EPOW - Ecology Picture of the Week

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Desert Tracks

Credit & Copyright:  Dr. Bruce G. Marcot
  

Explanation:  What is this spaghetti tangle, as seen from our Fokker 50 plane flight over the Gobi Desert savanna, en route south from Ulaanbaatar to Dalanzadgad, Mongolia?   These are the scars of desert travelers.  No, not camels, but vehicles, winding and weaving their way across the steppe.         We, too, soon found ourselves in a 4-van convoy, crisscrossing the Gobi grasslands to get to our ger (yurt) camp.  I kept an eye on our driver's speedometer, and at several points we reached a zippy 105 kilometers per hour (65 miles per hour), with a dust rooster tail behind every vehicle.         The scars of our passage, along with countless others in years, decades, prior, will remain on the desert land likely for many decades to come.   A study of the impact of unpaved roads in Mongolia (Keshkamat et al. 2012) found there to be virtually no restrictions to vehicle movement, speed, or direction ... and that environmental impacts of these road systems include local decimation of plants and animals, habitat degradation, soil compaction, increased soil erosion, and damage to aquatic habitats and water quality at streambed crossings.  Recovery to some degree of revegetation can take 10-15 years, but revegetation is often by invasive plant species such as tumbleweed (Salsola collina), fringed sagebrush (Artemisia frigida), and Chinese wild-ryegrass (Leymus chinensis), instead of native grasses and forbs.   Recovery to a pristine state with native vegetation could take much longer, if at all possible.   Further impacts can include vehicle-generated dust that can linger in the air and can be blown onto otherwise healthy grassland, and the dirt tracks themselves become further scoured by the stiff desert winds.  Vehicle-generated dust also can adversely affect livestock grazing and health and can add to vehicle accidents (Greening 2011).     This "bowtie" pattern is a river-bed crossing, where multiple dirt tracks in the Gobi Desert converge to incise the passage.  This creates streambed sedimentation, erosion, and degradation of the aquatic habitat and water quality for people and animals alike.    So what can be done?  Paving roads that bisect sensitive ecosystems such as deserts, tropical rainforests, and even alpine and arctic tundra have impacts of their own.  Impacts can be lessened with appropriate control of road use, vehicle speeds, and avoiding off-road driving, as well as building passes over riverbeds and allowing for natural drainage of slopes.        So now, buckle up, and enjoy the ride!       Information:      Greening, T.  2011.  Quantifying the impacts of vehicle-generated dust: a comprehensive approach.  The World Bank, Department for International Development, Washington, D.C.  71 pp.      Keshkamat, S. S., N.-E. Tsendbazar, M.H.P. Zuidgeest, A. van der Veen, and J. de Leeuw.  2012.  The environmental impact of not having paved roads in arid regions:  an example from Mongolia.  Ambio 41(2):202-205.