Publications

Background Exposure to harmful levels of ultraviolet-B radiation (UVB), a component of solar radiation, has been suggested as a potential cause of amphibian declines.Methods We measured solar radiation (UVB, ultraviolet-A, and visible) wavebands in breeding ponds of Bufo boreas (boreal toad, a montane species that has undergone severe population declines) and Bufo woodhousii (Woodhouse’s...

Armoring of limestone is a common cause of failure in limestone-based acid-mine drainage (AMD) treatment systems. Limestone is the least expensive material available for acid neutralization, but is not typically recommended for highly acidic, Fe-rich waters due to armoring with Fe(III) oxyhydroxide coatings. A new AMD treatment technology that uses CO2 in a pulsed limestone bed reactor...

Saxe and Beck (1) raise two groups of questions regarding the mass-balance approach in our paper. (i) Only some of the data and calculations used for the mass balance were provided; the apparent number of samples collected is not sufficient to support a reliable mass balance; measurements were not made on all tributaries.

In order to reveal patterns of reproductive aging in birds we focus on a short lived species, the Japanese quail and the American kestrel, which has a life span of medium length. Quail have been studied extensively in the laboratory as models for understanding avian endocrinology and behavior, and as a subject for toxicological research and testing. In the lab, Japanese quail show age...

The Delmarva fox squirrel, Sciurus niger cinereus, is a federally listed endangered subspecies whose range has been reduced by 90%. In an attempt to increase both population size and range, translocation sites were established beginning in the 1960's by moving squirrels from the natural range to sites outside the current range. Although translocations have served as the primary component...

Predicting extinction risks has become a central goal for conservation and evolutionary biologists interested in population and community dynamics. Several factors have been put forward to explain risks of extinction, including ecological and life history characteristics of individuals. For instance, factors that affect the balance between natality and mortality can have profound effects...

The Colombian small-eared shrew, Cryptotis colombiana Woodman and Timm, was described from the Colombian Andes in 1993. Its original allocation to the C. nigrescens group recently was questioned based on several cranial characters the species appeared to share with some members of the C. thomasi group. We review characteristics of the C. nigrescens and C. thomasi groups, and we describe...

The threatened Kirtland's warbler Dendroica kirtlandii breeds in stands of young jack pine Pinus banksiana growing on well-drained soils in Michigan, USA. We summarize information documenting the range expansion of Kirtland's warbler due to increased habitat management in the core breeding range in the Lower Peninsula of Michigan during 1990–2000. We collected records and conducted...

The illegal use of pesticide-laced baits for predator control is a wildlife crime that is underreported, inadequately documented, and insufficiently punished. The crime occurs when some ranchers, farmers, and hunting groups illegally lace baits with pesticides to control avian and mammalian predators. The activity has poisoned birds protected by the Endangered Species Act, Migratory Bird...

The measurement of contaminant tissue concentrations or exposure-related effects in biota has been used extensively to monitor pollution and environmental health. Terrestrial vertebrates have historically been an important group of species in such evaluations, not only because many are excellent sentinels of environmental contamination, but also because they are valued natural resources...

A method for the determination of 146 polychlorinated biphenyls (PCBs), including four non-ortho- and eight mono-ortho-substituted congeners, and 26 chlorinated pesticides is described. The method consists of ultrasonic extraction, Florisil cleanup, HPLC fractionation over porous graphitic carbon (PGC), and final determination with GC/ECD, GC/MS, or both. Two PCB congeners (PCB 30 and...

Humans have been damming rivers for millennia, and our more ambitious efforts over the past century have arguably altered river ecosystems more extensively than any other anthropogenic activity. Effects of damming on river biota include decimation of migratory fauna (e.g., diadromous and potamodromous fishes and crustaceans), lost fisheries, and imperilment of obligate riverine taxa...