Archipiélago de Revillagigedo
The property is part of a submarine mountain range, with the property’s four islands representing the tips of four volcanoes which range from 380 km to 1,000 km west from Mexico’s mainland. The Archipiélago de Revillagigedo, through a combination of geographical isolation and distinct geomorphology, has a unique assemblage of fauna and flora, with particularly important populations of threatened fish and bird species. The site also acts as a staging place for migratory bird and cetacean species such as the humpback whale.
Archipiélago de Revillagigedo
MIXED NATURAL & CULTURAL WORLD HERITAGE SITE
2016: Inscribed on the World Heritage List under natural criteria vii, ix and x
STATEMENT OF OUTSTANDING UNIVERSAL VALUE
The UNESCO World Heritage Committee issued the following Statement of Outstanding Universal Value at the time of inscription:
The Archipiélago de Revillagigedo is located in the eastern Pacific Ocean, 386 km southwest of the southern tip of the Baja California Peninsula, and 720 to 970 km west of the Mexican mainland. The Archipiélago de Revillagigedo is a serial nomination made up of four remote islands and their surrounding waters: Isla San Benedicto, Isla Socorro, Isla Roca Partida and Isla Clarión. The property covers 636,685 ha and includes a marine protected area extending 12 nautical miles around each of the islands. A very large buffer zone of 14,186,420 ha surrounds all four islands. Ocean depths within the buffer zone of the property reach 3.7 km, particularly to the west of Isla Roca Partida, and to the west and south of Isla Clarión. Due to their volcanic origin, depths around the islands increase abruptly at distances of between 10-12 km from the island shorelines. The Archipiélago de Revillagigedo is part of a submarine mountain range with the four islands representing the peaks of volcanoes emerging above sea level. Apart from two small naval bases, the islands are uninhabited. The Archipiélago de Revillagigedo represents an exceptional convergence of two marine biogeographic regions: the Northeastern Pacific and Eastern Pacific. More particularly, the property lies along the junction where the California and Equatorial current mix generating a complex and highly productive transition zone. The islands and surrounding waters of the Archipiélago de Revillagigedo are rich in marine life and recognised as important steppingstones and stop overs for wide ranging species. The property harbours abundant populations of sharks, rays, large pelagic fish, Humpback Whales, turtles and manta rays; a concentration of wildlife that attracts recreational divers from around the world. Each of the islands displays characteristic terrestrial flora and fauna and their relative isolation has resulted in high levels of species endemism and micro-endemism, particularly among fish and bird species, many of which are globally threatened. The islands provide critical habitat for a range of terrestrial and marine creatures and are of particular importance to seabirds with Masked, Blue-footed, Red-footed and Brown Boobies, Redbilled Tropicbirds, Magnificent Frigatebirds and many other species dependent on the island and sea habitats. The Archipiélago de Revillagigedo is the only place in the world where the critically endangered Townsend’s Shearwater breeds.
Criterion (viii): Both the landscape and seascape of the Archipiélago de Revillagigedo exhibit impressive active volcanos, arches, cliffs, and isolated rock outcrops emerging from the middle of the ocean. The clear surrounding waters create exceptional scenic vistas with large aggregations of fish gathering around the steep walls and seamounts, as well as large pelagic marine species including Giant Manta Rays, whales, dolphins and sharks. One of the most remarkable aspects of the property is the concentration the Giant Manta Rays which aggregate around the islands and interact with divers in a special way that is rarely found anywhere in the world. Furthermore, the property encompasses an underwater seascape with abyssal plains at depths close to 4,000 meters and sheer drops in crystal clear water, all contributing to an awe-inspiring underwater experience. A large population of up to 2,000 Humpback Whales visits the islands. The songs of these majestic cetaceans can be heard during the winter months and while diving, add another sensory dimension to the marine seascape.
