Guadalupe Island
Isla Guadalupe | |
---|---|
Ensenada | |
Delegación | Ensenada |
Demographics | |
Population | 213 (2010) |
Additional information | |
Official language: Spanish |
Guadalupe Island (Spanish: Isla Guadalupe) is a volcanic island located 241 kilometres (130 nautical miles) off the western coast of
The two other Mexican island groups in the Pacific Ocean that are not on the continental shelf are the Revillagigedo Islands and Rocas Alijos. Guadalupe Island and its islets are the westernmost region of Mexico.[2]
Discovery and history
The first known sighting of Guadalupe Island was in 1602 when a Spanish expedition headed by Sebastián Vizcaíno sailed by but did not land on the island. In the late 18th and 19th centuries the island was frequently visited by fur seal, otter, and elephant seal hunters. Goats were probably introduced by seal hunters in the early 1800s and quickly increased their numbers, nearly eradicating the indigenous vegetation.[3]
Administration and population
The 2010
Campo Oeste ("West Camp", also called Campo Tepeyac, with 15 buildings) is a small community of abalone and lobster fishermen, located on the western coast,[6] specifically on the north side of West Anchorage, a bay that provides protection from the strong winds and swells that whip the islands during winter. Generators provide electricity, and a military vessel brings 30,000 litres (7,900 US gal)[citation needed] of freshwater. The number of fishermen varies annually depending on the fishing season. Ten months of the year the 30 families of the fishing cooperative "Abuloneros and Langosteros of Guadalupe Island" are present.[7]
Additional temporary fishing camps are Campo Norte ("North Camp", four buildings), Campo Lima (Campo Corrals) (one building) and Arroyitos (four buildings).[8]
At the southern tip, on Melpómene Cove, there is a weather station staffed by a detachment from the Mexican Ministry of the Navy.[when?] The site is called Campamento Sur ("South Encampment").[citation needed]
Campo Bosque was established as a temporary camp in 1999 in the
Campo Pista is located at the small airport, near the center of the island (29°01′24.04″N 118°16′21.75″W / 29.0233444°N 118.2727083°W, elevation: 592 m, direction: 05/23).
Because Guadalupe Island is located within a
Geology
Guadalupe Island has a rugged landscape composed of two
Geography
The island measures 35 kilometres (22 mi) north-south and up to 9.5 kilometres (6 mi) east-west, with a total area of 243.988 km2 (94+13⁄64 sq mi). It features a chain of high volcanic mountain ridges which rises to a height of 1,298 metres (4,259 ft) at its northern end (Mount Augusta). Its smaller counterpart on the southern end is the 975 metres (3,199 ft) El Picacho.[16] The southern part of the island is mostly barren, but there are scattered stands of trees at higher elevations of the northern part of the island and in the Twin Canyon area on the northeast coast. The coast generally consists of rocky bluffs with detached rocks fronting some of them. Two high and prominent islets are within three kilometres (1.9 mi) of the southwestern end of the island, separated from one another by a gap called Tuna Alley:
- Islote Afuera (Outer Islet, also Islote Zapato), 28°51′53″N 118°17′41″W / 28.86472°N 118.29472°W, 1.5 ha (4 acres), the most distant, steep with almost vertical walls above and below water
- Islote Adentro (Inner Islet, also El Toro), 28°52′18″N 118°17′34″W / 28.87167°N 118.29278°W, 0.393 km2 (97 acres), with two smaller islets nearby:
