Science. 1990 Mar 2;247(4946):1043-8. doi: 10.1126/science.247.4946.1043.
Studies of ecosystem processes on the Jornada Experimental Range in southern New Mexico suggest that longterm grazing of semiarid grasslands leads to an increase in the spatial and temporal heterogeneity of water, nitrogen, and other soil resources. Heterogeneity of soil resources promotes invasion by desert shrubs, which leads to a further localization of soil resources under shrub canopies. In the barren area between shrubs, soil fertility is lost by erosion and gaseous emissions. This positive feedback leads to the desertification of formerly productive land in southern New Mexico and in other regions, such as the Sahel. Future desertification is likely to be exacerbated by global climate warming and to cause significant changes in global biogeochemical cycles.
对新墨西哥州南部乔纳达实验牧场生态系统过程的研究表明，半干旱草原的长期放牧会导致水、氮和其他土壤资源的空间和时间异质性增加。土壤资源的异质性促进了沙漠灌木的入侵，这导致了在灌木树冠下土壤资源的进一步本地化。在灌木之间的荒芜地区，土壤肥力因侵蚀和气体排放而丧失。这种正反馈导致新墨西哥州南部和其他地区（如萨赫勒地区）曾经肥沃的土地沙漠化。未来的沙漠化可能会因全球气候变暖而加剧，并导致全球生物地球化学循环发生重大变化。