Criterion (ix): The Archipiélago de Revillagigedo is located in the northern part of the Tropical East Pacific Province, a transitional zone influenced mainly by the California current but mixed with the warm waters from the North Equatorial Current. This location results in the convergence of a multitude of fauna and flora, and creates a unique set of biological and ecological processes. The isolation and relatively pristine state of these islands has supported evolutionary processes which result in a high degree of endemicity in both the terrestrial as well as marine realms. In the marine realm the waters surrounding these islands are composed of majestic aggregations of sharks, rays, cetaceans, turtles and fish, a number of which are endemic or near-endemic. On land, important evolutionary processes have led to the speciation of 2 endemic lizards, 2 endemic snakes, 4 endemic birds, at least 33 endemic plant species, and innumerable invertebrates. In addition, 11 endemic subspecies of birds have evolved on the islands, indicating the potential for future evolution on these remote and well protected islands.
Criterion (x): The geographic isolation of the Archipiélago de Revillagigedo, shaped by the prevailing oceanographic conditions, results in high marine productivity, rich biodiversity and exceptional levels of endemism, both terrestrial and marine. The islands are the only breeding site for the Townsend’s Shearwater, one of the rarest seabirds in the world. The Archipiélago de Revillagigedo is also home to the endemic Socorro Dove, Socorro Mockingbird, Socorro Wren, Clarion Wren (as well as 11 endemic bird subspecies), 2 lizards, 2 snakes and numerous endemic plants and invertebrates, all of which contribute to the importance of these islands in conserving terrestrial biodiversity. In the marine realm at least 10 reef fish species have been identified as endemic or near-endemic including the spectacular Clarión Angelfish, which can be observed in ‘cleaning stations’ feeding on the ectoparasites of the Giant Manta Rays. These rays, some of them unusually completely black, aggregate in some of the largest numbers known worldwide. The property is a haven for a rich diversity of shark species with up to 20 having been recorded. Up to 2,000 Humpback Whales also migrate through these nutrient rich and productive waters. The islands are also of significant importance to seabirds notably Masked, Blue-footed, Redfooted and Brown Boobies, Red-billed Tropicbirds, Magnificent Frigate birds and many other species which can be seen soaring around the rocky outcrops where they nest and fish in the sea.
The Archipiélago de Revillagigedo is remote and largely uninhabited so threats to the property are relatively low. Invasive introduced species represent the greatest threat to the ecology of these islands and their surrounding waters. Major conservation successes by the Mexican Government working with NGOs have seen the eradication of larger invasives such as pigs and sheep from various islands. Ongoing vigilance will be needed to ensure the natural systems of the archipelago are not impacted by damaging invasive species. Enhanced biosecurity measures directed by a biosecurity plan are required to protect the ecosystems of the archipelago from this threat. To date, tourism has been restricted by the Mexican Government to a set number of diving boats, and no people are allowed on-shore without a permit. Diving carrying capacities and regulations are set in the management plan, and given the restricted number of potential dive sites and their small area, it is unlikely that diving impacts within the area will increase. Fishing is restricted through the marine area zoning system; however, there are concerns regarding policing and instances of sport fishing. The extension of a no-take fishing zone by 12 nautical miles to align with the property boundaries is considered essential to bolster protection of the island’s marine resources as is the enforcement of strengthened fishing regulations in the property’s large buffer zone. In conclusion, the property is of adequate size and includes all elements necessary to express its outstanding values in the terrestrial and marine realms. Integrity of the marine area will be further strengthened if the entire area of the property becomes a no-take zone, and fishing regulations are strengthened in the large proposed buffer zone. For terrestrial values it must be noted that past development, i.e. the introduction of invasive sheep, pigs, cats, rabbits and mice, have considerably damaged some of its values, but rats were never introduced to the islands which is exceptional for subtropical islands of this size. It is to be commended that pigs and sheep have been eradicated and the numbers of cats on Socorro have been severely reduced with the hope that they too will be eradicated.
