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USGS2003

Use of North American Breeding Bird Survey data to estimate population change for bird conservation regions

Conservation planning requires information at a variety of geographic scales, and it is often unclear whether surveys designed for other purposes will provide appropriate information for management at various scales. We evaluated the use of the North American Breeding Bird Survey (BBS) to meet information needs for conservation planning in Bird Conservation Regions (BCRs). The BBS originally was developed to provide regional estimates for states, provinces, physiographic regions, and larger areas. Many analyses have used physiographic regions within states/provinces as strata. We evaluated potential consequences of using BCRs instead of the BBS physiographic regions, testing for spatial differences in sample intensity within states and provinces. We reclassified the BBS survey routes to BCRs and conducted route regression trend (interval-specific population change) analyses for a variety of regions and time intervals. Our results were similar to those based on traditional BBS regions and suggest minimal consequences of the reclassification for the BBS sample. We summarized population change within BCRs and assessed the efficiency of the BBS in estimating population change for 421 species surveyed. As would be expected from an omnibus survey, many species appeared to be poorly monitored by the BBS, with 42% of species encountered at <1 bird per route from the survey, and 28% of trend estimates too imprecise to detect a 3% per year change over 35 years. Our results indicated that the quality of the survey for estimation of population change varied among BCRs. Population trends of species were heterogeneous over space and time, varying among BCRs for 76% of species and over time for 39% of species. Regional heterogeneity also existed in trends of species groups from the BBS. While 49% of all species in the survey had increasing populations, grassland breeding birds showed consistent declines, with only 18% of species having positive trend estimates. Bird Conservation Regions appear to provide reasonable strata for summary of BBS data.

Journal of Wildlife Management↗

USGS2018

Managing conflicts in the River of Grass

Chances are, you would not pack up and move to a new home without first researching the neighborhood, reviewing your finances, and maybe investigating schools nearby. Similarly, you would not buy the first car you find on a magazine cover without first reviewing the technical specifications, exploring your options, and perhaps taking a test drive. Even when making simple purchases online, you probably shop around, check out customer reviews, and scan seller feedback ratings. Rarely do we act on impulse alone when faced with decisions. Rather, we typically start with a vision of what we want before gathering the necessary information, weighing our options, prioritizing our values, and evaluating possible tradeoffs. In making choices that range from lighthearted to life-changing, we use this commonsense strategy every day of our lives. Environmental decision-making is no different. For decades, natural resource managers faced with complicated problems have made decisions by breaking them into smaller components that are easier to approach. And like our day-to day decisions, the process is ideally guided by a shared vision of the future. However, it can become complicated when multiple, seemingly disparate views on what the future should hold emerge. As Lewis Carroll once wrote, “If you don’t know where you are going, any road will get you there.” Divining a vision of the future for the Florida Everglades and making supporting decisions is a complex undertaking. But unlike Alice thrust through the looking glass, we have tools and techniques to help us make sense of it all. The application of tools to help decision-making can move us closer to the successful restoration of this imperiled landscape.

Florida↗

USGS2013

Evaluation of a new model of aeolian transport in the presence of vegetation

Aeolian transport is an important characteristic of many arid and semiarid regions worldwide that affects dust emission and ecosystem processes. The purpose of this paper is to evaluate a recent model of aeolian transport in the presence of vegetation. This approach differs from previous models by accounting for how vegetation affects the distribution of shear velocity on the surface rather than merely calculating the average effect of vegetation on surface shear velocity or simply using empirical relationships. Vegetation, soil, and meteorological data at 65 field sites with measurements of horizontal aeolian flux were collected from the Western United States. Measured fluxes were tested against modeled values to evaluate model performance, to obtain a set of optimum model parameters, and to estimate the uncertainty in these parameters. The same field data were used to model horizontal aeolian flux using three other schemes. Our results show that the model can predict horizontal aeolian flux with an approximate relative error of 2.1 and that further empirical corrections can reduce the approximate relative error to 1.0. The level of error is within what would be expected given uncertainties in threshold shear velocity and wind speed at our sites. The model outperforms the alternative schemes both in terms of approximate relative error and the number of sites at which threshold shear velocity was exceeded. These results lend support to an understanding of the physics of aeolian transport in which (1) vegetation's impact on transport is dependent upon the distribution of vegetation rather than merely its average lateral cover and (2) vegetation impacts surface shear stress locally by depressing it in the immediate lee of plants rather than by changing the bulk surface's threshold shear velocity. Our results also suggest that threshold shear velocity is exceeded more than might be estimated by single measurements of threshold shear stress and roughness length commonly associated with vegetated surfaces, highlighting the variation of threshold shear velocity with space and time in real landscapes.

