We sampled the vertebrate fauna caught in a pipeline trench near Daly Waters, Northern Territory in the mid Dry season of 1999, and compared the species composition with that of a standardised quadrat-based survey protocol (using pitfall traps, Elliott traps and nocturnal and diurnal active searches). The proportion of records of snakes, pygopodids, frogs, two dragon species, the gecko Diplodactylus ciliaris and the rodent Pseudomys delicatulus was markedly greater in the pipeline than in the quadrat-based survey; this disparity was also evident in a pronounced size difference in the reptile species composition of the two techniques. The comparison demonstrates that the standard survey protocol has substantial biases against some species and groups of species and that additional sampling effort or specific new trapping techniques may be required for these taxa.
The species composition of captures in this pipeline study differed substantially from the results from a larger section of this pipeline route constructed in 1994, possibly due to differences in season, habitats spanned, construction procedure or differences between years in climate. Mortality of animals recorded in this pipeline study was 11%, substantially less than that recorded in other pipeline studies. We suggest operational procedures to minimise wildlife mortality in pipeline construction, including construction during the most benign season; minimising the distance and time the trench is kept open; interrupting the trench with frequent escape ramps; and frequent inspection of trenches for captured wildlife.