RUI: Pattern Formation and Lanscape Change in a Sand Plain Oak Savanna and Woodland

9419922戴维斯这个项目是对明尼苏达州中东部沙地平原橡树稀树草原栖息地变化的研究。作为明尼苏达州的一个受威胁的栖息地，橡树稀树草原在没有火灾的情况下被转化为橡树林地。在这个过程中，一片片的橡树扩展、连接和包围着一片片的草原。相反，当重新引入火灾时，橡树林地被开辟出来，因为成片的树木缩小、细分，甚至消失。因此，对这些以橡木为主的环境中栖息地变化的研究在一定程度上是对格局形成的研究。这项研究的目的之一是确定影响栖息地橡树格局发展的因素。要调查的因素包括地形影响、口袋地鼠的影响、火，以及现有草本和木本植被的影响。第二个目标是量化橡树植被变化的一些重要的物理和生物后果，包括对灌木和草本植被、袋鼠和茅草蚁分布、凋落层、橡树补给和火灾强度的影响。该项目的方法包括使用地统计学和地理信息系统分析航空照片和从地面网格收集空间参考数据；调查树荫、水和周围景观对幼苗存活和生长的影响的试验性花园研究；以及衡量火灾和物理移除灌木和橡树树苗对草本植物群落影响的试验区研究。发展这一方法是为了能够在几个空间和时间尺度上研究模式的形成。通过不仅阐明格局，而且阐明产生格局的过程和机制，这项研究将有助于我们理解橡树稀树草原和林地环境中的立地历史和栖息地变化。这项研究收集的信息将作为雪松溪长期生态研究项目的一部分，专门补充关于橡树再生的研究。最后，拟议中的项目将提供数据，从而改善中西部北部最受威胁的栖息地之一的管理计划。

9419922 Davis This project is a study of habitat change in a sand plain oak savanna in east central Minnesota. A threatened habitat in Minnesota, oak savannas are converted to oak woodlands in the absence of fire. In this process, patches of oak trees expand, connect, and encircle patches of prairies. Conversely, when fire is reintroduced, oak woodlands are opened up as patches of trees shrink, subdivide, and even disappear. Thus, the study of habitat change in these oak dominated environments is partly a study of pattern formation. One of the objectives of this study is to identify factors that influence the pattern development of oaks in the habitat. Factors to be investigated include landform effects, effects of pocket gophers, fire, and effects of existing herbaceous and woody vegetation. A second objective is to quantify some of the important physical and biological consequences of the changes in the oak vegetation, including effects on shrubby and herbaceous vegetation, pocket gopher and thatch ant distribution, litter layer, oak recruitment, and fire intensity. The project's methodology includes analysis of aerial photographs and spatially referenced data collection from a ground grid using geostatistics and GIS; an experimental garden study to investigate the effects of shade, water, and surrounding landscape on seedling survivorship and growth; and an experimental plot study to measure the effects of fire and the physical removal of shrubs and oak saplings on the herbaceous community. The methodology has been developed to permit the study of pattern formation at several spatial and temporal scales. %%% By elucidating mot only the patterns but the processes and mechanisms that produce the patterns, this study will contribute to our understanding of site history and habitat change in oak savanna and woodland environments. Information gathered from this study will specifically complement studies on oak regeneration as part of the Cedar Creek Long-term Ecological Research Project. Fin ally, the proposed project will provide data that can lead to improved management plans for one of the upper midwest's most threatened habitats.