Journal of Geophysical Research F: Earth Surface↗

USGS2018

Stable pack abundance and distribution in a harvested wolf population

Harvesting gray wolves ( Canis lupus ) could affect the abundance and distribution of packs, but the frequency of change in pack occurrence (i.e., turnover) and relative effects of harvest compared to environmental factors is unclear. We used noninvasive genetic sampling, hunter surveys, and occupancy models to evaluate the effect of harvest on occurrence and turnover of packs in a population of wolves managed with intensive harvest in the Canadian Rocky Mountains, 2012–2014. We tested 2 alternative hypotheses: the abundance and distribution of wolf packs were dynamic because of harvest or the abundance and distribution of wolf packs were generally stable regardless of harvest. We found the mean annual probability for wolf pack occupancy ranged 0.72–0.74 and the estimated distribution of wolf packs was consistent over time, 2012–2014. Our top model indicated wolf pack occupancy was positively associated with forest cover and the probability of detecting a wolf pack was positively associated with the intensity of harvest for wolves in that area. We observed frequent turnover of individuals within packs that were genetically sampled consecutive years but not of entire packs. Because turnover of packs occurred infrequently during our study, we could not reject our hypothesis that occurrence of packs was generally stable in a harvested population of wolves. Our results suggest environmental factors have a stronger effect than harvest on the abundance and distribution of wolf packs in southwestern Alberta, but harvest appears to strongly influence turnover of individuals within packs. We hypothesize local dispersal from within the study area and neighboring packs on the periphery of the study area helped promote pack stability. © 2018 The Wildlife Society.

Alberta↗

USGS2024

Acute toxicity of lampricides to non-target species of concern in the Lake Champlain watershed

Previous research evaluated the toxicity of the lampricide 4-nitro-3-(trifluoromethyl)phenol (TFM) and the combination of TFM with 1 % niclosamide (TFM:1%Nic) to multiple non-target species in the Laurentian Great Lakes. However, few toxicity studies have been conducted for species of concern in Lake Champlain (NY and VT). We conducted 12-hour flow-through toxicity tests with 4 species of native mussels, 6 species of fish, and 1 amphibian species. All tests included exposure of invasive larval Petromyzon marinus (sea lamprey) and were conducted with concentrations that bracketed the predicted minimum lethal concentration required to control larval sea lamprey. Mussel species’ NOEC, LOEC, LC 25 , and LC 50 values ranged from 1.33 to 2.12, 1.71–2.66, 1.75–3.05, and 2.03–4.84 times field determined LC 99.9 s for sea lamprey (×SL LC99.9 ) in TFM-only toxicity tests, and from 1.36 to 1.70, 1.68–2.03, 1.86–2.10, and 2.35–2.68 × SL LC99.9 for TFM:1%Nic toxicity tests, respectively. Fish species NOEC, LOEC, LC 25 , and LC 50 values ranged from 0.60 to 1.89, 0.73–2.13, 0.72–2.11, and 0.76–2.18 × SL LC99.9 in TFM-only toxicity tests, and from 0.64 to 2.48, 0.85–3.10, 0.74–3.05, and 0.78–3.16 × SL LC99.9 for TFM:1%Nic toxicity tests, respectively. Amphibian species NOEC, LOEC, LC 25 , and LC 50 values ranged from 0.74 to 0.75, 0.85–0.95, 0.83–0.87, and 0.85–0.91 × SL LC99.9 in TFM-only toxicity tests, and from 0.63 to 0.65, 0.80–0.88, 0.77–0.82, and 0.78–0.87 × SL LC99.9 for TFM:1%Nic toxicity tests, respectively. Generally, mussel species were tolerant, fish sensitivities were variable, and the amphibian species was sensitive to TFM and TFM:1%Nic.

