Factors Influencing Vegetation Trends in Dryland Zones

土地退化是一项重大威胁，它可以减少农业生产并造成极端的人类痛苦。在干旱地区尤其如此，那里的气候、土壤和人类活动相互作用导致荒漠化，干旱和半干旱地区生态系统服务的减少或丧失，对人类、动物和植物产生负面影响。几乎整个美国的西半部都被认为是干旱地区，我国20世纪30年代的沙尘暴经常被引用为沙漠化的一个典型的大规模例子。严重的干旱、不适当的农业做法和脆弱的土壤造成了大平原南部广泛的沙尘暴和巨大的作物和牲畜损失。在半干旱的非洲和亚洲部分地区，严重的干旱和饥荒也与荒漠化有关。由于它影响到全球很大一部分人口，因此1994年签署了《联合国防治荒漠化公约》（UNCCD）。尽管有这些历史事件和全球关注，但荒漠化仍然是一个知之甚少且经常引起争议的环境过程。科学研究经常审查有关其在地方、区域和全球范围内的速度、程度和严重程度的基本问题，但很少有明确的答案。其中最大的一个问题是，荒漠化一旦开始，是否可以逆转，如果可以，如何逆转？本研究使用了一个试验案例，在这个案例中，1970年代和1980年代的干旱引发了广泛的荒漠化，而最近的卫星图像显示，那里出现了大规模的植被增加，或者可能出现相反的荒漠化。北卡罗来纳大学教堂山分校的科林·韦斯特博士和亚伦·穆迪博士将探索是什么因素推动了旱地植被变绿的趋势。这项研究将检验当地土地利用实践驱动区域植被趋势的假设。这项研究将在布基纳法索北部进行，其中一名研究人员自2002年以来一直在那里进行长期的人类学工作。在美国国家科学基金会（National Science Foundation）之前的支持下，研究小组收集了一系列卫星图像，这些图像显示了不同地区的绿化（荒漠化可能正在逆转）和褐化（荒漠化可能正在加速）。以这些结果为指导，他们通过询问当地农民和牧民对环境变化的看法来寻求这些模式的真相。这位人类学家、他的研究生和当地合作者将利用高分辨率卫星图像在被认为是变绿、褐变和混合的地区举办研讨会。其他学生将使用遥感程序处理和分析这些图像，以测量三个区域的植被数量。该研究预测，绿色区域将比棕色区域拥有更多的树木，而混合区域将处于中间状态。在讲习班上，当地资源使用者还将寻求他们对气候、土地利用实践和土壤如何相互作用产生这些模式的看法。该奖项反映了美国国家科学基金会的法定使命，并通过使用基金会的知识价值和更广泛的影响审查标准进行评估，被认为值得支持。

Land degradation is a significant threat that can reduce agricultural production and cause extreme human suffering. This is particularly true in drylands where climate, soils, and human activities interact to produce desertification, the reduction or loss of ecosystem services in arid and semi-arid regions that negatively affect people, animals, and plants. Nearly the entire western half of the United States is considered a dryland and our country's Dust Bowl of the 1930s is often cited a classic large-scale example of desertification. Severe droughts, inappropriate agricultural practices, and fragile soils caused widespread dust storms and enormous crop and cattle losses in the southern Great Plains. Severe droughts and attending famines in semi-arid Africa and parts of Asia have also been linked to desertification. Because it affects a huge portion of the globe's population, there is a United Nations Convention to Combat Desertification (UNCCD), which was signed in 1994. Despite these historical events and global concern, desertification remains a poorly understood and often controversial environmental process. Basic questions concerning its rate, extent and severity at local, regional and global scales are frequently examined in scientific studies but rarely definitively answered. One of the largest of these questions concerns whether or not desertification, once started, can be reversed and, if so, how? This study uses a test case where droughts in the 1970s and 1980s initiated widespread desertification and where recent satellite images suggest large-scale clusters of increased vegetation, or potentially desertification in reverse. Dr. Colin West and Dr. Aaron Moody of the University of North Carolina at Chapel Hill will explore what factors drive vegetation trends in the greening of dryland zones. This study would test the hypothesis that local land-use practices drive regional vegetation trends. The research would take place in northern Burkina Faso, where one of the researchers has conducted long-term anthropological work since 2002. With previous support from the National Science Foundation, the research team has assembled a time series of satellite images that show distinct areas of both greening (where desertification may be in reverse) and browning (where desertification may be accelerating). Using these results as a guide, they seek to ground-truth these patterns by asking local farmers and herders about their perceptions of environmental change. The anthropologist, his graduate students, and local collaborators will conduct workshops using high-resolution satellite images in areas considered greening, browning and mixed. Using remote sensing procedures, other students will process and analyze these images to measure the amount of vegetation in the three zones. The study predicts that green zones will have more trees than brown zones and that the mixed zone will be intermediate. Workshops will local resource users will also seek their perspectives on how climate, land-use practices, and soils interact to produce these patterns.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.