Artificial environments have hard surfaces positioned at different orientations that attract a wide diversity of sessile invertebrate species, forming fouling communities. Fouling communities play a large role in the spread of a species introduction, as organisms gain purchase in artificial environments and use them as a stepping-stone into neighboring natural systems. These man-made systems harbor a large diversity of species, and there are often vastly different communities present on both vertical and horizontal surfaces. We used a species abundance dataset at three time periods spanning 30 years, collected from fouling panels in a high tidal flow estuary at the mouth of the Piscataqua River (New Castle, New Hampshire) in the southern Gulf of Maine to measure differences in community composition between horizontal and vertical panels. Early successional communities on settlement panels were photographed one year after installment in late summer to capture the highest diversity seasons. Organisms were then identified to the lowest taxonomic level, and communities on the underside of horizontal and vertical panels were compared. Vertical and horizontal communities from 1980 and 2004 were similar, while those from 2009 statistically differed from one another. Vertical and horizontal surfaces in the 1980s were dominated by the blue mussel Mytilus edulis, which declined in later years, and was replaced by invasive ascidians. Species diversity increased between the 1980 and 2004 sampling, but declined by the 2009 sampling. This study captures changes of species composition in early successional communities on vertical and horizontal surfaces at a single locale from three time periods spanning over 30 years.

人工环境具有位于不同方向的坚硬表面，吸引了多种固着无脊椎动物物种，形成污垢群落。污垢群落在物种引入的传播中发挥着重要作用，因为生物体在人工环境中获得购买力，并将其用作进入邻近自然系统的踏脚石。这些人造系统拥有多种多样的物种，并且垂直和水平表面上通常存在截然不同的群落。我们使用了跨越 30 年的三个时间段的物种丰度数据集，这些数据集是从缅因州南部皮斯卡塔夸河（新罕布什尔州纽卡斯尔）河口高潮汐流河口的污垢面板收集的，以测量群落组成的差异水平面板和垂直面板之间。定居点面板上的早期演替群落在安装一年后的夏末进行了拍摄，以捕捉多样性最高的季节。然后将生物体识别到最低的分类水平，并对水平和垂直面板下侧的群落进行比较。1980年和2004年的纵向和横向社区相似，而2009年的纵向和横向社区在统计上存在差异。20世纪80年代的垂直和水平表面以蓝贻贝为主贻贝在后来的几年中逐渐减少，并被入侵性海鞘所取代。1980 年至 2004 年采样期间，物种多样性有所增加，但 2009 年采样期间，物种多样性有所下降。这项研究捕捉了 30 多年的三个时间段内单个地点垂直和水平表面上早期演替群落物种组成的变化。