Baltimore Ecosystem Study: Riparian vegetation data - 5 of 11 - 1999 seedling data

This is one of 11 datasets generated in a study of riparian vegetation in the Baltimore Ecosystem Study from 1999-2004. Comparisons of vegetation between the rural/suburban (upper) and urban (lower) sections of the watershed show distinct patterns across an urban to rural gradient. In the lower, more urban section of the watershed, wetland tree species are either absent or occur as small stems while upland species are abundant, in mixed sizes. A comparison of the number of wetland and upland species in the mostly urbanized Gwynns Falls riparian zone with non-urbanized Piedmont floodplains throughout Maryland shows approximately twice as many upland species in the urban floodplain than in non-urbanized floodplains. The majority of shrubs in riparian zones through the Gwynns Falls are upland species. For herbaceous species, frequencies of upland and wetland species are about equal in the upper and middle regions of the watershed, but upland species are more common in the more urban lower floodplains by a factor of greater than two.本数据集为1999年至2004年巴尔的摩生态研究（Baltimore Ecosystem Study）中河岸植被（riparian vegetation）研究生成的11套数据集之一。对该流域（watershed）农村/郊区段（上游）与城市段（下游）的植被开展对比分析，可观测到沿城乡梯度分布的显著差异模式。在流域下游城市化程度更高的区域，湿地树木物种（wetland tree species）要么完全缺失，要么仅以矮小植株的形式存在，而高地物种（upland species）则大小混杂且分布丰富。将城市化程度较高的格林斯瀑布（Gwynns Falls）河岸带与马里兰州（Maryland）境内未城市化的皮埃蒙特泛滥平原（Piedmont floodplains）的湿地、高地物种数量进行对比，结果显示城市泛滥平原的高地物种数量约为未城市化泛滥平原的两倍。格林斯瀑布流域河岸带的灌木大多为高地物种。对于草本植物（herbaceous species）而言，流域上游与中游区域的高地、湿地物种出现频率大致相当，但在城市化程度更高的下游泛滥平原中，高地物种的出现频率是湿地物种的两倍以上。