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Teresa Newton

Publications and source records attributed to Teresa Newton.

10 recordsLinked to original sources

Estimation of vital population rates to assess the relative health of mussel assemblages in the Upper Mississippi River

Native freshwater mussels are a guild of benthic, filter feeding invertebrates that perform important ecological functions in rivers. Because of their long lifespans (30–50 years or longer), mussels are slow to respond to human‐induced alterations. Thus, development of sensitive indicators of mussel population responses to river conditions and management would be beneficial. Compared to marine species, estimation of vital rates (e.g. survival, growth) in freshwater mussels has received little attention. We placed passively integrated transponder tags on 578 mussels of four species ( Amblema plicata , Cyclonaias pustulosa , Obliquaria reflexa , and Pleurobema sintoxia ) in a well‐studied mussel assemblage in a side channel of the upper Mississippi River. Growth and survival of tagged mussels were assessed annually for 4 years across core (high density) and peripheral (low density) areas of the assemblage. Overall survival was highly variable, ranging from c . 15 to 90%, and was related to life history, habitat quality, and hydrologic events. Survival, which varied significantly among species and over time, was consistently higher in the dense and species‐rich core of the mussel assemblage, relative to the periphery because substrates were consistently more stable in the core of the mussel bed relative to the periphery. Substrate movement during low flows was an order of magnitude lower in the core relative to the periphery, and survival was inversely related to stability of river substrates. Patterns in habitat‐specific survival indicate source–sink population dynamics such that mussels in the core habitat provide recruitment to the periphery, but mussels in the periphery are subject to unsustainably low survival; additional studies to track the source of recruitment in the periphery are needed to test this hypothesis. Growth rate did not vary significantly between core and peripheral areas but did vary by species. Growth rate (proportional change per year) declined with age, and was similar at mean age for A. plicata (0.016 per year), P. sintoxia (0.015 per year), and C. pustulosa (0.013 per year), but much lower for O. reflexa (0.008 per year). Effective management decisions for mussels requires a better understanding of how vital rates govern populations and how they vary across a suite of physical and biological factors. Information on how population vital rates vary among species and over time gives managers another tool to understand how mussels may respond to management actions such as habitat restoration projects. Given the importance of substrate stability inferred from this study, management actions that maintain or increase substrate stability are likely to result in high quality mussel assemblages and may restore a valuable component of ecosystem function in this region.

Minnesota, Wisconsin

Mussel community assessment tool for the Upper Mississippi River system

Upper Mississippi River (UMR) resource managers need a quantitative means of evaluating the health of mussel assemblages to measure effects of management and regulatory actions, assess restoration techniques, and inform regulatory tasks. Our objective was to create a mussel community assessment tool (MCAT), consisting of a suite of metrics and scoring criteria, to consistently compare the relative health of UMR mussel assemblages. We developed an initial MCAT using quantitative data from 25 sites and 10 metrics. Metrics fell in five broad groups: conservation status and environmental sensitivity, taxonomic composition, population processes, abundance, and diversity. Metric scoring categories were based on quartile analysis: 25% scoring as good, 50% scoring as fair, and 25% scoring as poor. Scores were meant to facilitate establishing management priorities and mitigation options for the conservation of mussels. Scoring categories assumed that a healthy mussel assemblage consists of species with a variety of reproductive and life-history strategies, a low percentage of tolerant species, and a high percentage of sensitive species; shows evidence of adequate recruitment, a variety of age classes, and low mortality; and has high abundance, species richness, and species and tribe evenness. Metrics were validated using a modified Delphi technique. MCAT metrics generally reflected the professional opinions of UMR resource managers and provided a consistent evaluation technique with uniform definitions that managers could use to evaluate mussel assemblages. Additional data sets scored a priori by UMR resource managers were used to further validate metrics, resulting in data from 33 sites spanning over 980 km of the UMR. Initial and revised MCAT scores were similar, indicating that data represent the range of mussel assemblages in the UMR. Mussel assemblages could be evaluated using individual metrics or a composite score to suit management purposes. With additional data, metrics could be calibrated on a local scale or applied to other river systems.

Illinois, Iowa, Minnesota, Missouri, Wisconsin

Influence of surrounding land-use on mussel growth and glycogen levels in the St. Croix and Minnesota River basins

Freshwater mussels face threats from climate change and changing land use that are dramatically altering their habitat. The health of mussel populations and the state of current and past environmental conditions can be monitored by measuring mussel growth and glycogen levels. In this study we measured growth and glycogen levels in mussels from two small river basins impacted by different land uses. The Snake River in the St. Croix Basin had low levels of suspended sediments and was surrounded mostly by forest and some developed land. The Chippewa, Cottonwood, and Le Sueur rivers in the Minnesota River Basin had significantly higher annual suspended sediment loads and highly agricultural basins. Mussel growth was highest in the Le Sueur and Cottonwood rivers followed by the Chippewa and the Snake rivers. Mussels in the Minnesota Basin rivers all had higher foot glycogen concentrations than the Snake River. These patterns were similar for two mussel species, suggesting that environmental conditions are likely determining levels of growth. Although agriculture had a negative effect on mussel population abundance and diversity, it had a positive effect on growth and glycogen levels.

