The material presented in this report is the result of a stream monitoring survey for Notropis topeka (Topeka Shiner) in southwest Minnesota as per a contractual agreement between me, George R. Cunningham, and the Minnesota Department of Natural Resources (DNR) under PO# 3000074815. Notropis topeka (Topeka Shiner) was historically widespread in smaller stream systems (1st through 3rd order) throughout the central portion of the tallgrass prairie biome of the United States. Since the 1970's, the species has exhibited widespread range contraction and is estimated to occur in only 10 to 15 percent of its historic geographic distribution (Tabor 2002, USFWS 2009). The decline of this species is the result of habitat loss resulting from the near complete conversion of the tallgrass prairie biome for agricultural purposes (Cross 1967; Eddy and Underhill 1974; Gelwicks and Bruenderman 1996; Pflieger 1997; Berg et al. 2004). Specifically, the conversion of the tallgrass prairie ecoregions from a perennial grassland systems with meandering, sinuous stream channels connected to their floodplains to a row crop agriculture landscape created stream conditions of ditched and straightened channels as well as down cut and degraded stream channels, resulting in widespread alteration of stream channels disconnected from their floodplains. Moreover, the construction of thousands of small flood control dams throughout the range of N. topeka, (combined with the conversion of the grassland ecoregions), has created pronounced functional changes to riverine ecosystem dynamics including: alterations to natural hydrographs, disruption of sediment dynamics and floodplain connectivity, increased turbidity, higher water temperatures, loss of aquatic vegetation, and introduced species (particularly sight feeding predators). In response to the rapid and dramatic decline in distribution and potential abundance of this species, the U.S. Fish and Wildlife Service (USFWS) designated the species as endangered under the Endangered Species Act of 1973 (Tabor 1998). In 2004, the DNR began a presence/absence survey effort to monitor N. topeka populations in Minnesota at randomly selected sites within the federally designated critical habitat for the species in southwestern Minnesota. A protocol was established (Ceas and Anderson 2004) to conduct a presence/absence survey for this species at twenty (20) randomly selected 1?mile long stream segments from within the Big Sioux and Rock River drainages of southwestern Minnesota. Surveys were conducted annually from 2004 to 2010 by Ceas and continued in 2012 to 2014 with Nagle and Larson. This 2015 survey is a continuation of this monitoring process. Analysis of data from the annual surveys conducted from 2004 to 2010 found N. topeka at an average of 76.4% of sites over this period (Nagle and Larson 2014). However, this percentage dropped to 60% starting in 2010 and declined further in 2012 and 2013 (40% and 30% respectively), with a slight improvement observed in 2014 (Nagle and Larson 2014). Although the monitoring protocol used for this species is not designed to systematically evaluated population trends, a simply criteria to evaluate relative abundance indicates a decline of this species (Ceas and Larson 2010; Nagle and Larson 2014). Results from monitoring surveys conducted in 2015 are detailed in this report with a discussion regarding previous survey efforts and results.
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Minnesota Water Research Digital Library