Long Term Ecological Research Program: Shortgrass Steppe

9632852 Burke短草草原（SGS）占据LTER草原站点所在的生产力梯度的中间沿着。它在北美草原中是独一无二的，因为它在干旱和草食动物的强烈选择下有着漫长的进化历史，从而形成了一个非常适应家畜放牧的生态系统。SGS的显着特点是其植被和地下生物活动和有机物的集中。SGS植被的特点是生长缓慢的植物，它们要么耐放牧，要么耐干旱。地下生物活动的高度集中反映了植物生产的分布和地下异养生物能量流的增强。另一部分原因是，草原中的大多数生物活性元素储存在土壤有机质中，不受自然干扰。SGS LTER项目自1982年以来一直在运行，目前支持46个长期实验，许多短期实验，并非常重视综合模拟分析。SGS LTER的工作分为五个主要领域：种群和过程、地球化学动力学、古生态学和古土壤学、水和能量动力学以及干扰。此外，SGS还参与了许多综合活动，这些活动将很快在综合卷中概述。该研究计划的独特之处之一是强调将SGS生态系统的知识融入模拟模型。这些模型被广泛使用，它们将继续作为SGS LTER计划未来研究的整合思想和发展假设的手段。

9632852 Burke The shortgrass steppe (SGS) occupies the middle of the productivity gradient along which the LTER grassland sites lie. It is unique among North American grasslands for its long evolutionary history of intense selection by both drought and herbivory, leading to an ecosystem that is very well adapted to withstand grazing by domestic livestock. The distinctive features of the SGS are both its vegetation and the concentration of biological activity and organic matter belowground. The vegetation of the SGS is characterized by low-growing plants that are either tolerant or resistant to grazing and drought. The large concentration of biological activity belowground reflects the distribution of plant production and the enhanced rates of energy flow through heterotrophs belowground. It is also explained in part by the fact that most biologically active elements in grasslands are protected from natural disturbances by being stored in soil organic matter. The SGS LTER project has been in operation since 1982 and currently supports 46 long-term experiments, numerous short-term experiments, and has a large emphasis on integrative simulation analysis. SGS LTER work is divided into five major areas: populations and processes, biogeochemical dynamics, paleoecology and paleopedology, water and energy dynamics, and disturbances. In addition, the SGS is involved in many synthesis activities which will soon be summarized in a synthesis volume. One of the unique aspects of this research program is the emphasis on integrating knowledge about SGS ecosystems into simulation models. These models are used widely, and they will continue to serve as a mean of integrating ideas and developing hypotheses for future research in the SGS LTER program.