| Description |
The image accompanying this occurrence record was digitised from a transparency, originally exposed by Tony Dominelli on 09/09/1975. We have submitted this record to give some personal, historical context to the precarious situation in which the Mallee Emu-wren is currently cast. We have been visiting some five sites, over the past fifty years (Tony Dominelli) and thirty years (Tony and Jenny Dominelli). Each of these sites in the 1960's through 1980's, held robust and healthy breeding populations of Mallee Emu-wren. Each site contained the optimum habitat prescription for the foraging, breeding and territorial imperatives of the Mallee Emu-wren. Each site had expansive, dense and proximate hummocks of triodia, up to one metre tall or more, situated on inter-dune depressions and along dune sides or in the case of one site, a sheltered sand plain, with an easterly, northerly and westerly aspect. The current consensus among some researchers, implies, that too frequent, too intense and ill-timed, burning is directly associated with the rapid decline of the Emu-wren and we entirely concur, having no reason to doubt the verity of this proposition. However, we think that this, is not the entire story. NOTE: We cannot recall any of the sites we have regularly visited over, some thirty years as partners and more than fifty years, in respect of Tony Dominelli, being BURNT in all that time. Yet, the Emu-wren population has 'crashed at these sites, with only a handful of sightings in the past 28 years. There are, certainly, more nuances to this conundrum than is at first evident. Regular, average winter rainfall has declined in this area between 1951 and 2017 by approx. 5mm. This may not seem like significant amount. But in the Mallee, for shallow rooted ground flora and small tuberous-rooted plants 5mm average rainfall reductionis the difference between flowering in any given winter or not. Failing winter rainfall, year on year has a cumulative effect, subsoil moisture retention, the available 'seed bank' and the capacity of ground flora to accumulate enough seed in the soil, to respond with a mass-flowering event, in seasons of EXCEPTIONAL winter rainfall. The one feature that strikes us today, when visiting the Hattah region and wider environs and comparing the same Spring scenes 40-50 years ago, is the striking absence of mass-flowering events. Such mass-flowering events. not only build the seed bank, but sustain a resilient insect population and therefore a protein resource for birds, retiles and small mammals. Gone are the 'yellow seas' of Scencio, Loudonia, Bulbine, Waitzia, Helichrysum and a myriad more. The tiny 5gm Emu-wren generally feed themselves and their young on the smallest of insects, no larger than a white-fly, the very insect forms that proliferate during mass-flowering events. There is much uncertainty here, but well worth pondering. |