Protection and Management Requirements
The Archipiélago de Revillagigedo is Mexican federal territory and all parts of the property are hence state owned and controlled. The property is protected under a range of legislation pertinent to different agency jurisdictions with the principle protective legislation being the General Law of Ecological Balance and the Protection of the Environment (LGEEPA). The islands are managed as a natural protected area by the Natural Commission of Natural Protected Areas (CONANP) in close collaboration with a number of other government authorities and various NGO and university partners. Of particular importance is the effective collaboration with the Mexican Navy who provide staffing and infrastructure support to monitor the islands and ensure the enforcement of regulations. This cooperation among agencies is doubly important to augment relatively modest staffing and government financial resources which are applied to the property.
Improved monitoring is needed to prevent sport fishers entering no fishing zones and to manage their impacts. Efforts are also needed to ensure that fishing in the very large surrounding buffer zone is managed to be sustainable so as to counteract the potential or real threat of over-fishing in the region.
Management emphasis should be applied to the control and where possible eradication of alien invasive species from the islands and their marine environments. A biosecurity plan should also direct quarantining and response mechanisms to ensure protection from potential introduction threats. This is particularly important to maintain the island’s rat free status which is both unusual in a sub-tropical island system and crucial to maintaining healthy functioning ecosystems and protecting key species.
Additional research and inventory is needed to better understand the biodiversity values of the property in particular submarine and deep sea ecosystems.
2004: The property is designated as a Ramsar Site, Wetland of International Importance.
2016: The property is inscribed as a World Heritage site under the natural criteria vii, ix and x.
IUCN MANAGEMENT CATEGORY
8.42.13 (Revilla Gigedo Island)
The property is located between N 17o 39’19” and N 20o 0’31”; and W 110o 4’41” and W 115o 28’17” in the Tropical Eastern Pacific in Mexico’s Exclusive Economic Zone. The property is split between four islands, the most easterly of which, Isla San Benedicto, is 386 km south-west from Cabo San Lucas, Baja California Sur, and 720 west of Manzanillo, Colima. Isla Clarión is the furthest from shore, being 1,000 km from the Mexican mainland.
DATES AND HISTORY OF ESTABLISHMENT
1533: The Spanish explorer Hernando de Grijalva discovers Isla Socorro whilst trying to find a route to south-east Asia and names it Isla Tomas;
1542: Isla San Benedicto first discovered and originally named ‘Los Inocentes’;
1569: Isla Roca is first discovered;
1608: Isla Tomas is renamed by Martin Yanez de Armida to Isla Socorro in honour of his wife;
1779: Isla Clarión is discovered;
1793: James Colnett, a British explorer, is captured on Isla Socorro after visiting the Galapagos. He is released by the new Spanish viceroy in Mexico City, III Count of Revilla Gigedo, James Colnett names the island group after him, creating the prevailing name to this day;
1869: The Mexican Government grants a lease for a group of Australians and Canadians to start raising cattle and sheep on Isla Socorro, but the failed project was quickly abandoned;
1874: The first topographic survey of Revillagigedo was completed by an expedition led by the U.S.A;
1957: The Secretariat of the Mexican Navy establishes a permanent military base on Isla Socorro;
1994: A scientific research network specialised on the property is organised, which still convenes regularly for conferences;
1994: The Archipiélago de Revillagigedo is designated as a national Biosphere Reserve.
2016: The property is inscribed as a World Heritage site under natural criteria vii, ix and x
In accordance to article 42 of the Political Constitution of the Mexican United States, the property is a federal property. As such, and in accordance with article 48, the property belongs to the Mexican Government.
The property has four component parts:
|Component part||Area (ha)|
|Isla San Benedicto||137,002|
|Isla Roca Partida||112,636|
The component parts of the property do not have individual buffer zones; however, there is a 14,186,420 ha buffer zone for the property as a whole.
Ocean depths within the property descend to 3,700 metres, especially to the west of Isla Roca Partida. Isla Socorro is the highest of the four islands, reaching 1,050 metres above sea level (a.s.l). The smaller Isla San Benedicto reaches only 374 metres a.s.l, whereas the height of Isla Roca Partida and Isla Clarión are not stated.