New York, Vermont↗

USGS2012

Evaluating changes in matrix based, recovery-adjusted concentrations in paired data for pesticides in groundwater

Pesticide concentration data for waters from selected carbonate-rock aquifers in agricultural areas of Pennsylvania were collected in 1993–2009 for occurrence and distribution assessments. A set of 30 wells was visited once in 1993–1995 and again in 2008–2009 to assess concentration changes. The data include censored matched pairs (nondetections of a compound in one or both samples of a pair). A potentially improved approach for assessing concentration changes is presented where (i) concentrations are adjusted with models of matrix-spike recovery and (ii) area-wide temporal change is tested by use of the paired Prentice-Wilcoxon (PPW) statistical test. The PPW results for atrazine, simazine, metolachlor, prometon, and an atrazine degradate, deethylatrazine (DEA), are compared using recovery-adjusted and unadjusted concentrations. Results for adjusted compared with unadjusted concentrations in 2008–2009 compared with 1993–1995 were similar for atrazine and simazine (significant decrease; 95% confidence level) and metolachlor (no change) but differed for DEA (adjusted, decrease; unadjusted, increase) and prometon (adjusted, decrease; unadjusted, no change). The PPW results were different on recovery-adjusted compared with unadjusted concentrations. Not accounting for variability in recovery can mask a true change, misidentify a change when no true change exists, or assign a direction opposite of the true change in concentration that resulted from matrix influences on extraction and laboratory method performance. However, matrix-based models of recovery derived from a laboratory performance dataset from multiple studies for national assessment, as used herein, rather than time- and study-specific recoveries may introduce uncertainty in recovery adjustments for individual samples that should be considered in assessing change.

Pennsylvania↗

USGS2011

Quantile equivalence to evaluate compliance with habitat management objectives

Equivalence estimated with linear quantile regression was used to evaluate compliance with habitat management objectives at Arapaho National Wildlife Refuge based on monitoring data collected in upland (5,781 ha; n = 511 transects) and riparian and meadow (2,856 ha, n = 389 transects) habitats from 2005 to 2008. Quantiles were used because the management objectives specified proportions of the habitat area that needed to comply with vegetation criteria. The linear model was used to obtain estimates that were averaged across 4 y. The equivalence testing framework allowed us to interpret confidence intervals for estimated proportions with respect to intervals of vegetative criteria (equivalence regions) in either a liberal, benefit-of-doubt or conservative, fail-safe approach associated with minimizing alternative risks. Simple Boolean conditional arguments were used to combine the quantile equivalence results for individual vegetation components into a joint statement for the multivariable management objectives. For example, management objective 2A required at least 809 ha of upland habitat with a shrub composition ≥0.70 sagebrush ( Artemisia spp.), 20–30% canopy cover of sagebrush ≥25 cm in height, ≥20% canopy cover of grasses, and ≥10% canopy cover of forbs on average over 4 y. Shrub composition and canopy cover of grass each were readily met on >3,000 ha under either conservative or liberal interpretations of sampling variability. However, there were only 809–1,214 ha (conservative to liberal) with ≥10% forb canopy cover and 405–1,098 ha with 20–30% canopy cover of sagebrush ≥25 cm in height. Only 91–180 ha of uplands simultaneously met criteria for all four components, primarily because canopy cover of sagebrush and forbs was inversely related when considered at the spatial scale (30 m) of a sample transect. We demonstrate how the quantile equivalence analyses also can help refine the numerical specification of habitat objectives and explore specification of spatial scales for objectives with respect to sampling scales used to evaluate those objectives.

