The Western Pacific archipelagic nation of Tuvalu, formerly known as the Ellice Islands, is situated northeast of Australia and is approximately halfway between Australia and Hawaii. It lies east-northeast of the Santa Cruz Islands (belonging to the Solomons), southeast of the Republic of Naoero (Nauru), south of Kiribati, west of Tokelau, northwest of Samoa and Wallis and Futuna and north of Fiji. It is a very small island country of . Due to the spread-out islands it has the 38th largest Exclusive Economic Zone of . In size, it is the second-smallest country in Oceania.Rodgers, K. A., and Carol Cantrell. The biology and geology of Tuvalu: an annotated bibliography. No. 1. Australian Museum, 1988.
The islands of Tuvalu consists of three reef islands and six atolls, containing approximately of reef platforms. The reef islands have a different structure to the atolls, and are described as reef platforms as they are smaller tabular reef platforms that do not have a salt-water lagoon, although they have a completely closed rim of dry land, with the remnants of a lagoon that has no connection to the open sea or that may be drying up. For example, Niutao has two lakes, which are brackish to saline, and are the degraded lagoon as the result of coral debris filling the lagoon.
The soils of Tuvalu's islands are usually shallow, porous, alkaline, and coarse-textured, with carbonate mineralogy and high pH values of up to 8.2 to 8.9. The soils are usually deficient in most of the important nutrients needed for plant growth (such as nitrogen, potassium and micronutrients such as iron, manganese, copper and zinc), so garden beds need to be enhanced with mulch and fertiliser to increase their fertility. The Tuvalu islands have a total land area of only about 26 km2, less than .
The land is very low-lying, with narrow coral atolls. The highest elevation is above sea level on Niulakita. Over four decades, there had been a net increase in land area of the islets of 73.5 ha (2.9%), although the changes are not uniform, with 74% increasing and 27% decreasing in size. The sea level at the Funafuti tide gauge has risen at 3.9 mm per year, which is approximately twice the global average. The rising sea levels are identified as creating an increased transfer of wave energy across reef surfaces, which shifts sand, resulting in accretion to island shorelines, although this process does not result in additional habitable land. As of March 2018 Enele Sopoaga, the prime minister of Tuvalu, stated that Tuvalu is not expanding and has gained no additional habitable land.
Tuvalu experiences two distinct seasons, a wet season from November to April and a dry season from May to October. Westerly gales and heavy rain are the predominant weather conditions from November to April, the period that is known as Tau-o-lalo, with tropical temperatures moderated by easterly winds from May to October.
Geography
Location: Oceania, island group of nine islands comprising three reef islands and six true atolls in the South Pacific Ocean. The islands of Tuvalu are spread out between the latitude of 5° to 10° south and longitude of 176° to 180°, west of the International Date Line.
Geographic coordinates: to
Map references: Oceania
Area: total: 26 km2 land: 26 km2 water: 0 km2
Area – comparative: 0.1 times the size of Washington, D.C.
Land boundaries: 0 km
Coastline:
Maritime claims: contiguous zone:
exclusive economic zone: and territorial sea:
Tuvalu's Exclusive Economic Zone (EEZ) covers an oceanic area of approximately .
On 29 August 2012 an Agreement between Tuvalu and Kiribati concerning their Maritime Boundary, was signed by their respective leaders that determined the boundary as being seaward of Nanumea and Niutao in Tuvalu on the one hand and Tabiteuea, Tamana and Arorae in Kiribati on the other hand, along the geodesics connecting the points of latitude and longitude set out in the agreement.
In October 2014 the prime ministers of Fiji and Tuvalu signed the Fiji-Tuvalu Maritime Boundary Treaty, which establishes the extent of the national areas of jurisdiction between Fiji and Tuvalu as recognized in international law under the 1982 United Nations Convention on the Law of the Sea.
Climate: tropical; moderated by easterly trade winds (March to November); westerly gales and heavy rain (November to March).
Terrain: low-lying and narrow coral atolls.
Elevation extremes: lowest point: Pacific Ocean 0 m highest point: unnamed location, on Niulakita.
Extreme points:
This is a list of the extreme points of Tuvalu, the points that are farther north, south, east or west than any other location:
Northernmost point – Lakena islet, Nanumea Easternmost point – Niuoko islet, Nukulaelae Southernmost point – Niulakita Westernmost point – Lakena islet, Nanumea
Natural resources: fish. coconut
Land use: arable land: 0% permanent crops: 60% forest: 33.3% other: 6.7% (2022 est.)
Irrigated land: 0 km2
Trees and shrubs
Most common trees Thaman (2016) described about 362 species or distinct varieties of vascular plants that have been recorded at some time on Tuvalu, of which only about 59 (16%) are possibly indigenous. The most common trees found on all islands are coconut (Cocos nucifera) stands, hibiscus (Hibiscus tiliaceus), papaya (Carica papaya), pandanus (Pandanus tectorius), salt bush (Scaevola taccada), Premna serratifolia, Tournefortia samoensis, zebra wood (Guettarda speciosa), Kanava (Cordia subcordata), (beach cordia) and terminalia (Terminalia samoensis). Indigenous broadleaf species, including Fetau (Calophyllum inophyllum), make up single trees or small stands around the coastal margin. While Coconut palms are common in Tuvalu, they are usually cultivated rather than naturally seeding and growing. Tuvaluan traditional histories are that the first settlers of the islands planted Coconut palms as they were not found on the islands.
