Coral reefs of Kiribati
Banaba | |
Highest elevation | 81 m (266 ft)[1] |
---|---|
Highest point | Unnamed location on Banaba |
Administration | |
The Coral reefs of Kiribati consists of 32 atolls and one raised coral island, Banaba (Ocean Island), which is an isolated island between Nauru and the Gilbert Islands. The islands of Kiribati are dispersed over 3.5 million km2 (1.4 million sq mi) of the Pacific Ocean and straddle the equator and the 180th meridian, extending into the eastern and western hemispheres, as well as the northern and southern hemispheres.[2] 21 of the 33 islands are inhabited. The groups of islands of Kiribati are:
- Gilbert Islands: 16 atolls located some 1,500 kilometres (932 mi) north of Fiji.
- Phoenix Islands: 8 atolls and coral islands located some 1,800 kilometres (1,118 mi) southeast of the Gilberts.
- Line Islands: 8 atolls and one reef, located about 3,300 kilometres (2,051 mi) east of the Gilberts.
The recognizable reef systems in these
The reefs in the Gilbert Islands are exposed to the effects of pollution and over-utilisation of the reef resources by the residents of the islands,[6][7][8][9] which is similar to the threats to the Coral reefs of Tuvalu, which are to the south east of the Gilbert Islands. In contrast, most of atolls of the Phoenix Islands and Line Islands are uninhabited.[10][11]
The isolation of the Phoenix Islands, most of which are uninhabited, means they are among the most pristine coral reefs on Earth.[12]
Areas of high biodiversity and conservation value
Key Biodiversity Areas
A total of 22 Key Biodiversity Areas (KBAs) - areas of high biodiversity and conservation value - have been identified in Kiribati, with the KBAs encompassing both marine and terrestrial systems (such as bird nesting or feeding environments).[13] The 22 identified KBAs cover an approximate total area of 4 thousand km2 (1.5 thousand sq mi) or approximately 74% of the total land, lagoon and reef habitat of Kiribati.[13] As of 2013, 12 of the 22 KBAs have been completely or partially established as conservation areas by the government of Kiribati or by local village communities.[13]
The North Tarawa Conservation Area includes marine zones.[3][14]
Four marine reserves were specifically set aside for the conservation of grouper. These are all located in the Gilbert Islands on the atolls of Butaritari, Tabiteuea, Nonouti, and Onotoa and are managed by the Fisheries Division.[3]
Phoenix Islands Protected Area
The 2006 declaration of the Phoenix Islands Protected Area (PIPA), with a size of 408,250 km2 (157,630 sq mi), created, at that time, the world's largest designated marine protected area (MPA), which was also designated as the world's largest and deepest UNESCO World Heritage Site in 2010.[15] The U.S. administered Pacific Remote Islands Marine National Monument is currently the world's largest designated MPA, and is to the north and north-east of the PIPA.
The PIPA constitutes 11.34% of Kiribati's Exclusive Economic Zone (EEZ). The PIPA conserves one of the world's largest intact oceanic coral archipelago ecosystems, includes 14 known underwater
There are three atolls with associated lagoons and perimeter coral reefs in the PIPA, Orona (Hull), Nikumaroro (Gardner), and Canton Island (Abariringa), and five low islands surrounded by fringing reefs, Manra (Sydney), Rawaki (Phoenix), McKean, Birnie and Enderbury, and also two submerged reefs, Winslow and Carondelet. The area contains seven main habitats: island, lagoon, coral reef, deep reef, seamount, deep benthos, and open ocean, which are all represented within PIPA and the Kanton Island protection zone.[20]
In the PIPA Management Plan 2015–2020, which was implemented following a Kiribati government decision in January 2014, there is a total ban on commercial fishing within the PIPA boundaries extending to the limits of the Territorial Sea (to 12 nm) and in all lagoons of the 8 PIPA islands, (Canton, Manra, Rawaki, Birnie, Mckean, Enderbury, Nikumaroro and Orona) to ensure there is no impact to marine and terrestrial species including habitats.[21]
Two submerged reefs, Winslow and Carondelet, and at least 14 known seamounts together with open ocean and deep-sea habitat are an integral part of the Phoenix Islands Protected Area. The New England Aquarium (NEAq) and Woods Hole Oceanographic Institution have carried out scientific research expeditions of these seamount habitats, which have been identified being rich in deep-water coral and biodiversity supporting a variety of oceanic pelagic species. PIPA has been identified as an important feeding and spawning site for species of tuna.[21][22] The dominant taxonomic group across all depths were the octocorals, followed by antipatharians, scleractinians, and then zoantharians.[22]
As of 2015[update], Canton Island had a population of 20, down from 61 in 2000.[23][24] Because it is inhabited, management of Canton Island is described in the Canton Resource Use Sustainability Plan (KRUSP), which covers a 12 nm radius around the atoll. Over 50% of the island and lagoon are protected in a conservation zone.[25]
Structure of the reefs of Kiribati
The
Banaba is an elevated limestone cap surrounded by a fringing reef. The low islands of Makin, Tamana, Arorae, Enderbury, Flint and Vostok Island all lack lagoons but have a fringing reef.[3]
State of the reefs of Kiribati
Gilbert Islands
The reef environment of Kiribati includes approximately 200 species of corals and about 1,000 species of shellfish.