Colorado↗

USGS2013

Using the KINEROS2 modeling framework to evaluate the increase in storm runoff from residential development in a semi-arid environment

The increase in runoff from urbanization is well known; one extreme example comes from a 13 hectare residential neighborhood in southeast Arizona where runoff was 27 times greater than an adjacent grassland watershed over a forty‐month period from 2005 to 2008. Rainfall‐runoff modeling using the newly‐described KINEROS2 urban element and tension infiltrometer measurements indicate that 17±14 percent of this increase in runoff is due to a 53 percent decrease in the saturated hydraulic conductivity of constructed pervious areas, as compared to the undeveloped grassland. Directly connected impervious areas, primarily streets and driveways, cause 56 percent of the increase in runoff, and indirectly connected impervious areas, primarily rooftops and sidewalks, and a decrease in canopy interception account for the remaining 27 percent increase. Tension infiltrometer measurements show that saturated hydraulic conductivity (K s ) is about double in the grassland watershed than in the urban watershed, 6.2 ± 3.5mm/hr and 2.9 ± 1.6mm/hr, respectively. K s in the urban watershed identified from calibrating the rainfall‐runoff model to measured runoff is 9.5 ± 2.8 mm/hr—higher than what was measured but much lower than the 26 mm/hr value indicated by a soil‐texture based KINEROS2 parameter look‐up table. A new component of the KINEROS2 modeling framework, the urban element, forms the basis for the model by simulating a contiguous row of houses and the adjoining street as a series of pervious and impervious overland flow planes. Tests using different levels of discretization found that watershed geometry can be represented in a simplified manner, although more detailed discretization led to better model performance.

Arizona↗

USGS1998

In-situ alteration of minerals by acidic ground water resulting from mining activities: Preliminary evaluation of method

The chemical composition of the Cu-mining-related acidic ground water (pH ∼ 3.5 to near neutral) in Pinal Creek Basin, Arizona has been monitored since 1980. In-situ experiments are planned using alluvial sediments placed in the ground-water flow path to measure changes in mineral and chemical composition and changes in dissolution rates of subsurface alluvial sediments. The test results should help refine developed models of predicted chemical changes in ground-water composition and models of streamflow. For the preliminary test, sediment from the depth of the well screen of a newly drilled well was installed in three wells, the source well (pH 4.96) and two up-gradient wells (pHs 4.27 and 4.00). The sediment was placed in woven macrofilters, fastened in series to polyvinyl chloride (PVC) pipes, and hung at the screened level of each well. After interacting with the slowly moving ground water for 48 days, the test sediments were removed for analysis. There was no evidence that any of the materials used were biologically or chemically degraded or that the porosity of the filters was diminished by ferric hydroxide precipitation. These materials included 21-μm-pore (21PEMF) and 67-μm-pore polyester and the 174-μm-pore fluorocarbon Spectra/mesh macrofilters containing the in-situ sediment, the polypropylene (PP) macrofilter support structures, and the Nylon (NY) monofilament line used to attach the samples to the PVC pipe. Based on chemical and mineral composition and on particle-size distribution of the sediment before and after ground-water exposure, the 21PEMF macrofilter was chosen as the most suitable macrofilter for the long-term in-situ experiment. Tests also showed that the PP support structures and the NY monofilament line were sufficiently durable for this experiment.

Arizona↗

USGS2025

Exploring management and environment effects on edge-of-field phosphorus losses with linear mixed models

