This chapter examines potential metrics for their correlations with independent measures of the environmental quality of Wisconsin lakes and for their temporal and spatial variability when environmental quality is stable. Fish assemblages reflect the overall integrity of biological communities and are excellent indicators of the environmental quality of aquatic ecosystems. Several types of environmental indices based on fish assemblages have been developed, with the most widely used and most effective based on the Index of Biotic Integrity. The Sparkling Lake data were used to quantify within-year variation in metric values in the absence of significant changes in environmental quality. In Sparkling Lake, inclusion of young-of-year fish in calculations had different effects on species richness as estimated by seining. The proportion of individuals as intolerant species had a stronger correlation with Trophic State lndex (TSI) than the number of intolerant species for both methods; the index sample relation with TSI was stronger than the fyke sample's for this metric as well.

Associations between environmental variables and reproductive condition of six catostomid (family Catostomidae) species were evaluated in the Baraboo River, Wisconsin. Electrofishing and hoop net surveys conducted from Mar. to Jun. of 2001 and 2002 revealed white sucker (Catostomus commersoni) reached spawning condition first, followed by quillback (Carpiodes cyprinus) in both years. These two species were followed by the overlapping spawning times of spotted sucker (Minytrema melanops), golden redhorse (Moxostoma erythrurum), shorthead redhorse (M. macrolepidotum), and silver redhorse (M. anisurum). The first axis of a principal component analysis (PCA; based on six environmental variables) explaining 47% of the variation in the environmental variables represented water temperature, flow, and day of the year. The second axis explaining an additional 26% of variation depicted the magnitude of shorter-term changes in water temperature and flow. The best-fitting multinomial logit model to explain variation in reproductive condition of white sucker, shorthead redhorse, and silver redhorse included the first two PCA axes, species, year, and sex along with several first order interactions as predictor variables. The model predicted general temporal trends in reproductive condition over the spawning season but sampling noise precluded the model from identifying fine-scale temporal variation in spawning. Temporal variation in catostomid reproductive condition appears to be driven by complex interactions among species and environmental cues.

Ten thousand years ago, a tree grew near a lakeshore somewhere in North America. For 140 years or more, fish swam in its shade and insects hatched on its branches and leaves; some were eaten by birds, some fell into the water to be eaten by fish, some survived to continue the cycle of life. Birds nested and foraged in its branches, perhaps kingfishers dropped like rocks, propelled by gravity to their next meal; eagles perched among its highest branches. A wood frog chorus would start each evening in spring near the first crotch, and often red squirrels would chatter for whatever reason red squirrels chatter. Then one day it happened: after years of increasing decay near the end of its life, the tree snapped at the butt during a windstorm, and fell with a thunderous crash into the lake; 140 years of silence and quiet rustling, punctuated by a single quick loud finale. Within a minute, the waves that had acknowledged the tree’s entry into the water subsided, and all was quiet again.

Walleye (Sander vitreus) populations are cyclic because of biotic and abiotic factors, and wind activity, wave energy, and water levels may be influential given walleye spawn close to shore. We installed an anemometer and tridirectional velocimeter on a spawning reef in Big Crooked Lake, Wisconsin, in 2005 to determine wind–wave relationships and wave energy exceedance of critical velocities of both egg (affecting transport) and substrates (affecting abrasion or burial). To evaluate egg movement, we delineated egg locations at adhesive, postspawn, and black-eyed stages and surveyed on-shore for stranded eggs. We monitored water level with a staff gauge. Wind and wave velocities were significantly (p < 0.01) correlated, and wave velocities were significantly higher (p < 0.01) nearshore (2.0 m) than further from shore (4.6 m). Mean nearshore wave velocities were often sufficient to initiate movement of nonadhesive eggs (45% of records) and fine sand (39%) during egg incubation. Surveys indicated waves moved eggs closer to shore and some onto shore. Water level fluctuations (range = 2.4 cm) likely did not strand or desiccate eggs. We documented that wind and wave activity transports eggs and substrates and should be considered a critical factor in annual walleye egg survival and year-class strength.

