The arid zone encompasses land that has an imbalance between precipitation and losses through evaporation. Globally, arid zones comprise large part of many countries in the mid-latitudes in both the Northern and the Southern hemispheres. Both Australia and Iran are countries with a large arid zone. This negative water balance in the arid zone affects the type of land use in these countries. At the driest end of the spectrum only the hardiest livestock, camels, and some locally adapted sheep and goats provide subsistence to nomadic peoples. In other parts of the arid zone, the search for forage and water has generated development of a number of management systems involving nomadic, seminomadic and settled herding practices. Maximum forage productivity of livestock in the rangeland depends on the amount of water to which the livestock has access. Livestock can use the range forage in the best way with no harms to the rangeland in order to produce the maximum livestock products if there are enough water resources. Due to the limited drinking water resources in the arid regions and the range ecosystem sensitivity in these regions, the optimum use and in general, water resources management are of considerable importance. Adaptations of livestock and people are discussed here before attention is turned to the impact of livestock on the resource base that is the vegetation (principally forage/browse) and water on which the pastoralists depend. پرونده مقاله

The impacts of Dust and Sand Storms (DSS) on people, crops, livestock, infrastructure and health are well documented. Data have accumulated on the deleterious effects of dust aerosols when they settle on plants. Sand blasting of low growing plants is a common cause of failure in reforestation efforts. Burial of plants by moving sands are also a cause of much damage. The physics of moving sand and dust particles is outlined and the mechanics of each type of damage is elaborated. The physical effects of dust accumulating on leaf surfaces, leaf physiology such as photosynthesis, transpiration, stomatal conductance and leaf temperature of many different species of plants were investigated. It was found that dust decreases stomatal conductance in the light, and increased it in the dark by plugging the stomata, when the stomata were open during dusting. When dust of smaller particles was applied, the effect was greater. However, the effect was negligible when the stomata were closed during dusting. The dust decreased the photosynthetic rate by shading the leaf surface. The paper also reviews experimental work on the physiological effects of dust on photosynthesis, stomatal function, respiration and transpiration. Examples are drawn from western Iran where oak woodlands (Quercus brantii) are under threat from dust that blows in from Iraq and Syria. پرونده مقاله

This is the second of series on the impact of dust. It focuses on the physical, chemical and physiological effects of dust particles and aerosols. Plants of all types and classes (from algae to forest trees and everything in between) are adversely affected either directly through abrasion by airborne particles or through interference with plant physiology or indirectly through the impact on soil as particles are deposited in the soil surface with effects on the soil chemistry, soil texture and soil structure. The literature that is reviewed spans decades and the biomes from which examples are drawn cover regions from the Arctic Circle to the equator, from deserts to tropical rainforests. The physiological responses of plants underlie and precede ecological changes at the community level and these changes have implications for such important relationships as predator-prey as shelter food supply and other essential ecosystem services either cease to be provided or are severely curtailed. It was found that all species have maximum dust deposition in the winter season followed by summer and rainy seasons. Chlorophyll content decreased and ascorbic acid content increased with the increase of dust deposition. There was significant negative and positive correlation between dust deposition and chlorophyll and ascorbic acid content, respectively. پرونده مقاله

Natural resources play a fundamental role in the economy of country and create the situation to achieve the goals of sustainable society, these valuable resources have to be conserved and used with care. Destroying the forests and rangelands will lead to a dark future full of poverty, starvation and environmental pollution. Forests and rangelands play a considerable role in reducing air pollution, minimizing soil erosion, protect against destructive floods, creating a pleasant place of recreation and relaxation while also allowing recharge of underground water resources. In short, ensure the preservation of resources essential for life on the earth. This is Part 3 of a comprehensive review of the impact of dust particles and aerosols. Part 1 (Squires, 2016a) examined the mechanisms by which dust particles and aerosols become airborne and the effect of particle size on deposition patterns. Part 2 (Squires, 2016b) focussed on the impact of particulates on the physiology, and productivity of plants. In this paper, attention is directed to the impact on human health of dust and aerosols generated from dust storms and from industrial sites (mines, factories and from roadside dust generated by passing vehicles). Effects of such dust range from nuisance (that arises from loss of visibility) to increased costs of clean-up of premises, through to serious health problems generated by inhalation of dust particles and aerosols. پرونده مقاله

It is very easy to view land degradation and desertification as purely biophysical phenomena for which there are neat technological solutions. Yet millions of real people live in the affected lands, and they both cause land degradation and are impacted by it, so scientists and land managers need to find a good balance between reductionist rigor and societal applicability. The concept of Land Degradation Neutral World (LDN) offered great promise to meet the commitments made in the various National Action Plans as a road map for achieving goals for the affected country reports to the United Nations Convention to Combat Desertification (UNCCD). The operationalization of LDN is more challenging. We must recognize the consequences of past inaction on land degradation, climate change and biodiversity loss. Land degradation plays a key role in this ‘vicious triangle’ of threats to our sustainability. The LDN agenda provides a framework, and commitment to it by all nations affected by land degradation, is the key to successful outcomes by 2030. Adoption of the idea and implementation of measures could lead to reaching LDN, one of the UN’s sustainable development goals that was agreed in 2015, but it won’t be easy and there is an obligation for the richer nations to provide financial and technical support to affected party countries. پرونده مقاله