Evaluating how weather, farm management, and soil conditions impact phosphorus (P) loss from agricultural sites is essential for improving our waterways in agricultural watersheds. In this study, rainfall characteristics, manure application timing, tillage, surface condition, and soil test phosphorus (STP) were analyzed to determine their effects on total phosphorus (TP) and dissolved phosphorus (DP) loss using 125 site-years of runoff data collected by the University of Wisconsin Discovery Farms and Discovery Farms Minnesota. Three linear mixed models (LMMs) were then used to evaluate the influence of those factors on TP and DP losses: (1) a model that included all runoff events, (2) manured sites only, and (3) precipitation events only. Results show that the timing of manure application relative to the timing of a runoff event only had a marginal association with P loads and concentrations, although the majority of the runoff events were collected after 10 days of manure application. Tillage was as influential factor, with greater DP loads and concentrations associated with no-till, especially during frozen conditions. Fields in this study had high STP values, but the model results only showed positive associations between DP load and DP flow-weighted mean concentration (FWMC) loss at the 0- to 15-cm depth. The precipitation event LMM (which included precipitation characteristics) was the model that resulted in the largest R 2 value. While the predictive capacity of the LMMs was low, they did illuminate the relative importance of management and environmental variables on P loss, and can be used to guide future research on P loss in this region.

Minnesota, Wisconsin↗

USGS2018

Stock structure, dynamics, demographics, and movements of walleyes spawning in four tributaries to Green Bay

To test assumptions related to the current conceptual model for walleye Sander vitreus management in Green Bay, we evaluated whether: 1) spawning aggregations in the Fox, Menominee, Oconto, and Peshtigo rivers represent genetically distinct stocks; 2) population dynamics and demographics vary among walleye spawning at these locations; 3) walleye spawning in these rivers contribute to the fishery in northern Green Bay, and 4) walleye spawning in these rivers exhibit spawning site fidelity or if they stray among rivers. Genetic differentiation among the four tributaries was low and sex-specific total length (TL), mean TL at age 5, and age-class diversity were generally similar among rivers and observed differences were not consistent. Movements of walleye inferred from angler tag returns suggest that walleye spawning (and tagged) in the four tributaries typically remain within southern Green Bay; however, this assertion may be confounded by the distribution of angling effort that provides tag recoveries. Straying rates among rivers ranged from 0 to 23% and were likely sufficient to preclude genetic differentiation among stocks. Collectively, results suggest that walleye spawning in the Fox, Menominee, Oconto, and Peshtigo rivers do not function as separate stocks and do not significantly contribute to the fishery outside of southern Green Bay. The primary assumption of the current conceptual model that remains to be tested is whether the walleye fishery in southern Green Bay is supported primarily by fish spawning in these four rivers, or if there are substantial contributions from fish spawning at other unknown locations.

Wisconsin↗

USGS2010

Revisions of rump fat and body scoring indices for deer, elk, and moose

Because they do not require sacrificing animals, body condition scores (BCS), thickness of rump fat (MAXFAT), and other similar predictors of body fat have advanced estimating nutritional condition of ungulates and their use has proliferated in North America in the last decade. However, initial testing of these predictors was too limited to assess their reliability among diverse habitats, ecotypes, subspecies, and populations across the continent. With data collected from mule deer ( Odocoileus hemionus ), elk ( Cervus elaphus ), and moose ( Alces alces ) during initial model development and data collected subsequently from free-ranging mule deer and elk herds across much of the western United States, we evaluated reliability across a broader range of conditions than were initially available. First, to more rigorously test reliability of the MAXFAT index, we evaluated its robustness across the 3 species, using an allometric scaling function to adjust for differences in animal size. We then evaluated MAXFAT, rump body condition score (rBCS), rLIVINDEX (an arithmetic combination of MAXFAT and rBCS), and our new allometrically scaled rump-fat thickness index using data from 815 free-ranging female Roosevelt and Rocky Mountain elk ( C. e. roosevelti and C. e. nelsoni ) from 19 populations encompassing 4 geographic regions and 250 free-ranging female mule deer from 7 populations and 2 regions. We tested for effects of subspecies, geographic region, and captive versus free-ranging existence. Rump-fat thickness, when scaled allometrically with body mass, was related to ingesta-free body fat over a 38–522-kg range of body mass ( r 2 = 0.87; P < 0.001), indicating the technique is remarkably robust among at least the 3 cervid species of our analysis. However, we found an underscoring bias with the rBCS for elk that had >12% body fat. This bias translated into a difference between subspecies, because Rocky Mountain elk tended to be fatter than Roosevelt elk in our sample. Effects of observer error with the rBCS also existed for mule deer with moderate to high levels of body fat, and deer body size significantly affected accuracy of the MAXFAT predictor. Our analyses confirm robustness of the rump-fat index for these 3 species but highlight the potential for bias due to differences in body size and to observer error with BCS scoring. We present alternative LIVINDEX equations where potential bias from rBCS and bias due to body size are eliminated or reduced. These modifications improve the accuracy of estimating body fat for projects intended to monitor nutritional status of herds or to evaluate nutrition's influence on population demographics.

