Abstract To understand functional mechanisms and ecological conditions of the Baltic coastal lakes (BCL) for the need of their restoration, the current state of knowledge on environmental, ecological, and evolutionary processes responsible for biological diversity is presented. This has allowed the classification of coastal lakes along the southern Baltic Sea coast as freshwater, transitional, and brackish ones. Principles of their functioning are explained here on the basis of the theory of alternative stable states in shallow lake ecosystems (brackish vs. freshwater) separated by adaptive cycles (transitional lakes). Successful concepts for the design and application of restoration of degraded coastal aquatic ecosystems is conditioned by both marine and terrestrial factors. Thus, the restoration plans of the southern Baltic coastal lakes, contrary to freshwater inland lakes, require some specific criteria to be applied due to (i) various connectivity of lakes with the sea, (ii) intrusion of seawater of low salinity as well as (iii) genetic heterogeneity of lake basins. Awareness of these findings makes it possible to trace and predict the threats posed to coastal lakes, as well. As an example, recommendations on the holistic restoration of Lake Jamno are presented. The presented data is useful for determining the state of preservation and methods of management of coastal aquatic habitats under high human pressure.

中文翻译：

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沿海湖泊的连通性和复杂性作为其恢复的决定因素——以波罗的海南部为例

摘要 为了了解波罗的海沿岸湖泊 (BCL) 的功能机制和生态条件以适应其恢复的需要，介绍了有关负责生物多样性的环境、生态和进化过程的知识现状。这使得沿着波罗的海南部海岸的沿海湖泊可以分为淡水、过渡性和咸水湖泊。此处根据由适应性循环（过渡湖泊）分隔的浅湖生态系统（咸水与淡水）中的替代稳定状态理论解释了它们的功能原理。设计和应用恢复退化沿海水生生态系统的成功概念受到海洋和陆地因素的制约。因此，波罗的海南部沿海湖泊的恢复计划，与淡水内陆湖泊相反，由于 (i) 湖泊与海洋的各种连通性，(ii) 低盐度海水的入侵以及 (iii) 湖盆的遗传异质性，需要应用一些特定的标准。对这些发现的认识也使得追踪和预测对沿海湖泊构成的威胁成为可能。例如，提出了关于贾姆诺湖整体恢复的建议。所提供的数据可用于确定在人类高压下沿海水生栖息地的保护状态和管理方法。对这些发现的认识也使得追踪和预测对沿海湖泊构成的威胁成为可能。例如，提出了关于贾姆诺湖整体恢复的建议。所提供的数据可用于确定在人类高压下沿海水生栖息地的保护状态和管理方法。对这些发现的认识也使得追踪和预测对沿海湖泊构成的威胁成为可能。例如，提出了关于贾姆诺湖整体恢复的建议。所提供的数据可用于确定在人类高压下沿海水生栖息地的保护状态和管理方法。