Coastal ecosystems are often formed through two-way interactions between plants and their physical landscape. By expanding clonally, landscape-forming plants can colonize bare unmodified environments and stimulate vegetation-landform feedback interactions. Yet, to what degree these plants rely on clonal integration for overcoming physical stress during biogeomorphological succession remains unknown. Here, we investigated the importance of clonal integration and resource availability on the resilience of two European beach grasses (i.e. Elytrigia juncea and Ammophila arenaria) over a natural biogeomorphic dune gradient from beach (unmodified system) to foredune (biologically modified system). We found plant resilience, as measured by its ability to recover and expand following disturbance (i.e. plant clipping), to be independent on the presence of rhizomal connections between plant parts. Instead, resource availability over the gradient largely determined plant resilience. The pioneer species, Elytrigia, demonstrated a high resilience to physical stress, independent of its position on the biogeomorphic gradient (beach or embryonic dune). In contrast, the later successional species (Ammophila) proved to be highly resilient on the lower end of its distribution (embryonic dune), but it did not fully recover on the foredunes, most likely as a result of nutrient deprivation. We argue that in homogenously resource-poor environments as our beach system, overall resource availability, instead of translocation through a clonal network, determines the resilience of plant species. Hence, the formation of high coastal dunes may increase the resistance of beach grasses to the physical stresses of coastal flooding, but the reduced marine nutrient input may negatively affect the resilience of plants.

中文翻译：

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海滩草沿着生物地貌连续梯度的恢复力：资源可用性与克隆整合。


沿海生态系统通常是通过植物与其自然景观之间的双向相互作用而形成的。通过克隆扩张，景观形成植物可以在裸露的未改造环境中殖民，并刺激植被-地貌反馈相互作用。然而，这些植物在生物地貌演替过程中在多大程度上依赖克隆整合来克服物理压力仍然未知。在这里，我们研究了克隆整合和资源可用性对两种欧洲海滩草（即 Elytrigia juncea 和 Ammophila arenararia）在从海滩（未改造系统）到 foredune（生物改造系统）的自然生物地貌沙丘梯度上的恢复力的重要性。我们发现植物的恢复力（通过其在干扰（即植物修剪）后恢复和扩展的能力来衡量）独立于植物各部分之间根茎连接的存在。相反，梯度上的资源可用性在很大程度上决定了植物的恢复能力。先锋物种 Elytrigia 显示出对物理压力的高度恢​​复能力，无论其在生物地貌梯度（海滩或胚胎沙丘）上的位置如何。相比之下，后来的演替物种（Ammophila）被证明在其分布的低端（胚胎沙丘）具有高度的恢复能力，但它在前丘上没有完全恢复，很可能是营养匮乏的结果。我们认为，在我们的海滩系统这样的同质资源匮乏的环境中，整体资源的可用性，而不是通过克隆网络的易位，决定了植物物种的恢复能力。 因此，高沿海沙丘的形成可能会增加海滩草对沿海洪水物理压力的抵抗力，但海洋养分输入的减少可能会对植物的恢复能力产生负面影响。