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Post-2012 Drought Recolonization Survey in Iowa
By Aleshia Kenney and Kristen Lundh (U.S. Fish and Wildlife Service Rock Island Field Office)
After one of the worst droughts in the state’s history struck Iowa in 2011 and 2012, we conducted surveys in July 2013 to help determine the effect of the drought on the endangered Topeka shiner.
During last summer's drought (2012), miles of streams designated as Critical Habitat for the Topeka shiner went completely dry. Entire watersheds became so devoid of water that not even intermittent puddles existed. Most tributary streams were completely dry, leaving only the main rivers, nearby gravel pits and seemingly random pools (e.g., under bridges and plunge pools below structures) as possible sources of available water.
We restored more than 50 oxbows within the North Raccoon River watershed to provide habitat for Topeka shiners, and we know that most support fish. During the drought, almost all of the restored oxbows went dry.
The weather cycle returned to more normal conditions in 2013 with a few precipitation events causing floods. As a result of this flooding, the restored oxbows reconnected with their streams.
During this study we will sample restored oxbows to determine:
The oxbows that we will sample are those that were sampled in 2009 during an intense sampling effort that provided baseline fish population data for six restored oxbows. Along with resampling these six oxbows we'll also sample any restored oxbows nearby. Sampling results will help us determine the extent that the drought of 2012 affected Topeka shiners.
This study will provide information needed to determine the population status of this species in important tributary streams and in floodplain wetlands adjacent to them. We will also obtain information on the recolonization of fish species into floodplain habitats after the drought of 2012 when habitat essential for Topeka shiners almost disappeared. Information collected will help guide future management decisions regarding population status and recovery actions. Climate models predict extreme weather events will become more frequent. Obtaining population density data after the drought of 2012 and comparing it to baseline population estimates from the same place during normal climate years will help researchers and managers evaluate the impact of the 2012 drought on an already imperiled species. Results from this study will used to guide and focus restoration efforts in years to come.
Last updated: July 24, 2013