Publications

Ammonia is a relatively toxic compound generated in water and sediments by heterotrophic bacteria and accumulates in sediments and pore water. Recent data suggest that unionid mussels are sensitive to un-ionized ammonia (NH3) relative to other organisms. Existing sediment exposure systems are not suitable for ammonia toxicity studies with juvenile unionids; thus, we modified a system to...

We conducted a series of in situ tests to evaluate the effects of pore‐water ammonia on juvenile Lampsilis cardium in the St. Croix River (WI, USA). Threats to this river and its associated unionid fauna have accelerated in recent years because of its proximity to Minneapolis–St. Paul, Minnesota, USA. In 2000, caged juveniles were exposed to sediments and overlying water at 12 sites for...

Over the past decade, bird conservation activities have become the preeminent natural resource conservation effort in North America. Maturation of the North American Waterfowl Management Plan (NAWMP), establishment of Partners in Flight (PIF), and creation of comprehensive colonial waterbird and shorebird conservation plans have stimulated unprecedented interest in, and funding for, bird

Abstract has not been submitted

Freshwater mussels are emersed (exposed to air) during conservation activities such as surveys and relocations. Success of these activities depends upon the ability of mussels to survive emersion and to re-burrow in the substratum. We evaluated the acute sublethal effects of emersion on three species of unionid mussels [pocketbook, Lampsilis cardium (Rafinesque, 1820); pimpleback...

We analyzed fish abundance and environmental data collected over nine years from six side channels of the unimpounded upper Mississippi River between river km 46.7 and 128.7. A partial canonical correspondence analysis revealed differences in fish assemblages and environmental factors correlated with the six side channels. Fishes correlated with open side channels represented large river...

We conducted a factorial experiment, in outdoor mesocosms, on the effects of zebra mussels and water column mixing (i.e., turbulence) on the diet, growth, and survival of larval fathead minnows (Pimephales promelas). Significant (P 0.05) larval mortality occurred by the end of the experiment with the highest mortality (90%) occurring in the presence of both turbulence and zebra mussels...

Because of the declines in diversity and abundance of native freshwater mussels (superfamily Unionoidea), and the potential decimation of populations of native mussels resulting from the rapid spread of the exotic zebra mussel Dreissena polymorpha, management options to eliminate or reduce the threat of the zebra mussel are needed. Relocating native mussels to refugia (artificial and...

We developed a method to estimate mortality rates of adult fish caused by entrainment through the propellers of commercial towboats operating in river channels. The method combines trawling while following towboats (to recover a fraction of the kills) and application of a hydrodynamic model of diffusion (to estimate the fraction of the total kills collected in the trawls). The sampling...

We used radio telemetry to evaluate the movement and habitat use of paddlefish Polyodon spathula in the upper Mississippi River and two tributary rivers. Radio transmitters were surgically implanted into 71 paddlefish in Navigation Pools 5A and 8 of the upper Mississippi River, the Chippewa River, and the Wisconsin River during fall 1994 through fall 1996. Radiotagged paddlefish were...

Previous research reported that concentrations of selenium in the livers of 88a??95% of lesser scaup from locations in Lake Erie, Lake St. Clair, and Lake Michigan, USA were either elevated (10a??33 A?g/g dry weight [dw]) or in the potentially harmful range (>33 A?g/g dw). In order to determine the geographic extent of these high selenium concentrations, we collected lesser scaup in...

Blackbirds frequently use ripening sunflower (Heltantbus annuus) as a food source in the northern Great Plains. In 1999 and 2000, the avicide DRC-1339 (3-chloro-4-methylaniline hydrochloride) was used experimentally on fall-ripening sunflower fields in North Dakota so researchers could evaluate its effectiveness for reducing crop depredations by blackbirds. DRC-1339 was applied to rice...