Madison, WI, United States
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Clare J.D.J.,University of Wisconsin - Stevens Point | Clare J.D.J.,University of Maine, United States | Anderson E.M.,University of Wisconsin - Stevens Point | MacFarland D.M.,Bureau of Wildlife Management | Sloss B.L.,University of Wisconsin - Stevens Point
Wildlife Society Bulletin | Year: 2015

Determining cost-effective field methods for detecting carnivores is critical for effective survey and monitoring studies. As the bobcat (Lynx rufus) undergoes range expansion in the northern and eastern United States, field methods may be useful for informing revisions in population management. We paired 2 scat detection-dog teams and 16 remote cameras at 4 survey sites within central Wisconsin, during summer 2011, and compared detection totals, detection probabilities, and costs between methods. Laboratory expenditures are an additional cost for scat collection, and we modeled the probability that a collected scat was genetically confirmed as bobcat as a function of dog, handler, site, and the strength of the dog's behavior. We estimated that detection-dog surveys required only 2 days to achieve a 90% probability of detecting a bobcat in a 4-km2 area, while a single camera station would require 7-8 weeks. But a month of detection-dog surveys cost 33% more than a 4-month camera survey, with projected cost differences increasing annually. There were dog-specific differences in collection rate, and the probability that a collected scat was genetically confirmed as bobcat was best predicted by the individual dog associated with collection and the survey area, rather than the handler or the dog's observed response. We recommend cameras as a generally more cost-efficient bobcat survey method, and we advise against relying on the strength of an individual dog's response as a means of screening samples for genetic analysis. However, the most appropriate survey method is likely to be goal-dependent, and we recommend that detection-dog contractors both advertise and match the strengths and weaknesses of specific dogs with the needs of clientele. © The Wildlife Society, 2014.


Rutkiewicz J.,University of Michigan | Nam D.-H.,University of Michigan | Cooley T.,Wildlife Disease Laboratory | Neumann K.,Saving Our Avian Resources | And 4 more authors.
Ecotoxicology | Year: 2011

In this study, we assessed mercury (Hg) exposure in several tissues (brain, liver, and breast and primary feathers) in bald eagles (Haliaeetus leucocephalus) collected from across five Great Lakes states (Iowa, Michigan, Minnesota, Ohio, and Wisconsin) between 2002-2010, and assessed relationships between brain Hg and neurochemical receptors (NMDA and GABA A) and enzymes (glutamine synthetase (GS) and glutamic acid decarboxylase (GAD)). Brain total Hg (THg) levels (dry weight basis) averaged 2.80 μg/g (range: 0.2-34.01), and levels were highest in Michigan birds. THg levels in liver (r p = 0.805) and breast feathers (r p = 0.611) significantly correlated with those in brain. Brain Hg was not associated with binding to the GABA A receptor. Brain THg and inorganic Hg (IHg) were significantly positively correlated with GS activity (THg r p = 0.190; IHg r p = 0.188) and negatively correlated with NMDA receptor levels (THg r p = -0245; IHg r p = -0.282), and IHg was negatively correlated with GAD activity (r s = -0.196). We also report upon Hg demethylation and relationships between Hg and Se in brain and liver. These results suggest that bald eagles in the Great Lakes region are exposed to Hg at levels capable of causing subclinical neurological damage, and that when tissue burdens are related to proposed avian thresholds approximately 14-27% of eagles studied here may be at risk. © 2011 Springer Science+Business Media, LLC.


Glisson W.J.,Plant Science and Conservation | Glisson W.J.,University of Idaho | Brady R.S.,Bureau of Wildlife Management | Paulios A.T.,Bureau of Wildlife Management | And 2 more authors.
Journal of Wildlife Management | Year: 2015

Wetland loss, biological invasions, and ecological restoration are major factors altering wetland resources in the Midwestern United States. Large-scale plant-community change associated with these factors is an under-investigated, potentially strong driver of habitat suitability for wetland-dependent wildlife, such as secretive marsh birds (SMBs), which are of widespread conservation concern. We employed multi-year, hierarchical Bayesian occupancy modeling to investigate sensitivity of 3 SMB species (American bittern, sora, and Virginia rail) to habitat and vegetation characteristics in Wisconsin, USA. We contrasted habitat characteristics and SMB occupancy in natural wetlands with those restored under the federally funded Wetlands Reserve Program (WRP). We also examined the extent to which SMB occupancy was explained by 3 levels of habitat assessment that encompassed different spatial scales and levels of sampling effort (landscape, rapid, and intensive). All species were significantly associated with variables derived from intensive assessment, and showed high sensitivity to differences in plant-community composition and vegetation quality. Both American bittern and Virginia rail were negatively associated with abundance of the invasive wetland grass, Phalaris arundinacea (reed canarygrass), and were positively associated with an indicator of plant-community quality (mean coefficient of conservatism, or C-value). Sora occupancy was positively associated with Typha (cattail) abundance. For all 3 species, occupancy was greater in natural sites than in restored sites, which were characterized by greater Phalaris abundance and lower mean C-values. Our results show broad agreement between botanical and avian indicators of wetland quality, suggesting that enhancing the condition of wetland vegetation can yield ancillary benefits for SMBs. In this region, efforts to control Phalaris and restore diverse, native-dominated plant communities are likely to increase wetlands' capacity to support SMBs. © 2015 The Wildlife Society.


