Dunes are defined as accumulations of sand that have been forming for a few years. They are mainly formed by wind which lifts, carries, and deposits grains of sand. The formation of coastal dunes begins with sand on the beach that has been exposed to the air for a long period of time and has dried out, making it susceptible to displacement by the wind.
The coastal dunes of the peninsula of Baja California form miles of pristine coastline. The scenic beauty of the coastal dunes is one of the most appreciated attractions in the region. Their beauty and their recreational functions make the coastal dunes highly valued by many tourists and locals alike.
The coastal dunes of the Punta Mazo Natural Reserve are located in the San Quintin Bay, northwest of the Baja California Peninsula. This dune system has a strong population of the Baja California Legless Lizard (Anniella geronhnensis) and Dithyrea maritima (Brassicaceae), a globally endangered species. Punto Mazo is also home to 73 plant species, 16 of which are endemic to the region.
In the summer, it serves as a primary breeding site for migratory bird species such as the Snowy Plover (Charadrius nivosus) and Least Tern (Sterna antillarum). This coastal dune system comprises one of the most pristine systems as it has not been disturbed by off-road vehicles.
El Socorro is home to an impressive 155 species of dune plants, making it the most floristically diverse in the Peninsula of Baja California. This dune system is also home to the black-tailed jackrabbit (Lepus californicus), field mice (Peromyscus eremicus) and reptiles, such as the rattlesnake (Crotalus ruber) and the Baja California Legless Lizard (Anniella geronimensis). In fact, it stands out as one of the largest areas of high species richness and perhaps the most at risk of environmental degradation.
Currently, El Socorro is fragmented by multiple pathways and some isolated construction. It is also facing threats from a highly aggressive invasive plant species, Common Iceplant (Mesembryanthemum crystallinum).
The coastal dune system of Laguna Manuela is located within the Valle de los Cirios Flora and Fauna Protection Area. The dunes run along the coastline of the Manuela Lagoon and are among the highest and most well-conserved dunes in the country.
The Laguna Manuela provides an important refuge for migratory seabirds who fly in for the winter from the United States and Canada. During this time there are often several species of pelicans, terns, ospreys and more. Many of these seabirds make their nests within the Laguna Manuela dune system.
Guerrero Negro constitutes one of the most impressive dune systems. It is located in the north of the state of Baja California Sur, adjacent to the Pacific Ocean and is among the largest and best-preserved dunes in the country.
While the Guerrero Negro dunes are exploited for salt production and dune ecotourism, they are very well managed.
The coastal dune system of El Vizcaíno is the system that has the largest area of dunes. These dunes are well-studied geologically as researchers attempted to demonstrate the differences between coastal and continental dunes. In fact, it has been hypothesized that the sands of the Vizcaíno dunes are influenced by more than one source of rock in comparison with other North American desert dunes.
El Vizcaíno is home to several endemic plant species such as Dwarf Saltbush (Atriplex barclayana), a short-lived perennial plant, and Baja Bush Sunflower (Encelia ventorum), a semi-shrubby species.
The coastal dune system of La Bocana faces the Pacific Ocean and is characterized by a single dune cord. It is 500 meters at its widest and is well defined with vegetation that is endemic to the coastal dunes.
These dunes are well-conserved as there are only a few local roads fragmenting them, with the exception of San Juancio where a large part of the community is on the dunes.
The Bahía Magdalena dune system forms the Magdalena Bay and due to its isolation, it is one of the best preserved. This coastal dune system is made up of extensive barrier islands that are separated from the mainland by wetlands and mangroves. In fact, Bahía Magdalena contains half of the state of Baja California Sur’s artisan fishery activities.
The flora of this dune system contains 506 taxa of vascular plants.
The coastal dune system of Punta Arena is composed of transgressive dunes where coastal scrub vegetation predominates. It is a wide deflation plain where no large dune ridges or deep hollows are apparent.
In the summer, Snowy Plovers (Charadrius nivosus) have been observed nesting in the Punta Arena dune system.
The coastal dune systems located on the coast of the Gulf of California, such as the Mulegé dune system, are very rare. In some areas, the dunes are separated by very narrow channels that connect introductory river water with water from the ocean.
While these dune systems are rare, they are incredibly valuable to the region’s biodiversity. For example, Belding’s Yellowthroat, a bird endemic to Baja California Sur, breeds exclusively in the freshwater marshes of the peninsula from Mulegé south.
The San Basilio dune system is small and isolated as it is located in bays with little to no access. In some areas, the dunes are separated by very narrow channels that connect introductory river water with water from the ocean.
This dune system supports a plethora of coastal species, several of which are rare and endangered.
The dunes of El Cajete, found near the city of La Paz, are part of a well-defined dune system that extends to the sandy bar of El Mogote.
Two-thirds of this dune system is well preserved, although relatively fragmented by the presence of local roads, while, on the eastern side, opposite La Paz, the construction of exclusive residential and tourist developments has displaced the coastal vegetation. Additionally, recreational activities, such as motorcycling, have destabilized the dunes at the base of El Mogote.