Australian Wetlands Database

Ramsar wetlands

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The Dales

Overview

Key facts and figures:

Date of listing:

21 October 2002

Section of the rainforest above the waterfall (1987), Photo: Colin Totterdell

Australian Ramsar site number:

61

Criteria: 

1, 2, 3, 4, 8

State/Territory:

External Territories

Area:

583 hectares

Drainage Division or IMCRA  region:

Christmas Island Province

Wetland type: 

  • 6 - Water storage areas; reservoirs/barrages/dams/impoundments (generally over 8 ha)
  • C - Coral reefs
  • D - Rocky marine shores; includes rocky offshore islands, sea cliffs
  • E - Sand, shingle or pebble shores; includes sand bars, spits and sandy islets; includes dune systems and humid dune slacks
  • M - Permanent rivers/streams/creeks; includes waterfalls
  • N - Seasonal/intermittent/irregular rivers/streams/creeks
  • Xf - Freshwater, tree-dominated wetlands; includes freshwater swamp forests, seasonally flooded forests, wooded swamps on inorganic soils
  • Y - Freshwater springs; oases
  • Zk(a) - Karst and other subterranean hydrological systems, marine/coastal
  • Zk(b) - Karst and other subterranean hydrological systems, inland

Key features of the site:

Christmas Island is an Australian External Territory located in the Indian Ocean approximately 2800 kilometres west of Darwin and 500 kilometres south of Jakarta, Indonesia. The Island is approximately 13 500 hectares in size and contains two Ramsar wetlands: The Dales and Hosnies Spring. The Dales Ramsar site covers 583 hectares and is located on the western coastline of Christmas Island. The western boundary of the Ramsar site extends 50 metres seaward from the low water mark and incorporates part of the coastline. The Dales are located within the Christmas Island National Park which is managed by Parks Australia.

The Ramsar site has a near-pristine system of seven watercourses collectively known as The Dales. The Dales includes permanent and perennial streams, permanent springs, and include the majority of surface water on the Island. Most rainfall on Christmas Island filters down through the soil and limestone, and surface runoff only occurs after heavy rain. The Dales contain numerous wetland types including surface and karst features, and inland and coastal wetlands.

The Dales support a number of unique ecological and geomorphic features including anchialine cave communities, surface karst including the unique stepped tufa deposits at Hugh's waterfall, a stand of Tahitian chestnuts, a large number of endemic terrestrial species and a significant number of seabirds including Abbott's booby, red-footed booby and the brown booby, all of which breed at the site.

Vegetation in The Dales ranges from tall plateau rainforest to lower coastal vegetation. Migratory or vagrant bird species use The Dales as a staging site during migration, and a landfall for vagrant bird species outside their range.

Christmas Island is also an important habitat, breeding and spawning area for land crabs. The endemic red crab, tens of millions of which live on the island, migrate from the forest to the coast each year for the breeding season. Blue crabs in particular are reliant on the Ramsar site, as they require freshwater to maintain renal function. During the wet season there is sufficient surface water in forests to maintain gill functioning in blue crabs and they can range over large areas of Christmas Island. However, during the dry season they are restricted to permanent freshwater sources, such as that provided by The Dales.

The Dales are used for conservation and recreation, including sightseeing, walking and camping.

Justification of the listing criteria:

The Dales Ramsar site meets five of the nine criteria:

Criterion 1: The Dales is located in the Christmas Island Integrated Marine and Coastal Regionalisation of Australia (IMCRA) bioregion. It is made up of many wetland types in a near-pristine state, including surface and subterranean karst systems. This system of wetlands, particular the karst wetlands, is unique to the bioregion.

Criterion 2: The Dales provide essential habitat for two wetland-dependent nationally threatened species, the Abbott's booby and the Christmas Island frigatebird.

Criterion 3: Christmas Island is recognised for its high conservation value. Of particular note is the land crab diversity, with Christmas Island supporting the greatest diversity of land crabs on an oceanic island in the world. All 20 species of land crab found on the island occur within the Ramsar site, with the site especially important for the blue crab. The Dales also support a 10 hectare monodominant stand of Tahitian chestnut, which is unique in the bioregion.

Criterion 4: The Dales is a significant migratory route for red crabs, blue crabs and robber crabs. The freshwater streams provide critical habitat for the blue crabs as the larvae emerge from the ocean and return inland. In addition the site provides important habitat for land crab spawning, with all 20 species which occur in the site, migrating to the ocean to spawn with their larval stages being marine.

Criterion 8: The mass spawning and development of the larvae of red crabs corresponds to the arrival and aggregation of juvenile whale sharks off shore of Christmas Island to feed on the immature stages of red crabs. The offshore waters of The Dales are believed to provide an important habitat and feeding area for the whale sharks.

Please see the More Information page for additional information on this Ramsar site and access to the Ramsar Information sheets and other associated site documents.