healthy population at Katanning, spanning two Native Settlement reserves and some private property. This population appears to be increasing; a 2004 survey found nearly 1400 adult plants and over 500 seedlings. A small population at Dudinin, spanning a nature reserve and private property. This population is apparently in decline. No seedlings have ever been reported at this location, and from 1997 to 2004 the number of reported adults fell from around 110 to 13. A recently discovered healthy population on private property at Toolibin. A 2004 survey counted 188 adults, 35 seedlings, and 36 dead plants. The species grows in sand dunes of white, white-grey or yellow-brown sand, amongst a system of ephemeral salt creeks. Populations occur both in low-lying areas near creeks, and atop dunes. The vegetation has been described as low open woodland over heath, and as tall open shrubland with some scattered trees. Ecology Little has been published on the ecology of B. oligantha. Its lifespan is probably around 10 to 30 years. Six species of honeyeater have been observed feeding at its flowers, as have insects including honeybees, ants, butterflies, beetles and native bees. Both birds and insects function as pollinators, but honeybees are probably not very effective: in one study only about 4% of honeybees collected pollen, and they tended to move from inflorescence to inflorescence on the same plant, rather than moving between plants. Assessments of the mating system of this species have found that outcrossing rates vary between populations, with populations in disturbed environments tending to be more inbred than populations in relatively intact bushland. This has been attributed to a range of causes. Firstly, the higher density of disturbed populations leads to greater rates of mating between neighbouring plants, resulting in more genetic structure and thus more effective selfing. Secondly, disturbed populations usually lack an understorey, and so cannot support a resident population of honeyeaters; instead, they rely upon sporadic visits for pollination. The greatly reduced pollination rates means fewer outcrossing fertilisations on average, leading to less selection against inbred fertilisations. Like many plants in south-west Western Australia, B. oligantha is adapted to an environment in which bushfire events are relatively frequent. Most Banksia species can be placed in one of two broad groups according to their response to fire: reseeders are killed by fire, but fire also triggers the release of their canopy seed bank, thus promoting recruitment of the next