|Most recent IBA monitoring assessment|
|Year of assessment||Threat score (pressure)||Condition score (state)||Action score (response)|
|2016||very high||not assessed||not assessed|
|For more information about IBA monitoring please click here|
The IBA consists of the entire of Christmas Island as all of the island is used by some endemic bird species, and most threats need to be managed on a whole-island basis. It is located in the north-east Indian Ocean, approximately 2800 km west of Darwin and 360 km south of Java Head (Indonesia), and is administered as an Australian territory. The Island is 135 km2 of which 85 km2 (63%) is National Park. In addition, a marine park extends 50 m seaward of the low water mark for 46 km (63%) of the coastline. Australian Exclusive Economic Zone waters extend out 370 km to the east, south and west, but only to about 165 km to the north where they border the Indonesian Exclusive Economic Zone. Christmas Island is the summit of a submarine mountain, with coastal cliffs rising steeply to a central plateau dominated by stands of rainforest. The climate is equatorial with a wet season (north-west monsoons) from December to April and a dry season (south-east trade winds) throughout the rest of the year. Christmas Island's avian biogeography is influenced by both the Sunda and Australian aviafaunas but belongs to neither. It is biogeographically unique. The vegetation is predominantly a floristically depauperate but structurally complex rainforest at the interior of the island, with semi-deciduous vine thickets on coastal terraces. Approximately 25% of the island has been cleared of native vegetation and comprises open rocky ground, weed fields, secondary growth and urban areas (Stokes 1988; Flora of Australia 1993; Director of National Parks 2000; Johnstone and Darnell 2004).
Twenty-three species of birds breed on Christmas Island. Eleven of these are endemic: five species (Papasula abbotti, Fregata andrewsi, Ducula whartoni, Ninox natalis and Zosterops natalis) and six subspecies (Phaethon lepturus fulvus, Fregata minor listeri (taxonomic revision in prep), Accipiter fasciatus natalis, Chalcochaps indica natalis, Collocalia esculenta [=linchii?] natalis and Turdus poliocephalis erythropleurus). Accipiter fasciatus natalis is probably better treated as an endemic species, although no recent taxonomic assessment has been made. It would qualify as threatened under IUCN criteria were it elevated to species rank. The Collocalia is probably an endemic subspecies of C. linchii rather than C. esculenta, on biogeographical and morphological grounds. Ducula, Chalcochaps, Collocalia, Turdus and Zosterops are abundant. Ninox and Accipiter are both uncommon, probably naturally. Three species have colonised Christmas Island since its settlement in 1888: Falco cenchroides (c. 1940s), Egretta novaehollandiae (c. 1930s) and Amaurornis phoenicurus (c. 1992). This is probably due to the creation of suitable habitat following forest clearing. Falco cenchroides is abundant but the other two are uncommon. Three species have been introduced: Gallus gallus, Passer montanus and Lonchura oryzivora; all are largely commensal and not found in natural habitats. The only other breeding landbird is Egretta sacra. Christmas Island is one of only two islands in the world where eight species of Pelicaniformes breed together. Four of these (Papasula abbotti, Fregata andrewsi, Fregata minor listeri and Phaethon lepturus fulvus) breed nowhere else. The other four are Sula sula, Sula leucogaster, Fregata ariel and Phaethon rubricauda westralis. Seven of these species breed in internationally significant numbers on Christmas Island; Fregata ariel was first reported breeding in 2002. Anous stolidius also breeds in large numbers. Approximately 100 species of migrants and vagrants have been recorded on Christmas Island, none of which regularly occur in large numbers. These species originate largely from the Sunda region but many also originate from Australia. Many have not been recorded elsewhere in Australia.
Non-bird biodiversity: There are at least 225 endemic animals (species and subspecies; James 2005) and 18 endemic vascular plants (Flora of Australia 1993) on Christmas Island. Endemic animals include: four mammals; five reptiles; three marine fish; nine marine sponges; one brachypod; eight terrestrial gastropods; one terrestrial olygochaete; and 190+ arthropods (James 2005). However, there are probably many undescribed endemic terrestrial and subterranean invertebrates. The land crab fauna is diverse and unparalleled (Hicks et al. 1984). The endemic red crab plays a significant part in determining the floristics and structure of the forests. Several insect genera are endemic (James 2005). The subterranean fauna is poorly known, but may be amongst the most significant in the world (Humphries and Eberhard 2001).
BirdLife International (2019) Important Bird Areas factsheet: Christmas Island. Downloaded from http://www.birdlife.org on 20/04/2019.