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Madison, WI, United States

Anich N.M.,501 Golf Course Road | Worland M.,07 Sutliff Avenue | Martin K.J.,801 Progress Road
Wilson Journal of Ornithology

Spruce Grouse (Falcipennis canadensis) are listed as threatened in Wisconsin, and the boreal habitats in which they occur are likely to be threatened by changing climatic conditions. However, the limited information available on Spruce Grouse in the Upper Great Lakes region makes it unclear which habitat features are important for Spruce Grouse nesting in Wisconsin. We radiotracked 30 female Spruce Grouse in northern Wisconsin from 2007-2012 and located 25 nests. Eighteen of 25 nests were beneath black spruce (Picea mariana) trees. Only three nests were in upland, and only one in a stand of jack pines (Pinus banksiana), in contrast to studies from Michigan and Ontario. Overall concealment was a good predictor of nest sites for Spruce Grouse, but not a good predictor of nest survival. Nest survival was associated with moderately dense and uniform 0-0.5 m lateral vegetation cover. Seventeen of 25 nests were successful, with a daily survival rate of 0.985, overall productivity of 1.0 young/female, and 1.9 young/successful nest. Annual survival of adult males was estimated at 54%, adult females at 40%, and juvenile survival at 14% and 24% by two different methods. Estimates of λ of 0.65 and 0.67 suggest a declining population, but the upper confidence limit exceeds 1, not ruling out a stable or slightly increasing population. Protecting black spruce swamps will protect important nesting habitat for Spruce Grouse in Wisconsin. © 2013 by the Wilson Ornithological Society. Source

Perennial coolwater streams (maximum daily mean water temperature 20.7-24.6°C; 90th percentile annual exceedence flow ≥ 0.0283 m 3/s) are common in the Laurentian Great Lakes region of North America, including the state of Wisconsin, but they lack specific and effective bioassessment tools. I used landscape-scale ecological modeling of geographically referenced data on stream location, stream and valley slope, watershed surficial geology, air temperatures, riparian and watershed land cover, watershed road and population densities, and watershed nutrient and wastewater inputs to classify Wisconsin stream sites based on water temperature, flow, and degree of environmental degradation. Fish data from sites classified as perennial coolwater were then analyzed with objective standardized procedures to develop coolwater indices of biotic integrity (IBI). Because of substantial differences in their fish assemblages, separate IBI's were formulated for cool-cold transition (20.7-22.5°C) and cool-warm transition (22.6-24.6°C) streams. The cool-cold transition IBI had five metrics: numbers of darter, madtom, and sculpin species, of coolwater species, and of intolerant species, and the percentages of individuals as tolerant species and as generalist feeders. Scoring criteria differed between northern and southern Wisconsin (boundary at 44.6°N latitude) for the coolwater species metric. The cool-warm transition IBI also had five metrics: numbers of native minnow, of intolerant, and of benthic invertivore species, and percentages of individuals as tolerant species and as omnivores. Scoring criteria differed between small and large streams (boundary at 200 km 2 watershed area) for the intolerant species, benthic invertivore species, and percentage tolerants metrics. In validation tests, scores for both IBI's were significantly related to independent measures of human disturbance, indicating that the IBI's would be useful tools for assessing the environmental quality of coolwater streams. However, for any given level of human disturbance, scores for both IBI's varied substantially, suggesting that multiple IBI samples from multiple sites would be needed to provide a reliable evaluation of a particular stream segment. © 2012 Elsevier Ltd. All rights reserved. Source

Oele D.L.,801 Progress Road | Lawson Z.J.,291 North State House Circle | McIntyre P.B.,University of Wisconsin - Madison
North American Journal of Fisheries Management

