Research Seminar - Hawkesbury Institute for the Environment

This talk will range over a number of topics, from macro-level research on Cumberland Plain woodland, to micro-level research on germination of Grevillea seeds. Cumberland Plain woodland (CPW) was the dominant pre-settlement vegetation type in western Sydney, and bore the brunt of clearing for agricultural use from the early 19th Century on. Reduced to scattered small remnants, there have been attempts by agencies such as Greening Australia to restore CPW on former agricultural land.

Research at UWS has identified a number of problems that have hindered these attempts; the soil seed bank on such sites is dominated by weeds and lacks native species; a dense sward of largely exotic grasses limits recruitment opportunities; and residual levels of soil nutrients, particularly nitrate. Ways of addressing these problems are being developed, by manipulating plant demographic processes using reseeding and/or fire, and altering plant-soil feedback mechanisms by soil carbon addition.

Further research at UWS has identified the seed coat of east Australian Grevillea species as the proximal cause of seed dormancy. Of the known mechanisms of seed coat dormancy, the mechanical constraint model is the only one remaining unfalsified. Evidence from recent experiments that are consistent with the mechanical constraint model will be presented.