Editing Teraina (section)

== Ecology ==
[[Ecological]]ly, Teraina is also highly interesting, for several reasons. Firstly, as is readily apparent from its peculiar geographical and geological features, it possesses a combination of [[ecosystem]]s that is quite unique in the entire world. Secondly, it holds the world's largest population of a rare bird [[species]] though it is over {{convert|2,500|km|mi nmi|abbr=on}} from that bird's original home. Furthermore, it was until fairly recently home to some enigmatic [[dabbling duck]]s which are now [[extinct]]. Last, the island's [[biodiversity]] seems to prove quite conclusively that, probably by about 1200 AD or so, the island was temporarily inhabited by a significant number of humans.

At present, there is no formal protection for the islands' ecosystems or species, but it has been suggested to legally protect key habitat, namely the boglands.<ref name = teebaki1993 /> Though it is globally [[endangered]], the [[Rimatara lorikeet]] (''Vini kuhlii'') does not appear to be in need of formal protection;<ref name = bli2007>BLI (2007)</ref> it actually benefits from human land use change and the [[feral cat]]s. The former provides the birds with more habitat, while the cats have so far managed to keep Teraina completely free of [[black rat]]s (''Rattus rattus'') which due to their tree-climbing habits would seriously jeopardize the species' existence, should they become established in numbers.<ref name = bli2007 /> Given the negative experience e.g. from [[Rennell Island]], maintenance of a vigorous [[tilapia]] fishery would seem to be advisable. These fish certainly represent a valuable source of protein on Teraina, and in fact were originally introduced for that purpose.

=== Flora ===
Over 30 species of flowering plants are known from the island, but most seem to be not originally native. ''[[Cocos nucifera]]'', the coconut palm, is the most conspicuous tree on Teraina. It is found planted, but also constitutes one of the dominant forest trees. The palms occur in wet forest around the bogs, mixed with ''[[Pandanus]]'' (screwpine), and an undergrowth dominated by the [[fern]]s ''[[Asplenium|Asplenium pacificum]]'' and ''[[Phymatosorus scolopendria]]''. In more elevated places near the beach, ''[[Pisonia]]'' (catchbird tree) atoll forest is found, though Teraina has not that much of this ubiquitous Pacific ecosystem for its size.<ref name = teebaki1993 />

The most conspicuous plants of the boglands are the [[Araceae|arum]] ''[[Cyrtosperma merkusii]]'' and the giant bulrush (''[[Schoenoplectus californicus]]'').<ref name = teebaki1993 />

Among the local crops, [[sugar-apple]] (''Annona squamosa''), [[breadfruit]] (''Artocarpus altilis''), [[papaya]] (''Carica papaya''), [[banana]]s (''Musa'' [[cultivar]]s, including [[Fe'i banana]]s<ref>[http://faculty.washington.edu/jsachs/lab/www/Research/Kiribati_Expedition_2005/Xmas134.jpg Image] washington.edu</ref>) and [[apple guava]] (''Psidium guajava'') are the most significant, apart from the coconuts. [[Frangipani]] (''Plumeria'') and [[hibiscus]] are popular as [[ornamental plant]]s.<ref name = resture2004 />

=== Birds ===
[[File:Red-footed booby.jpg|thumb|left|[[Red-footed booby|Red-footed boobies]] at [[Palmyra Atoll]], Teraina's neighbor island]]
Though numerous [[seabird]]s nest on Teraina, for many such species the limited habitat makes it a less important rookery than other, similar-sized raised atolls. About 10 species of seabirds breed here, most significantly tree-nesters like the [[little white tern]] (''Gygis microrhyncha'') and the [[red-footed booby]] (''Sula sula'').<ref name = teebaki1993 /> The [[eastern reef egret]] (''Egretta sacra''), widespread throughout the region, can also be found on Teraina.