- Church Rock
- Roca del Skip
Elsewhere, the other islets are very small and close to the shore, all less than one kilometre (1⁄2 nmi) away:
- Islote Negro, 28°54′23″N 118°17′18″W / 28.90639°N 118.28833°W, 8.8 ha (21+3⁄4 acres), to the southwest
- Roca Hundida, 28°55′00″N 118°18′00″W / 28.91667°N 118.30000°W, 0.3 ha (3⁄4 acre), to the southwest
- Islote Bernal, 28°56′04″N 118°17′53″W / 28.93444°N 118.29806°W, 1.1 ha (2+3⁄4 acres), to the southwest
- Palto Muerto, 28°56′49″N 118°17′42″W / 28.94694°N 118.29500°W, 0.5 ha (1+1⁄4 acres), 2 km (1 nmi) north of Islote Bernal
- unnamed islet, 28°56′59″N 118°17′48″W / 28.94972°N 118.29667°W, 0.2 ha (1⁄2 acre), 4 km (2 nmi) north of Islote Bernal
- Steamboat Rock, 0.3 ha (3⁄4 acre), to the west
- Roca Elefante, 0.1 ha (1⁄4 acre), to the northwest (the westernmost)
- Roca Elefante is the westernmost point in both Mexico and Latin America.[2]
Climate
The island has two major
Most
Rainfall averages 133 millimetres (5.2 in) near sea level at the south end, but appears to be much more at the high north end. An estimate for the rainfall in the northern highlands is possible by way of taking Pinus radiata as an indicator, which is native to that area of the island. In other places where Pinus radiata is native, it grows best with about 750 millimetres (30 in) of rainfall but under some conditions can survive with as little as half that much. The effective moisture is much greater because of fog drip.[17]
Month | Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec | Year |
---|---|---|---|---|---|---|---|---|---|---|---|---|---|
Record high °C (°F) | 27.8 (82.0) |
30.0 (86.0) |
30.0 (86.0) |
28.4 (83.1) |
29.5 (85.1) |
31.3 (88.3) |
31.7 (89.1) |
35.0 (95.0) |
32.2 (90.0) |
32.2 (90.0) |
30.6 (87.1) |
28.8 (83.8) |
35.0 (95.0) |
Mean daily maximum °C (°F) | 18.9 (66.0) |
19.6 (67.3) |
19.8 (67.6) |
20.1 (68.2) |
20.8 (69.4) |
21.8 (71.2) |
23.0 (73.4) |
23.9 (75.0) |
24.2 (75.6) |
23.2 (73.8) |
21.6 (70.9) |
20.1 (68.2) |
21.4 (70.5) |
Daily mean °C (°F) | 15.5 (59.9) |
15.6 (60.1) |
15.6 (60.1) |
16.1 (61.0) |
16.7 (62.1) |
17.6 (63.7) |
19.0 (66.2) |
20.1 (68.2) |
20.3 (68.5) |
19.4 (66.9) |
17.9 (64.2) |
16.3 (61.3) |
17.5 (63.5) |
Mean daily minimum °C (°F) | 11.8 (53.2) |
11.6 (52.9) |
11.6 (52.9) |
12.0 (53.6) |
12.4 (54.3) |
13.1 (55.6) |
14.5 (58.1) |
15.9 (60.6) |
16.4 (61.5) |
15.5 (59.9) |
13.8 (56.8) |
12.5 (54.5) |
13.4 (56.1) |
Record low °C (°F) | 3.5 (38.3) |
3.4 (38.1) |
2.2 (36.0) |
1.0 (33.8) |
6.2 (43.2) |
7.6 (45.7) |
8.0 (46.4) |
8.8 (47.8) |
5.4 (41.7) |
6.2 (43.2) |
4.5 (40.1) |
0.9 (33.6) |
0.9 (33.6) |
Average precipitation mm (inches) | 16.3 (0.64) |
21.6 (0.85) |
18.0 (0.71) |
9.5 (0.37) |
1.1 (0.04) |
1.2 (0.05) |
0.4 (0.02) |
0.2 (0.01) |
0.6 (0.02) |
5.1 (0.20) |
12.3 (0.48) |
22.2 (0.87) |
108.5 (4.27) |
Average precipitation days (≥ 0.1 mm) | 2.16 | 2.00 | 2.55 | 1.10 | 0.37 | 0.14 | 0.12 | 0.07 | 0.17 | 0.82 | 1.89 | 2.32 | 13.71 |
Average relative humidity (%)
|
79 | 79 | 78 | 78 | 79 | 82 | 83 | 81 | 81 | 80 | 79 | 79 | 80 |
Source: Colegio de Postgraduados[18] |
Ecology
Guadalupe Island was a major destination for Russian and American fur hunters seeking the Guadalupe fur seal (Arctocephalus townsendi) in the 18th and 19th centuries. Captain Auguste Duhaut-Cilly reported in 1827 that a Sandwich Islands (Hawaiian Islands) brig "had spent several months there and collected three thousand sealskins".[19] The northern elephant seal (Mirounga angustirostris) was also ruthlessly hunted for the oil in its blubber.
