Coping with hydrogeomorphic variations in a prairie river: resiliency in young‐of‐the‐year fishes

Abstract

Young-of-the-year (YOY) fish in sand-bed rivers of grassland ecoregions frequently encounter dynamic habitat conditions produced by highly variable flow and resulting changes in geomorphic complexity of the river. How these vulnerable life history stages cope with changes in habitat condition and location is largely unknown. Therefore, we examined biodiversity and abundance of YOY fish (larvae and juveniles) at two spatiotemporal scales in response to dynamic flow conditions in the Kansas River. During the summer of 2004, we collected and identified 13 745 YOY fish from various moderate to zero-flow habitats. Patterns of community structure through time were compared with the river's hydrogeomorphic characteristics, as determined by aerial photographs and measurements of instream flow rate and other water quality characteristics.Our initial hypothesis was that species richness and total YOY abundance would be maximized in larger and longer-lived slackwater habitats. In contrast, our data suggest that dominant fishes in these highly dynamic ecosystems have adapted to hydrological variations with a more generalist lifestyle by either: (i) temporarily using higher flow habitats (except possibly the thalweg) to cope with intermittent loss of prime habitat; or (ii) extending spawning through favourable and demanding conditions. In contrast to current theories, our results suggest that conditions for YOY success are optimized in dynamic prairie rivers during the intermediate flows that maximize habitat heterogeneity and availability.

Recruitment ecology of pelagic‐broadcast spawning minnows: paradigms from the ocean advance science and conservation of an imperilled freshwater fauna

“…Instead, plains larvae are distributed among shallow slackwaters and eddies (Pease et al . ; Moore and Thorp ; Turner et al . ).…”

Extreme drought causes fish recruitment failure in a fragmented Great Plains riverscape

“…For instance, the low flow recruitment hypotheses (LFRH) postulate that periods of low flow when water temperatures and prey densities are high can be advantageous to small-bodied fishes that produce multiple clutches of planktonic (suspended by currents) or demersal (sinking) ova during a protracted summer spawning season (Humphries, King, & Koehn, 1999). Dryland river studies have found that small-bodied fish recruitment is unrelated to flow (Hoagstrom, Archdeacon, Davenport, Propst, & Brooks, 2014), recruitment is most successful at intermediate flows (Moore & Thorp, 2008), or that exceptionally low flow periods are detrimental to recruitment for some populations (Durham & Wilde, 2009;Perkin, Gido, Costigan, Daniels, & Johnson, 2015;. Dryland river studies have found that small-bodied fish recruitment is unrelated to flow (Hoagstrom, Archdeacon, Davenport, Propst, & Brooks, 2014), recruitment is most successful at intermediate flows (Moore & Thorp, 2008), or that exceptionally low flow periods are detrimental to recruitment for some populations (Durham & Wilde, 2009;Perkin, Gido, Costigan, Daniels, & Johnson, 2015;.…”

Intrafragment riverscape conservation for an imperiled, small-bodied, pelagic-broadcast spawning minnow: speckled chub (Macrhybopsis aestivalis)

“…(Table 1). optimal flow regime for M. aestivalis presumably includes sequential, short-duration flow peaks that maximize retention of pelagicbroadcast propagules (Dudley and Platania 2007;Zymonas and Propst 2009) and likely invigorate ecological productivity (sensu Leigh et al 2010) set apart by intervening flow-recession periods of adequate duration for recruitment (sensu Moore and Thorp 2008). The flow regime associated with highest M. aestivalis recruitment (i.e., 2008) fit this description (Fig.…”