Kiritimati

During the dispute over the Caroline Islands between Germany and Spain in 1885 which was arbitrated by Pope Leo XIII, the sovereignty of Spain over the Caroline and Palau islands as part of the Spanish East Indies was analysed by a commission of cardinals and confirmed by an agreement signed on 17 December 1885. Its Article 2 specifies the limits of Spanish sovereignty in South Micronesia, being formed by the Equator and 11°N Latitude and by 133° and 164° Longitude. In 1899, Spain sold the Marianas, Carolines, and Palau to Germany after its defeat in 1898 in the Spanish–American War. However Emilio Pastor Santos, a researcher of the Spanish National Research Council, claimed in 1948[18] that there was historical basis to argue that Kiritimati ("Acea" on the Spanish maps) and some other islands had never been considered part of the Carolines, supported by the charts and maps of the time.[lower-alpha 4] Despite having sought acknowledgement of the issue regarding interpretation of the treaty, no Spanish government has made any attempt to assert sovereignty over Kiritimati, and the case remains a historical curiosity.[19]

During the Cold War Kiritimati was used for nuclear weapons testing by the United Kingdom and the USA.[20] The United Kingdom conducted its first hydrogen bomb test series, Grapple 1–3, at Malden Island from 15 May to 19 June 1957 and used Kiritimati as the operation's main base. On 8 November 1957, the first H-bomb was detonated over the southeastern tip of Kiritimati in the Grapple X test. Subsequent tests in 1958 (Grapple Y and Z) also took place above or near Kiritimati.

The United Kingdom detonated some 5 megatonnes of TNT (21 PJ) of nuclear payload near and 1.8 megatonnes of TNT (7.5 PJ) directly above Kiritimati in 1957–1958, while the total yield of weapons tested by the United States in the vicinity of the island between 25 April and 11 July 1962 was 24 megatonnes of TNT (100 PJ). During the British Grapple X test, yield was stronger than expected, resulting in the blast demolishing buildings and infrastructure.[21] Islanders were usually not evacuated during the nuclear weapons testing, and data on the environmental and public health impact of these tests remains contested.[22] Servicemen believe that cancer and genetic damage were consequences of their occupational exposure and have sought apologies and compensation without success.[23] A spokesperson for the U.K.'s Department of Defence stated in 2018 that "the National Radiological Protection Board has carried out three large studies of nuclear test veterans and found no valid evidence to link participation in these tests to ill health."[24]

The United States also conducted 22 successful nuclear detonations over the island as part of Operation Dominic in 1962. Some toponyms (like Banana and Main Camp) come from the nuclear testing period, during which at times over 4,000 servicemen were present. By 1969, military interest in Kiritimati had ended and the facilities were mostly dismantled. However, some communications, transport, and logistics facilities were converted for civilian use, which Kiritimati uses to serve as the administrative centre for the Line Islands.[1]

• 
  The British Grapple Y test on 28 April 1958
• 
  The bombs for the British Grapple Z1 and Z4 tests were hoisted by balloon; this is the East Point balloon anchor.
• 
  A US test in the Operation Dominic series, 1962
• 
  Memorial tablet in Paisley remembering the people involved in the tests

Most of the atoll's food supplies have to be imported. Potable water can be in short supply, especially around November in La Niña years. A large and modern jetty, handling some cargo, was built by the Japanese at London. Marine fish provide a large portion of the island's nutrition, although overfishing has caused a drastic decrease in the populations of large, predatory fish over the last several years.[26]

Exports of the atoll are mainly copra (dried coconut pulp); the state-owned coconut plantation covers about 51 square kilometres (20 sq mi). In addition aquarium fish and seaweed are exported. A 1970s project to commercially breed Artemia salina brine shrimp in the salt ponds was abandoned in 1978. In recent years there have been attempts to explore the viability of live crayfish and chilled fish exports and salt production.[1]

Cassidy International Airport (CXI) is located just north of Banana and North East Point. It has a paved runway with a length of 6,900 feet (2,103 m) and was for some time the only airport in Kiribati to serve the Americas, via an Air Pacific (now Fiji Airways) flight to Honolulu, Hawaii. American Te Mauri Travel offers weekly charter flights from Honolulu.