In the Central Gilbert Islands atolls of Abaiang, Abemama and Maiana, 3 species of giant clam (Tridacna) occur: Tridacna squamosa; Tridacna maxima; and Hippopus hippopus),[3] although the stocks of the giant clam have been largely exhausted.[32]
Phoenix Islands
The 2000 surveys identify that, at the time of these surveys, the reefs were in an excellent state of health, and free from the bleaching that has plagued reefs in other parts of the Pacific with no evidence of any coral diseases.[12]
The coral reefs of the Phoenix Islands were notable for their moderate Live Coral Cover (LCC) of 20-40% and evidence of high physical breakage of coral by wave energy on the southern, eastern and northern reefs of the islands (the windward sides), which create coral rubble in the lagoons and base of the reefs.
The effect of exposure to storms is indicated by the dominance trends with storm resistant encrusting/submassive forms in windward sites, its somewhat lower abundance at leeward sites and a corresponding increase in more delicate plate forms, and the dominance of the more fragile table and staghorn corals in protected lagoon sites.[12] Coral species diversity is higher on the larger islands of Nikumaroro, Kanton and Orona, which indicates the importance of the larger area of reef on these islands for support of biodiversity. Carpeting soft corals (Sinularia and Lobophytum) were found at the bottom of the lagoons of Kanton and Orona, which are the only true lagoons in the Phoenix Islands.[12]
Crown-of-thorns starfish (Acanthaster planci), cushion star and other coral predators, such as the corallivorous snail Drupella spp., are found on the reefs of the Phoenix Islands, although there has not been any indication of destructive outbreaks of those predators on the reefs.[12]
Species of giant clam (Tridacna) occur in low numbers: Tridacna squamosa, Tridacna maxima, but not Tridacna gigas.[12]
The 2000 surveys identified the following coral species as being the most abundant coral species at the specific sites on each atoll that was surveyed:[12]
Genus: | Species: | Abundant on reefs at: | |
---|---|---|---|
Acropora | Acropora cytherea Acropora lovelli |
Kanton, Nikumaroro, Orona | |
Montipora | Montipora efflorescens | Kanton, Nikumaroro, Rawaki, Orona | |
Favites | Favites pentagona | Nikumaroro, Manra | |
Echinopora | Echinopora lamellosa | Kanton, Manra, Orona | |
Leptastrea | Leptastrea purpurea | Kanton, Nikumaroro, Enderbury, Rawaki, Orona | |
Pocillopora | Pocillopora verrucosa | Kanton, Nikumaroro, Enderbury | |
Pocillopora | Pocillopora grandis | Rawaki | |
Pavona | Pavona maldivensis Pavona minuta Pavona varians Pavona clavus |
Kanton, Nikumaroro, Enderbury, Rawaki, Orona | |
Goniastrea | Goniastrea stelligera Goniastrea edwardsi |
Kanton, Enderbury, Rawaki, Manra, Orona | |
Porites | Porites lutea | Enderbury, Rawaki | |
Cyphastrea | Cyphastrea chalcidicum | Rawaki, Manra, Orona | |
Herpolitha | Herpolitha limax | Manra | |
Fungia | Fungia danai Fungia fungites Fungia scutaria |
Manra | |
Oxypora | Oxypora lacera | Nikumaroro | |
Hydnophora | Hydnophora rigida | Kanton | |
Millepora (hydrocorals) | Millepora platyphylla | Kanton |
Line Islands
Surveys of the Northern Line Islands in 2007 identified a shifted from domination by reef-building stony corals and
