Specifically, channel incision, caused by hydrologic alterations,

Specifically, channel incision, caused by hydrologic alterations, may produce bank heights (measured see more as bank height ratio) that prohibit flooding, and disconnect stream channels with the floodplain where seepage areas used for breeding are found. The effect of activities such as the removal of large woody debris, channelization and stream straightening are all known to cause altered hydrology and bank destabilization (Smith et al. 1993; Shields et al. 1994). Slackwater Darters, like most species in the subgenus Ozarka, have distinct breeding and non-breeding habitats (Page 1983). Fish migrate from resident

stream habitat in the winter, and move onto breeding sites around February, buy LY2606368 during periods of high rainfall typical of the winter months. Breeding habitat is characterized by areas of seepage water, either in small streams or in seasonally I-BET151 mw flooded fields (Boschung

1979; Boschung and Neiland 1986). Characteristic vegetation includes Juncus, where Slackwater Darter are known to attach eggs, and adults and juveniles migrate downstream to larger streams in early spring, where they are rarely collected (Boschung 1979; Boschung and Neiland 1986). In 1976, Boschung estimated, via mark/recapture, the population of Slackwater Darter in Cemetery Branch (Cypress Creek system) as 800–1,200 individuals. He also noted that bank heights in this stream were 30–45 cm above the stream channel, and emphasized the importance of connectivity of stream channels and floodplain seepage areas for successful migration to spawning areas. Slackwater Darters are Wnt inhibitor endemic to tributaries of the Tennessee River in Alabama and Tennessee. The species is historically known from headwaters of the Buffalo River and Shoal Creek, Tennessee; from

Cypress Creek and Brier Fork systems, Alabama and Tennessee; and Limestone Creek and Swan Creek systems, Alabama (Fig. 1) (USFWS 1984, J Powell, USFWS, personal communication). Because the species aggregates in relatively small areas during the breeding season (Boschung 1979; Boschung and Neiland 1986), it is assumed that detectability during this time is higher at these locations than in non-breeding habitat outside of the spawning season. In a comprehensive survey conducted 1992–1994, Slackwater Darters were present at 22 sites (all presumed breeding sites) in these streams (146 new and historical sites sampled). Of the 21 historical sites surveyed (breeding and non-breeding sites), Slackwater Darter was found at only 10 (all breeding sites), a 45 % reduction of the originally known range since the 1970s (McGregor and Shepard 1995). Fig. 1 Distributional range of Etheostoma boschungi, based on this study. Circles indicate positive detection in the current study; squares are historical sites where the species was not detected in the 2001–13 sampling period.

Leave a Reply

Your email address will not be published. Required fields are marked *

*

You may use these HTML tags and attributes: <a href="" title=""> <abbr title=""> <acronym title=""> <b> <blockquote cite=""> <cite> <code> <del datetime=""> <em> <i> <q cite=""> <strike> <strong>