**2. Special Issue**

This Special Issue collects a set of twelve contributions authored by forty researchers on the topic of "Shoreline Dynamics and Beach Erosion". Of course, this collection of papers does not cover the entire range of subjects concerning the dynamics and spatialtemporal evolution of shorelines and beach systems, but, in our opinion, it contributes to the growing body of knowledge. In particular, these papers address the study of coastal systems of variable complexity located in different geographic areas (Figure 1) and climatic contexts from various points of view by using multi- and interdisciplinary approaches and providing new experimental data and methodologies.

**Figure 1.** Geographical distribution of the contributions included in the Special Issue.

We hope that the papers of this issue serve to foster additional research, stimulate scientific discussion, and promote reflections on how to achieve a better understanding of the coastal systems morphodynamics, or even present research opportunities in this field, contributing, in the end, to the safeguarding of coastal zones and beaches. From an operational point of view, we expect that their results may contribute to the development of pragmatic approaches through which the competent institutions and administrations can implement intervention strategies to eliminate, reduce, and/or compensate coastal erosion, as well as support the resilience and sustainable development of coastal areas.

The contributions included in this issue refer to different continents, from the Americas to Africa, Europe, and South East Asia (Figure 1). The review paper written by Pranzini and William [16], which deals with theoretical concepts and, therefore, does not refer to a specific geographic area, represents the only exception.

The papers have been categorized into three groups according to the major research topics addressed, as presented in Table 1.


**Table 1.** Grouping of contributions according to major research topics covered.

A first group of papers (Group 1, Table 1) focuses on the morphodynamics and hydrodynamics of coastal systems. In detail, the papers written by Andreeva et al. [17] and Uda and Noshi [18] highlight that coastal morphodynamics assessed by analyzing the formation, location, and movement of coastal bars and sand spits strongly depends on the wave climate that controls the erosion and movement of sediments along the coast. Seul et al. [19], based on the petrographic analysis and characterization of beach sediments, have created an index that aids in understanding both the nature and origin of sediments, as well as the characteristics of wave climate responsible for their transport. The paper by Buccino et al. [20] illustrates how numerical modelling can be used for investigating the relationships between incident wave characteristics and beach shape. Finally, the review paper by Pranzini and William [16], which uses examples from the literature to analyze some of the major processes responsible for the evolution of a beach, highlights that the use of the term "beach equilibrium" is not entirely appropriate, since the sedimentary budget depends on numerous non-feedback-regulated factors.

A second consistent group of papers (Group 2, Table 1) analyzes some of the major driving factors of coastal erosion in different geographical and geomorphological contexts. In detail, these papers deal with the effects of subsidence [21], storm surges [22], and hurricanes [23] on the studied coastal systems, which adapt to new morphological conditions in different times. Furthermore, the paper by Guerra-Medina and Rodríguez [24] highlights how such control factors can decisively influence the economic and social decisions of a community and, especially, tourism activities.

Finally, the third group of papers (Group 3, Table 1) focuses on the development and application of models/indexes suitable for coastal erosion vulnerability assessments for developing mitigation strategies for coastal ecosystem in relation to human and natural pressures. In detail, the papers by Di Crescenzo et al. [25] and Di Paola et al. [26] illustrate the identification and application of indexes that allowed them to assess the susceptibility of the coastline to undergo erosion, respectively, in high rocky coast and sandy beach contexts. The paper by Chacón Abarca et al. [27] deals with the evaluation of a model to help the community reducing the negative effects on ecosystems caused by physical and human changes in lagoon coastal environments. It illustrates a developed tool that considers the inter-relationships between natural systems and the factors inducing alterations in the coastal lagoon environment, providing insights into human actions that can reduce these negative consequences on ecosystems.

**Funding:** This research received no external funding.

**Data Availability Statement:** No new data were created or analyzed in this study. Data sharing is not applicable to this article.

**Acknowledgments:** We thank our informants and supporting staff for their contribution to the Special Issue.

**Conflicts of Interest:** The authors declare no conflict of interest.
