Coasts, Volume 2, Issue 3 (September 2022) – 5 articles

Wetlands are periodically flooded terrestrial and aquatic environments, which provide benefits to a community known as ecosystem services (ESs). This research identified, classified, and spatialized the level of relevance of ecosystem services provided by wetlands in the Galinhos-Guamaré semi-arid estuarine system, State of Rio Grande do Norte, Northeast Brazil. ESs were analyzed using the Common International Classification of Ecosystem Services (CICES), v.4.3, and geographic information system (GIS) using a mosaic of Sentinel-2A images. The services provided by wetlands were classified into provision, regulation and maintenance, and cultural sections, with six divisions, 12 groups, and 22 classes being identified. The capacity of a number of wetlands to provide services was identified in 34 mangrove forests, 32 estuaries, 30 tidal flats, 26 solar saltworks, 23 apicum (tidal flats), and seven in shrimp ponds. However, it is noteworthy that these habitats are associated with ecosystems with great ecological, socioeconomic, and cultural importance, where the general approach presented here requires more detailed research in each macrohabitat, which should be considered as a priority for conservation. Full article

Can Gio (CG), a mangrove forest with a dense network of tidal creeks, gradually grew and spread seaward on a coastal platform, which was built since about 8 ka before present (BP). Along with this development, a sand ridge began to form and moved back with the shoreline withdrawal landward in the Late Holocene. This mangrove environment is likely abandoned from the mainland but was, however, the place for settlement of ancient Vietnamese a few centuries BC. The CG mangrove forest was severely destroyed during the American War and was restored since 1980. However, the historical change of the landscape along the Saigon-Dong Nai River (SG-DNR) since the Late Holocene is not completely unraveled. By analyzing sediment cores with a multiproxy approach, we investigated the recent geological development with regard to the variation of the intensity of the East Asian palaeomonsoon and regarding the accommodation space, as both regulate the development of this coastal environment. A recently significant shift in the coastline, mainly due to a change of hydroclimatic factors, was observed. A continuous coastline retreat occurred over the last millennium, changing the depositional environment and reshaping the CG mangrove landscape. Along the present coast and tidal channels, partially strong erosion and bank failures occur, alternating with accretion at other coastal sections. This development tends to increase progressively. Full article

The purpose of this study was to analyse the shoreline movement of the Niger delta, specifically focusing on the spatial pattern of the delta’s shoreline behaviour during 1986–2019. We employed satellite data of medium spatial resolution (20–30 m) to delimit the delta shorelines representing specific time in order to determine the rates of the delta shoreline migration. Our results show that the delta shoreline has changed nearly in equal proportion between erosion (50.3%) and accretion (49.7%), at mean (maximum) rates of 3.9 m/yr. (26 m/yr.) of erosion, and 4.0 m/yr. (27 m/yr.) of accretion. Further analysis indicates that the highest shoreline migration is seaward (>200 m) though the ratio of the shoreline distance in recession (54%) exceeds that which is in accretion. Our analysis did not reveal any entrenched spatial pattern of shoreline behaviour but rather highlights a random occurrence of hotspots in both shoreline erosion and accretion over space and time. We have also showed that by applying the statistical mean-removed shoreline approach, the overall trend of a delta shoreline movement can be vividly discriminated. In conclusion, since the Niger delta shoreline dynamics is most intense at the delta river mouths, we suggest this is likely due to the interaction between waves and river discharge in these locations. Full article

Islands provide the opportunity to explore management regimes and research issues related to the isolation, uniqueness, and integrity of ecological systems. K’gari (Fraser Island) is an Australian World Heritage property listed based on its outstanding natural value, specifically, the unique wilderness characteristics and the diversity of ecosystem types. Our goal was to draw on an understanding of the natural and cultural environment of K’gari as a foundation on which to build a management model that includes First Nations Peoples in future management and research. Our research involved an analysis of papers in the peer-reviewed scientific literature, original reports, letters, and other manuscripts now housed in the K’gari Fraser Island Research Archive. The objectives of the research were: (1) to review key historical events that form the cultural, social, and environmental narrative; (2) review the major natural features of the island and threats; (3) identify the gaps in research; (4) analyse the management and conservation challenges associated with tourism, biosecurity threats, vegetation management practices, and climate change and discuss whether the requirements for sustaining island ecological integrity can be met in the future; and (5) identify commonalities and general management principles that may apply globally to other island systems and other World Heritage sites listed on the basis of their unique natural and cultural features. We found that the characteristics that contribute to island uniqueness are also constraints for research funding and publication; however, they are important themes that warrant more investment. Our review suggests that K’gari is a contested space between tourist visitation and associated environmental impacts, with an island that has rich First Nations history, extraordinary ecological diversity, and breathtaking aesthetic beauty. This juxtaposition is reflected in disparate views of custodianship and use, and the management strategies are needed to achieve multiple objectives in an environmentally sustainable way whilst creating cultural equity in modern times. We offer a foundation on which to build a co-management model that includes First Nations Peoples in governance, management, research, and monitoring. Full article

Coastal erosion is a common phenomenon along the world’s coasts. Studying it is complex because such studies must cover large portions of land, and it is necessary to understand the multiple processes that interact in each area, so it is important to recognize regional patterns that allow for defining representativeness in relation to the surrounding dynamics. Spatial statistics can be used in coastal geomorphology to identify and quantify trends in coastal morphodynamics. This study analyzes and interprets the spatio-temporal patterns present in the changes in a shoreline, that is, the processes of erosion and coastal sedimentation in the Pacific and the Colombian Caribbean. The results are derived from the detection of significant changes in the coastline via satellite images. For this study, the shoreline of Colombia was digitized for the years 1986 and 2016, thus obtaining changes in the shoreline at a medium temporal scale. The Global Moran’s Index, Local Moran’s Index and Getis–Ord Index were used to explain the spatial statistics. The Global I Moran values for the Pacific were I = 0.190, z = 31.063 and p = 0.01, and for the Caribbean I = 0.624, z = 74.545 and p = 0.01, which suggests good grouping in the Caribbean and very low grouping for the Pacific. The local indices (Moran’s and Getis–Ord) allowed us to visualize and spatialize the significant points of coastal erosion and sedimentation. According to the results, three conceptual models are herein proposed that relate the indices with the geomorphological characteristics: (a) the greater the geomorphological heterogeneity, the greater the grouping; (b) the greater the geomorphological homogeneity, the lower the degree of clustering; (c) the greater the geomorphological complexity, the lower the degree of clustering. Finally, it is confirmed that coastal erosion and sedimentation processes predominate along low coasts. Full article