David L. Galat

Flooding to Restore Connectivity of Regulated, Large-River Wetlands Natural and controlled flooding as complementary processes along the lower Missouri River

You can always count on finding the Mississippi just where you left it last year. But the Missouri is a tawny, restless, brawling flood. It cuts corners, runs around at night, fills itself with snags and traveling sandbars, lunches on levees, and swallows islands and small villages for dessert. Its perpetual dissatisfaction with its bed is the greatest peculiarity of the Missouri.... It makes farming as fascinating as gambling. You never know whether you are going to harvest corn or catfish (Fitch 1907, p. 637).

10 – Missouri River Basin

Publisher Summary The Missouri River basin is the second largest in the US, surpassed in area only by the Mississippi River basin of which it is a part. A wide range of climatic conditions, geologic complexity, and topographic relief exist within the three physiographic divisions that contribute to the Missouri River basin. From west to east, these divisions and the number of physiographic provinces within each are: Rocky Mountain System, Interior Plains, and Interior Highlands. Convergence of the air masses and the midcontinent location of the basin produce extreme seasonal variability in weather. Daily fluctuations can also be sudden and severe. Winters are relatively long and cold; spring is cool, moist, and windy; summers are fair and hot; and autumn is cool, dry, and windy. The basin is largely semiarid. Thirteen terrestrial ecoregions are represented in the Missouri River basin, reflecting its altitudinal, latitudinal, and climatic gradients. From west to east these ecoregions grade from Rocky Mountain coniferous forests, to shrub steppe, then short, mixed, and tall grasslands, and finally to mixed hardwood forests.

TESTING THE BIOLOGICAL BASIS OF A STREAM HABITAT CLASSIFICATION USING BENTHIC INVERTEBRATES

The biological basis of a physical channel unit classification system for a warmwater stream was evaluated. We compared measures of benthic invertebrate communities in 11 channel units in three segments of the Jacks Fork River, Missouri, USA, in two different seasons. Within-group community similarity, as measured by Whittakers percentage similarity, significantly increased by grouping the entire fauna into three flow habitat groups, and in most cases, community similarity significantly increased by further division into the 11 channel units. Community structure, measured as the ranking of abundance of fauna at the family level of taxonomy, was consistent for the same channel units from different segments of stream during the same season, as well as over time as measured by correlation analysis. Communities most consistent both spatially and over time were edgewaters, high gradient riffles, and races, while the least concordant faunas were from vegetated edgewaters, forewaters, and obstruction pools. Channel units did not maintain unique faunal relations over space or time when measured by the community-level measures of diversity, taxon richness, and abundance. We conclude that channel units have properties not found at other spatial scales and serve as an appropriate scale to coordinate interdisciplinary management goals and strategies.

Large-Scale Factors Associated with Sicklefin Chub Distribution in the Missouri and Lower Yellowstone Rivers

Abstract The conservation and management of imperiled fishes requires information on the factors influencing their distribution. The sicklefin chub Macrhybopsis meeki is an imperiled, small-bodied, riverine fish largely restricted to the main-stem Missouri, lower Yellowstone, and middle Mississippi rivers. We tested the association of sicklefin chub presence/absence with physical habitat, temperature, turbidity, flow, and piscivore abundance between July and October 1996– 1997 at a riverscape spatial scale encompassing about 48–192-km-long segments over nearly 2,000 km of the Missouri and lower Yellowstone rivers. Four of the 64 variables examined were significantly associated with sicklefin chub presence/absence: distance to upstream impoundment, flow constancy (a measure of flow variability), mean turbidity, and percent of total annual flow occurring in August. The frequency of occurrence of sicklefin chub was highest when study segments were over 301 km downstream from an impoundment, flow constancy wa...

A Conceptual Life-History Model for Pallid and Shovelnose Sturgeon

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Distributional Patterns of the Threatened Niangua Darter, Etheostoma nianguae, at Three Spatial Scales, with Implications for Species Conservation

Abstract The Niangua darter, Etheostoma nianguae, is a threatened stream fish endemic to the Osage River basin in south-central Missouri. We studied the darters distributional patterns at three spatial scales (stream, reach, and microhabitat) to assist ongoing conservation efforts. Darter presence-absence as a function of one or more habitat variables was modeled with logistic regression at each scale. The most important predictors of presence-absence were stream link magnitude, mean confluence difference (CD), reach length or gradient, streambed elevation, bank erosion index, water depth, and substrate mean particle size. At the stream scale, darters were present in larger streams (e.g., fifth order) with small CDs. A relatively small CD, for example, described the convergence of two streams of roughly equal size in the drainage basin, whereas a relatively large CD indicated a substantial difference at a confluence. We propose that the CD metric represents a large-scale zoogeographic barrier to E. nianguae, excluding this species from any tributary stream that flows into a receiving stream that is three or more stream orders larger than the tributary. Within one occupied stream, the Little Niangua River, darters were found disproportionately in reaches (1) located in the mid- to lower sections of the stream (elevations 230–250 m above sea level), (2) with riffles spaced 40–80 m apart or with gradients of 2–4 m × km−1, and (3) with relatively uneroded banks. Within occupied reaches, they were commonly located in microhabitats 20–40 cm deep with substrate particles averaging 30–50 mm in diameter. Multivariate model precision ranged from 29–57% within single scales. The models can be used to guide conservation and recovery efforts by ranking sites in the Osage basin based on their relative suitability for E. nianguae.

