Spatially Explicit Modelling of Fish Population Persistence in Australian Dryland Rivers

In Australia’s dryland rivers fish habitat frequently consists of isolated waterholes, which contract during the dry period, but are replenished and connected by seasonal floods.  Waterhole persistence is governed by these reconnections, and multi-year droughts can reduce the number of waterholes that persist in the landscape. Here we outline the development and use of a spatially explicit demographic model to explore interactions between waterhole persistence and fish population viability in an Australian dryland river.

The model brings together empirical data on waterhole persistence times and future hydrologic scenarios to explore landscape dynamics and habitat persistence and connectivity. This information is coupled with demographic information derived from repeat field surveys of population structure, and genetic and acoustic- tracking studies of fish movement.  Sedimentation and water resource development pose increasing threats to overall levels of waterhole persistence in many dryland rivers, and the models are being used to better understand the potential risks to population persistence associated with different levels of water resource development.

Preliminary results suggest fish populations are resilient to drought cycles under historic and foreseeable water use scenarios. As well as presenting an overview of the model and results, we also emphasise the potential role of numerical models in conceptualising problems, assembling existing ideas and data, guiding empirical data collection, and aiding dialogue within interdisciplinary teams.

See more of: Riverscape Ecology: Theory and Application for Understanding and Conserving Lotic Fishes
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