Distribution of Cyprinid Fish Reproductive Guilds in a Fragmented Great Plains Riverscape

Great Plains stream fish assemblages changed dramatically during the past half-century, resulting in species extirpations, range expansions, and a general pattern of faunal homogenization.   Fragmentation of large Great Plains rivers is associated with the extirpation of cyprinid fish belonging to the pelagic-spawning reproductive guild, but effects of fragmentation on other guilds remain untested.  Here we present spatiotemporal patterns in distribution throughout a fragmented river network for four reproductive guilds of cyprinids characterized by pelagic release of semi-buoyant eggs (PS), demersal eggs (PD), and adhesive eggs (PA), as well as benthic release of adhesive eggs (BA).  We sampled 16 sites weekly during the 2011 reproductive season spaced throughout the Ninnescah and Arkansas rivers of Kansas to assess abundance and distribution of each guild.  Preliminary results suggest PS and PD guilds were absent from fragmented portions of the riverscape upstream of dams; whereas, PA and BA guilds persisted in higher abundances.  Furthermore, reproductively mature members of PS and PD guilds occurred in highest abundances just downstream of obstructions, consistent with accounts of guild members making upstream migrations for spawning.  Our findings provide support for mechanistic linkages between reproduction and alterations to rivers as drivers of fish assemblage change in the Great Plains.