Mortality of Paddlefish in Hoop Nets in the Lower Missouri River, Missouri

Abstract Mortality of paddlefish Polyodon spathula collected in hoop nets was observed in the lower Missouri River, Missouri, in 1997. Unbaited hoop nets of three mesh sizes (2.5, 5.0, and 7.5-cm, bar measure) were fished from Mar to Oct in two habitats (inside-bend steep-cut banks and outside-bend revetted banks). In 462 net-days of effort we caught 23 paddlefish in 5.0- and 7.5-cm-mesh nets but none in the 2.5-cm-mesh nets; 35% of the paddlefish collected were found dead. Most paddlefish (90%) were collected along outside-bend revetted banks in May, Jun, and Jul. Mortality was not associated with water temperature; however, 80% of paddlefish collected from May through Jul in 7.5-cm-mesh nets were dead versus 21% in 5.0-cm-mesh nets. We estimated that one paddlefish would be killed for every 37 net-days of effort, based on random placement of hoop nets within macrohabitats. Our data indicate that bycatch mortality of paddlefish in hoop nets should be considered and evaluated further in the lower Missouri...

A Comparison of Measures of Riverbed Form for Evaluating Distributions of Benthic Fishes

Abstract A method to quantitatively characterize the bed forms of a large river and a preliminary test of the relationship between bed-form characteristics and catch per unit area of benthic fishes is presented. We used analog paper recordings of bathymetric data from the Missouri River and fish data collected from 1996 to 1998 at both the segment (∼101–102-km) and macrohabitat (∼10–1–100-km) spatial scales. Bed-form traces were transformed to digital data with image analysis software. The slope, mean residual, and SD of the residuals of the regression of depth versus distance along the bottom, as well as mean depth, were estimated for each trace. These four metrics were compared with sinuosity, fractal dimension, critical scale, and maximum mean angle for the same traces. Mean depth and sinuosity differed among segments and macrohabitats. Fractal-based measures of the relative depth of bottom troughs (critical scale) and smoothness (maximum mean angle) differed among segments. Statistics-based measures o...

The influence of river stage on endangered least terns and their fish prey in the Mississippi River (USA)

Spatial and temporal availability of small fishes, as forage for interior least terns (Sterna antillarum), was compared to the least tern reproductive period during 1993 and 1994 in the lower Mississippi River, Missouri. Timing of forage availability and least tern reproduction was also related to river stage and temperature regimes. Four deep-water habitats (main channel, secondary channel, side channel, and connected slough) and two shallow-water habitats (main-channel interface and side-channel interface) were sampled using a seine and neuston net, yielding 67 245 fish≤10 cm. Catch-per-volume and richness were highest in shallow-water habitats in both years. Highest catches in deep- and shallow-water habitats occurred between 56 and 64 days after peak spring flows in both years. Water temperature was increasing rapidly during the spring flood peak each year. About 80% of total fish catch consisted of taxa known to spawn in floodplain habitats, supporting the connection between the spring flood and the timing and amount of forage available for nesting least terns. Timing of least tern reproduction was related to falling river stages in May and increased forage–fish availability in June. A conceptual model integrates the abiotic factors of hydrology and sand island area to least tern reproduction and small fish availability.

Reproductive Ecology and Captive Breeding of the Threatened Niangua Darter Etheostoma nianguae

Abstract The Niangua darter Etheostoma nianguae is a threatened stream fish endemic to the Osage River basin of Missouris Ozark uplands. We studied the darters reproductive behavior under natural conditions in the wild to assist recovery efforts. In addition, techniques for captive propagation were developed in the event that wild populations should suffer precipitous declines. Seven spawning events were witnessed by snorkelers in swift riffle areas at mean (± SD) water depths of 23 ± 5 cm, column current velocities of 83 ± 12 cm/s and focal current velocities of 43 ± 9 cm/s. This combination of depth and velocity was used only for spawning; darters were found at slower velocities and greater depths when not spawning during spring and at slower velocities during summer. Niangua darters in captivity spawned in 38 liter aquaria with fine uniform substrate and no current velocity, and larvae were reared to the juvenile stage. Time from fertilization to hatching was 10–11 d at 16 C. Larvae swam up 3 d after hatching and remained in the water column 31–33 d before returning to the substrate. We suggest a spawning protocol that includes capturing wild males and females during April, isolating spawning pairs in 38 liter aquaria with fine substrate and maintaining low light levels during hatching. Young can be reared on brine shrimp nauplii, zooplankton and, later, frozen adult brine shrimp. A chronology of Niangua darter reproductive and early life history events is provided.