The native milfoil weevil, Euhrychiopsis lecontei (Dietz), shows potential to be an effective biological control for Eurasian watermilfoil, Myriophyllum spicatum L. To better define shoreland habitat requirements for overwintering success, univariate and multivariate (discriminate analysis) statistical methods were used to identify the habitat variables that best define weevil overwintering habitat at two lakes in Portage County, Wisconsin: Thomas Lake, a glacial seepage lake, and Springville Pond, an impoundment of the Little Plover River. Weevil presence and abundance along the shore were evaluated in relation to the presence of milfoil fragments along shore, distance from shoreline, height above water, habitat type, soil texture, soil and duff moisture, soil and duff organic matter, duff depth, and duff composition. The results suggest that higher elevation sites closer to shore, with more duff material, are associated with weevil presence, and that management activities that remove duff material from the shoreland, such as mowing and raking, may be disadvantatgeous to weevil populations. It was inconclusive whether duff composition was truly correlated with weevil abundance, suggesting that lake residents and lake managers may not need to be concerned about planting specific plant species for weevil habitat.

Summer stream temperatures limit the distribution of Brook Trout Salvelinus fontinalis and are affected by riparian vegetation. We used riparian and instream habitat surveys along with stream temperature loggers placed throughout streams to determine the potential for riparian vegetation shading to increase the length of stream that is thermally suitable for Brook Trout. Twelve streams located throughout central Wisconsin were evaluated in the summers of 2007 and 2008. Across all streams, nonparametric ANCOVA modeling was used to identify spatial temperature patterns within a year for individual stream segments. Riparian tree-vegetated segments had a significantly lower mean change in stream temperature per kilometer of stream compared with grass-vegetated segments during the periods of maximum daily and weekly average temperatures, when we accounted for upstream temperature. Riparian grass-vegetated segments increased on average 1.19 degrees C/km (SE, 0.44) during the maximum daily average temperature period and 0.93 degrees C/km (SE, 0.39) during the maximum weekly average temperature period, whereas tree-vegetated segments decreased 0.48 degrees C/km (SE, 0.39) and 0.30 degrees C/km (SE, 0.25) during those respective time periods. Maximum weekly average temperatures were also modeled with different shading levels using a heat budget temperature model, U.S. Fish and Wildlife Service's Stream Segment Temperature Model. Across 11 study streams (one stream model could not be calibrated), modeled stream temperatures in equilibrium with their environmental conditions ranging from 23.2 degrees C to 28.3 degrees C at 0% shading could be reduced to 18.8-23.5 degrees C with 75% shading. Modeled increases in shade up to 75% from the current average of 34% increased the length of surveyed stream thermally suitable to Brook Trout by 4.9km on Sucker Creek. We conclude that riparian forests are important for maintaining thermal conditions suitable for Brook Trout in central Wisconsin streams and can be managed to increase the amount of stream habitat thermally suitable for Brook Trout.

Life-history theory suggests that delayed maturation is beneficial to birds when costs of breeding early in life are high. We compared selected aspects of the biology of male Cooper's Hawks (Accipiter cooperii) that began breeding at 1 year of age (SY males) vs. males that began breeding >= 2 years of age (ASY males) in an effort to elucidate what renders breeding of SY males rare. Of the 732 males of known age whose breeding we studied over 32 years (1980-2011) 13 (2%) were SY and 719 (98%) were ASY. During this period, the incidence of breeding of SY males changed markedly, as 12 of the instances of breeding of SY males were recorded in the first half of our study, only 1 in the latter half. We suggest that SY males could acquire nest sites more readily in the first half of the study when the breeding population of ASY males was apparently lower. Males breeding in their second year were on average similar in size to ASY males but were molting more extensively than were ASY males. ASY males lived longer than males breeding in their second year, and maximum lifetime production of young was greater, so SY males may have sacrificed greater longevity for breeding early. A strategy of facultative breeding in response to the constraints of higher numbers of older breeding males and restraints of trade-offs in energy allocation may explain why SY male Cooper's Hawks rarely breed.

