Publications

Recreationists unintentionally trample vegetation, erode soil, and disturb wildlife. Such human-related impacts present a dilemma for managers charged with the dual objectives of providing recreational opportunities and preserving natural environments. This paper presents some of the principal findings and management implications from research on visitor impacts to protected areas...

Estimates of annual survival rates for a multispecies sample of neotropical birds from Panama have proven controversial. Traditionally, tropical birds were thought to have high survival rates for their size, but analyses by Kart et al. (1990. Am. Nat. 136:277-91) contradicted that view, suggesting tropical birds may not have systematically high survival rates. A persistent criticism of...

Preventing environmental contaminants from reducing wildlife populations is the greatest concern in wildlife toxicology. In the Great Lakes, environmental contaminants have a history of reducing populations of many species of fish-eating birds. Endocrine effects may have contributed to declines in fish-eating bird populations, but the overriding harm was caused by DDE-induced eggshell...

To be sustainable, ecotourism requires the protection of natural environments and processes both from development and operation of the tourism infrastructure, and from the activities of ecotourists within protected areas. This book chapter reviews the international literature on the study of visitor or recreation-related resource impacts with special reference to ecotourism. Four case...

No abstract available.

Unbiasedness is probably the best known criterion for evaluating the performance of estimators. This note describes unbiasedness, demonstrating various failings of the criterion. It is shown that unbiased estimators might not exist, or might not be unique; an example of a unique but clearly unacceptable unbiased estimator is given. It is shown that unbiased estimators are not translation

No abstract available.

This compact disc (CD) contains the first 28 reports in the Contaminant Hazard Reviews (CHR) that were published originally between 1985 and 1994 in the U.S. Department of the Interior Biological Report series. The CD was produced because printed supplies of these reviews--a total of 84,000--became exhausted and demand remained high. Each review was prepared at the request of...

Discharges of fecal bacteria (fecal coliform bacteria and Escherichia coli ) to the middle main stem of the Cuyahoga River from storm water, combined sewers, and incompletely disinfected wastewater have resulted in frequent exceedances of bacteriological water-quality standards in a 23-mile reach of the river that flows through the Cuyahoga Valley National Recreation Area. Contamination...

No abstract available.

Seven small tributary streams with drainage areas ranging from 12.6 to 71.9 square miles, representative of both limestone and freestone settings, in the Lower Susquehanna River Basin were sampled for algae, nutrients, water quality, habitat, land use, hydrology, fish, and invertebrates. Nutrients, site characteristics, and selected characteristics of the invertebrate and fish...

Garnet crystals, some of gem quality, have been sought by rock hounds for many years in the alluvial deposits of the Alder Gulch-Ruby River area. Since 1995, garnet have been extracted from these gravels for industrial products at two separately own placer mines in the region: (1) at Cominco American's "Ruby Garnet" operation at Alder , Montana and (2) at the "Sweetwater Garnet"...