Age estimates based on calcified structures are central to the analysis and management of fish populations. A variety of structures have been used in studies of Northern Pike Esox lucius despite limited data on whether the structures provide comparable results. We quantified precision and bias of ages estimated from cleithra, otoliths, anal fin rays, and scales of Northern Pike sampled in tributaries of Green Bay, Lake Michigan. For three independent readers, the precision (CV) of age estimates did not significantly differ among otoliths, cleithra, and anal fin rays but was significantly lower for scales than for the other structures. Similarly, partial agreement among readers was greater than 90% for ages estimated from otoliths, cleithra, and anal fin rays, whereas partial agreement was 76% for scale-based ages. We discuss the tradeoffs associated with precision and bias for each structure in the context of reader experience, fish age, and management goals. We recommend that when fish mortality is not a concern, otoliths or cleithra should be used to achieve high-precision aging of Northern Pike. For strictly nonlethal sampling scenarios, the anal fin rays of Northern Pike will yield more precise age estimates than scales. Received January 20, 2015; accepted September 17, 2015 © 2015, © American Fisheries Society 2015. Source

Meyer M.W.,WDNR Science Services | Rasmussen P.W.,801 Progress Road | Watras C.J.,University of Wisconsin Trout Lake Station | Fevold B.M.,Ecology and Science LLC | Kenow K.P.,U.S. Geological Survey

We assessed the ecological risk of mercury (Hg) in aquatic systems by monitoring common loon (Gavia immer) population dynamics and blood Hg concentrations. We report temporal trends in blood Hg concentrations based on 334 samples collected from adults recaptured in subsequent years (resampled 2-9 times) and from 421 blood samples of chicks collected at lakes resampled 2-8 times 1992-2010. Temporal trends were identified with generalized additive mixed effects models and mixed effects models to account for the potential lack of independence among observations from the same loon or same lake. Trend analyses indicated that Hg concentrations in the blood of Wisconsin loons declined over the period 1992-2000, and increased during 2002-2010, but not to the level observed in the early 1990s. The best fitting linear mixed effects model included separate trends for the two time periods. The estimated trend in Hg concentration among the adult loon population during 1992-2000 was -2.6% per year, and the estimated trend during 2002-2010 was +1.8% per year; chick blood Hg concentrations decreased -6.5% per year during 1992-2000, but increased 1.8% per year during 2002-2010. This bi-phasic pattern is similar to trends observed for concentrations of methylmercury and SO 4 in lake water of an intensely studied seepage lake (Little Rock Lake, Vilas County) within our study area. A cause-effect relationship between these independent trends is hypothesized. © 2011 Springer Science+Business Media, LLC. Source

Wang L.,University of Michigan | Infante D.,Michigan State University | Lyons J.,801 Progress Road | Stewart J.,U.S. Geological Survey | And 2 more authors.
River Research and Applications

Regional assessment of cumulative impacts of dams on riverine fish assemblages provides resource managers essential information for dam operation, potential dam removal, river health assessment and overall ecosystem management. Such an assessment is challenging because characteristics of fish assemblages are not only affected by dams, but also influenced by natural variation and human-induced modification (in addition to dams) in thermal and flow regimes, physicochemical habitats and biological assemblages. This study evaluated the impacts of dams on river fish assemblages in the non-impoundment sections of rivers in the states of Michigan and Wisconsin using multiple fish assemblage indicators and multiple approaches to distinguish the influences of dams from those of other natural and human-induced factors. We found that environmental factors that influence fish assemblages in addition to dams should be incorporated when evaluating regional effects of dams on fish assemblages. Without considering such co-influential factors, the evaluation is inadequate and potentially misleading. The role of dams alone in determining fish assemblages at a regional spatial scale is relatively small (explained less than 20% of variance) compared with the other environmental factors, such as river size, flow and thermal regimes and land uses jointly. However, our results do demonstrate that downstream and upstream dams can substantially modify fish assemblages in the non-impoundment sections of rivers. After excluding river size and land-use influences, our results clearly demonstrate that dams have significant impacts on fish biotic-integrity and habitat-and-social-preference indicators. The influences of the upstream dams, downstream dams, distance to dams, and dam density differ among the fish indicators, which have different implications for maintaining river biotic integrity, protecting biodiversity and managing fisheries. © 2010 John Wiley & Sons, Ltd. Source

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