Cooper's Hawk (Accipiter cooperii) populations breeding in the northern portion of the species' range exhibit variation in morphological traits that conforms to predictions based on differences in prey size, tree stand density, and migratory behavior. We examined genetic structure and gene flow and compared divergence at morphological traits (P-ST) and genetic markers (F-ST) to elucidate mechanisms (selection or genetic drift) that promote morphological diversification among Cooper's Hawk populations. Cooper's Hawks appear to conform to the genetic pattern of an east west divide. Populations in British Columbia are genetically differentiated from north-central populations (Wisconsin, Minnesota, and North Dakota; pairwise microsatellite F-ST = 0.031-0.050; mitochondrial DNA Phi(ST) = 0.177-0.204), which suggests that Cooper's Hawks were restricted to at least two Pleistocene glacial refugia. The strength of the Rocky Mountains Great Plains area as a barrier to dispersal is further supported by restricted gene-flow rates between British Columbia and other sampled breeding populations. Divergence in morphological traits (P-ST) was also observed across study areas, but with British Columbia and North Dakota differentiated from Wisconsin and Minnesota, a pattern not predicted on the basis of F-ST and Phi(ST). interpopulation estimates. Comparison of P-ST and F-ST estimates suggests that heterogeneous selection may be acting on Cooper's Hawks in the northern portion of their distribution, which is consistent with hypotheses that variation in prey mass and migratory behavior among populations may be influencing overall body size and wing chord. We were unable to distinguish between the effects of genetic drift and selection on tail length in the study populations. Received 26 July 2011, accepted 20 March 2012.

Spawning habitat, the cornerstone of self-sustaining, naturally reproducing walleye Sander vitreus populations, has received limited quantitative research. Our goal was to quantitatively describe the structure and quantity of natural walleye spawning habitat and evaluate potential selection of habitat in Big Crooked Lake, Wisconsin. In 2004 and 2005, we located and delineated walleye egg deposition polygons through visual snorkel and scuba surveys. We also delineated recently deposited, adhesive egg patches daily along one spawning reef in 2005. To determine habitat selection, we quantified and compared spawning and lakewide available habitat at different scales. In both years, walleyes used similar spawning habitat, including three geomorphic types: linear shorelines, a point bar, and an island. Walleyes used only 14% of the entire lake shoreline and 39% of the shoreline comprised of gravel (6.4-76.0 mm), cobble (76.1-149.9 mm), or coarser substrates for spawning in 2005, indicating selection of specific spawning habitat. Lakewide, walleyes spawned close to shore (outer egg deposition polygon boundary mean distance = 2.7 m), in shallow water (outer egg deposition polygon boundary mean depth = 0.3 m), and over gravel substrate (percent coverage mean = 64.3) having low embeddedness (mean = 1.30). Our best nearshore (0-13-m) resource selection function predicted an increase in the relative probability of egg deposition with the increasing abundance of gravel, cobble, and rubble (150.0-303.9-mm) substrates and a decrease with increasing distance from shore and water depth (89.9% overall correct classification). Adhesive egg patches confirmed that walleyes actively chose nearshore, shallow-water, and coarse-substrate spawning habitat. The quantitative habitat information and predictive models will assist biologists in developing walleye spawning reef protection strategies and potentially aid in designing and evaluating artificial spawning reefs.

Aquatic macrophyte communities were assessed in 53 lakes in Wisconsin, U.S.A. along environmental and land use development gradients to determine effects human land use perturbations have on aquatic macrophytes at the watershed and riparian development scales. Species richness and relative frequency were surveyed in lakes from two ecoregions: the Northern Lakes and Forests Ecoregion and the Southeastern Wisconsin Till Plain Ecoregion. Lakes were selected along a gradient of watershed development ranging from undeveloped (i.e., forested), to agricultural to urban development. Land uses occurring in the watershed and in perimeters of different width (0–100, 0–200, 0–500, and 0–1000m from shore, in the watershed) were used to assess effects on macrophyte communities. Snorkel and SCUBA were used to survey aquatic macrophyte species in 18 quadrats of 0.25m2 along 14 transects placed perpendicular to shore in each lake. Effects of watershed development (e.g., agriculture and/or urban) were tested at whole-lake (entire littoral zone) and near-shore (within 7m of shore) scales using canonical correspondence analysis (CCA) and linear regression. Overall, species richness was negatively related to watershed development, while frequencies of individual species and groups differed in level of response to different land use perturbations. Effects of land use in the perimeters on macrophytes, with a few exceptions, did not provide higher correlations compared to land use at the watershed scale. In lakes with higher total watershed development levels, introduced species, particularly Myriophyllum spicatum, increased in abundance and native species, especially potamids, isoetids, and floating-leaved plants, declined in abundance. Correlations within the northern and southeastern ecoregions separately were not significant. Multivariate analyses suggested species composition is driven by environmental responses as well as human development pressures. Both water chemistry and land use variables loaded positively with the first CCA axis indicating that these factors are correlated. Land use pressures in Wisconsin are greater in the southeastern portion of the state where lakes have higher concentrations of water chemistry variables including alkalinity, conductivity, pH, calcium, magnesium, and nitrogen. This creates a complex gradient that influences species composition of macrophyte communities from lake to lake.

