The Tubul-Raqui Coastal Wetland: A Chilean Ecosystem of High Conservation Value Severely Disturbed by the 2010 Earthquake

Given the great extent of the Tubul-Raqui marshland, in addition to its high biodiversity and biological productivity, combined with a low degree of human disturbance, this wetland corresponds to one of the most important ones in Chile. This chapter describes its main features and effects caused by the February 2010 earthquake. The wetland continues to provide nesting and shelter sites for numerous resident and migratory bird species, many of which have conservation problems. The major anthropogenic threats to the conservation of the wetland and its different habitats have historically been bird hunting and deforestation of river shores that affect the sedimentation of the rivers that feed it. As for the structure of the physical habitat, water quality and aquatic biota of the wetland, since the earthquake of 2010 a series of relevant environmental changes have occurred. Some of them were expressed immediately during the earthquake, while others still continue to manifest themselves. The main changes resulting from the earthquake have resulted from its uprising of about 1.6 m above sea level, which has led to the total drying of the network of internal channels that irrigate the wetland, and partial one of the main channels of the rivers Tubul and Raqui. This has also limited the exchange with the sea, generating a decrease in the salinity of the waters to the interior of the wetland. The two most important benthic species for the artisanal fishery, the “Pelillo” seaweed (Gracilaria sp.), and the “navajuela” bivalve (Ensis macha), were severely affected and there is still no evidence of any degree of recolonization. Although the ecosystem was severely affected by the earthquake, it retains properties that allow it to remain within the country’s most important coastal wetlands.