Publications

Although large-scale transformation of Everglades landscapes has occurred during the past century, the patterns of association among hydrologic factors and southern Everglades freshwater marsh vegetation have not been well-defined. We used a 10-year data base on the aquatic biota of Shark Slough to classify vegetation and describe plant community change in intermediate- to long...

Recent advances in molecular technology have opened a new chapter in species conservation efforts, as well as population biology. DNA sequencing, MHC (major histocompatibility complex), minisatellite, microsatellite, and RAPD (random amplified polymorphic DNA) procedures allow for identification of parentage, more distant relatives, founders to new populations, unidentified individuals...

No abstract available.

The Osprey population associated with Darwin Nature Reserve and the Rybinsk Reservoir increased from only a few pairs prior to the creation of the reservoir in the late 1940s , to about 45-50 pairs in 1994. Productivity rates were excellent in 1988 and 1989 (1.38 young/occupied nest), but extremely low in 1987 (0.47 young/occupied nest). A chemical spill into the Volga River in early...

As scientists, managers and landowners, we have come to realize that to best understand the local and regional value of individual wetlands, we need to take a broad geographic, taxonomic, and management view. In December 1994, a symposium was held in Reno, Nevada that addressed this topic for shorebirds by bringing together researchers and managers from the Western Great Basin to discuss...

We assayed diets of Townsend's ground squirrels (Spermophilus townsendii) in a semi-arid shrub steppe in Idaho by analyzing 1,432 fecal samples during 1991–1994. Dietary composition differed between adults and juveniles but not between males and females. Sand-berg's bluegrass (Poa secunda), a perennial bunchgrass, was the most common item in diets. Diets varied among habitats that...

I examined the relationship of diets to skull morphology of extant northern bears and used this information to speculate on diets of the recently extinct cave (Ursus spelaeus) and short-faced (Arctodus simus) bears. Analyses relied upon published skull measurements and food habits of Asiatic (U. thibetanus) and American (U. americanus) black bears, polar bears (U. maritimus), various...

Records of grizzly bear (Ursus arctos) deaths are currently used by managers to indicate trends in actual grizzly bear mortality and to judge the effectiveness of management. Two assumptions underlie these current uses: first, that recorded mortality is an unbiased indicator of actual mortality, and second, that changes in mortality after implementation of management strategies are...

No abstract available.

The 27,000 ha Fort Lewis Military Reservation is situated in the Puget lowlands and contains a wide variety of aquatic habitats offering potential refuge for native amphibians. We surveyed amphibians on Fort Lewis from 1992 through 1995 to examine occupancy patterns relative to wetland characteristics. We documented 9 native amphibians and 1 introduced anuran (Rana catesbeiana) that...

Heavy visitor use in many areas of the world have necessitated development of ways to assess visitation impacts. Arches National Park recently completed a Visitor Experience and Resource Protection (VERP) plan. Integral to this plan was developing a method to identify biological indicators that would both measure visitor impacts and response to management actions. The process used in...

Biological soil crusts, consisting of cyanobacteria, green algae, lichens, and mosses, are important in stabilizing soils in semi-arid and arid lands. Integrity of these crusts is compromised by compressional disturbances such as foot, vehicle, or livestock traffic. Using a portable wind tunnel, we found threshold friction velocities (TFVs) of undisturbed crusts well above wind forces...