National Recovery Plan for Lister’s Gecko Lepidodactylus listeri and the Christmas Island Blind Snake Typhlops exocoeti prepared for the Department of the Environment and Heritage by Dr Hal Cogger Published by the Australian Government Department of the Environment and Heritage. Made under the Environment Protection and Biodiversity Act 1999 (EPBC Act): 10 November 2006 ISBN 0642 552258 © Commonwealth of Australia This publication is copyright. Apart from any use permitted under the Copyright Act 1968, no part may be reproduced by any process without prior written permission from the Commonwealth. Requests and inquiries regarding reproduction should be addressed to: Assistant Secretary Natural Resource Management Policy Branch Department of the Environment and Heritage GPO Box 787 CANBERRA ACT 2601 Note: This recovery plan sets out the actions necessary to stop the decline of, and support the recovery of, the listed threatened species or ecological community. The Australian Government is committed to acting in accordance with the plan and to implementing the plan as it applies to Commonwealth areas. The plan has been developed with the involvement and cooperation of a broad range of stakeholders, but individual stakeholders have not necessarily committed to undertaking specific actions. The attainment of objectives and the provision of funds may be subject to budgetary and other constraints affecting the parties involved. Proposed actions may be subject to modification over the life of the plan due to changes in knowledge. This plan should be cited as follows: Cogger, H. (2006). National Recovery Plan for Lister’s Gecko Lepidodactylus listeri and the Christmas Island Blind Snake Typhlops exocoeti. Department of the Environment and Heritage, Canberra. This recovery plan is available from the Department’s web site at: www.deh.gov.au/biodiversity/threatened/recovery, or from the Department’s Community Information Unit: Email: [email protected] Mail: Community Information Unit Department of the Environment and Heritage GPO Box 787 CANBERRA ACT 2601 Freecall: 1800 803 772 Supplementary information on the threatened reptiles which are the subject of this Recovery Plan is available as a separate document entitled Background Information on Lister’s Gecko (Lepidodactylus listeri) and the Christmas Island Blind Snake (Typhlops exocoeti), available online at www.deh.gov.au/biodiversity/threatened/recovery Cover photos: Lepidodactylus listeri (upper, left) and Typhlops exocoeti (lower, right) - © Dr Hal Cogger Contents Summary ...................................................................................................................................... 1 Distribution and Ecology ............................................................................................................ 1 Habitat Critical to Survival ........................................................................................................ 1 Threats ......................................................................................................................................... 3 Recovery Plan Objectives ......................................................................................................…. 5 Recovery Actions .....................................................................................................................… 5 Costs .......................................................................................................................……….......... 7 Biodiversity Benefits ....................................................................................................….…...... 7 Management Actions ...........................................................................................................…... 7 Monitoring, reporting and review ......................................................................................…... 8 Performance Criteria ..........................................................................................................….... 8 Interests that may be affected by the Recovery Plan’s Implementation......…................…... 8 Social and economic impacts .....................................................................................…............. 9 References .....................................................................................................................…........... 9 Summary Lister’s Gecko, Lepidodactylus listeri, and the Christmas Island Blind Snake, Typhlops exocoeti, are reptile species endemic to Christmas Island. Both are currently listed as Vulnerable (T. exocoeti as Ramphotyphlops exocoeti) under the Environmental Protection and Biodiversity Act 1999 (EPBC Act). They are also listed as Vulnerable by IUCN (IUCN 2004). However the current conservation status of both is effectively unknown; Lister’s Gecko was last seen in 1987, and the last blind snake record was made in 1986. James (2004) has recorded significant declines in other, previously common endemic Christmas Island reptiles since the last targeted reptile survey in 1998 (Cogger & Sadlier, 2000). These declines, in relation to the range and relative abundance recorded in the first targeted reptile survey conducted in 1979, can only be termed “catastrophic”. Consequently this Recovery Plan has been constructed within a context of no recent sightings of either threatened species but a clear record of substantial recent declines of other endemic reptiles on Christmas Island. There is a possibility that one or both of these species is now extinct. A number of actions are identified that are needed to secure any remaining populations, including investigation of the potential threats to the species and to the integrity of the habitats in which they have been found in the past. The primary action required is to determine, through survey and monitoring, the presence, location and status of any remaining populations. Distribution and Ecology Lister’s Gecko is a small (average snout-vent length ca. 50 mm) arboreal species found active on tree trunks at night or sheltering in the day under bark of living or dead trees (Gibson-Hill, 1947). The Christmas Island Blind Snake is a fossorial snake found in the sub-surface soil and surface litter of the forest floor and almost certainly, like most of its congeners, preying on the eggs, larvae and pupae of ants and termites that it devours in large numbers. It is usually active on the surface only at night. The two species occur only on Christmas Island. All provenanced records are shown in Figures 1 and 2 below. Habitat Critical to Survival Lister’s Gecko: The only records for which habitat information is available (rather than inferred) were made in 1938-1940 (Gibson-Hill, 1947) and 1979 (Cogger and Sadlier, 1981; Cogger et al., 1983). These observations indicated that at the time these papers were written the gecko was: • most abundant in primary forest on the plateau, but that within this area it will readily adapt to disturbed habitats and secondary growth that includes at least some mature trees; • least abundant on the terraces sampled on the north-eastern, eastern and southern sides of the island; • apparently absent from all mined areas even when covered by dense shrubby vegetation; and • an arboreal species found active on tree trunks at night (from near ground level to the canopy of even large rainforest trees) or sheltering during the day under the bark of living or dead trees (Gibson-Hill, 1947, records them only from under the bark of dead trees, both standing and fallen). All recorded eggs were located under bark on standing tree trunks, within human reach. At the time of the 1979 study, there is little doubt that the primary forest on the plateau would have been regarded as the island habitat most critical to survival of Lister’s Gecko. Until fuller 1 knowledge of the current population size and ecological requirements is available, this habitat should be regarded as potential habitat critical to survival. The general characteristics of this habitat, including a description of its floristics and structure are provided by Gillison (1976) and are illustrated in Cogger et al. (1983) and Clarke (1995). Christmas Island Blind Snake: The few records with information on locality or habitat suggest that this species occurs primarily where the deeper soils and primary rainforests occur on the island’s central plateau. Most of this area is now located within the boundaries of Christmas Island National Park, managed for conservation by Parks Australia North (PAN), and is therefore secure as far as land tenure. However, this original primary habitat is currently being subject to immense environmental stress due to recent droughts and the explosive increases in populations of the Yellow Crazy Ant (Anoplolepis gracilipes) and its mutualist scale insects - Tachardina aurantiaca and introduced Coccus celatus (vide O’Dowd et al. 2003). Until knowledge of the population size and ecological requirements of the blind snake is available and understood, all forested parts of the island should be regarded as potential habitat critical for this species. Given the absence of any records of either species for nearly 20 years, despite periodic intensive searches, and given the profound habitat changes that have occurred directly or indirectly during this period, it is not possible at this time to map habitat critical to the survival of these species. Rather, habitats in which the species were last recorded should be treated as surrogates for habitat critical