Black-tailed prairie dog populations one year after treatment with rodenticides

Three rodenticide treatments, zinc phosphide with prebait, strychnine with prebait, and strychnine without prebait, were applied to black-tailed prairie dog Cynomys ludovicianus colonies in west central South Dakota. Results were compared immediately posttreatment and for one year after application. Zinc phosphide was the most effective for reducing prairie dog numbers immediately. When burrow activity levels of prairie dogs were initially reduced by 45% with strychnine only, they returned to untreated levels within ten months. When initial reductions were 95% with zinc phosphide, however, the number of active burrows was still reduced 77% in September the following year. Strychnine with prebait treatment showed initial reductions of 83% in burrow activity. Bait consumption by prairie dogs was highest for zinc phosphide.     

Dynamic landforms and plant communities in a pluvial lake basin

Mapping units were developed based on landform, soils, and plant communities for the 40,000 ha of salt desert vegetation located below the maximum level of pluvial Lake Gilbert in Grass Valley, Nevada. Lake plain, beach, and bar features of the pluvial lake provide the dominant landforms. Fine textured lake sediments have produced salt- and Na-affected soils. The distribution and structure of plant communities are related to depth of the groundwater table, fluctuations in this depth, and the salt content of the groundwater. Wind and water erosion combine to continually evolve new environments for colonization by plants in this ecosystem.       

Anthropogenic ocean acidification over the twenty-first century and its impact on calcifying organisms

Today's surface ocean is saturated with respect to calcium carbonate, but increasing atmospheric carbon dioxide concentrations are reducing ocean pH and carbonate ion concentrations, and thus the level of calcium carbonate saturation. Experimental evidence suggests that if these trends continue, key marine organisms--such as corals and some plankton--will have difficulty maintaining their external calcium carbonate skeletons. Here we use 13 models of the ocean-carbon cycle to assess calcium carbonate saturation under the IS92a 'business-as-usual' scenario for future emissions of anthropogenic carbon dioxide. In our projections, Southern Ocean surface waters will begin to become undersaturated with respect to aragonite, a metastable form of calcium carbonate, by the year 2050. By 2100, this undersaturation could extend throughout the entire Southern Ocean and into the subarctic Pacific Ocean. When live pteropods were exposed to our predicted level of undersaturation during a two-day shipboard experiment, their aragonite shells showed notable dissolution. Our findings indicate that conditions detrimental to high-latitude ecosystems could develop within decades, not centuries as suggested previously.     

Relationship between prospective memory and vigilance: Evidence from ERP

Event-related potentials (ERPs) were used in this study to investigate the neural correlates of prospective memory (PM) and vigilance. Twenty college or graduate students participated in this study. They were administered a PM and a vigilance task and physiological data were collected at the same time. Behavioral results showed that the RT associated with PM cues was longer than those associated with vigilance targets. ERP results showed that PM cues and vigilance targets did not show significant difference in the N2 but PM cues evoked greater N300 than vigilance targets, and vigilance targets evoked greater parietal positivity/P3 than PM cues, suggesting vigilance and PM have similar but also distinctive neural basis.