Airport on Christmas island (Kiritimati), Republic of Kiribati

Air Pacific ran flights to Kiritimati until 2008, when they stopped over concerns about the condition of the runway.[27] Services resumed in 2010.[28] A monthly air freight service is flown using a chartered Boeing 727 from Honolulu operated by Asia Pacific Airlines.[29]

Aeon Field is an abandoned airport, constructed before the British nuclear tests.[30] It is located on the southeastern peninsula.

There is a small amount of tourism, mainly associated with anglers interested in lagoon fishing (for bonefish in particular) or offshore fishing. Week-long ecotourism packages during which some of the normally closed areas can be visited are also available.[1]

In recent years, surfers have discovered that there are good waves during the Northern Hemisphere's winter season and there are interests developing to service these recreational tourists.[31] There is some tourism-related infrastructure, such as a small hotel, rental facilities, and food services.

In the early 1950s, Wernher von Braun proposed using this island as a launch site for crewed spacecraft, based on its proximity to the equator, and the generally empty ocean down-range (east).

There is a Japanese JAXA satellite tracking station. The abandoned Aeon Field had at one time been proposed for reuse by the Japanese for their now-canceled HOPE-X space shuttle project.

Kiritimati is also located fairly close to the Sea Launch satellite launching spot at 0° N 154° W, about 370 kilometres (200 nmi) to the east in international waters.

Despite its proximity to the Intertropical Convergence Zone (ITCZ), Kiritimati is located in an equatorial dry zone and rainfall is rather low except during El Niño years; 873 mm (34.4 in) on average per year, in some years it can be as little as 177 mm (7.0 in) and much of the flats and ponds can dry up such as in late 1978. On the other hand, in some exceptionally wet years abundant downpours in March–April may result in a total annual precipitation of over 2,500 mm (98 in). Kiritimati is thus affected by regular, severe droughts. They are exacerbated by its geological structure; climatically "dry" Pacific islands are more typically located in the "desert belt" at about 30°N or S latitude. Kiritimati is a raised atoll, and although it does occasionally receive plenty of precipitation, little is retained given the porous carbonate rock, the thin soil, and the absence of dense vegetation cover on much of the island, while evaporation is constantly high.[2] Consequently, Kiritimati is one of the rather few places close to the Equator which have an effectively arid climate.[1]

The temperature is constantly between 24 °C and 30 °C (75 °F and 86 °F) with more diurnal temperature variation than seasonal variation. Easterly trade winds predominate.[1]

At the first census done in the Gilbert and Ellice Islands colony in 1931, there were only 38 inhabitants on the island, most of them workers of the Emmanuel Rougier Company. After WWII in 1947 there were 52 inhabitants. After the nuclear tests, in 1963, this had increased to 477, reducing to 367 by 1967 but increasing again to 674 in 1973, 1,265 in 1978, 1,737 in the 1985 census, 2,537 in 1990, 3,225 in 1995, 3,431 in 2000, 5,115 in 2005, 5,586 in 2010 and 6,456 in 2015. This was the fastest population growth in Kiribati.

The natural vegetation on Kiritimati consists mostly of low shrubland and grassland. What little woodland exists is mainly open coconut palm (Cocos nucifera) plantation. There are three small woods of catchbird trees (Pisonia grandis), at Southeast Point, Northwest Point, and on Motu Tabu. The latter was planted there in recent times. About 50 introduced plant species are found on Kiritimati; as most are plentiful around settlements, former military sites and roads, it seems that these only became established in the 20th century.[1]

Tree heliotrope (Heliotropium foertherianum) in typical habitat on a Hawaiian island.

