School of Geography and the Environment, Oxford University Centre for the Environment, University of Oxford, Oxford, OX1 3QY, UK.
Sci Rep. 2017 Jun 20;7(1):3887. doi: 10.1038/s41598-017-04341-0.
Drylands are home to over 2 billion people globally, many of whom use the land for agricultural and pastoral activities. These vulnerable livelihoods could be disrupted if desert dunefields become more active in response to climate and land use change. Despite increasing knowledge about the role that wind, moisture availability and vegetation cover play in shaping dryland landscapes, relatively little is known about how drylands might respond to climatic and population pressures over the 21 century. Here we use a newly developed numerical model, which fully couples vegetation and sediment-transport dynamics, to simulate potential landscape evolution at three locations in the Kalahari Desert, under two future emissions scenarios: stabilising (RCP 4.5) and high (RCP 8.5). Our simulations suggest that whilst our study sites will experience some climatically-induced landscape change, the impacts of climate change alone on vegetation cover and sediment mobility may be relatively small. However, human activity could strongly exacerbate certain landscape trajectories. Fire frequency has a primary impact on vegetation cover, and, together with grazing pressure, plays a significant role in modulating shrub encroachment and ensuing land degradation processes. Appropriate land management strategies must be implemented across the Kalahari Desert to avoid severe environmental and socio-economic consequences over the coming decades.
旱地在全球范围内为超过 20 亿人提供了家园，其中许多人将土地用于农业和畜牧业活动。如果沙漠沙丘由于气候和土地利用变化而变得更加活跃，这些脆弱的生计可能会受到干扰。尽管人们越来越了解风、水分可用性和植被覆盖在塑造旱地景观方面的作用，但对于旱地在 21 世纪如何应对气候和人口压力，人们知之甚少。在这里，我们使用一种新开发的数值模型，该模型完全耦合了植被和输沙动态，以模拟喀拉哈里沙漠三个地点在两种未来排放情景下的潜在景观演变：稳定（RCP4.5）和高（RCP8.5）。我们的模拟表明，尽管我们的研究地点将经历一些气候引起的景观变化，但气候变化本身对植被覆盖和泥沙流动性的影响可能相对较小。然而，人类活动可能会强烈加剧某些景观轨迹。火灾频率对植被覆盖有主要影响，并且与放牧压力一起，在调节灌木入侵和随后的土地退化过程中起着重要作用。必须在整个喀拉哈里沙漠实施适当的土地管理策略，以避免在未来几十年内产生严重的环境和社会经济后果。
