Publications

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The natural establishment of woody seedlings on abandoned agricultural fields was investigated at sites in Louisiana and Mississippi. Series of disked and undisked plots originating at forest edges and oriented in cardinal directions were established on fields at each site. During the firest 2 years, seedling recruitment was dominated by sweetgum, sugarberry, and elms at both sites...

Three different types of Nuttall oak (Quercus nuttallii Palmer) seedlings were planted on floodprone, former cropland in Mississippi, Louisiana, and Texas. The three types of 1+0 seedlings planted at each site in January and February of 1995 were bareroot seedlings, seedlings grown in 164 square centimeters plastic containers, and container grown seedlings inoculated with vegetative...

Most wetland losses in the southern region over the past 200 years have occurred in bottomland hardwood forests. By 1980 the original extent of palustrine bottomland in Texas had been reduced by 63%, from roughly 16 to 6 million acres. Additional losses have occurred during more recent years as a result of conversion to agriculture and timber harvests; these factors and the need to...

Releases of the Frank Lyon, Jr., Nursery Pond into Lake Maumelle were monitored during 1991 through 1996 to assess the impact that the releases have on the water quality of Lake Maumelle. Results indicated that the water-quality impact of the nursery pond release into Lake Maumelle is variable, and appears to be related to the volume of the nursery pond at release and the amount of...

Based on usage of the parent compounds and studies of their dissipation in corn fields, atrazine (6-chloro-N-ethyl-N'-(1-methylethyl-1,3,5-triazine-2,4-diamine)), cyanazine (2-[[4-chloro-6-(ethylamino)-1,3,5-triazin-2-yl]amino]-2-methylpropionitrile), and simazine (6-chloro-N,N'diethyl-1,3,5-triazine-2,4-diamine) are thought to be the important contributors of desethylatrazine (6-chloro...

Ecological change is constant and profound, yet it often occurs at temporal and spatial scales that are difficult to measure and interpret. This publication demonstrates how diverse data bases, archived in different formats and at numerous locations, can be brought together to provide an integrated perspective on the relationship between land use and landcover change. The authors provide...

Spectroscopic interferences are probably the largest class of interferences in ICP-MS and are caused by atomic or molecular ions that have the same mass-to-charge as analytes of interest. Current ICP-MS instrumental software corrects for all known atomic “isobaric” interferences, or those caused by overlapping isotopes of different elements, but does not correct for most polyatomic...

This study determined the relative sensitivity of five species of aquatic macrophytes and six species of algae to four commonly used herbicides (atrazine, metribuzin, alachlor, and metolachlor). Toxicity tests consisted of 96-h (duckweed and algae) or 14-d (submerged macrophytes) static exposures. The triazine herbicides (atrazine and metribuzin) were significantly more toxic to aquatic...

Tree ring analysis was used to document the long-term effects of municipal wastewater on the growth rate of baldcypress (Taxodium distichum (L.) Rich.]. The study site, a swamp in St. Martin Parish, Louisiana, has received municipal wastewater for the last 40 years. Growth chronologies from 1920 to 1992 were developed from cross-dated tree core samples taken from treated and control...

To assess the extent of sediment contamination in the Upper Mississippi River (UMR) system after the flood of 1993, sediment samples were collected from 24 of the 26 navigational pools in the river and from one site in the Saint Croix River in the summer of 1994. Whole-sediment tests were conducted with the amphipod Hyalella azteca for 28 days measuring the effects on survival, growth...

An expert meeting was organized by the World Health Organization (WHO) and held in Stockholm on 15-18 June 1997. The objective of this meeting was to derive consensus toxic equivalency factors (TEFs) for polychlorinated dibenzo-p-dioxins (PCDDs) and dibenzofurans (PCDFs) and dioxinlike polychlorinated biphenyls (PCBs) for both human, fish, and wildlife risk assessment. Based on existing...