Beach naupaka (Scaevola taccada) is the most common shrub on Kiritimati; beach naupaka scrub dominates the vegetation on much of the island, either as pure stands or interspersed with tree heliotrope (Heliotropium foertherianum) and bay cedar (Suriana maritima). The latter species is dominant on the drier parts of the lagoon flats where it grows up to 2 m (6.6 ft) tall. Tree heliotrope is most commonly found a short distance from the sea- or lagoon-shore. In some places near the seashore, a low vegetation dominated by Polynesian heliotrope (Heliotropium anomalum), yellow purslane (Portulaca lutea) and common purslane (P. oleracea) is found. In the south and on the sandier parts, Sida fallax, also growing up to 2 m tall, is abundant. On the southeastern peninsula, S. fallax grows more stunted, and Polynesian heliotrope, yellow and common purslane as well as the spiderling Boerhavia repens, the parasitic vine Cassytha filiformis, and Pacific Island thintail (Lepturus repens) supplement it. The last species dominates in the coastal grasslands. The wetter parts of the lagoon shore are often covered by abundant growth of shoreline purslane (Sesuvium portulacastrum).[1]

Perhaps the most destructive of the recently introduced plants is sweetscent (Pluchea odorata), a camphorweed, which is considered an invasive weed as it overgrows and displaces herbs and grasses. The introduced creeper Tribulus cistoides, despite having also spread conspicuously, is considered to be more beneficial than harmful to the ecosystem, as it provides good nesting sites for some seabirds.[1]

Despite massive declines in recent decades, more sooty terns continue to nest on Kiritimati than anywhere else in the world.

The Christmas shearwater was named after Kiritimati.

Brown-morph red-footed booby. Those on Kiritimati will reuse nests for several years, unlike in most other colonies.

See also "Extinction" below.

More than 35 bird species have been recorded from Kiritimati. As noted above, only the bokikokiko (Acrocephalus aequinoctialis), perhaps a few Rimitara lorikeets (Vini kuhlii) – if any remain at all – and the occasional eastern reef egret (Egretta sacra) make up the entire landbird fauna. About 1,000 adult bokikokikos are to be found at any date, but mainly in mixed grass/shrubland away from the settlements.[1]

On the other hand, seabirds are plentiful on Kiritimati, and make up the bulk of the breeding bird population. There are 18 species of seabirds breeding on the island, and Kiritimati is one of the most important breeding grounds anywhere in the world for several of these:[1]

Phaethontiformes

• Eastern red-tailed tropicbird (Phaethon rubricauda melanorhynchus[lower-alpha 5]) – important breeding colony; 8,000 birds before the 1982–1983 decline, fewer than 3,000 in 1984

Charadriiformes

• Micronesian black noddy (Anous minutus marcusi) – 20,000 birds before the 1982–1983 decline
• Little white tern (Gygis microrhyncha[lower-alpha 6]) – 8,000 birds before the 1982–1983 decline
• Central Pacific sooty tern (Onychoprion fuscatus oahuensis[lower-alpha 5]) – largest breeding colony in the world; around 7,000,000 birds before the 1982–1983 decline
• Spectacled tern (Onychoprion lunatus) – important breeding colony; 6,000 birds before the 1982–1983 decline
• Central blue-grey noddy (Procelsterna cerulea cerulea) – important breeding colony, possibly the largest worldwide of this subspecies; 4,000 birds before the 1982–1983 decline

Procellariiformes

• Polynesian storm petrel (Nesofregetta fuliginosa) – important breeding colony; 1,000 birds before the 1982–1983 decline
• Phoenix petrel (Pterodroma alba) – largest breeding colony in the world; 24,000 birds before the 1982–1983 decline
• Christmas shearwater (Puffinus nativitatis) – largest subpopulation worldwide on Motu Upua; 12,000 birds before the 1982–1983 decline
• Wedge-tailed shearwater (Puffinus pacificus[35]) – among the very largest breeding colonies in the world; about 1,000,000 birds before the 1982–1983 decline

Pelecaniformes

• Indopacific lesser frigatebird (Fregata ariel ariel) – important breeding colony; 9,000 birds before the 1982–1983 decline
• Central Pacific great frigatebird (Fregata minor palmerstoni[lower-alpha 5]) – important breeding colony; 12,000 birds before the 1982–1983 decline, 6,500 afterwards
• Austropacific masked booby (Sula dactylatra personata) – important breeding colony; 3,000 birds before the 1982–1983 decline
• Indopacific red-footed booby (Sula sula rubripes[lower-alpha 5]) – 12,000 birds before the 1982–1983 decline