Bolenbaugh J.R.,University of Arkansas | Cooper T.,U.S. Fish and Wildlife Service | Brady R.S.,Bureau of Wildlife Management | Willard K.L.,University of Arkansas | Krementz D.G.,University of Arkansas
Waterbirds | Year: 2012

The migratory population of the King Rail (Rallus elegans) has declined dramatically during the past 50 years, emphasizing the need to document the distribution and status of this species to help guide conservation efforts. In an effort to guide King Rail breeding habitat protection and restoration, a landscape suitability index (LSI) model was developed for the Upper Mississippi River and Great Lakes Region Joint Venture (JV). To validate this model, 264 sites were surveyed across the JV region in 2008 and 2009 using the National Marshbird Monitoring protocol. Two other similarly collected data sets from Wisconsin (250 sites) and Ohio (259 sites) as well as data from the Cornell Laboratory of Ornithology's eBird database were added to our data set. Sampling effort was not uniform across the study area. King Rails were detected at 29 sites with the greatest concentration in southeastern Wisconsin and northeastern Illinois. Too few detections were made to validate the LSI model. King Rail detection sites tended to have microtopographic heterogeneity, more emergent herbaceous wetland vegetation and less woody vegetation. The migrant population of the King Rail is rare and warrants additional conservation efforts to achieve stated conservation population targets.


PubMed | University of Michigan, Michigan State University, Bureau of Wildlife Management, Wildlife Disease Laboratory and McGill University
Type: Journal Article | Journal: Journal of Great Lakes research | Year: 2015

Polybrominated diphenyl ethers (PBDEs) are persistent and toxic flame-retardant chemicals widespread in the Great Lakes ecosystem. These chemicals are now being regulated and phased-out of the region; therefore it remains important to understand the extent of contamination in order to track the efficacy of recent actions. Here,


Graves B.M.,Ohio State University | Rodewald A.D.,Ohio State University | Hull S.D.,Bureau of Wildlife Management
Wilson Journal of Ornithology | Year: 2010

We examined the influence of woody vegetation on reclaimed surface mines on relative abundance of Grasshopper Sparrows (Ammodramus savannarum), Henslow's Sparrows (A. henslowii), Eastern Meadowlarks (Sturnella magna), Savannah Sparrows (Passerculus sandwichensis), Bobolinks (Dolichonyx oryzivorus), and Dickcissels (Spiza americana) as well as nest-site selection and nesting success of Grasshopper and Henslow's sparrows and Eastern Meadowlarks. Grasshopper and Henslow's sparrows were the most abundant grassland species on reclaimed mines. Numbers of Grasshopper, Henslow's, and Savannah sparrows, and Bobolinks were negatively associated with percent cover of woody vegetation within 100 m of survey locations. Only Grasshopper Sparrows responded to woody vegetation at nest-patch scales, as random locations had >2.5 times as much woody cover as nest locations. Daily nest survival (DNS) was negatively associated with amount of woody vegetation within 100 m of Grasshopper (DNS 0.76 ± 0.001 SE) and Henslow's sparrow nests (DNS 0.94 ± 0.020 SE), but only marginally negatively related to daily nest survival of Eastern Meadowlark nests (DNS 0.87 ± 0.006 SE). Avoidance of woody vegetation by grassland birds and the comparatively lower daily nest survival of Grasshopper and Henslow's sparrow nests near woody vegetation suggests managers of reclaimed surface mines who manage to conserve grassland birds should direct efforts towards reducing woody encroachment. © 2010 by the Wilson Ornithological Society.


Dornbos P.,University of Michigan | Strom S.,Bureau of Wildlife Management | Basu N.,University of Michigan
Ecotoxicology | Year: 2013

River otters are fish-eating wildlife that bioaccumulate high levels of mercury (Hg). Mercury is a proven neurotoxicant to mammalian wildlife, but little is known about the underlying, sub-clinical effects. Here, the overall goal was to increase understanding of Hg's neurological risk to otters. First, Hg values across several brain regions and tissues were characterized. Second, in three brain regions with known sensitivity to Hg (brainstem, cerebellum, and occipital cortex), potential associations among Hg levels and neurochemical biomarkers [N-methyl-d-aspartic acid (NMDA) and gamma-aminobutyric acid (GABAA) receptor] were explored. There were no significant differences in Hg levels across eight brain regions (rank order, highest to lowest: frontal cortex, cerebellum, temporal cortex, occipital cortex, parietal cortex, basal ganglia, brainstem, and thalamus), with mean values ranging from 0.7 to 1.3 ug/g dry weight. These brain levels were significantly lower than mean values in the muscle (2.1 ± 1.4 ug/g), liver (4.7 ± 4.3 ug/g), and fur (8.8 ± 4.8 ug/g). While a significant association was found between Hg and NMDA receptor levels in the brain stem (P = 0.028, r p = -0.293), no relationships were found in the cerebellum and occipital cortex. For the GABA receptor, no relationships were found. The lack of consistent Hg-associated neurochemical changes is likely due to low brain Hg levels in these river otters, which are amongst the lowest reported. © 2013 Springer Science+Business Media New York.


