Global ETD Search

11	Effects of Cattle Disturbance on Aquatic Macroinvertebrates in Missouri Farm Ponds Mittelhauser, Jennifer 07 1900 (has links) I surveyed macroinvertebrate assemblages in ponds in three grazing regimes (ungrazed, rotationally grazed, and continuously grazed) in spring and summer of 2019 on the Osage Plains ecoregion of Missouri. Total suspended solids, turbidity, and organophosphates were lower in ungrazed ponds than in both grazed treatments, and water transparency and aquatic macrophyte cover was significantly higher. Richness was positively correlated with average depth, deepest depth, and water transparency and negatively correlated with turbidity and organophosphate levels. Overall, ungrazed ponds supported higher taxa richness and diversity across all taxa, as well as higher Diptera: Chironomidae, Odonata, and Trichoptera richness. Ungrazed ponds contained 29 unique genera and three unique families compared to two unique genera and two families in rotationally grazed ponds, and one 6 unique genera and one family in continuously grazed units. PerMANOVA results confirmed differences in habitat variables between ungrazed treatments and both grazed treatments; PCA analysis indicated that decreased taxa abundances were mostly associated with nitrate, bank slope, temperature, and pH and, while transparency and vegetation (emergent and cattails) were associated with increased abundances. PerMANOVA results confirmed seasonal differences in ungrazed ponds and continuously grazed treatments for total taxa and families. Chironomid communities differed between treatments and between seasons for ungrazed ponds and both grazing treatments. Fish presence reduced abundance of total taxa across seasons and in spring and Chironomidae taxa across seasons. pond macroinvertebrates cattle disturbance cattle grazing aquatic insects farm ponds Biology, Ecology Biology, Entomology
12	Time-Related Changes in Water Quality of Stock Tanks of Southeastern Arizona Wallace, D. E., Schreiber, H. A. 20 April 1974 (has links) From the Proceedings of the 1974 Meetings of the Arizona Section - American Water Resources Assn. and the Hydrology Section - Arizona Academy of Science - April 19-20, 1974, Flagstaff, Arizona / This study attempts to determine the water quality changes in stock tanks and what factors are instrumental in the changes, and to assess the effects of the changes. Algal growth was the most prominent change taking place in the tanks with time. Little change in the water chemistry was noted until just before the tanks dried up. As algae died, ions tied up by the algae were released to the water, causing an increase in concentration of many of the nutrients. In order to determine the impact of various factors on algal growth, the data from eight stock tanks were analyzed by stepwise linear regression. Although 20 variables were used in the complete analysis, six variables were associated with 56.3 percent of the variance: time (since first sampling), total n, potassium, pH, inflow (recharge to the tanks), and hco3 concentration. Time and total n explained 51.3 percent of the variance, and potassium increased the variance to 52.8 percent. The pH reversed the relative positions of time and total n, with total n becoming dominant. The last two factors, inflow and hco3 were negative (resulting in a decrease in algal population) and increased the coefficient of variance to 56.3 percent. Hydrology -- Arizona. Water resources development -- Arizona. Hydrology -- Southwestern states. Stock water Ponds Algae Water chemistry Regression analysis Water quality Arizona Farm ponds Water harvesting Standing waters Water storage Nutrients Hydrogen ion concentration Inorganic compounds Water analysis Variability Time Nitrogen compounds Potassium Inflow Bicarbonates Algal growth Stock tanks Stepwise linear regression

Search results

Effects of Cattle Disturbance on Aquatic Macroinvertebrates in Missouri Farm Ponds

Time-Related Changes in Water Quality of Stock Tanks of Southeastern Arizona