Darren Johnson

Establishing a standard ploidy assessment method using grass carp from Ohio, 2015-2016

In 2015-2016, the Ohio Division of Wildlife’s undercover law enforcement purchased 1,200 grass carp (Ctenopharyngodon idella). Fish heads and eyeballs were sent overnight to U.S. Geological Survey Wetland and Aquatic Research Center for ploidy analysis. Field and laboratory standard operating procedures were established and followed. Fish lengths, fish weights, and eyeball weights were obtained from the U.S. Fish and Wildlife Service’s feral carp ploidy program for grass carp and black carp (Mylopharyngodon piceus) and the Ohio grass carp. Internal 2µm or 4µm bead standards were used in establishing nuclear sizes from Nile tilapia (Oreochromis niloticus), known diploid (n=20) and triploid (n=20) carp blood, as well...

Categories: Data; Tags: Aquatic Biology, Asian carp, DNA, Ohio, USGS Science Data Catalog (SDC), All tags... biosecurity, biota, environment, flow cytometry, nucleus, ploidy, Fewer tags

Effects of shading on the rare plant species, Trillium texanum (Melanthiaceae)

The original distribution of the study species Trillium texanum is seep spring baygalls in east-central Texas and extreme northwestern Louisiana. Experiments to determine the effects of shading on T. texanum were conducted using short-term shade cloth treatments (full sunlight vs. 30% shading for 2-3 weeks), and a dryness treatment (moist vs. less moist). Mean height and cover responses of individuals were determined in conservation gardens located in Lafayette, Louisiana.

Categories: Data; Tags: Botany, Ecology, Louisiana, Texas, USGS Science Data Catalog (SDC), All tags... biota, climate change, climate drying, disturbance fugitive, east-central Texas, effects of climate change, endangered species, environment, floodplain, habitat alteration and disturbance, northwestern Louisiana, rare, endangered, and threatened species, ruderal species, seed bank, seep spring drying, shade experiment, Fewer tags

Effects of shading on the rare plant species, Physostegia correllii (Lamiaceae)

The original distribution of the study species Physostegia correllii included freshwater floodplains of large rivers in the southcentral U.S. (Colorado, Rio Grande, Mississippi). Experiments to determine the effects of shading on P. correllii were conducted using short-term shade cloth treatments (full sunlight vs. 30% shading for 2-3 weeks). Mean height and cover responses of individuals were determined in conservation gardens located in Lafayette, Louisiana. Physostegia correllii plants were grown in shaded environments for 2.5 weeks.

Categories: Data; Tags: Botany, Colorado River, Ecology, Louisiana, Lower Rio Grande, All tags... Mississippi River, Rio Grande, Texas, USGS Science Data Catalog (SDC), biota, climate change, climate drying, disturbance fugitive, effects of climate change, endangered species, environment, floodplain, habitat alteration and disturbance, rare, endangered, and threatened, ruderal species, seed bank, seep spring drying, shade experiment, southcentral U.S., Fewer tags