Clare J.D.J.,University of Wisconsin - Stevens Point | Anderson E.M.,University of Wisconsin - Stevens Point | MacFarland D.M.,Bureau of Wildlife Management
Journal of Wildlife Management | Year: 2015

The abundance of low-density species like carnivores is logistically difficult to directly estimate at a meaningful scale. Predictive distribution models are often used as a surrogate for density estimation. But because density can continue to increase as occupancy asymptotes at 1, occupancy may have little value as an index, and home range expansion in marginal habitat may further confound the association. We sought to estimate bobcat population size at a landscape scale (14,286 km2) in central Wisconsin, which provided an opportunity to relate predicted occurrence to individual space use and population density. We sampled bobcats using motion-sensitive trail cameras at 9 arrays across central Wisconsin. We estimated bobcat site-specific occupancy, and regressed these estimates as linear or asymptotic functions of site-specific density to determine the strength and shape of their association. We subsequently modeled both parameters relative to habitat covariates and repeated the regression process. A linear functional relationship between density and occupancy was most supported when detection parameters were held constant (wi=0.97, R2=0.72) and when detection, occurrence, and density were modeled as a function of habitat covariates (wi=0.99, R2=0.95). This suggests that repeated presence-absence data alone may be an efficient and reliable method for inferring spatial patterns in bobcat density or identifying habitat types with greater density potential in the northern parts of its range. Bobcat occupancy and density were both positively associated with surrounding woody cover and wetland edge density. Our most supported spatially explicit capture-recapture model estimated bobcat abundance as 362 adult individuals (95% CI 272-490) across the study area. © 2015 The Wildlife Society.


Strom S.M.,Bureau of Wildlife Management | Brady R.S.,Bureau of Wildlife Management
Ecotoxicology | Year: 2011

Wetlands play a major role in the export of methylmercury (MeHg) to a watershed. The large contribution of wetlands to watersheds in northern Wisconsin, coupled with the acidic environment of this area, makes these habitats especially vulnerable to mercury (Hg) accumulation by biota. The purpose of this study was to compare Hg accumulation between northern Wisconsin wetlands and southern Wisconsin wetlands using the swamp sparrow (Melospiza georgiana) as a representative species. The swamp sparrow was selected as a representative passerine species in which to examine Hg in these habitats, because during their breeding season, they feed at a higher trophic level than many of their counterparts. During the breeding seasons of 2007 and 2008, blood samples were collected from swamp sparrows inhabiting wetlands in both northern and southern Wisconsin and analyzed for total Hg. The mean concentration of total Hg in swamp sparrows from northern wetlands was 0.135 ± 0.064 μg/ml while the mean concentration of total Hg in swamp sparrows from southern wetlands was 0.187 ± 0.106 μg/ml. Results revealed no significant difference (P = 0.17) between Hg accumulation in swamp sparrows from less-acidic wetlands in southern Wisconsin and Hg in swamp sparrows from acidic wetlands in northern Wisconsin. The results are contrary to those observed in other species such as common loon, tree swallow and river otter where higher accumulation has been observed in individuals from acidic habitats. Reasons for the lack of this accumulation pattern in swamp sparrows are unclear and warrant further study. © 2011 Springer Science+Business Media, LLC.


PubMed | Bureau of Wildlife Management
Type: Comparative Study | Journal: Ecotoxicology (London, England) | Year: 2011

Wetlands play a major role in the export of methylmercury (MeHg) to a watershed. The large contribution of wetlands to watersheds in northern Wisconsin, coupled with the acidic environment of this area, makes these habitats especially vulnerable to mercury (Hg) accumulation by biota. The purpose of this study was to compare Hg accumulation between northern Wisconsin wetlands and southern Wisconsin wetlands using the swamp sparrow (Melospiza georgiana) as a representative species. The swamp sparrow was selected as a representative passerine species in which to examine Hg in these habitats, because during their breeding season, they feed at a higher trophic level than many of their counterparts. During the breeding seasons of 2007 and 2008, blood samples were collected from swamp sparrows inhabiting wetlands in both northern and southern Wisconsin and analyzed for total Hg. The mean concentration of total Hg in swamp sparrows from northern wetlands was 0.135 0.064 g/ml while the mean concentration of total Hg in swamp sparrows from southern wetlands was 0.187 0.106 g/ml. Results revealed no significant difference (P = 0.17) between Hg accumulation in swamp sparrows from less-acidic wetlands in southern Wisconsin and Hg in swamp sparrows from acidic wetlands in northern Wisconsin. The results are contrary to those observed in other species such as common loon, tree swallow and river otter where higher accumulation has been observed in individuals from acidic habitats. Reasons for the lack of this accumulation pattern in swamp sparrows are unclear and warrant further study.

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