Document ID: chunk:federal_register_of_legislation:F2007B00384:body:0:p6
Version: federal_register_of_legislation:F2007B00384
Segment Type: other
Provision Reference: 
Character Range: 13898–16704

tropical equatorial climate, with a mean annual rainfall of 2,110 millimetres, reduced during years when the El Niño effect is in operation.  The tropical climate leads to a marked seasonality in rainfall, with the dry season from May to November (August to October being the driest months, although some rainfall is received during this period) and the wet season from December to April when the north-west monsoon prevails (January to March being the wettest months).  This seasonality is not expressed in other factors, with relative humidity stable year round at 80-90%, and similarly with temperature at 23 to 29°C.

The native vegetation of the island is predominantly evergreen, with a dense canopy, epiphytes, emergent trees and a sparse forest floor harvested by numerous land crabs.  In addition to the primary rainforest (30 to 40 metres with emergents to 50 metres), other vegetation zones have been delineated as: marginal (terrace) rainforest (20 to 30 metres); open, scrubby and vine forests; coastal fringe; shorecliffs/spray zone; and mined areas (DuPuy 1993a).

B.1.2 Distribution of Asplenium listeri

Asplenium listeri is endemic to Christmas Island (DuPuy 1993b).

Historical

The species is named for naturalist Joseph Jackson Lister, who visited in H M Survey Vessel Egeria in September-October 1887.  Lister collected a specimen of the fern, probably near Flying Fish Cove towards the north-eastern corner of the island.  A single specimen was reported by H N Ridley in 1906 from this same vicinity at Toms Ladder (DuPuy 1993b).  There is no longer evidence for the species in this area, despite attempts to locate the type locality (Green pers. comm.).

Known

The species is now known from five localities.

Population 1 was the first locality recorded (and the only one known at the time the species was nominated for listing) at Gannet Hill, above the limestone terraces on the eastern side of the island.  Because the original collections by Lister and Ridley no longer exist, the species was newly described from a single specimen collected at this locality in April 1987 (DuPuy 1993b).

Three additional localities were located during a survey of flora in March-April 2002
(Holmes & Holmes 2002):
    * Population 2 - on the eastern terrace of the island on the Greta Beach Road a few kilometres south-west of the Gannet Hill locality.
    * Population 3 - on the southern side of the island at Aldrich Hill approximately 9 kilometres to the west of the Greta Beach Road locality.
    * Population 4 - near Sydney's Dale (Dale No.6) on the western side of the island; about 4 kilometres west of Aldrich Hill and 13 kilometres west of Greta Beach Road/Gannet Hill.
      Note: this population was not relocated despite two attempts (Claussen pers. comm.).

These populations