Utilising adaptive management practices in the conservation of a Declared Rare Acacia species
Dufty, P., Garkaklis, M., Ladd, P.G. and Huston, R. (2007) Utilising adaptive management practices in the conservation of a Declared Rare Acacia species. In: 11th International Mediterranean Ecosystems (MEDECOS) Conference (2007), 2 - 5 September, Perth, Western Australia.
Introduction: Of the estimated 8,000 species in the Southwest Botanical Province of Western Australia, about 25% are either under threat or have poorly known conservation status, with a third of the 564 Acacia taxa in the region considered in this category (Yates and Broadhurst 2002), Acacia chapmanii subsp. Australis RS,Cowan and Maslin is typical of many of these species, It has an aging population with little recruitment. is confined to narrow linear remnants on road and rail reserves, and has patches of limited extent in one managed reserve. As little was specifically known about the biology of A chapmanii, strategies for assisting population recovery were based on general characteristics of Acacia population biology and likely landscape processes in the area it occupies, The strategy developed was a stepped process using an adaptive management approach based on a scientific model with replicated trial plots and controls (Blumstein 2007), An adaptive management approach enables decisions to be made on management strategies as soon as conclusive results are evident.
After elimination of factors such as Phytophthora cinnamomi and rising saline water tables, the most likely factor contributing to decline appears to be lack of disturbance, such as fire, with no recorded fire in over 20 years. As many Acacia taxa in the transitional rainfall zone of southwest Western Australia are stimulated to germinate by the heat of a fire, the initial experiment utilized a control burn of small plots designed to have minimal impact on the majority of the community in which the species occurs. No herbivore impact was measured as all plots were fenced.
Initial results following monitoring of the germination response for A chapmanii, both from the soil seed bank as well as from planted seed showed no seedlings surviving in unburnt plots. The success of seedling survival from the soil seed bank in burnt plots led to the decision in 2005 to measure ecosystem scale behaviour on this community following a normal autumn Department of Environment and Conservation (DEC) fuel reduction burn, which more closely resembles a wildfire. This research was designed to measure whether regeneration of A. chapmanii, and other species, was similar to the first burn and the influence of herbivory on seedling survival.
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|Murdoch Affiliation:||School of Environmental Science|
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