Baltimore Ecosystem Study: Riparian vegetation data - 3 of 11 – 1999_riparian_Herb_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年巴尔的摩生态系统研究（Baltimore Ecosystem Study）中针对河岸植被（riparian vegetation）的研究生成的11项数据集之一。对该流域农村/郊区（上游段）与城市（下游段）的植被开展对比分析，可发现其沿城市-农村梯度呈现出清晰的分布模式。在该流域城市化程度更高的下游段，湿地木本植物要么缺失，要么仅以幼茎形式存在；而旱地物种则数量丰富，且个体大小参差不齐。针对城市化程度较高的格温斯福尔斯（Gwynns Falls）河岸带（riparian zone）与马里兰州全域非城市化皮埃蒙特（Piedmont）泛滥平原（floodplains）的湿地及旱地物种数量展开对比后发现，城市泛滥平原的旱地物种数量约为非城市化泛滥平原的两倍。格温斯福尔斯流域河岸带的绝大多数灌木均为旱地物种。对于草本植物（herbaceous species）而言，流域上游及中游区域的旱地与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，旱地物种的出现频率是湿地物种的两倍以上。