Northern elephant seals were thought to be
Guadalupe shares the
Originally brought to the island in the 19th century by European whalers and sealers for provisions when stopping over, the population eventually eliminated most vegetation; the number of feral goats declined to a few thousand. Before this collapse, the main impact of the feral goat population was about the turn of the 19th/20th century. Naturalist A. W. Anthony wrote in 1901:
"It is directly due to the despised Billy-goat that many interesting species of plants formerly abundant are now extinct, and also that one or more of the birds peculiar to the island has disappeared, and others are following rapidly."[22]
After the crash, the feral goat population once again grew, this time more slowly, until it had reached the new, lower
French sea captain Auguste Duhaut-Cilly remarked on the tall trees on the north of Guadalupe Island as he sailed past on January 2, 1827.
In November 1850, U.S. Army Lt.
Many islands or
The movement of the cool, nutrient-rich water current promotes phytoplankton production and attracts both coastal and deep-water species, including spanish mackerel, yellowfin tuna and great white sharks.[23]
Guadalupe is considered one of the best spots in the world for sightings of the great white shark (Carcharhodon carcharias), because of its clear water and large population of pinnipeds, their primary prey.[24] Because of the aggregation of over 350 identified white sharks, the island has hosted a recreational cage diving industry from one boat in 2005, to as many as eight operators in 2019, bringing thousands of shark enthusiasts to the island. In 2019 the Mexican Department SEMARNANT suspended cage diving and sport fishing between May and December to evaluate tourism’s impact on the several hundred protected white sharks congregating there. The Mexican Government said the closure was intended to gather information to adopt the best sustainability practices that guarantee their conservation. As of January 10, 2023, cage diving with great white sharks at Isla Guadalupe, Mexico, is permanently prohibited. The Mexican Government’s ban covers all tourism inside the reserve, including film production and liveaboard diving.[25]
The island has been recognised as an Important Bird Area (IBA) by BirdLife International.[26]
Habitat types
Before the
- Flora of the coastal lowlands and rocky cliffs: mainly up to 200 metres (660 ft) above mean sea level(ASL), but higher on the steep cliffs. Largely unresearched due to difficult access, the cliffs might even harbor remnant specimens of the presumably extinct plants.
- giant coreopsis(Coreopsis gigantea), a non-endemic native species, is also abundant.
- California boxthorn(Lycium californicum); none of these is endemic.
- Herbland dominated by introduced plants: 600–800 metres (2,000–2,600 ft) ASL, mainly on the central plateau. This habitat is almost entirely a consequence of overgrazing; hardly anything of the original ecosystem remains. Dominant introduced plants are red-flowering currant (Ribes sanguineum) and the endemic Hesperelaea palmeri, which have now disappeared from the island.
- Guadalupe palm groves: 400–900 metres (1,300–3,000 ft) ASL on the northwest side of the island. There are hundreds of palm trees remaining, mainly in a single patch of this habitat. At least one other major palm forest existed at the western coast; it was still present in 1906 at "Steamer Point".[30] As reproduction is presumably still ongoing, the species will likely recover in due time.
- Guadalupe cypress forest: 800–1,000 metres (2,600–3,300 ft) ASL. Presently some 4,000 old trees, essentially limited to the central-northern part. Other cypress forests, such as a major stand NE of the present patch which was still extant in 1906,[30]were destroyed by the goats early in the 20th century. There is still reproduction, but the water table appears to have declined to below the level required by the cypresses, and mortality of the old trees is high and can be expected to continue even after the removal of the goats.
- Guadalupe palm – island oak – Monterey pine woodland: 900–1,000 metres (3,000–3,300 ft) ASL. This habitat has all but disappeared during the 20th century,[30] due to the decline in numbers of the oaks and pines.
- Guadalupe pine cloud forest with some island oak: restricted to above 1,000 metres (3,300 ft) ASL on the N-NE point of the island. The population of the pine has declined by about two-thirds during the last 35 years; it presently stands at about 130 old trees in the main population and about the same number scattered elsewhere. Reproduction is ongoing, with several hundred seedlings having successfully established themselves since 2000,[29] and with the elimination of goat browsing, the pines will likely make a full recovery. The situation of the oak is direr; there are only 20 trees or so remaining (by about 1950, there were 100) and they appear past reproductive age. Not being restricted to Guadalupe, seedlings could be imported from elsewhere.