Among [[migratory bird]]s, the [[ruddy turnstone]] (''Arenaria interpres''), [[sanderling]] (''Calidris alba''), [[bristle-thighed curlew]] (''Numenius tahitiensis''), [[Pacific golden plover]] (''Pluvialis fulva''), and [[grey-tailed tattler|grey-tailed]] (''Tringa brevipes'') and [[wandering tattler]]s (''T. incana'') use Teraina as stopover location or winter quarters on a regular basis. Other [[shorebird]]s, [[gull]]s, and occasionally [[duck]]s of [[North America]]n and [[East Asia]]n species may occur as vagrants.

In historic times, two [[species]] of landbirds and one [[subspecies]] of duck have been recorded. The latter, [[Coues's gadwall]] (''Anas strepera couesi''), was the only distinct subspecies of the widespread [[gadwall]].<ref name = streets1877 /> It is surrounded by considerable mystery, mainly as regards the origin of the population, the age and therefore validity of the subspecies (it is sometimes disputed to be significantly distinct), and the causes and date of its disappearance. Only two specimens are known – a couple that is not fully mature, and therefore only limited information can be gleaned from it. What is certain is that there was a duck population of some size in the mid-1870s,<ref name = streets1877 /> while in 1900 all were gone.

The [[bokikokiko]] (''Acrocephalus aequinoctialis'') is Kiribati's [[endemism|endemic]] [[Acrocephalus (bird)|reed-warbler]]. This small greyish [[passerine]] is well-known, due to its bold and inquisitive habits, and its song, a series of alternating higher and lower squeaks after which it is named.

The [[Rimitara lorikeet]] (''Vini kuhlii'') is present with about 1,000 birds. It is a tiny [[parrot]] with brilliant plumage and an endearing and highly social behavior, owing to which they were known to late 19th century settlers as "love-birds".<ref name = streets1877 /> This species was originally native to the [[Austral Islands|Austral]] and [[Cook Islands]] in SE Polynesia, a long distance to the south. They were treasured by the natives of the [[Society Islands]] and were an item of high value in inter-island trade; these birds were kept as pets, and in addition their feathers were used in crafts and art.<ref>Tregear (1891)</ref> In any case, there is considerable evidence from [[Ancient Hawaiʻi]] that [[Polynesian navigation|Polynesian seafarers]] travelled between southeastern Polynesia and [[Hawaiʻi]] with some regularity, perhaps as early as 400 AD, but certainly by about 1200 AD. Since it is almost inconceivable – given the prevailing winds, ocean currents, known trade routes, and the difficulty with which these birds can be kept alive during voyages<ref name = streets1877 /> – that ''Vini kuhlii'' was transported from the Austral or Cook Islands to the [[Gilbert Islands]] and from there to Teraina, the presence of the birds there is best explained by them having been introduced by SE Polynesian travelers. Today, the species is [[extinct]] on many islands on which it formerly occurred, while the Teraina population, considered crucially important for its survival, contains some 60% of the remaining global wild population.<ref name = bli2007 /> Ironically, the reason for the Rimitara lorikeet thriving on Teraina is the replacement of native forest with coconut plantations; these birds feed mainly on the [[nectar]] of coconut palm flowers and nest in old coconut shells or husks.<ref name = bli2007 /><!-- not a general ref for paragraph -->