The property is part of a submarine mountain range, with the four islands representing four volcanic peaks that emerge above sea level. The archipelago is rare in the sense that it demonstrates the geological evolution of the islands, and as such is of significant interest to geologists for studying the history of the earth.
Isla Socorro is a shield volcano and reportedly the only sicilic peralkaline volcanic island in the Pacific Ocean (Bohrson & Reid 1997). The volcano is still active, with the most recent noted activity in 1993 (Siebe et al. 1995). The northern component of the island has been formed by basaltic lava flows and cinder cones, and the basaltic rocks of Cerro Evermann, the volcano dome of Isla Socorro, created stepped terraces of pumice and lapilli deposits.
Isla San Benedicto’s volcano erupted in 1948 and 1952 resulting in explosive pyroclastic flows that destroyed the island’s biota. The eruption created two small lava domes in the crater and an extrusion of a prominent coastal lava delta at the southeast base of the cone.
Isla Roca Partida is the crest of a submarine stratovolcano, it is the smallest of the four islands and has a geology that more closely resembles the acid rocks of Isla Socorro and Isla San Benedicto than the basic rocks of Isla Clarión (Richards 1952).
Isla Clarión was formed by volcanic eruptions during the Miocene and older Eocene. Lithologic units appear to show distinct eruptive or depositional phases in its creation, with all rocks being basic, unlike the other three islands.
The property is located at the convergence of two marine biogeographic regions: the North-eastern Pacific and Eastern Pacific. More specifically, the property is situated where the nutrient-rich temperate waters of the California current meet the warm waters of the Equatorial current, generating a complex and productive transition zone. The property has an average annual temperature of 22oC. The climate is regulated by tropical depressions and hurricanes that occur during the summer and are characteristic of the Eastern Pacific. Annual rainfall falls largely between the months of August and October. The four islands are generally considered dry, with a mean annual precipitation of 600 mm per year. The waters surrounding the islands fluctuate between ~\~~29oC in the summer and ~\~~23oC in the winter. Isla Socorro shows a tropical semi-dry climate until approximately 400 metres a.s.l. where it transitions to a subtropical climate humid climate.
The property has a total of 202 recorded plant species, spanning 62 families and 157 genera (Flores-Palacios et al. 2009). This has led to some authors stating that the islands have a low floral species richness (Miranda 1960; Rzedowski & Huerta 1978). The proportion of endemic species, however, is high: 32% of plant species on Isla Socorro, 26% on Clarión and 45% on San Benedicto (Challenger 1998).
Isla Socorro has the highest species richness of the four islands, supporting 118 native and 47 introduced species (León de la Luz et al. 1994). The vegetation on the island is generally tropical, with cloud forest spanning much of the island between sea level and 950 metres a.s.l. There are also patches of grassland characterised by Aristida vaginata and Cestrum pacificum (León de la Luz et al. 1994; Flores-Palacios et al. 2009). There are 39 plant species endemic to the archipelago and 30 species endemic to the island (Flores-Palacios et al. 2009).
Isla Clarión’s vegetation is predominantly shrub, and does not have the species richness or abundance of Isla Socorro. The island’s flora has been strongly affected by introduced rabbits. Isla San Benedicto used to have similar floral communities as Isla Socorro; however, after the volcanic eruption in the early 1950s the island lost all of its vegetation. The island is now steadily going through successional stages and has 12 recorded species, all of which are endemic to either the archipelago or the island itself. Isla Roca Pertida does not support any vegetation due to its geomorphology.
The archipelago also supports algal species, though these do not demonstrate the same level of endemism as their terrestrial counterparts. The algal species are broadly speaking very similar and the same species can be found in the Gulf of California (Hull et al. 2006).
The waters surrounding the property are important for feeding, reproduction and movement of cetaceans in the Mexican Pacific, with six species of marine mammal being recorded within the property. The property is particularly important for whales, especially the humpback whale (Megaptera novaeangliae) which concentrates around Isla Socorro between January and March and may be a key staging area for one of the Mexican Pacific’s two main humpback whale populations.
