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Columbia, MO, United States

Siepker M.J.,51 Joe Jones Boulevard | Michaletz P.H.,500 East Gans Road
Transactions of the American Fisheries Society | Year: 2013

Large reservoirs provide important sport fisheries, but managing these fisheries is difficult because of the multiple biological and environmental variables that interact to shape them. Understanding how sport fish recruitment responds to parental stock and environmental influences would improve our management capabilities. We compiled long-term datasets for 15 Missouri reservoirs and used them to examine the influence of parental stock abundance and a suite of environmental variables on the recruitment of Largemouth Bass Micropterus salmoides, Spotted Bass M. punctulatus,White Crappie Pomoxis annularis, and Black Crappie P. nigromaculatus. Comparisons of log-linear, Ricker, and Beverton-Holt stock-recruit models revealed that the log-linear model was the most parsimonious for Largemouth Bass, White Crappie, and Black Crappie, but the Ricker model was best for Spotted Bass. However, stock-recruit models alone explained less than 13% of the variation in Largemouth Bass, Spotted Bass, and White Crappie recruitment while explaining about 33% of the variability in recruitment of Black Crappie. Largemouth Bass recruitment was positively related to spring rises in water levels, summer water levels, and average summer air temperatures, whereas Spotted Bass recruitment was positively related to spring air temperatures. White Crappie recruitment was positively related to total phosphorus levels and drops in spring water levels. Black Crappie recruitment was best explained by the model positively relating recruitment to spawning stock abundance, spring water levels, and summer water levels, while negatively relating recruitment to rapid drops in spring water levels. With the exception of models for Black Crappie, the best models did not include spawning stock abundance, and environmental variables appeared more important in explaining variation in recruitment. However, environmental variables in these models explained only a modest amount of variation (27-44%) in recruitment, revealing the complexity of recruitment processes in large reservoirs. © American Fisheries Society 2013. Source

Hiller T.L.,Mississippi State University | Belant J.L.,Mississippi State University | Beringer J.,500 East Gans Road
Journal of Zoology | Year: 2015

The distribution of animals is influenced by numerous factors including spatial distribution and temporal availability of resources. We tested the spatial resource variability hypothesis (increasing landscape heterogeneity results in increasing amount of space use) and the temporal resource variability hypothesis (temporal variation in resources reduces amount of space use) using location data from radiomarked American black bears Ursus americanus in Missouri and Arkansas, USA. We used 95% utilization distributions (UDs) to define individual seasonal space use and constructed 22 models using covariates that described composition, spatial arrangement and diversity of land cover types (an index of heterogeneity or patchiness); seasonal hard mast production; and seasonal use of land cover to test our hypotheses using linear modeling and small-sample Akaike information criterion (AICc) model selection approaches. The AICc best performing model supported the spatial resource variability hypothesis and included Shannon diversity index [95% confidence limit (CL) of coefficient=1.56-2.42] and sex (male; 95% CL of coefficient=0.05-0.49) as covariates that explained variation in transformed values of UD size. Predicted and observed values during model evaluation were highly correlated (r=0.90). As land cover heterogeneity increased, UD size increased, likely a consequence of bears responding to greater patchiness to maintain sufficient resources. Further, the Shannon diversity index was greater for males than females , suggesting larger bodied males used larger areas to meet their higher energetic costs due to landscape fragmentation. Studies of resource hypotheses in solitary species should consider intraspecific allometric relationships such as sexual size dimorphism as has been addressed using group size in social species. © 2015 The Zoological Society of London. Source

