Ecotones are ecological boundaries or areas of transition between ecosystems. They are sensitive indicators of global change, and studying their dynamics can be useful to predict habitat shifts and landscape transformation. The Ulva-Zostera ecotone in Elkhorn Slough (California, United States) is a good example of a transitional area between habitat-forming macrophytes in a highly eutrophic coastal system. This study focused on understanding its driving factors, spatiotemporal trends, and overall ecological implications. A combination of habitat monitoring, recruitment and transplant experiments, and sediment analysis were used to describe the ecological characteristics of the system. Ecotone dynamics were driven by seasonality of Ulva spp., its distribution across the ecotone delimited by processes affecting its early developmental stages. While water quality and light availability were not linked to abundance and distribution of Ulva spp., sediment composition likely affected macrophyte distribution and overall ecosystem structure. Remarkably, physico-chemical conditions that hinder growth and expansion of Ulva spp. occur where eelgrass (Zostera marina) is present. Understanding the processes involved in habitat boundary dynamics is important to identify stressors and anticipate change at larger scales.

生态带是生态系统之间的生态边界或过渡区。它们是全球变化的敏感指标，研究它们的动态有助于预测栖息地变化和景观变化。Elkhorn Slough（美国加利福尼亚州）的Ulva-Zostera交错带是高度富营养化沿海系统中形成栖息地的大型植物之间过渡区的一个很好的例子。本研究侧重于了解其驱动因素、时空趋势和整体生态影响。栖息地监测、补充和移植实验以及沉积物分析的组合被用来描述系统的生态特征。环带动态受石莼的季节性驱动spp.，其分布在由影响其早期发育阶段的过程划定的跨带中。虽然水质和光照可用性与石莼属的丰度和分布无关，但沉积物成分可能影响大型植物分布和整体生态系统结构。值得注意的是，阻碍石莼属生长和扩张的物理化学条件。发生在鳗草（Zostera marina ）存在的地方。了解栖息地边界动态所涉及的过程对于识别压力源和预测更大规模的变化非常重要。