Adjunct Professor Jonathan Majer presented his talk on “Invertebrate surveillance on Barrow Island – a bare necessity”. Jonathan, now retired and working as a consultant, has the rare privilege of having a new ant species named after him, Melophorus majeri. His presentation condensed several years of work preparing a baseline and the following surveys of the wide array of invertebrate life of the Island. Using many techniques to gather the maximum number of invertebrate species, the results have been computed statistically to achieve a census of invertebrate fauna that compares areas of natural habitat and disturbed sites where project work is to be established. The work, commencing in 2005, has involved a team of researchers based at Curtin University.

Barrow Island, situated 60 km off the northwest coast of the Pilbara, is 202 km² in area and the second largest island off WA (after Dirk Hartog Island). Geographically, it has existed as an island for only 8000 years and was first thought to be part of the mainland when sighted during the 1803 Baudin expedition.

There is no evidence to indicate that the island was previously permanently inhabited. In its recent history it was used as a base for whalers, a guano industry and a slave trade for the pearling industry of the 19^th century. It is the site of Australia’s oldest and largest onshore oilfield, first discovered in 1964 by WAPET, and is currently being developed for Chevron’s Gorgon gas processing plant.

Barrow Island has been an important A-class marine nature reserve for the last 40 years. It has several endemic species and high biodiversity with its internationally significant shorebirds, diverse subterranean fauna assemblages, regionally significant turtle habitat and is, importantly, free from introduced mammal species. In the absence of rabbits, rats, mice and foxes the island is in a good environmental condition. The focus of its future is to balance development projects with biodiversity protection. The company (Chevron) is proactive in its approach to achieving this aim with its biosecurity quarantine management program.

As part of the environmental safeguards, there are strategies to eradicate new species should they be introduced to the island. All equipment imported is new, flat-packed, fumigated and sealed and measured quarantine checks are undertaken to prevent fungal infection. The beam pumps (aka nodding neddies) have been kept to a minimum. Currently between 4000 and 6000 personnel are involved in the developmental work on the island and staff movement is restricted to specific zones.

Part of the current developments is a proposed system for sequestering CO₂ below ground into suitable saline aquifers in the limestone bedrock.

Jonathan’s project work covered several phases: a pilot survey to design sampling methodology (2005), a detailed survey of terrestrial invertebrates before project work commenced (2006-9) and quarantine surveillance and environmental monitoring (from 2009 onwards).

During the pilot survey, many collecting techniques were used including, pitfall traps (wet and barrier types), portable Winkler sacks to sample litter, window traps, blue sticky termite traps, light traps (for both at night and daytime), vacuum sacs, and hand collecting around human infrastructures. All capture methods were compared and studied to achieve a balance between what was practical and maximum sampling efficiency. From this work a baseline survey was completed between 2006 and 2009 and included a gas plant survey site of native habitat (where the development will take place), and disturbed sites (NIS Non indigenous survey) such as the airport and dump sites. During that time it was noted how seasonal changes such as a wet summer (2006) alter the number of species present.

Identification work on the collected fauna has been achieved attracting and using a large team of pre-eminent taxonomic experts, many of whom are international taxa specialists. For this identification work, some specialists have been remunerated, but many are retired academics and the involvement of this group has been a valuable asset in itself. Twenty five WA State taxonomists covered the hymenoptera, spiders, pseudoscorpions, scorpions and Myriapods, terrestrial mollusca, hymenoptera (bees), Coleoptera, Acari (ticks), Isopod crustaceans and Odonata.  Twelve interstate taxonomists covered Thysanoptera, Collembola, Heteroptera, Psocoptera, Diptera, Phasmatodea, Thysanura, Homopteran sucking bugs, Orthoptera and Mantodea, Blattodea, Hymenoptera (wasps) and Neuroptera. International experts covered Isoptera, Strepsiptera and Emiidina. The high load of some of this identification work has had an impact on planning and report schedules. Over the last 18 months some of the data are still in the process of analysis.

The initial survey results produced 1873 species, including 43 that are new, 23 historical NIS and 6 putative. This compares with an EstimateS predictor of 2481 species.

Among key findings of this work and based on indicator taxa (beetles, wasps, Homoptera, ants, flies and collembola), there is:

• no strong association between vegetation types and soils,
• very strong seasonal occurrence patterns of species, and
• some taxa are ubiquitous and unchanging, some taxa are variable between seasons, and differences between years can be as strong as between seasons.

Currently, quantitative surveillance and environmental monitoring are key issues. For the likely threats to the established taxa on the island, arriving from unpredictable sources, five exemplar species have been selected to study: big-headed ant (Pheidole megacephala), white Italian snail (Theba pisana),

paper wasp (Polistes humilis), Formosan termite (Coptotermes formosanus) and the Oriental tomato thrips (Ceratothripoides claratris). There is a need to balance where to put traps and how many are required to establish changes to the baseline species count. It was necessary to design a surveillance system, using multiple detection methods combining the costs of each method and recognising risk zones. Results are compared and planning work based on statistical considerations. There has been an increase in species, to 2067 (from the initial 1873), with no new NIS being found. Further non-baseline species (NBS) have now been sampled bringing the current total species to 2397. An interesting question is whether the ‘extras’ are NBS or NIS.

All species collected are photographed and “pinned” (a classic technique for insects) and data can be electronically researched as a reference collection. The culmination of all this survey work has been to develop the most comprehensive invertebrate survey in Australia at a substantial cost, funded by Chevron. An exhibition is scheduled in the foyer of the QV1 building in St George’s terrace from 17^th November.

Jonathan’s concluding poser was “Is Barrow Island an example of a Noah’s Ark situation; somewhere where species can be observed and conserved?”

Susan Stocklmayer

For those interested the Pests and Diseases Image Library (PaDIL) has section on Barrow Island. Just click the highlighted area and a new browser window will open. You are not required to register to view and download Content from the PaDIL website.