Age-0 gizzard shad Dorosoma cepedianum are the main prey fish for white crappies Pomoxis annularis in many US reservoirs. However, these prey fish commonly outgrow their vulnerability to white crappie predation in some, but not all, northern Missouri reservoirs. Potential variables that could influence abundance, growth and mortality of age-0 gizzard shad were examined in three reservoirs that differed with respect to age-0 gizzard shad growth rates. Because of thermal effluent from a power plant, gizzard shad spawned earlier in Thomas Hill Lake and initial densities of larvae were greater than in the other reservoirs. Larval and juvenile gizzard shad grew slowest in Thomas Hill Lake, followed by Mark Twain Lake and Long Branch Lake. Growth rate of larvae increased with increasing water temperature and food abundance, but decreased with increasing conspecific density. Similar relationships were found for juvenile growth, except that growth declined with increasing temperature. The slower growth of larvae and juveniles in Thomas Hill Lake was probably a consequence of their greater densities relative to their food abundance and higher water temperatures during the juvenile stage. Conversely, both larvae and juvenile gizzard shad grew more rapidly and juveniles attained large sizes in Long Branch Lake owing to their lower densities relative to their available food. Mortality of larvae and juveniles was mostly similar among the reservoirs. Because of their greater abundance and slower growth, gizzard shad were available as prey for white crappies for a longer period in Thomas Hill Lake than in the other reservoirs. © 2014 John Wiley & Sons A/S. Source

Sunde M.,University of Missouri | He H.S.,University of Missouri | Hubbart J.A.,University of Missouri | Scroggins C.,500 East Gans Road
Applied Geography | Year: 2016

Increased impervious surface (IS) cover is often the primary disturbance contributing to altered hydrology in urbanizing watersheds, affecting various components of the hydrologic balance. To improve the understanding of how future urban development will influence watershed streamflow characteristics, and to develop growth strategies that preserve water resources, it is necessary to combine detailed estimates of future IS cover with hydrologic models. A coupled modeling approach is presented to help address this problem. Pixel-based percentage IS cover for the period 2011-2031 was derived using the Imperviousness Change Analysis Tool (I-CAT) for three urban growth scenarios and coupled with the Soil Water Assessment Tool (SWAT) to simulate the potential hydrologic impacts of future urbanization in Hinkson Creek watershed, located in the Midwestern U.S. state of Missouri. Increases to average annual streamflow (+12.81% to +19.74%), increases to average annual surface runoff (+14.32% to +16.77%), reductions to evapotranspiration (-8.68% to -13.37%), and slight increases to baseflow were observed for the three growth scenarios. The approach used here created a range of possible future conditions for the study watershed and presented a framework that allows planners to couple realistic IS cover estimates with hydrologic models. Additionally, this study emphasized that a controlled, more environmentally conscious growth pattern does not necessarily produce less pronounced hydrologic impacts for the study watershed compared to an uncontrolled growth pattern, underscoring the importance of considering neighboring watersheds when analyzing the hydrologic impacts of urban development for an area. © 2016 Elsevier Ltd. Source

Taylor C.A.,University of Illinois at Urbana - Champaign | Engelbert B.S.,University of Illinois at Urbana - Champaign | DiStefano R.J.,500 East Gans Road
Freshwater Crayfish | Year: 2015

We conducted a study to investigate methods to assess crayfish populations typically found in low gradient, lentic, floodplain habitats in Missouri. We used a random site selection process that allowed us to capture all known species from this region of Missouri. We compared two sampling methods for primary burrowing crayfishes at our sampling sites: hook-and-line capture technique and burrow excavation. Adjacent standing water habitats at sites were also sampled using a timed search method. Hook-and-line capture success was substantially less than reported in the literature (0.7% versus 80%), while burrow excavation was higher than reported (64% versus 40.7%). We successfully captured six crayfish species using burrow excavation, whereas lentic timed search sampling captured nine species in adjacent standing waters at our sampling sites. Our results suggest that additional efforts sampling lentic habitats rather than additional time searching for and excavating burrows is more likely to capture total community richness. We found a seasonal influence on burrow occupancy surveys, as Julian day was positively correlated to finding active crayfish burrows. Crayfish capture in standing water was positively affected by soil temperature, and negatively correlated to Julian day. © Copyright 2015 by The Author(s). Source

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