A disjunct population of the annual form of the seagrass Zostera marina that occurred in the upper intertidal zone of Yaquina Bay, Oregon was sampled to determine whether there were differences in recruitment, growth, survivorship and morphology associated with microtopographic location on the sand flat. Population responses of seagrass found in areas differing by only a few cm in vertical elevation were compared. There was higher plant abundance and higher number of shoots per plant in microtopographic low areas. Plants in lower areas also had significantly longer shoots, greater total above ground biomass, greater biomass per shoot, and greater biomass of reproductive spathes than plants growing in immediately adjacent, microtopographic high areas. Cover of green macroalgae was higher and accumulated more rapidly in microtopographic high areas as compared to low areas, and both spatially and temporally was correlated with decreased recruitment and increased plant loss in these slightly elevated areas. While impacts of desiccation may have played some role in determining the influence of microtopographic variation on the annual Z. marina population, macroalgal effects appear to be predominant.

海草Zostera码头的年度形式的离散种群对俄勒冈州Yaquina湾上潮间带的岩层进行了采样，以确定在沙地上的微地形位置相关的募集，生长，生存和形态上是否存在差异。比较了在垂直高度仅几厘米的区域发现的海草种群响应。在微地形低洼地区，植物丰度更高，每株植物的芽数更高。与在紧邻的微地形高地区生长的植物相比，位于较低区域的植物还具有更长的枝条，更高的地上生物量总量，更高的单枝生物量以及更大的繁殖区生物量。与低洼地区相比，微地形高处的绿色大型藻类的覆盖率更高，积累速度更快，在这些略微升高的区域中，空间和时间均与减少的招聘和增加的植物损失相关。虽然干燥的影响可能在确定微观地形变化对年度变化的影响中起了一定作用在滨海Z.种群中，大型藻类效应似乎占主导地位。