Factors Influencing Vegetation Trends in Dryland Zones

土地退化是一个重大威胁，可能会减少农业生产并造成极端的人类痛苦。在旱地尤其如此，气候、土壤和人类活动相互作用，造成荒漠化，干旱和半干旱地区的生态系统服务减少或丧失，对人、动物和植物产生负面影响。几乎整个美国西半部都被认为是旱地，我们国家20世纪30年代的沙尘暴经常被引用为典型的大规模荒漠化的例子。严重的干旱、不适当的农业措施和脆弱的土壤在大平原南部造成了大范围的沙尘暴和巨大的作物和牲畜损失。半干旱的非洲和亚洲部分地区的严重干旱和饥荒也与荒漠化有关。因为它影响到全球很大一部分人口，所以1994年签署了《联合国防治荒漠化公约》(《荒漠化公约》)。尽管有这些历史事件和全球关注，荒漠化仍然是一个鲜为人知、往往有争议的环境过程。关于其在地方、区域和全球范围内的比率、程度和严重性的基本问题经常在科学研究中得到审查，但很少有明确的答案。其中最大的问题之一是，荒漠化一旦开始，是否可以逆转，如果可以，如何逆转？这项研究使用了一个测试案例，20世纪70年代和80年代的干旱引发了大范围的荒漠化，最近的卫星图像表明，大规模的植被集群增加，或者潜在的荒漠化。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地区绿化的植被趋势。这项研究将检验这样一种假设，即当地的土地利用实践推动了区域植被趋势。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。在国家科学基金会以前的支持下，研究小组收集了一系列卫星图像，显示了不同的绿化区域(荒漠化可能相反)和褐化(荒漠化可能正在加速)。以这些结果为指导，他们试图通过询问当地农民和牧民对环境变化的看法来证实这些模式的真实性。这位人类学家、他的研究生和当地的合作者将在被认为是绿色、棕色和混合的地区使用高分辨率卫星图像开展研讨会。使用遥感程序，其他学生将处理和分析这些图像，以测量三个区域的植被数量。这项研究预测，绿化区的树木将比棕色区多，混合区的树木将处于中间状态。研讨会将向当地资源使用者征求他们对气候、土地利用实践和土壤如何相互作用以产生这些模式的看法。该奖项反映了NSF的法定使命，并通过使用基金会的智力优势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.