PARENT SESSION
Contributed Oral Session 51: Arid Land Management, Vegetation, and Nutrient Dynamics
Tuesday, August 9, 8:00 AM - 11:30 AM, Meeting Room 522 A, Level 5, Palais des congrès de Montréal
How low can you go? Plant diversity remains low after a large wildfire in the arid zone.
Wardle, Glenda*,1, Dickman, Chris1, Greenville, Aaron1, Tamayo, Bobby1, 1 The University of Sydney, Sydney, NSW, Asutralia
ABSTRACT- The arid Australian environment oscillates between spectacular boom periods, when biotic productivity and diversity are high, and busts, when biotic resources are depleted. Here we investigate the dynamics of this complex system after a wildfire that burnt over two million hectares of spinifex grasslands in late 2001 and early 2002. Using a series of fixed quadrats, we compare plant diversity in burnt and unburnt areas at both large regional (5000 km2) and local scales. All sites had similar species numbers prior to the fire. As rainfall has been relatively localised and low since the fire, the above- ground plant diversity has also remained low. Mean plant diversity in the two unburnt sites is 1.8 ±0.9 and 3.8 ±2.7 species per 5m x 5m quadrat (n=30 for each site). One of the burnt sites, at Field River, received sufficient rain for diversity to reach 15.3±3.4 species per quadrat, however, diversity at the other burnt site is low; 4.7±2.2 species per quadrat (n=30 for each site). Above-ground vegetation has been dominated by mallee-form eucalypts, Grevillea juncifolia and other resprouters that have regenerated after the fire. The recovery of the previously dominant spinifex biomass awaits a peak rainfall event. Clearly, a single fire can have long-term effects on diversity in this arid environment. Understanding how these episodic events drive the dynamics of seed production, seed fate and ultimately plant diversity is a requirement for effective management of the desert environment.
Key words: arid zone, wild fire, unpredictable rainfall, multiple spatial scales