Stony corals plus coralline algae strongly dominated the reefs at Kingman Reef (71% LCC) with numerous large coral colonies (primarily table and branching Acropora spp.).[34] Cover of stony corals plus coralline algae dropped to 48% LCC at Palmyra, 38% LCC at Tabuaeran, and 21% LCC at Kiritimati.[34] The types of coral were much more variable at Tabuaeran than the other atolls. Some sites on the reefs at Tabuaeran were dominated by coralline algae and Acropora corals (maximum 63% combined cover), whereas other sites were dominated by fleshy algae (79% combined cover of turf and macro-algae). However, turf algae were the most common group overall (36% cover), whereas dead corals carpeted by turf and macroalgae more uniformly dominated the reefs at Kiritimati (68% mean combined cover).[34] The numbers of juvenile colonies 1 cm (0.39 in) to 5 cm (2.0 in) of Acropora, Pocillopora and Fungiidae corals, were more than 6 times higher at Kingman Reef and Palmyra than at Tabuaeran and Kiritimati.[34]
Giant clams (Tridacna) were also more abundant at Kingman Reef than elsewhere in the Line Islands. Clams are harvested for consumption at Kiritimati.[34]
Some coral species that remain at risk in Kiribati due to the gaps in the protection of Key Biodiversity Areas include: Acropora echinata (procumbens), Acropora vaughani, Alveopora verrilliana, and Montipora patula, all recorded only on Tabuaeran in the Line Islands.[13]
Bleaching
There has been
The bleaching was a consequence of an increase in ocean temperatures that happened during the
Survey data (2004–2012) of the El Niño-influenced coral reefs in the Central Gilbert and Southern Gilbert Islands allowed for the evaluate the drivers of coral community response to, and recovery from, multiple heat stress events.[39] The results showed more limited bleaching during the 2009–2010 El Niño event, in contrast to a similar 2004–2005 event.[39] This difference was correlated with incoming light and historical temperature variability, rather than heat stress.[39] The researchers concluded there was growing resistance to bleaching-level heat stress among coral communities, due to the spread of “weedy” and temperature-tolerant species (such as Porites rus) and cloudy conditions during El Niño events.[39]
Impact of iron leaching from shipwrecks
The PIPA is in a naturally iron poor region. The introduction of iron oxides to this environment from the rusting shipwrecks and anchor gear, is linked to proliferation of turf algae and benthic bacterial communities, and degraded ‘black reefs’.[41][42] Monitoring from 2000 to 2015 recorded the black reef originating at the 1929 wreck of the SS Norwich City on Nikumaroro progressing northward to sites 1 kilometre (0.6 mi) away.[43] The 2015 expedition to the PIPA recorded the presence of black reefs on five atolls (Kanton, Nikumaroro, McKean, Rawaki, Enderbury) and on Carondelet seamount associated with shipwreck debris. No recovery has been documented at black reefs observed between 2005 and 2015.[43][41][42]
Bibliography
- Edward R. Lovell, Taratau Kirata and Tooti Tekinaiti (September 2002). "Status report for Kiribati's coral reefs" (PDF). Centre IRD de Nouméa. Retrieved 29 March 2021.
- Thomas, Frank R. (2003). "Kiribati: 'Some aspects of human ecology,' forty years later" (PDF). Atoll Research Bulletin. 501: 1–40. .
References
- ^ "19. Banaba" (PDF). Office of Te Beretitent - Republic of Kiribati Island Report Series. 2012. Archived from the original (PDF) on 23 September 2015. Retrieved 31 March 2021.
- ISBN 0275988953
- ^ a b c d e f g h i j Edward R. Lovell; Taratau Kirata; Tooti Tekinaiti (September 2002). "Status report for Kiribati's coral reefs" (PDF). Centre IRD de Nouméa. Retrieved 29 March 2021.
- ^ "Kingman Reef: National Wildlife Refuge, US Minor Outlying Islands". 2020. Retrieved 29 March 2021.
- ^ "Palmyra Atoll: National Wildlife Refuge, US Minor Outlying Islands". 2020. Retrieved 29 March 2021.