Journal of Wildlife Diseases↗

USGS2014

Developing and testing temperature models for regulated systems: a case study on the Upper Delaware River

Water temperature is an important driver of many processes in riverine ecosystems. If reservoirs are present, their releases can greatly influence downstream water temperatures. Models are important tools in understanding the influence these releases may have on the thermal regimes of downstream rivers. In this study, we developed and tested a suite of models to predict river temperature at a location downstream of two reservoirs in the Upper Delaware River (USA), a section of river that is managed to support a world-class coldwater fishery. Three empirical models were tested, including a Generalized Least Squares Model with a cosine trend (GLScos), AutoRegressive Integrated Moving Average (ARIMA), and Artificial Neural Network (ANN). We also tested one mechanistic Heat Flux Model (HFM) that was based on energy gain and loss. Predictor variables used in model development included climate data (e.g., solar radiation, wind speed, etc.) collected from a nearby weather station and temperature and hydrologic data from upstream U.S. Geological Survey gages. Models were developed with a training dataset that consisted of data from 2008 to 2011; they were then independently validated with a test dataset from 2012. Model accuracy was evaluated using root mean square error (RMSE), Nash Sutcliffe efficiency (NSE), percent bias (PBIAS), and index of agreement (d) statistics. Model forecast success was evaluated using baseline-modified prime index of agreement (md) at the one, three, and five day predictions. All five models accurately predicted daily mean river temperature across the entire training dataset (RMSE = 0.58–1.311, NSE = 0.99–0.97, d = 0.98–0.99); ARIMA was most accurate (RMSE = 0.57, NSE = 0.99), but each model, other than ARIMA, showed short periods of under- or over-predicting observed warmer temperatures. For the training dataset, all models besides ARIMA had overestimation bias (PBIAS = −0.10 to −1.30). Validation analyses showed all models performed well; the HFM model was the most accurate compared other models (RMSE = 0.92, both NSE = 0.98, d = 0.99) and the ARIMA model was least accurate (RMSE = 2.06, NSE = 0.92, d = 0.98); however, all models had an overestimation bias (PBIAS = −4.1 to −10.20). Aside from the one day forecast ARIMA model (md = 0.53), all models forecasted fairly well at the one, three, and five day forecasts (md = 0.77–0.96). Overall, we were successful in developing models predicting daily mean temperature across a broad range of temperatures. These models, specifically the GLScos, ANN, and HFM, may serve as important tools for predicting conditions and managing thermal releases in regulated river systems such as the Delaware River. Further model development may be important in customizing predictions for particular biological or ecological needs, or for particular temporal or spatial scales.