Few studies at a broad geographical scale have characterized intraspecific variation in morphology of woodland hawks in the genus Accipiter. From 1999 to 2007 we investigated morphological variation in large samples of live Cooper's Hawks (A. cooperii) nesting in four study areas: coniferous woodland around Victoria, British Columbia, Canada, isolated deciduous woodlands in short-grass prairies of northwestern North Dakota, towns and rural deciduous woodlands along the border of North Dakota and Minnesota, and urban and rural mixed deciduous and coniferous landscapes of Wisconsin. These sites span 2660 km across the northern part of the species' breeding range. We measured body mass (i.e., size), wing chord, tail length, tarsus diameter, hallux length, and culmen length of breeding adults, finding significant and clinal variation in body mass (or size). The smallest and most similar-sized birds occurred in British Columbia and western North Dakota, larger birds along the border between North Dakota and Minnesota, and the largest birds in Wisconsin. Several other characters varied significantly when mass was used as a covariate. Variation by study site in mean indices of sexual size dimorphism was negligible and not significant. We speculate that the morphological differences we found, in part, are the result of geographic isolation, where diets, migratory behavior, and structural characteristics of nesting habitats vary across landscape types.

Nocturnal migration is accompanied by sleep loss likely dependent upon the length of the migratory flight. Migrants may minimize the effect of sleep deficit by inserting brief naps into their daytime

There are few published data on annual survival and no reports of lifetime reproduction for breeding Cooper's Hawks (Accipiter cooperii). Breeding males (n = 105) in central and southeastern Wisconsin had an annual mortality rate of 19%, or a survival rate of 81% for birds <= 10 years of age. We did not detect significant differences in mortality rates between urban and rural habitats, nor between the earlier 13 years and later 13 years of this study. Male Cooper's Hawks produced from zero to 32 nestlings during their lifetimes. Body mass or size appeared unrelated to annual survivorship and lifetime reproduction, although lifetime reproduction was correlated strongly with longevity of breeding males. Fifteen of 66 males (23%) produced most (53%) of the nestlings. Our studies occurred in an area where breeding populations may be increasing with some of the highest reported productivity indices and nesting densities for this species. Habitat used for nesting on our Wisconsin study areas may be less important for survivorship and lifetime reproduction than acquisition of a nesting area in which a male will breed throughout his life.

We developed analysis of covariance (ANCOVA) models to predict fish species richness as a function of two simple landscape-scale, binary variables (surface water connectivity to other aquatic systems and human riparian development), with lake surface area as the covariate. All three variables were significantly related to species richness and explained 61% of the variance in a data set from 55 limnologically similar lakes in northern Wisconsin. We developed additional ANCOVA models to assess the relative effects of these three variables on four functional species groups, including gamefish, riverine, tolerant, and intolerant species. The number of gamefish species was greater in lakes with riparian development than in undeveloped lakes; this is probably related to introductions by management agencies and anglers. Connectivity increased the number of riverine species and intolerant species. Intolerant species may be more abundant because connecting streams provide colonization routes and decrease time between periodic extirpation and recolonization events. In addition, flowing water connections may provide a refuge from winter hypoxia and decrease extirpation rates of intolerant A species. Tolerant fishes were ubiquitous on the landscape and unaffected by the measured variables. Because simple landscape variables can dominate assemblage dynamics of small takes, and human-mediated introductions can increase species richness at low and moderate levels of disturbance, the use of fish as biological indicators for small lake assessment is not practical.