Kiritimati's lagoon and the saltflats are a prime location for migratory birds to stop over or even stay all winter. The most commonly seen migrants are ruddy turnstone (Arenaria interpres), Pacific golden plover (Pluvialis fulva), bristle-thighed curlew (Numenius tahitiensis), and wandering tattler (Tringa incana); other seabirds, waders, and even dabbling ducks can be encountered every now and then.[1] Around 7 October (±5 days), some 20 million sooty shearwaters pass through here en route from the North Pacific feeding grounds to breeding sites around New Zealand.[36]

The only mammals native to the region are the common Polynesian rat (Rattus exulans) and the goats. The rat seems to have been introduced by seafarers many centuries before Cook arrived in 1777 (he mentioned them already being present); goats have been extinct since 14 January 2004. Black rats (Rattus rattus) were present at some time, perhaps introduced by 19th century sailors or during the nuclear tests. They were not able to gain a foothold between predation by cats and competitive exclusion by Polynesian rats, and no black rat population is found on Kiritimati today.[1]

Up to 2,000 feral cats can in some years be found on the island; the population became established in the 19th century. Their depredations seriously harm the birdlife. Since the late 19th century,[2] they have driven about 60% of the seabird species from the mainland completely, and during particular dry spells they will cross the mudflats and feast upon the birds on the motus. Spectacled tern chicks seem to be a favourite food of the local cat population. There are some measures being taken to ensure the cat population does not grow. That lowering the cat population by some amount would much benefit Christmas and its inhabitants is generally accepted, but the situation is too complex to simply go and eradicate them outright (which is theoretically possible; see Marion Island) – see below for details. A limited population of feral pigs exists. They were once plentiful and wreaked havoc especially on the Onychoprion and noddies. Pig hunting by locals has been encouraged, and was highly successful at limiting the pig population to a sustainable level, while providing a source of cheap protein for the islanders.[1]

Mourning gecko, a common sight all over the tropical Pacific

A strawberry land hermit crab in its shell

There are some "supertramp" lizards which have reached the island by their own means. Commonly seen are the mourning gecko (Lepidodactylus lugubris) and the skink Cryptoblepharus boutonii; the four-clawed gecko (Gehyra mutilata) is seen less often.[1]

There are some crustaceans of note to be found on Kiritimati and in the waters immediately adjacent. The amphibious coconut crab (Birgus latro) is not as common as on Teraina. Ghost crabs (genus Ocypode), Cardisoma carnifex and Geograpsus grayi land crabs, the strawberry land hermit crab (Coenobita perlatus) are also notable.[1] Introduced brine shrimp Artemia salina populate the island's saline ponds.[1]

Egg collecting for food on a massive scale was frequent in the past but is now outlawed. It is to be noted that the sooty terns for example could sustain occasional collection of effectively all of a season's eggs (over 10 million), if given sufficient time to recover and if cats are absent. In theory, even egg collecting on a scale that significantly decreases costly food imports could be possible, but not until the cat and rat populations have been brought under control. Poaching remains a concern; with the population rising and spreading out on Kiritimati, formerly remote bird colonies have become more accessible; the red-tailed tropicbirds and the Sula especially are strongly affected by hunting and disturbance. Tropicbirds are mainly poached for their feathers, which are used in local arts and handicraft; it would certainly be possible to obtain them from living birds as was routinely done at the height of the Polynesian civilisation.[1]

It may seem that the former numbers of seabirds may only ever be approached again by the wholesale eradication of the feral cats. While this has been since shown to be feasible,[lower-alpha 7] it is not clear whether even a severe curtailing of the cat population would be desirable: Though it previously was assumed that the small Polynesian rat is of little, if any, harm to seabirds, even house mice have been shown to eat seabird nestlings. Most nesting birds, in particularly Procellariiformes, are now accepted to be jeopardised by Rattus exulans. Kiritimati's cats meanwhile, are very fond of young seabirds; it even seems that their behaviour shifts accordingly, with cats being generally less territorial, and congregating in numbers at active bird colonies; they generally eschew hunting rats when seabird chicks are in plenty.[1]

Possession of an unneutered female cat on Kiritimati is illegal, and owners need to prevent their domestic cats from running wild (such animals are usually quickly killed in traps set for this purpose). Nighttime cat hunting has made little effect on the cat population. As noted above, vigorous protection of active nesting grounds from cats by traps and poison, supplemented by shooting, while otherwise leaving them alone to hunt rats may well be the optimal solution.[1]

8 November 1957 Grapple X Round C1 – the first successful British hydrogen bomb test – detonates over Kiritimati's South East Point.