There are 63 terrestrial bird species recorded within the property, 16 of which breed on at least one of the islands. The property hosts 15 endemic terrestrial bird species, including the Socorro mockingbird (Mimus graysoni; CR) and Clarion wren (Troglodytes taneri, VU). It is believed that some bird species that used to inhabit the property may now have gone extinct in the wild, such as the San Benedicto rock wren (Salpinctes obsoletus exsul), after the volcanic eruption on San Benedicto (Brattstrom & Howell 1956) and the Socorro dove (Zenaida graysoni), which was last recorded in the property in 1972 (Soorae 2010). Additionally, 46 seabird species can be found within the property, either using the islands as breeding sites or the waters surrounding the islands. Of these seabird species, 12 use the property as a breeding ground, and one, the Townsend shearwater (Puffinus auricularis) is endemic to Isla Socorro. Although it has not been sighted in recent years (Wanless et al. 2009), the last census estimated the population to be in the region of 1,000 pairs (Martı́nez-Gómez & Jacobsen 2004).
Four species of turtle can be observed surrounding Isla Socorro: the olive ridley turtle (Lepidocelys olivacea), leatherback turtle (Dermochelys coriacea), hawksbill turtle (Eretmochelys imbricata) and green turtle (Chelonia mydas). The olive ridley turtle may also nest on Isla Clarión (Awbrey et al. 1984), and green turtles are known to nest on these islands too, which are considered as one of three main breeding grounds for the species in the Pacific (Blanco et al. 2013; Holroyd & Trefry 2010). The property is also important for the 20 recorded species of shark and five species of ray. Of the shark species present within the property, several are of particular note for their abundance: hammerhead shark (Sphyrna lewini), silky shark (Carcharhinus falciformis) and tiger shark (Galeocerdo cuvier), amongst others. Amongst ray species present in the property, giant manta rays (Manta birostris) are noteworthy for both their size and abundance, with aggregations of ten or more being sighted.
The property also supports 22 species of coral, 43 species of mollusc, as well as several species of crustacean. The deep-sea biota within the property is still little understood, though it is hypothesised that many additional species of echinoderms, nematodes and sponges are yet to be discovered.
The property, through a combination of geographical isolation and distinct geomorphology, has a unique assemblage of fauna and flora. In addition, it is situated within the Revillagigedos marine ecoregion which was not yet represented on the World Heritage List (Spalding et al. 2007). The property is considered one of the most irreplaceable protected areas in the world for the conservation of birds, ranking 32nd for all bird species and 19th for threatened bird species (Bertzky et al. 2013). Indeed, the property hosts particularly important populations of threatened fish and bird species (IUCN Evaluation), with high levels of endemism. It also acts as an important staging site for migratory bird and cetacean species. Furthermore, one of the four islands of the nominated property, Isla Socorro, is an Important Bird Area (IBA), designated for the presence of three Critically Endangered and one Endangered bird species on the IUCN Red List, as well as an Alliance for Zero Extinction (AZE) site (Birdlife International 2016).
The degree of the property’s isolation has meant that the islands were unknown until the 16th Century. Habitation on the archipelago has been non-existent until relatively recently, and even then, to a minimal degree. The first documented description of the property was in 1533, when the Spanish explorer Hernando de Grijalva discovered Isla Socorro whilst trying to navigate to south-east Asia. Towards the end of the 18th century all four islands had been discovered, but were still largely ignored as they were not found on any trade routes. It is believed that for short periods the islands were inhabited by traders, explorers and pirates, though only on a temporary basis to refill their supplies from the islands’ minimal natural resources. By the 19th Century, the island group was of interest for scientific research due to its degree of intactness, which was then quickly degraded in places by the island group’s first settlers in the 1870s, which released non-native grazers such as sheep. Research in various scientific fields continued on the archipelago throughout the 20th Century. By 1957, the archipelago’s strategic importance was recognised when the Mexican Navy established a permanent military base on Isla Socorro. Since then activities have been more controlled within the archipelago. No settlements of civil populations or indigenous groups currently live on the islands.