A ninth habitat type,
Endemism
Animals:
- Guadalupe fur seal (Arctocephalus townsendi) – only major breeding site
- Townsend's storm petrel (Hydrobates socorroensis) – only known breeding site
- Ainley's storm petrel (Hydrobates cheimomnestes) – only known breeding site
- Guadalupe rock wren (Salpinctes obsoletus guadalupensis) – endemic
- Guadalupe house finch (Haemorhous mexicanus amplus) – endemic
- Guadalupe pipefish (Syngnathus insulae) – endemic
- Guadalupe junco (Junco insularis) – endemic
- Guadalupe caracara (Caracara lutosa) – endemic, extinct
- Guadalupe Bewick's wren (Thryomanes bewickii brevicauda) – endemic, possibly extinct
- Endemic spiders:[31]
- Baeriopsis guadalupensis– near-endemic
- Brahea edulis (Guadalupe palm) – effectively endemic[note 2]
- Camissonia guadalupensis ssp. guadalupensis – endemic
- Castilleja fruticosa – endemic
- Cistanthe guadalupensis – endemic
- Hesperocyparis guadalupensis (Guadalupe cypress) – endemic
- Cryptantha foliosa – endemic
- Deinandra frutescens – endemic
- Deinandra greeneana ssp. greeneana – endemic
- Deinandra palmeri – endemic
- Dudleya guadalupensis – endemic
- Dudleya virens ssp. extima – endemic
- Eriogonum zapatoense – endemic
- Erysimum moranii – endemic
- Eschscholzia elegans – near-endemic
- Eschscholzia palmeri – endemic
- Galium angulosum – endemic
- Githopsis diffusa var. guadalupensis – endemic
- Hemizonia frutescens – endemic
- Hemizonia greeneana ssp. greeneana– endemic
- Hemizonia palmeri– endemic
- Heteromeles arbutifolia var. macrocarpa– probably endemic
- Lavatera lindsayi – endemic
- Lupinus niveus – endemic
- Marah guadalupensis – near-endemic or endemic[note 3]
- Perityle incana – endemic
- Phacelia phyllomanica – endemic
- Pinus radiata var. binata (Guadalupe Monterey pine) – near-endemic or endemic[note 4][28]
- Satureja palmeri – endemic; rediscovered in 2001–2003 surveys[29]
- Senecio palmeri – endemic
- Sphaeralcea palmeri – endemic
- Sphaeralcea sulphurea – endemic
- Stephanomeria guadalupensis – endemic
- Triteleia guadalupensis – endemic
Extinctions
Numerous
There have been 5–6 extinctions of birds:
- Guadalupe Bewick's wren (Thryomanes bewickii brevicauda), the late 1890s[22][32]
- Guadalupe spotted towhee (Pipilo maculatus consobrinus), the late 1890s
- Guadalupe caracara (Caracara lutosa), 1906 – intentionally made extinct by humans, ironically because it occasionally preyed on young goats
- Guadalupe red-shafted flicker (Colaptes auratus rufipileus), 1906 – the island was later recolonized by individuals of an extant mainland red-shafted northern flicker subspecies (which one is unknown)
- Guadalupe storm petrel (Hydrobates macrodactyla), the 1910s
- Guadalupe ruby-crowned kinglet (Corthylio calendula obscurus) – close to extinction (if, indeed, it still exists); it was not observed in 2000, despite thorough searches
Globally extinct plant taxa from Guadalupe Island are:[27][28][29]
- Castilleja guadalupensis
- Hesperelaea palmeri
- Pogogyne tenuiflora
and one species of plant incertae sedis
Notes
Its time zone is Pacific Standard Time
- ^ The maximum population that was reached in the late 19th century; nearly two feral goats per acre and more than four per hectare: León de la Luz et al (2003)
- ^ Some naturalized populations exist in California
- ^ Depending on whether this population belongs to Marah macrocarpus var. major or not
- ^ Depending on the taxonomic status of the Cedros Island population
References
- ^ Walther-Mendoza, Mariana; Ayala-Bocos, Arturo; Hoyos Padilla, Edgar; Reyes-Bonilla, Héctor (December 2013). "New records of fishes from Guadalupe Island, northwest Mexico" (PDF). Hidrobiológica. 23: 410–414. Archived (PDF) from the original on 2018-10-24.