Trichomoniasis is a digestive tract disease caused by ingestion of the protozoan Trichomonas gallinae. This disease can be a significant source of mortality. No deaths of nestlings could be attributed to trichomoniasis in Cooper's Hawks (Accipiter cooperii) breeding in urban and rural environs in Wisconsin, North Dakota, and British Columbia. We detected T. gallinae in four (5.2%) of 77 nestling Cooper's Hawks during 2006 and 2007 among 42 urban nests on new study areas in southeast Wisconsin and eastern North Dakota/western Minnesota. All four infected young fledged. We did not detect T. gallinae in 52 breeding adult Cooper's Hawks on two urban study sites, nor in 28 migrant hatching year (it = 24) and adult (n = 4) Cooper's Hawks at Hawk Ridge Bird Observatory, Duluth, Minnesota in 2006-2007. Overall, we detected T. gallinae in only 2.5% of 157 Cooper's Hawks in northcentral North America. These results suggest a low prevalence of T. gallinae in Cooper's Hawks in the northern part of this hawk's breeding range.

We compared benthic macroinvertebrate assemblage structure at snag and riffle habitats in 43 Wisconsin streams across a range of watershed urbanization using a variety of stream quality metrics. Discriminant analysis indicated that dominant taxa at riffles and snags differed; Hydropsychid caddisflies (Hydropsyche betteni and Cheumatopsyche spp.) and elmid beetles (Optioservus spp. and Stenemlis spp.) typified riffles, whereas isopods (Asellus intermedius) and amphipods (Hyalella azteca and Gammarus pseudolimnaeus) predominated in snags. Analysis of covariance indicated that samples from snag and riffle habitats differed significantly in their response to the urbanization gradient for the Hilsenhoff biotic index (BI), Shannon's diversity index, and percent of filterers, shredders, and pollution intolerant Ephemeroptera, Plecoptera, and Trichoptera (EPT) at each stream site (p <= 0.10). These differences suggest that although macroinvertebrate assemblages present in either habitat type are sensitive to detecting the effects of urbanization, metrics derived from different habitats should not be intermixed when assessing stream quality through biomonitoring. This can be a limitation to resource managers who wish to compare water quality among streams where the same habitat type is not available at all stream locations, or where a specific habitat type (i.e., a riffle) is required to determine a metric value (i.e., BI). To account for differences in stream quality at sites lacking riffle habitat, snag-derived metric values can be adjusted based on those obtained from riffles that have been exposed to the same level of urbanization. Comparison of nonlinear regression equations that related stream quality metric values from the two habitat types to percent watershed urbanization indicated that snag habitats had on average 30.2 fewer percent EPT individuals, a lower diversity index value than riffles, and a BI value of 0.29 greater than riffles.

The ability to age individual birds visually in the field based on plumage variation could provide important demographic and biogeographical information. We describe an approach to infer ages from a distribution of plumage scores of free-ranging male Kirtland's Warblers (Dendroica kirtlandii). We assigned ages to males using a scoring scheme (0-12 points) based on variation in plumage coloration, brightness, and contrast on three dorsal and three ventral body regions presumed to be age-related. The distribution of total additive plumage scores for 875 breeding males was normally distributed, indicating no distinct age classes. Thus, we developed provisional plumage-age classes of second year (SY) and after second-year (ASY), and compared them to the total plumage scores of a smaller subsample of known age (N = 92) and minimum age (N = 143) males. Plumage scores of known-age male Kirtland's Warblers increased nonlinearly with age (r(s) = 0.67), but with some overlap. The median plumage score for SY males (median = 5.0) was significantly lower than for third-year (TY) males (median = 7.0) and after third-year (3 year and older) males (median = 8.0), indicating that the plumage of male Kirtland's Warblers becomes more distinctive and brighter with age. Linear discriminant function analysis differentiated ASY male Kirtland's Warbler from SY males with 78.3% accuracy. Investigators could use the distribution of plumage scores and approximate age structures to document changes in male age structure during colonization, use, and abandonment of habitats by Kirtland's Warblers or other species that occupy early successional habitats. Aging free-ranging birds based on a plumage scoring scheme may be especially critical for demographic studies of less-studied species where it is unlikely that a banding program will be initiated, but where plumage-age inferences or management decisions must be made.