- ^ "North Tarawa Island Report 2012". Government of Kiribati.[permanent dead link]
- ^ "South Tarawa Island Report 2012". Government of Kiribati.[permanent dead link]
- ^ "2. Butaritari" (PDF). Office of Te Beretitent - Republic of Kiribati Island Report Series. 2012. Archived from the original (PDF) on 23 September 2015. Retrieved 31 March 2021.
- ^ "3. Marakei" (PDF). Office of Te Beretitent - Republic of Kiribati Island Report Series. 2012. Retrieved 31 March 2021.
- ^ "Pacific Regional Statistics - Secretariat of the Pacific Community" (PDF). www.spc.int. Retrieved 4 June 2017.
- ^ Morate, Orebwa (1 September 2016). "2015 Population and Housing Census" (PDF). Bairiki: National Statistics Office. Retrieved 31 March 2021.
- ^ .
- ^ a b c d van Dijken, S. G.; Anderson, P. (2013). Priority Areas for Conservation in Kiribati: Key Biodiversity Areas (PDF) (Report). Vol. 18. Conservation International Pacific Islands Programme, Secretariat of the Pacific Regional Environment Programme, Government of Kiribati Ministry of Environment. pp. 161–171. Retrieved 29 March 2021.
- S2CID 216371691. Retrieved 29 March 2021.
- ^ "Phoenix Islands Protected Area". Conservation International. 2020. Retrieved 29 March 2021.
- ^ "Phoenix Islands Protected Area". UNESCO. 2020. Retrieved 29 March 2021.
- ^ Pierce, R.J.; D. Brown (16 April 2008). "Phoenix Islands Restoration Project" (PDF). NZAID – PIPA. Retrieved 29 March 2021.
- ISBN 978-0-12-800214-8.
- Cosmos magazine. Cosmos Media Ltd. Archived from the originalon 10 February 2014. Retrieved 2013-06-07.
The Phoenix Islands Protected Area will be the size of California, the first that protects tuna and other ocean-going fish and the first to get funding using market-based mechanisms.
- ^ "World Heritage Nomination - IUCN Technical Evaluation Phoenix Islands Protected Area (Kiribati) - ID Nº 1325". Kiribati Government. 15 May 2015. Retrieved 29 March 2021.
- ^ a b "The State of Conservation of the Phoenix Islands Protected Area (Kiribati) (N 1325)". Kiribati Government. 2015. Retrieved 29 March 2021.
- ^ hdl:1912/25560.
- ^ Morate, Orebwa. "Pacific Regional Statistics - Secretariat of the Pacific Community" (PDF). www.spc.int. Retrieved 4 June 2017.
- ^ "2015 Population and Housing Census" (PDF). Bairiki: National Statistics Office. 1 September 2016. Retrieved 21 January 2021.
- .
- ^ Woodroffe, C. D.; Biribo, N. (2011). "Atolls". In D. Hopley (ed.). Encyclopedia of Modern Coral Reefs: structure, form and process. The Netherlands: Springer. pp. 51–71.
- ISBN 978-0-8160-4874-8.
- .
on p. 396 McNeil defines atoll as an annular reef enclosing a lagoon in which there are no promontories other than reefs and composed of reef detritus
- ^ a b Lobel, P.S. (1978). "Gilbertese and Ellice Islander names for fishes and other organisms" (PDF). Micronesica. 14 (2).
- ^ Thomas 2003, p. 23.
- ^ Thomas 2003, p. 17.
- ^ Thomas 2003, pp. 17–19.
- ^ "20. Kiritimati" (PDF). Office of Te Beretitenti - Republic of Kiribati Island Report Series. 2012. Archived (PDF) from the original on 14 July 2016. Retrieved 28 April 2015.
- ^ PMID 18301734.
- Gale A123079900.
- S2CID 1521635.
- ^ Eric Borneman (2008). "Reefkeeping". Reefkeeping Magazine. Retrieved 29 March 2021.
- . Retrieved 29 March 2021.
- ^ S2CID 71144417.
- ^ Karen Weintraub (15 August 2016). "Giant Coral Reef in Protected Area Shows New Signs of Life". UNESCO. Retrieved 29 March 2021.
- ^ S2CID 92277240.
- ^ PMID 21881615.
- ^ S2CID 34350055.