Short Virtual Presentation & Digital Poster 10th Australian Stream Management Conference 2021

Wetland wildfire: seedbank response to different watering regimes (#45)

Ben E Vincent 1 , Mark R Southwell 1 , Zachary B Lewis 1
  1. University of New England, Armidale, NSW, Australia

- Fire is a natural feature of inland floodplain wetlands. However, more is known about watering requirements of wetland vegetation communities than is understood about their responses to fire. In September 2019, a wildfire burnt >1300 hectares of the Gwydir Wetlands State Conservation Area (SCA), 50 km west of Moree, NSW. This fire presented the opportunity to address knowledge gaps about the response of aquatic vegetation to fire and the influence of different watering regimes on this response.

- We set up observational floristics plots to compare areas of burnt and unburnt vegetation to gauge the response of the three dominant vegetation communities to fire – two floodplain wetland vegetation communities; water couch - spike rush meadows and cumbungi reedbeds, and one flood dependent woodland; coolibah open woodland. Additionally, we collected soil samples from observational plots and conducted a mesocosm seedbank experiment to assess the effectiveness of three different follow-up watering regimes.

- Preliminary findings highlight the resilience of wetland vegetation following wildfire. However, vegetation response and recovery was primarily driven by availability of water, with the type of inundation (full flooding v’s waterlogged v’s rainfall only) dictating species composition.

- Wetlands in the conservation estate in regulated catchments are subject to prescribed management for both water and fire regimes. Findings highlight the influence of water availability in shaping vegetation recovery following wildfire. This information can assist land managers when making decisions relating to timing of prescribed burning and water delivery to assist vegetation recovery following fire in managed systems.

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