Delaware, New York, Pennsylvania↗

USGS2015

Status and conservation of interior Redband Trout in the western United States

In this article we describe the current status and conservation of interior (potamodromous) Redband Trout Oncorhynchus mykiss sspp. throughout its range in the western United States using extant data and expert opinion provided by fish managers. Redband Trout historically occupied 60,295 km of stream habitat and 152 natural lakes. Currently, Redband Trout occupy 25,417 km of stream habitat (42% of their historical range) and 124 lakes or reservoirs. Nonhybridized populations are assumed to occupy 11,695 km (46%) of currently occupied streams; however, fish from only 4,473 km (18%) have been genetically tested. Approximately 47% of the streams occupied by Redband Trout occur on private land, 45% on government lands, and 8% in protected areas. A total of 210 Redband Trout populations, occupying 15,252 km of stream habitat (60% of the current distribution) and 95,158 ha of lake habitat (52%), are being managed as “conservation populations.” Most conservation populations have been designated as weakly to strongly connected metapopulations (125; 60%) and occupy much more stream length (14,112 km; 93%) than isolated conservation populations (1,141 km; 7%). The primary threats to Redband Trout include invasive species, habitat degradation and fragmentation, and climate change. Although the historical distribution of interior Redband Trout has declined dramatically, we conclude that the species is not currently at imminent risk of extinction because it is still widely distributed with many populations isolated by physical barriers and active conservation efforts are occurring for many populations. However, the hybridization status of many populations has not been well quantified, and introgression may be more prevalent than documented here. We recommend (1) collecting additional genetic data and estimating distribution and abundance by means of a more rigorous spatial sampling design to reduce uncertainties, (2) collecting additional information to assess and predict the impacts of climate on populations, and (3) continuing to use this database to evaluate the status of Redband Trout and inform conservation efforts through time.

North American Journal of Fisheries Management↗

USGS2025

Trophic assessment of potential competition between invasive cichlids and sport fish in Puerto Rico reservoirs

Objective Several species of New World cichlids have recently invaded reservoirs in Puerto Rico, potentially jeopardizing established recreationally important, albeit nonnative, sport fish populations. Interactions between invasive species and important sport fish must be understood so that they can be mitigated when feasible. This study compared monthly prey consumption between three invasive cichlids (Jaguar Guapote Parachromis managuensis and two species of Amphilophus ) and two principal sport fishes (Largemouth Bass Micropterus nigricans and Butterfly Peacock Bass Cichla ocellaris ) to understand potential for competitive interactions. Methods Stomach contents were evaluated quarterly using gastric lavage for sport fish and destructive sampling techniques for invasive species. Prey proportion by mass was calculated for each individual, and mean prey proportion by mass was calculated for each species by reservoir, month, and overall. Multivariate hypothesis testing using permutational multivariate analysis of variance and visualization of potential diet overlap were performed via analysis of variance and nonmetric multidimensional scaling (NMDS), respectively. Results Fish were the most common prey type, and Threadfin Shad Dorosoma petenense was the most prevalent prey species. Although there were significant differences in diets of invasive cichlids and sport fishes ( P < 0.01), there also was considerable overlap based on low percentages of variation in diets explained by species (3–19% < pseudo- R 2 ) and NMDS visualizations. Diets varied little across reservoirs and months (≤4% pseudo- R 2 ; high overlap in NMDS space). Conclusion These data indicate that the diet of Jaguar Guapote and Amphilophus spp. may overlap with that of sport fish populations in Puerto Rico. Jaguar Guapote relied on Threadfin Shad more than other species, with Amphilophus spp. relying more on detritus and noncrayfish invertebrates. Thus, if prey are limited, Jaguar Guapote may have a more direct effect via competition for prey. Finally, we report evidence of Largemouth Bass recruitment failure and local extirpations that support a hypothesis that invasive cichlids are having negative effects on at least Largemouth Bass, although the mechanism is unclear.

Puerto Rico↗

USGS2022

Microbial source tracking and evaluation of best management practices for restoring degraded beaches of Lake Michigan

Attempts to mitigate shoreline microbial contamination require a thorough understanding of pollutant sources, which often requires multiple years of data collection (e.g., point/nonpoint) and the interacting factors that influence water quality. Because restoration efforts can alter shoreline or beach morphology, revisiting source inputs is often necessary. Microbial source tracking (MST) using source-specific molecular markers, genomic community analyses, and physical modeling was used to identify contamination sources along three Lake Michigan beaches of the Laurentian Great Lakes with historically high fecal indicator bacteria (FIB, E. coli ) concentrations. Genetic markers for human (Bacteroides HF183) and mixed gull species ( Catellicoccus marimammalium ) fecal sources were tested from water and sediment. Gene sequencing (16S rRNA) was used to identify similarities in bacterial communities in nearshore water, river inputs, sand, sediment, and groundwater. Synoptic surveys of water exchange were conducted to determine nearshore-offshore interactions of FIB. In addition to these MST studies, best management practices to mitigate FIB, including gull deterrence, slope grading, wetland establishment, and shoreline plantings, were reviewed for their effectiveness at reducing FIB concentrations over time. Using multiple tools for MST helped identify primary and secondary sources of FIB (gulls, stormwater inputs) and the physical processes that exacerbate FIB concentrations (onshore currents, limited circulation). Management actions were successful in the short-term at reducing FIB, but scope of success was temporally limited, with FIB concentrations often rebounding. Results highlight the usefulness of MST to inform best management practices and the need for a sustained adaptive approach that adjusts for changes in the coastal system.

