicity.

Spatio-Temporal Variability of Evapotranspiration over the Kingdom of Saudi Arabia.

by Mohammad ElNesr

ElNesr, M., & Alazba, A. (2010). Spatio-Temporal Variability of Evapotranspiration over the Kingdom of Saudi Arabia. Applied Engineering in Agriculture, ASABE, 26(5), 833-842. 

Climate change and variability is receiving much attention recently. Changes in the world temperature and other... more Climate change and variability is receiving much attention recently. Changes in the world temperature and other natural phenomenon such as rainfall variability are being considered as indicators to climate change. These changes can have significant effect on water resources and therefore on the livelihood of society especially in water scarce countries such Saudi Arabia. The Kingdom of Saudi Arabia suffers a chronic water scarcity, despite the fact that the agricultural sector consumes around 90% of the water budget in the kingdom. The objective of this article is to study the variability in reference evapotranspiration (ETo) demand over the kingdom during the period from 1980 to 2008 using Penman‐Monteith formula and to identify possible changes in the ETo as an indicator to climate change in the region. Studying ETo can be an incomparable indicator for climate change because it involves various parameters including temperature, humidity, and wind speed. Identifying changes in ETo can also help in future planning of agriculture‐water projects and identify lower and higher ETo zones for proper planning and management of agricultural projects in arid region. Results indicated that the average ETo varied from 5 mm/d in January to more than 15 mm/d in July with extreme value ranged from as low as 1.6 to 30 mm/d. The lowest ETo values were found in the southern region of the Kingdom during the month of November to February and starts to shift to the western region from the month of March to October. The results also indicated that the annual maximum and minimum daily averages of ETo steadily increased over the study period. The ETo annual daily average had increased from about 9.6 mm/d in 1980 to as high as 10.5 mm/d in 2008. Data analysis also revealed that the percentage areas of the Kingdom with high values of ETo depth, greater than 4000 mm/year, have also steadily increased in the study period from 25% to about 40%. On the other hand, areas having lower ETo values, less than 3600 mm/year have decreased over the studied area from about 30% in 1980 to as low as 12% of the kingdom total area. These results indicated clearly an increasing trend in the ETo over Saudi Arabia.

Development of a computer program to evaluate water requirements of vegetable crops in arid regions

by Mohammad ElNesr

Alazba, A.A., Alsadon, A.A., Alshahwan, I.M., Aldaood, A.S., &
El Nesr, M. N. (2010) “Development of a computer program to evaluate water requirements of vegetable crops in arid regions” {in Arabic}. Arab Univ. J. Agric. Sci. Vol:18 (2010)

>>Paper is in Arabic Language<<

Abstract will be translated later >>Paper is in Arabic Language<<

Abstract will be translated later

An outline of archaeological investigations for the Olympic Dam Expansion in arid northeast South Australia

by Ben Marwick

Hughes, P. P. Hiscock, M. Sullivan and B. Marwick. 2011. Journal of the Anthropological Society of South Australia 34:21-37

This is an outline of a large ongoing research-oriented salvage program that has evolved from past archaeological... more This is an outline of a large ongoing research-oriented salvage program that has evolved from past archaeological impact assessment studies at Olympic Dam in arid northeast South Australia.

A new formation process for calcic pendants from Pahranagat Valley, Nevada, USA, and implication for dating Quaternary landforms

by Brenda Buck

email for more information: buckb@unlv.nevada.edu

It has been assumed that soil pendants form in a similar manner as stalactites, in which innermost laminae are the... more It has been assumed that soil pendants form in a similar manner as stalactites, in which innermost laminae are the oldest and outer laminae
are the youngest. This study presents a new interpretation for soil pendant development. Pahranagat Valley, Nevada, pendants contain
features indicating continued precipitation through time at the clast–pendant contact, implying that the oldest deposits are not always found at
the pendant–clast contact, as other studies have assumed. These features include a void at the clast–pendant contact where minerals such as
calcium carbonate, silica, and/or fibrous silicate clays precipitate. In addition, fragments of the parent clast and detrital grains are incorporated
into the pendant and are displaced and/or dissolved and result in the formation of sepiolite. This study indicates that pendants are complex,
open systems that during and after their formation undergo chemical changes that complicate their usefulness for dating and
paleoenvironmental analyses.

Comparison of flood hazard assessments on desert piedmonts and playas: A case study in Ivanpah Valley, Nevada

by Brenda Buck

Abstract
Accurate and realistic characterizations of flood hazards on desert piedmonts and playas are... more Abstract
Accurate and realistic characterizations of flood hazards on desert piedmonts and playas are increasingly important given the rapid urbanization of arid regions. Flood behavior in arid fluvial systems differs greatly from that of the perennial rivers upon which most conventional flood hazard assessment methods are based. Additionally, hazard assessments may vary widely between studies or even contradict other maps. This study's chief objective was to compare and evaluate landscape interpretation and hazard assessment between types of maps depicting assessments of flood risk in Ivanpah Valley, NV, as a case study. As a secondary goal, we explain likely causes of discrepancy between data sets to ameliorate confusion for map users. Four maps, including three different flood hazard assessments of Ivanpah Valley, NV, were compared: (i) a regulatory map prepared by FEMA, (ii) a soil survey map prepared by NRCS, (iii) a surficial geologic map, and (iv) a flood hazard map derived from the surficial geologic map, both of which were prepared by NBMG. GIS comparisons revealed that only 3.4% (33.9 km2) of Ivanpah Valley was found to lie within a FEMA floodplain, while the geologic flood hazard map indicated that ~ 44% of Ivanpah Valley runs some risk of flooding (Fig. 2D). Due to differences in mapping methodology and scale, NRCS data could not be quantitatively compared, and other comparisons were complicated by differences in flood hazard class criteria and terminology between maps. Owing to its scale and scope of attribute data, the surficial geologic map provides the most useful information on flood hazards for land-use planning. This research has implications for future soil geomorphic mapping and flood risk mitigation on desert piedmonts and playas. The Ivanpah Valley study area also includes the location of a planned new international airport, thus this study has immediate implications for urban development and land-use planning near Las Vegas, NV.