LOCAL HUMAN POPULATION
Apart from the Mexican Navy bases, the islands are not inhabited. The number of navy personnel on Isla Socorro varies from 60 to 80 marines, whilst Isla Clarión has between 10 and 16.
VISITORS AND VISITOR FACILITIES
At present, there is no infrastructure specifically for visitors. On Isla Socorro and Isla Clarión, there are facilities that belong to the Mexican Navy, and which can accommodate visitors if agreed in advance. Visitors tend to be scientific researchers or representatives from the Mexican government, and tourist numbers are limited. On average there are 50 research visitors and 10 staff from the Ministry of the Environment and Natural Resources (SEMARNAT) that visit the property every year. The property does also support a small and low-impact diving tourism trade. Dive operators are based in Cabo San Lucas and La Paz and run approximately 15,000 dives per year (Reyes-Bonilla et al. 2012).
SCIENTIFIC RESEARCH AND FACILITIES
The military base contains a dock for vessels, a concrete runway for planes and advanced communication facilities.
The property is managed by the National Commission of Natural Protected Areas (CONANP), a decentralized agency of the Secretariat of the Environment and Natural Resources (SEMARNAT). There are six major management sub-programmes: i) protection, ii) management, iii) restoration, iv) knowledge, v) culture and vi) administration. The management sub-programme states in its objectives that it is critical that development, tourism activities, fishing and research are all undertaken within the environmental carrying capacity of the property. The restoration sub-programme is specifically focussed on identifying areas susceptible to degradation and performing preventative or corrective management measures. An example of the restoration sub-programme is the eradication plan for feral sheep on Isla Socorro, which has successfully removed all sheep from the island and is now working on removing feral cats. As a result of this success, the management authorities are now considering reintroducing the locally extinct Socorro dove.
Although the property supports an extremely low human presence, there are minor impacts arising from the presence of the Mexican Navy. The Biosphere Reserve Decree prohibits the creation of new settlements; therefore, there are no direct management constraints from human development. The indirect impacts of humans on the archipelago, however, are very clear. At various points in the property’s history, humans have introduced non-native species such as donkeys, cattle, goats, chickens, sheep, rabbits and cats. These species are responsible for the alteration of species abundance and community composition on the islands (Jehl & Parkes 1982). In places, these introduced species have had serious impacts, e.g. localised extirpations, soil erosion and habitat degradation. More recently, there has been an invasion of the Centro-American locust (Schistocerca piceifronsi), although still understudied, it is thought that this locust may be causing significant damage to the property’s natural heritage. The marine component of the property is impacted most by the fishing activities searching for high-value species such as yellow-fin tuna.
The property also experiences several natural hazards, ranging from tropical storms, which are more frequent but produce less damage, to volcanic activity, which is less frequent but has the potential to destroy an entire island’s biota. To a lesser extent, the property also experiences occasional fires, which can be created from lightning during tropical storms.
CONANP has six permanent staff managing the property with support from a number of volunteers, especially in the peak tourist season. These staff are based in an office in Baja California and Baja California Sur.
In recent years, there have been three main sources of funding for the property: the federal government, the Conservation Program for Sustainable Development (PROCODES) and the Conservation Program for Species at Risk (PROCER). PROCODES and PROCER have both been one or two year payments resulting in the federal government funding acting as the property’s main income. The federal allocation was 150,000 Mexican pesos (USD\$ 7,344) but rose to 302,000 (USD\$ 14,787) in 2014, the majority of which being spent on operational costs.
Director of World Natural Heritage and MAB Program, National commission of Natural Protected Areas (CONANP), Camino al Ajusco No. 200, Col. Jardines en la Montana, Deleg. Tlalpan, Mexico, D.F. 14210.
