Artificial defences in coastal marine ecosystems in Chile: Opportunities for spatial planning to mitigate habitat loss and alteration of the marine community structure

Many coastal habitats are actually replaced with hard infrastructures which alter the taxonomic/functional structure of natural ecosystems worldwide. Few information about habitat loss and species composition in South American coasts are available compared with other coasts. Here, I examine the distribution and identity of coastal artificial infrastructures, especially artificial breakwaters, present along the coast of Chile and the proportion of natural habitat loss derived from their construction. Differences in species taxonomic/functional composition in artificial breakwaters and natural habitats present in northern Chile are also examined. I also propose/discuss opportunities for coastal planning based on habitat rehabilitation and ecological engineering in Chile, which could guide future marine infrastructures construction. An important proportion of natural habitat has been replaced by artificial coastal defences along the coast of Chile, accounting for about 200km of total coastal length. Given their specific uses and functions, artificial granite breakwaters are one of the most important coastal infrastructures present in Chile (62% of the total of artificial breakwaters present). Differences in taxonomic/functional structure between artificial breakwaters and natural adjacent habitats are significant, and appear related to contrasting spatial heterogeneity. Artificial infrastructures like granite breakwaters can facilitate presence of native and non-native species, which live in the marine-terrestrial interphase (crabs, rats). The present study highlights how the recent proliferation of coastal artificial infrastructures is replacing important natural habitats in Chile, and how the taxonomic/functional structure of coastal ecosystems can be negatively impacted. Furthermore, this study showed how artificial infrastructures can have direct consequences for human-health security and specific guidelines can be conducted to buffer impacts on ecosystem structure to match social livelihood and wellness.