- ^ a b Bada, Ferdinand (August 13, 2019). "The Most Extreme Points of Mexico". WorldAtlas. Archived from the original on 2022-05-29. Retrieved 2022-12-12.
- ^ Oberbauer, Thomas. "A Compilation of Estimated Historic and Current Vegetation Community Structure on Guadalupe Island, Mexico" (PDF). IWS Org. pp. 143–145. Retrieved 10 May 2021.
- ^ "Censo de Población y Vivienda 2010" (in Spanish). Instituto Nacional de Estadística, Geografía e Informática (INEGI). 2010.
- ^ Aronson, James and Thibaud (March 11, 2015). "Guadalupe Island, Baja California: Invasive mammal eradication and perspectives for ecological restoration". Natural History of Ecological Restoration. In collaboration with Edouard Le Floc’h. Archived from the original on 2022-05-21. Retrieved 2019-02-10.
- ^ a b c d e "Isla Guadalupe". Conservación de Islas. Archived from the original on 2018-08-18.
- ^ "Isla Guadalupe". Instituto Nacional de Ecologia (in Spanish). Ine.gob.mx. November 7, 2002. Archived from the original on 27 September 2007. Retrieved 20 November 2014.
- ^ "Reserva Espacial de la Biosfera: Isla de Guadalupe". Instituto Nacional de Ecología (in Spanish). March 31, 2005. Archived from the original on 5 October 2008. Retrieved 20 November 2014.
- ^ "Decreto RB Isla Guadalupe". Comisión Nacional de Mejora Regulatoria (in Spanish). 2004. Archived from the original on 2007-09-27.
- ^ Avioneta Isla Guadalupe Archived 2017-07-06 at the Wayback Machine. panoramio.com 29°01′09.85″N 118°16′41.03″W / 29.0194028°N 118.2780639°W
- ^ "PLANE WRECKS: ISLA GUADALUPE". Islapedia. May 19, 2020. Retrieved 2022-03-04.
- ^ http://sdsharkdiving.com/isla-guadalupe/ Sdsharkdiving.com/isla-guadalupe. San Diego Shark Diving. Isla Guadalupe White Shark Trip – FAQs. Retrieved August 17, 2018.
- ^ http://www.squalodivers.com/guadalupe-island-giants-fortress/ Squalo Divers. Guadalupe Island, Giant Fortress. March 27, 2017. Retrieved August 17, 2018.
- .
- ^ a b "Guadalupe". Global Volcanism Program. Smithsonian Institution. Retrieved 2017-10-16.
- ^ Google Earth
- ^ Moran, Reid (1868) "The Flora of Guadalupe Island, Mexico", in Memoirs of the California Academy of Sciences
- ^ "Normales climatológicas para Isla Guadalupe, B.C." Colegio de Postgraduados. Archived from the original on February 19, 2013. Retrieved January 4, 2013.
- ^ ISBN 978-0-520-21752-2.
- ISBN 978-0-7735-0610-7.
- S2CID 85821330.
- ^ JSTOR 1361475.
- ^ https://nautilusliveaboards.com/2020/08/13/why-guadalupe-island-is-the-perfect-great-white-sharks-habitat/ Nautilus Dive Adventures, Why Guadalupe Island is the perfect Great White Sharks Habitat?
- ^ https://travel.padi.com/d/guadalupe-island/ Travel.padi.com. PADI Travel. Diving in Guadalupe Island. Retrieved August 17, 2018.
- ^ McGuire, David. "Mexico Closes down Great White Shark Cage Diving". Shark Stewards. Retrieved 19 April 2023.
- ^ "Isla Guadalupe". BirdLife Data Zone. BirdLife International. 2021. Retrieved 24 January 2021.
- ^ S2CID 10038493.
- ^ a b c d "Plant accounts: Guadalupe Island". California/Mexico Island Conservation Database (CMICD). 2007. Archived from the original on 8 December 2007. Retrieved 10 October 2007.
- ^ a b c d Junak, S.; Keitt, B.; Tershy, B.; Croll, D.; Sánchez, J.A. (November 13–14, 2003). "Recent conservation efforts and current status of the flora of Guadalupe Island, Baja California, Mexico". Presentation at "Workshop on Restoration and Conservation of Guadalupe Island". Instituto Nacional de Ecologia. Archived from the original on 2007-08-19.
- ^ JSTOR 1360977.
- ISSN 0161-8202.
- JSTOR 1361667.