As it thus seems clear that there was prehistoric human activity of some degree on Teraina, it is also likely that birds became extinct consequently, like on all such Outer Pacific islands for which research has been conducted. [[David Steadman]] in his comprehensive review lists several such hypothetical [[taxa]] for Kiribati as a whole. For Teraina specifically, considering the habitat and what birds still exist, one or more [[rail (bird)|rail]]s (''[[Gallirallus]]'' and/or ''[[Porzana]]''<ref>And perhaps one of the more aquatic ''[[Porphyrio]]'' swamphens as well. This is not explicitly mentioned by Steadman but plausible, given the unique lake habitat and the former presence of ''[[Porphyrio paepae]]'' on [[Hiva Oa]].</ref>), an imperial-[[pigeon]] (''[[Ducula]]''),<ref>Such a bird would probably be related to the [[Pacific imperial-pigeon|Pacific]] (''D. pacifica'')/[[Micronesian imperial-pigeon]] (''D. oceanica'') group occurring to the west of the Line Islands, or less likely to the [[Polynesian imperial-pigeon|Polynesian]] (''D. aurorae'')/[[Marquesan imperial-pigeon]]s (''D. galeata'') occurring to the south.</ref> and maybe a ''[[Todiramphus]]'' [[kingfisher]]<ref>Such a bird would probably have belonged to the [[sacred kingfisher]] (''T. sanctus'') group; that species today occurs as a vagrant in [[Micronesia]], and related forms are resident in SE Polynesia.</ref> or an ''[[Aplonis]]'' [[starling]]<ref>This would probably have been related to the [[Micronesian starling]] (''A. opaca'') and the recently-extinct [[Pohnpei starling]] (''A. pelzelni'') or somewhat less probably to the extinct [[Huahine starling|Huahine]] (''A. diluvialis'') and [[bay starling]]s (''A. ulietensis'') of the [[Society Islands]].</ref> make the most likely candidates for birds gone extinct prehistorically. It must be considered, however, that given the lack of fieldwork it is not quite clear what effect changing [[sea level]]s would have had on Teraina. If the sea level were only half a meter (c. 2&nbsp;ft) higher it is certainly possible that the forest and freshwater lake would be replaced by shrubland or dunes and a brackish lagoon. That notwithstanding, it is well possible that a [[Polynesian sandpiper]] related to or identical with the [[Christmas sandpiper]] from [[Kiritimati]] once lived on Teraina.<ref>Steadman (2006)</ref>

=== Other fauna ===
As with most outer Pacific islands, there are no native land [[mammal]]s.

Polynesian rats (''[[Rattus exulans]]'') are present on Teraina,<ref name = bli2007 /> apparently since prehistoric times. They may have arrived with flotsam after storms further west, or accidentally or deliberately (as food) been introduced by prehistoric seafarers. Their present-day impact on the bird population is minor, but if [[rail (bird)|rail]]s were once present on Teraina, the rats had probably some role in these birds' disappearance, and maybe in that of any other birds gone extinct in prehistoric times too. If a Polynesian sandpiper once bred on Teraina, it is almost certainly those rats that are responsible for these birds' disappearance; only a single [[taxon]] of ''Prosobonia'' remains today, precariously holding its own on atolls that are devoid of any rat species.

[[File:Oounagi070224.jpg|thumb|right|The widespread [[Anguilla marmorata|marbled eel]] is also found in Teraina's lake.]]
[[Feral]] [[dog]]s, [[cat]]s and [[pig]]s occur in varying numbers on Teraina; the cats especially are responsible for some decline in the number of ground-nesting seabirds.<ref name = teebaki1993 /> On the other hand, as noted above, the cats have thus far kept the rat population at bay.

[[Lake|Lacustrine]] species reported from Teraina include [[fish]]. and some unspecified "[[shrimp]]",<ref name = streets1877 /> i.e. (in all probability) a member of the [[Crustacea]]. Teraina's freshwater fish include the marbled eel (''[[Anguilla marmorata]]''), a ''[[Caranx]]'' freshwater [[trevally]], and ''[[Oreochromis]]'' tilapias and the milkfish (''[[Chanos chanos]]''). The latter two, and perhaps also the trevally, were introduced in recent times. The eels were already established by 1877;<ref name = streets1877 /> like many [[Anguillidae]] they are [[catadromous]] and able to migrate some distance on dry land. Thus it may be presumed that the lake is continuously being restocked from the Pacific, though apparently no actual field data exists on the habits of the eels of Teraina.

As on many [[Indopacific]] islands rich in coconut (''[[Cocos nucifera]]'') trees, the coconut crab (''[[Birgus latro]]'') is often encountered on Teraina.<ref name = streets1877 />

A few green turtles (''[[Chelonia mydas]]'') nest on the beaches. It is not a very important nesting site however and the [[clutch (eggs)|clutch]]es have a rather low probability of success, as Teraina is one of the Kiribati islands where turtle egg collecting is permitted.<ref name = teebaki1993 />