Fauna by-catch in pipeline trenches: conservation, animal ethics, and current practices in Australia

We use the Eastern Gas Pipeline (EGP) in southeastern Australia as a case study to examine the value of documenting and retrieving entrapped fauna from open pipeline trenches. Daily inspection of nearly 800 km of open pipeline trenches during construction of the EGP (1999-2000) resulted in the identification of 103 vertebrate species (45 reptiles, 24 mammals, 19 frogs, 14 birds, 1 fish). Of 7438 individuals found in the open trenches, 7125 (97%) were found alive and released. Of the 224 dead animals, 29 (13 %) were of two threatened mammal species, most of which drowned in low flooded sections of trenches following rainfall. Nine threatened species were found in trenches, and an additional 5 threatened species were found along the pipeline route. Importantly, most threatened species were found outside of protected areas. Our findings indicate that wildlife conservation should play an important role in pipeline construction, but more emphasis should also be placed within the broader arena of animal ethics, or the retrieval and release of unlisted species. Despite preventative measures taken to minimise mortality in trenches (e.g., ramped earth known as ‘trench plugs’ positioned every 500 m to allow entrapped animals to escape), smaller (< 75 g), less-mobile animals were unlikely to survive, unless retrieved. There is no current legislation governing the rescue of fauna from trenches during pipeline construction, despite the current increase in pipelines in Australia, although the measure is included as a recommendation in the Australian Pipeline Environmental Code of Practice. Our data indicate that retrieving trench fauna solely within protected areas or sensitive areas (e.g., national parks, nature reserves, selected areas of native vegetation or wetlands), as is sometimes currently practised, will not protect all, or even most, threatened species. Retrieving fauna from the entire trench as standard practice during pipeline construction would be beneficial to native fauna, and therefore to conservation bodies, industry, and the general community.