New Tool for Understanding Landscape Evolution in Drylands
- Jenny Lunn
- May 2, 2017
- 1 min read
Combining vegetation distribution models and sediment transport models offers a better understanding of how dryland environments change in response to different factors.
Drylands compose more than 40% of Earth’s surface. Although they are found on every continent and are tremendously diverse, a common feature of drylands is sparse vegetation and expanses of bare ground such as soil or sand. In such a context, the wind plays a significant role in moving loose sediments and shaping the landscape.
Understanding the processes of landscape evolution is important for the management of arid and semiarid areas upon which people depend for their livelihoods. But a long-standing problem in drylands research has been quantifying the transport of sediment by wind in the presence of vegetation and how this influences landscape evolution. For example, wind blowing toward a single tree, a cluster of low shrubs, or an expanse of patchy grass will have different effects in terms of the location and severity of erosion and the location and shape of sediment deposition.
However, predicting exactly what will happen is complex because of the range of factors at play. There are natural variables such as the distribution, type, and size of vegetation; the direction, speed, and consistency of wind; and the frequency, duration, and intensity of rainfall. Human influences are also at play, including growing crops on the land, grazing animals, and setting fire to vegetation, all of which change the availability of sediment and the behavior of wind as it passes over the landscape.
Ollivier Girard/CIFOR