The two recorded mangrove species in Tuvalu are the common Togo (Rhizophora stylosa) and the red-flowered mangrove Sagale (Lumnitzera littorea), which is only reported on Nanumaga, Niutao, Nui and Vaitupu. Mangrove ecosystems are protected under Tuvaluan law.
The land cover types found on Funafuti include inland broadleaf forest and woodland, coastal littoral forest and scrub, mangroves and wetlands, and coconut woodland and agroforest.
Native broadleaf forest
The native broadleaf forest is limited to 4.1% of the vegetation types on the islands of Tuvalu. The islets of the Funafuti Conservation Area have 40% of the remaining native broadleaf forest on Funafuti atoll. The native broadleaf forest of Funafuti would include the following species, that were described by Charles Hedley in 1896, which include the Tuvaluan name (some of which may follow Samoan plant names):
Fala or Screw Pine, (Pandanus) Puka or pouka, (Hernandia peltata) Futu, (Barringtonia asiatica) Fetau, (Calophyllum inophyllum) Ferra, (Ficus aspem), native fig Fau or Fo fafini, or woman's fibre tree (Hibiscus tiliaceus) Lakoumonong, (Wedelia strigulosa) Lou, (Cardamine sarmentosa) Meili, (Polypodium), fern Laukatafa, Asplenium nidus, bird's-nest fern Milo or miro, (Thespesia populnea) Ngashu or Naupaka, (Scaevola taccada) Ngia or Ingia, (Pemphis acidula), bush Nonou or nonu, (Morinda citrifolia) Pukavai, (Pisonia grandis) Sageta, (Dioclea violacea), vine Talla talla gemoa, (Psilotum triquetrum), fern Tausunu or tausoun, (Heliotropium foertherianum) Tonga or tongo, (Rhizophora mucronata), found around swamps Tulla tulla, (Triumfetta procumbens), whose prostrate stems trailed for several feet over the ground Valla valla, (Premna tahitensis) The blossoms that are valued for their scent and for use in flower necklaces and headdresses include: Fetau, (Calophyllum inophyllum); Jiali, (Gardenia taitensis); Boua (Guettarda speciosa); and Crinum.
Donald Gilbert Kennedy, the resident District Officer in the administration of the Gilbert and Ellice Islands Colony from 1932 to 1938, identified other trees found in the broadleaf forest:
Pua, (Guettarda speciosa) Kanava, (Cordia subcordata)
Charles Hedley (1896) identified the uses of plants and trees from the native broadleaf forest as including:
Food plants: Coconut; and Ferra, native fig (Ficus aspem). Fibre: Coconut; Ferra; Fala, Screw Pine, Pandanus; Fau or Fo fafini, or woman's fibre tree (Hibiscus tiliaceus). Timber: Fau or Fo fafini; Pouka, (Hernandia peltata); Ngia or Ingia, (Pemphis acidula); Miro, (Thespesia populnea); and Tonga, (Rhizophora mucronata). Dye: Valla valla, (Premna tahitensis); Tonga, (Rhizophora mucronata); and Nonou, (Morinda citrifolia). Scent: Fetau, (Calophyllum inophyllum); Jiali, (Gardenia taitensis); and Boua (Guettarda speciosa); Valla valla, (Premna tahitensis); and Crinum. Medicinal: Tulla tulla, (Triumfetta procumbens); Nonou, (Morinda citrifolia); Tausoun, (Heliotropium foertherianum); Valla valla, (Premna tahitensis); Talla talla gemoa (Psilotum triquetrum); Lou, (Cardamine sarmentosa); and Lakoumonong, (Wedelia strigulosa).
Thaman (1992) provides a literature review of the ethnobiology of the Pacific Islands.
Climate and natural hazards
El Niño and La Niña Tuvalu experiences the effects of El Niño and La Niña that flow from changes in ocean temperatures in equatorial and central Pacific. El Niño effects increase the chances of tropical storms and cyclones; while La Niña effects increase the chances of drought conditions in Tuvalu. On 3 October 2011, drought conditions resulted in a state of emergency being declared as water reserves ran low. Typically the islands of Tuvalu receive between 200mm to 400mm of rainfall per month, however a weak La Niña effect causes a drought by cooling the surface of the sea around Tuvalu.
Tropical cyclones Severe tropical cyclones are usually rare, but the low level of islands makes them very sensitive to sea-level rise. Tuvalu experienced an average of three cyclones per decade between the 1940s and 1970s, however eight occurred in the 1980s. The impact of individual cyclones is subject to variables including the force of the winds and also whether a cyclone coincides with high tides. A warning system, which uses the Iridium satellite network, was introduced in 2016 in order to allow outlying islands to be better prepare for natural disasters.
George Westbrook recorded a cyclone that struck Funafuti on 23–24 December 1883. A cyclone struck Nukulaelae on 17–18 March 1886. Captain Edward Davis of HMS Royalist, who visited the Ellice Group in 1892, recorded in the ship's diary that in February 1891 the Ellice Group was devastated by a severe cyclone. A cyclone caused severe damage to the islands in 1894.