There is no reliable data on the environmental and public health impact of the nuclear tests conducted on the island in the late 1950s.[1] A 1975 study[38] claimed that there was negligible radiation hazard; certainly, fallout was successfully minimised. More recently however, a Massey University study of New Zealand found chromosomal translocations to be increased about threefold on average in veterans who participated in the tests;[39] most of the relevant data remains classified to date.

The 1982–1983 "mega-El Niño" devastated seabird populations on Kiritimati. In some species, mortality rose to 90% and breeding success dropped to zero during that time.[1]

In general, El Niño conditions will cause seabird populations to drop, taking several years to recover at the present density of predators. Global warming impact on Kiritimati is thus unpredictable. El Niño events seem to become shorter but more frequent in a warmer climate.

Much of the island's infrastructure and habitation, with the notable exception of the airport area, is located to the leeward and thus somewhat protected from storms.

A rising sea level does not appear to be particularly problematic; the increasing flooding of the subsidiary lagoons would provide easily observed forewarning, and might even benefit seabird populations by making the motus less accessible to predators. In fact, geological data suggests that Kiritimati has withstood prehistoric sea level changes well.[2][40]

The biggest hazard caused by a changing climate would seem to be more prolonged and/or severe droughts, which could even precipitate the island's abandonment (as happened in 1905). However, it is not clear how weather patterns would change, and it may be that precipitation increases.

The type specimen of the Tuamotu sandpiper (Prosobonia cancellata) was collected on Christmas Island in 1778, probably on 1 or 2 January, during Captain Cook's visit.[41] The expedition's naturalist William Anderson observed the bird, and it was painted by William Ellis (linked below). The single specimen was in Joseph Banks's collection at the end of the 18th century, but later was lost or destroyed. There is some taxonomic dispute regarding the Kiritimati population.[42][43]

As all Prosobonia seem(ed) to be resident birds, unwilling to undertake long-distance migrations, an appropriate treatment would be to consider the extinct population the nominate subspecies, as Prosobonia cancellata cancellata or Kiritimati sandpiper, distinct from the surviving Tuamotu Islands population more than 2,000 km (1,200 mi) to the southeast. It may have been, but probably was not, limited to Kiritimati; while no remains have been found, little fieldwork has been conducted, and judging from the Tuamotu sandpiper's habits, almost all Line Islands would have offered suitable habitat.

The Kiritimati population of P. cancellata disappeared in the earlier part of the 19th century or so, almost certainly due to predation by introduced mammals. While Prosobonia generally manage to hold their own against Polynesian rats, they are highly vulnerable to the black rat and feral cats.[44] Given the uncertainties surrounding the introduction date and maximum population of the former, the cats seem to be the main culprits in the Kiritimati sandpiper's extinction.

The buff-banded rail (Gallirallus philippensis) might once have had a similar-looking relative on Kiritimati.

Given that the island was apparently settled to some extent in prehistoric times, it may have already lost bird species then. The geological data indicates that Kiritimati is very old and was never completely underwater in the Holocene at least; thus it might have once harboured highly distinct wetland birds.

The limited overall habitat diversity on Kiritimati nonetheless limits the range of such hypothetical taxa, as does biogeography due to its remote location. At least one, possibly several Gallirallus and / or Porzana rails make the most likely candidates, given their former presence in the region, and that conditions on Kiritimati would seem well suited. Perhaps a Todiramphus kingfisher was also present; such a bird would probably have belonged to the sacred kingfisher (T. sanctus) group, as that species today occurs as a vagrant in Micronesia, and related forms are resident in southeastern Polynesia. These birds would have fallen victim to the Polynesian rat. In the case of the rails (which would have almost certainly been flightless) hunting by occasionally resident Polynesians, in addition to predation by the imported rats, likely contributed to their extinction.[40]