Assessing the impact of infrastructure proliferation on shoreline dynamics around Mexico

This study addresses the lack of a national-scale, structure-level assessment of how coastal infrastructure interacts with shoreline dynamics in Mexico. We compiled a georeferenced inventory of coastal structures from 1995 to 2019 and evaluated their association with long-term shoreline trends using the global dataset of Luijendijk et al. (2018). The inventory indicates that, over 24 years, the number of structures increased from 570 to 1,030, with substantial variations regionally in patterns of structure density and expansion. Among these contrasts, the highest overall density (> 1 structure/km) was in the state of Yucatán, primarily due to the large number of groynes there. The inventory was linked to 517 filtered transects updrift and downdrift of the structures, and, in adjacent coasts, 45% showed stability, 33% accretion, and 22% erosion. Breakwaters and jetties were the features most commonly associated with erosive patterns. These contrasting responses were then examined in two local case studies: in Puerto Chiapas, the shoreline dynamics showed long-term, but relatively moderate, adjustments near the jetties; while in Antón Lizardo, successive growth in coastal infrastructure has amplified both erosion and accretion, reshaping the local sedimentary patterns. The integration of national-scale patterns with detailed local evidence, has given the first comprehensive assessment of how coastal structures in Mexico cumulatively influence shoreline behaviour. The findings underline the need to adopt planning strategies that incorporate sediment connectivity, multiscale impacts, and the implementation of nature-based and adaptive solutions to shoreline management problems.