Lagunaria swamp forest on Lord Howe Island - endangered ecological community listing

This Determination has been superseded by the 2010 Determination (Critically endangered ecological community listing)

NSW Scientific Committee - final determination

The Scientific Committee, established by the Threatened Species Conservation Act, has made a Final Determination to list Lagunaria Swamp Forest on Lord Howe Island, as an ENDANGERED ECOLOGICAL COMMUNITY in Part 3 of Schedule 1 of the Act. Listing of endangered ecological communities is provided for by Part 2 of the Act.

The Scientific Committee has found that:

1. Lagunaria Swamp Forest is confined to Lord Howe Island in New South Wales. On the island it is restricted to the lowlands area, which has largely been cleared for settlement. The major canopy dominant, Lagunaria patersonia subsp. patersonia is confined to Lord Howe Island and Norfolk Island. Lagunaria patersonia subsp. bracteatus occurs in Queensland. All Lagunaria patersonia plants in mainland New South Wales are introduced.

2. Lagunaria Swamp Forest on Lord Howe Island is a forest 10-15 m tall dominated by Lagunaria patersonia subsp. patersonia, sometimes growing with Hibiscus tileaceus and Myoporum insulare. Shrubs are generally sparse and may include Aegiceras corniculatum, Cryptocarya triplinervis and Celtis conferta subsp. amblyphylla. The groundcover may include Cyperus brevifolius, Cyperus lucidus, Commelina cyanea and Hydrocotyle hirta, and is generally sparse where the tree canopy is intact, but may be denser on edges and where the tree canopy has been disturbed.

3. Species that are characteristic of Lagunaria Swamp Forest on Lord Howe Island include:

Aegiceras corniculatum Apium prostratum subsp. howense
Atriplex prostrata Avicennia marina
Celtis conferta subsp. amblyphylla Commelina cyanea
Cryptocaryia triplinervis Cyperus brevifolius
Cyperus lucidus Ficus macrophylla subsp. columnaris
Flagellaria indica Hibiscus tileaceus
Howea forsteriana Hydrocotyle hirta
Lagunaria patersonia subsp. patersonia Lobelia anceps
Myoporum insulare Ochrosia elliptica
Oxalis 'corniculata' sens. lat. Parsonsia howeana
Sesuvium portulacastrum Sophora howinsula
Syzygium fullagarii Triglochin striata
Typha domingensis Vigna marina
Wollastonia biflora

4. The total species list of the community may be larger than that given above, with many species present at only one or two sites or in very small quantities. The species composition of a site will be influenced by the size of the site, recent rainfall or drought condition and by its disturbance history. The number of species, and the above ground relative abundance of species may change in response to changes in the disturbance regime. At any one time, above ground individuals of some species may be absent, but the species may be represented below ground in soil seed banks or as dormant structures such as bulbs, corms, rhizomes, rootstocks or lignotubers. The list of species given above is of vascular plant species, the community also includes micro-organisms, fungi, cryptogamic plants and a diverse fauna, both vertebrate and invertebrate. These components of the community are poorly documented.

5. The distribution of the community is restricted on Lord Howe Island to low-lying swampy areas at altitudes below 20 m. This distribution was mapped by Pickard (1983), who estimated that its original distribution may have covered as little as 6 ha distributed across five restricted locations on the island. None of these locations are protected within the Lord Howe Island Permanent Park Preserve, but Lagunaria Swamp Forest on Lord Howe Island falls entirely within the jurisdiction of the Lord Howe Island Board. Individual plants of Lagunaria patersonia may be scattered through the forests from sea level to about 600m elevation on Lord Howe Island, but such locations do not form a part of the Lagunaria Swamp Forest community.

6. Lagunaria Swamp Forest on Lord Howe Island has been seriously depleted by land clearing at all sites of its occurrence. The remaining fragments are only a few square metres in area, are degraded by edge effects, weed invasion and alteration to water regimes, and all but one site continue to be grazed by cattle. The community has been completely eliminated from some of its original locations, including an area behind Blinkys Beach, which was cleared in 1975 during construction of the airstrip. The destruction of habitat and degradation of remnants has been so comprehensive that Lagunaria Swamp Forest might already be extinct in New South Wales. The remnants are likely to include only a sample of the original flora and at least some appear to be transitional assemblages with other vegetation communities, although restoration might be possible.

7. In view of the above the Scientific Committee is of the opinion that Lagunaria Swamp Forest on Lord Howe Island is likely to become extinct in nature in New South Wales unless the circumstances and factors threatening its survival cease to operate, or it might already be extinct.

Associate Professor Paul Adam
Chairperson
Scientific Committee

Proposed Gazettal date: 05/12/03
Exhibition period: 05/12/03 - 06/02/04

Reference:

Pickard, J. (1983) Vegetation of Lord Howe Island. Cunninghamia 1: 133-265.



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Page last updated: 25 January 2016