The principal sources for the above information were the original nomination for World Heritage status, the IUCN evaluation report and the site’s management plan.
Awbrey, F.T. et al. (1984). Nesting green sea turtles (Chelonia mydas) on Isla Clarión, Islas Revillagigedos, Mexico. Bulletin of the Southern California Academy of Sciences, 83(2): 69-75.
Bertzky, B. et al. (2013). Terrestrial Biodiversity and the World Heritage List: identifying broad gaps and potential candidate sites for inclusion in the natural World Heritage network. IUCN, Gland, Switzerland and UNEP-WCMC, Cambridge, UK.
Birdlife International. (2016). Birdlife International. Available at: http://datazone.birdlife.org/home [Accessed December 19, 2016].
Blanco, G.S. et al. (2013). Movements and diving behavior of internesting green turtles along Pacific Costa Rica. Integrative zoology, 8(3): 293-306.
Bohrson, W.A. & Reid, M.R. (1997). Genesis of silicic peralkaline volcanic rocks in an ocean island setting by crustal melting and open-system processes: Socorro Island, Mexico. Journal of Petrology, 38(9): 1137-1166.
Brattstrom, B.H. & Howell, T.R. (1956). The birds of the Revilla Gigedo islands, Mexico. The Condor, 58(2): 107-120.
Challenger, A. (1998). Utilización y conservación de los ecosistemas terrestres de México: pasado presente y futuro.
Flores-Palacios, A., Martínez-Gómez, J.E. & Curry, R.L. (2009). La vegetación de Isla Socorro, Archipiélago de Revillagigedo, México. Boletín de la Sociedad Botánica de México 84:13-23.
Holroyd, G.L. & Trefry, H.E. (2010). The importance of Isla Clarion, Archipelago Revillagigedo, Mexico, for green turtle (Chelonia mydas) nesting. Chelonian Conservation and Biology 9(2): 305-309.
Hull, P. et al. (2006). An ecological and economic baseline for the Revillagigedo Archipelago Biosphere Reserve, Mexico. Expedition Report to UC Mexus Program.
Jehl, J.R. & Parkes, K.C. (1982). The status of the avifauna of the Revillagigedo Islands, Mexico. Wilson Bull, 94(1): 1-19.
León de la Luz, J.L. et al. (1994). Asociaciones vegetales. La Isla Socorro, Reserva de la Biosfera Archipiélago de Revillagigedo, México; Ortega Rubio, A., Castellanos, A., Eds.
Martı́nez-Gómez, J.E. & Jacobsen, J.K. (2004). The conservation status of Townsend’s shearwater Puffinus auricularis auricularis. Biological Conservation 116(1): 35-47.
Miranda, F. (1960). Vegetación. La Isla Socorro, Archipiélago de Revillagigedo.
Reyes-Bonilla, H., Cupul-Magaña, A.L. & Loreto-Viruel, R.M. (2012). Evaluación de la capacidad de carga para buceo en áreas naturales protegidas del mar Caribe y el golfo de California, México. Medio ambiente y polıtica turıstica en México, SEMARNAT, INE, UABCS, Mexico.
Richards, A.F. (1952). Geology of the Islas Revillagigedo, 3. Effects of erosion on Isla San Benedicto, 1961.
Rzedowski, J. & Huerta, L. (1978). vegetación de México, Limusa México.
Siebe, C. et al. (1995). Submarine eruption near Socorro Island, Mexico: Geochemistry and scanning electron microscopy studies of floating scoria and reticulite. Journal of volcanology and geothermal research, 68(4): 239-271.
Soorae, P.S. (2010). Global re-introduction perspectives: Additional case studies from around the globe, IUCN.
Spalding, M.D. et al. (2007). Marine ecoregions of the world: a bioregionalization of coastal and shelf areas. BioScience, 57(7): 573-583.
Wanless, R.M. et al. (2009). Birds of Clarion Island, Revillagigedo Archipelago, Mexico. The Wilson Journal of Ornithology, 121(4): 745-751.