Tibar Bay (, ) is a bay on the north coast of East Timor near Dili, its capital city. The bay forms part of the south shore of Ombai Strait, which separates the Alor Archipelago from the islands of Wetar, Atauro, and Timor in the Lesser Sunda Islands.
Geography
The bay is located approximately west of Dili, the capital city of East Timor, and immediately to the northwest of the similarly named suco of , which is part of the Liquiçá municipality. It extends approximately east-west and north-south ().
At the entrance to and inside the bay are sizeable areas of coral reef, much of it dead on the reef flats with diverse live coral on the reef slopes. Also within the bay are extensive tidal flats, mainly at the bay's southeastern corner, but also on its western and eastern sides.
The Tibar catchment is medium-sized (around ). It drains into the bay's southern side via defined watercourses and, in large storm events, across a delta (located behind the main highway). The catchment runs approximately south, to an elevation of AMSL.
Ecology
Flora
A survey carried out in 2016 determined that the vegetation in the bay was primarily mangrove forest. Three mangrove species were found, namely Sonneratia alba, which was the dominant species, Avicennia marina and Rhizophora stylosa. The report of another survey, carried out in 2017, stated that the dominant species in the area was Sonneratia albia, and that there were some clusters of Rhizophora apiculata, Ceriops tagal, and Lumnitzera.
The 2016 survey report estimated the total area of mangrove in the bay to be . Examination of Google Earth imagery showed that approximately 50% of mangrove in the area had been lost since 1984.
The mangrove habitat still in place as of 2016 was mature, but highly degraded through intensive land use, which was completely preventing recruitment of mangrove seedlings. Livestock were eating seeds, aerial roots and young plants, and there was also intensive use of mangrove trees, including as firewood, by local villagers. Some trees at the bay had apparently been ring-barked.
The mangroves in the bay in 2016 represented about 2% of East Timor's total remaining area of mangroves, and were of national significance.
The 2017 survey report estimated the total mangrove area of the bay to be . Tree density was relatively low, at around 100–400 trees per hectare, and the mangrove cluster was heavily degraded, due to direct and indirect human activities. The former activities included fish pond and salt pan development, mangrove cutting, and cattle grazing. The latter activities were sea level rise, and siltation due to erosion in the hills on the landward side of the mangroves.
There are also two main seagrass meadows in the bay. One is in the western sub-bay, and the other is on the bay's northeast side. A 2013 survey identified four species of seagrass in the meadows, with the dominant ones being Enhalus acoroides, Syringodium isoetifolium and Cymodocea rotundata. Small areas of Halophila ovalis were also present.
Fauna
The report of the 2013 survey observed that the bay has complex bathymetry providing diverse benthic habitat, as it is sheltered and receives nutrients from runoff from the nearby land. As such, it may provide recruits to adjacent parts of the coast.
According to the report of the 2016 survey, the fauna habitat at the bay includes the mangrove forest, an estimated of intertidal mudflats and sandflats, and terrestrial habitat.
The 2013 survey report noted that a local dive tourism operator had made frequent sightings of dugong along the coast immediately east of the bay, and that there were also anecdotal reports of saltwater crocodiles in the bay. The 2013 report also commented that among the birds living at the intertidal flats are two species listed as Near Threatened on the IUCN Red List: the Malaysian Plover (Charadrius peronnii) and the Black-tailed Godwit (Limnosa limosa).
The 2016 survey recorded a total of 104 bird species in the bay and its vicinity, including 39 shorebird species, 27 other waterbirds and 48 landbird species. Two of the shorebird species so recorded are considered globally Endangered (Far Eastern Curlew (Numenius madagascariensis) and Great Knot (Calidris tenuirostris)), a further eight of the recorded shorebird species are considered Near Threatened, and two of the landbirds and one of the waterbirds are similarly considered as Near Threatened.