Illinois, Wisconsin↗

USGS2008

Seasonal variation in sensitivity of larval sea lampreys to the lampricide 3-trifluoromethyl-4-nitrophenol

We evaluated the sensitivity of larval sea lampreys Petromyzon marinus to the lampricide 3-trifluoromethyl-4-nitrophenol (TFM) in a series of toxicity tests in spring and summer. Although noted previously, the seasonal variation in sensitivity to TFM had never been tested as a means of reducing TFM usage in stream treatments. A preliminary study consisted of three spring and four summer static toxicity tests conducted at 12??C. A more comprehensive study consisted of 12 spring and summer paired flow-through toxicity tests conducted both at seasonal water temperatures and at 12??C. The sensitivity of larval sea lampreys to TFM was greater in spring than in summer. The preliminary static toxicity tests indicated that the concentration of TFM needed to kill larval sea lampreys in spring (May and June) was about one-half that required in summer (August); the concentrations lethal to 50% and 99.9% of the test animals (the LC50 and LC99.9 values) were less in spring than in summer. Analysis of variance of the flow-through toxicity data indicated that season significantly affected both the LC50 and LC99.9 values. For all 12 paired flow-through toxicity tests, the spring LC50 and LC99.9 values were less than the corresponding summer values. For 9 of the 12 paired flow-through toxicity tests, the dose-response toxicity lines were parallel and allowed statistical comparison of the LC50 values. The spring LC50 values were significantly lower than the summer values in eight of the nine tests. Verification of a seasonal variation in the sensitivity of larval sea lampreys to TFM will allow inclusion of this factor in the selection model currently used by both the U.S. Fish and Wildlife Service and the Department of Fisheries and Oceans-Canada to schedule lampricide stream treatments. ?? Copyright by the American Fisheries Society 2008.

North American Journal of Fisheries Management↗

USGS2014

Population dynamics of bowfin in a south Georgia reservoir: latitudinal comparisons of population structure, growth, and mortality

The objectives of this study were to evaluate the population dynamics of bowfin (Amia calva) in Lake Lindsay Grace, Georgia, and to compare those dynamics to other bowfin populations. Relative abundance of bowfin sampled in 2010 in Lake Lindsay Grace was low and variable (mean±SD; 2.7±4.7 fish per hour of electrofishing). Total length (TL) of bowfin collected in Lake Lindsay Grace varied from 233–683 mm. Age of bowfin in Lake Lindsay Grace varied from 0–5 yr. Total annual mortality (A) was estimated at 68%. Both sexes appeared to be fully mature by age 2 with gonadosomatic index values above 8 for females and close to 1 for males. The majority of females were older, longer, and heavier than males. Bowfin in Lake Lindsay Grace had fast growth up to age 4 and higher total annual mortality than the other populations examined in this study. A chi-square test indicated that size structure of bowfin from Lake Lindsay Grace was different than those of a Louisiana population and two bowfin populations from the upper Mississippi River. To further assess bowfin size structure, we proposed standard length (i.e., TL) categories: stock (200 mm, 8 inches), quality (350 mm, 14 inches), preferred (460 mm, 18 inches), memorable (560 mm, 22, inches), and trophy (710 mm, 28 inches). Because our knowledge of bowfin ecology is limited, additional understanding of bowfin population dynamics provides important insight that can be used in management of bowfin across their distribution.

Georgia↗