Minnesota

Invasive silver carp may compete with unionid mussels for algae: First experimental evidence

1. Unionid mussels are imperiled throughout the United States, where their global diversity is highest. Silver carp (Hypophthalmichthys molitrix Valenciennes in Cuvier & Valenciennes, 1844), an invasive planktivorous fish, has spread throughout Midwestern rivers and currently threatens the Great Lakes. Because silver carp remove plankton and other particles from the water column, they may compete with mussels for food resources. This would be among the first examples of a direct competitive interaction between fish and mussels. 2. To examine the potential for competition, a 30-d tank experiment was performed with 2-yr old fatmucket mussels (Lampsilis siliquoidea Barnes, 1823) and age-1 silver carp in three treatments: fatmucket only, silver carp only, and fatmucket + silver carp. All tanks were given a commercial algal-based diet daily and dry mass of suspended particles (an estimate of available food) and NH4, NO3, and NO2 concentrations were quantified every 5 d to track food availability and changes in nutrients. Initial and final silver carp total length (mm) and mass (g), and fatmucket length (mm), height (mm), and surface area (mm2) were measured. 3. Survival was 100% over the test duration for both species. Fatmucket grew less in the fatmucket + silver carp treatment, while silver carp growth was low regardless of treatment. Fatmucket also exhibited increased movement in the presence of silver carp. Suspended particles did not differ among treatments. Dissolved nitrogen concentrations were higher in the silver carp treatments, suggesting that silver carp increase nutrient availability in aquatic systems. 4. Overall, the slower growth rates observed in the fatmucket + silver carp treatment compared to the mussel only treatment suggest exploitative competition between invasive planktivorous silver carp and fatmucket and this competition could contribute to additional stress on already imperiled mussels.

Midwest

Local scale spatial patterns of freshwater mussels in the Upper Mississippi River

Multiple physical and biological factors contribute to the structure of freshwater mussel communities in large rivers. Mussel distributions are frequently described as clumped or patchy. However, few surveys of mussel populations have been designed to quantify these spatial patterns. We used indicators of spatial autocorrelation to quantify spatial patterns of adult and juvenile (≤ 5 years of age) freshwater mussels at local scales (i.e., < 300 m), within 14 sites along ~700 km of the Upper Mississippi River, USA. Juveniles were patchily distributed in 43% of the sites, and adults were patchily distributed in 50%. Within sites, juveniles and adults displayed the same spatial pattern in 64% of the sites. At half of the sites, hotspots of adults and juveniles overlapped suggesting spatial and temporal persistence of habitat. Mussels have an important ecological role in rivers, and information on their spatial patterns aid our understanding of the spatial structure and function of riverine ecosystems, and the ecological consequences of population declines.

Illinois, Iowa, Minneapolis, Wisconsin

Simulated mussel mortality thresholds as a function of mussel biomass and nutrient loading

A freshwater “mussel mortality threshold” was explored as a function of porewater ammonium (NH 4 + ) concentration, mussel biomass, and total nitrogen (N) utilizing a numerical model calibrated with data from mesocosms with and without mussels. A mortality threshold of 2 mg-N L −1 porewater NH 4 + was selected based on a study that estimated 100% mortality of juvenile Lampsilis mussels exposed to 1.9 mg-N L −1 NH 4 + in equilibrium with 0.18 mg-N L −1 NH 3 . At the highest simulated mussel biomass (560 g m −2 ) and the lowest simulated influent water “food” concentration (0.1 mg-N L −1 ), the porewater NH 4 + concentration after a 2,160 h timespan without mussels was 0.5 mg-N L −1 compared to 2.25 mg-N L −1 with mussels. Continuing these simulations while varying mussel biomass and N content yielded a mortality threshold contour that was essentially linear which contradicted the non-linear and non-monotonic relationship suggested by Strayer (2014) . Our model suggests that mussels spatially focus nutrients from the overlying water to the sediments as evidenced by elevated porewater NH 4 + in mesocosms with mussels. However, our previous work and the model utilized here show elevated concentrations of nitrite and nitrate in overlying waters as an indirect consequence of mussel activity. Even when the simulated overlying water food availability was quite low, the mortality threshold was reached at a mussel biomass of about 480 g m −2 . At a food concentration of 10 mg-N L −1 , the mortality threshold was reached at a biomass of about 250 g m −2 . Our model suggests the mortality threshold for juvenile Lampsilis species could be exceeded at low mussel biomass if exposed for even a short time to the highly elevated total N loadings endemic to the agricultural Midwest.

PeerJ

Lethal and sub-lethal responses of native freshwater mussels exposed to granular Bayluscide®, a sea lamprey larvicide

The invasive sea lamprey ( Petromyzon marinus ) poses a substantial threat to fish communities in the Great Lakes. Efforts to control sea lamprey populations typically involve treating tributary streams with lampricides on a recurring cycle. The presence of a substantial population of larval sea lampreys in the aquatic corridor between Lakes Huron and Erie prompted managers to propose a treatment using the granular formulation of Bayluscide® that targets larval sea lampreys that reside in sediments. However, these treatments could cause adverse effects on native freshwater mussels—imperiled animals that also reside in sediments. We estimated the risk of mortality and sub-lethal effects among eight species of adult and sub-adult mussels exposed to Bayluscide® for durations up to 8 h to mimic field applications. Mortality was appreciable in some species, especially in sub-adults (range, 23–51%). The lethal and sub-lethal effects were positively associated with the duration of exposure in most species and life stage combinations. Estimates of the median time of exposure that resulted in lethal and sub-lethal effects suggest that sub-adults were often affected by Bayluscide® earlier than adults. Siphoning activity and burrowing position of mussels during exposure may have moderated the uptake of Bayluscide® and may have influenced lethal and sub-lethal responses. Given that the various species and life stages were differentially affected, it will be difficult to predict the effects of Bayluscide® treatments on mussels.

Journal of Great Lakes Research

Spatial patterns of native freshwater mussels in the Upper Mississippi River

Multiple physical and biological factors structure freshwater mussel communities in large rivers, and their distributions have been described as clumped or patchy. However, few surveys of mussel populations have been conducted over areas large enough and at resolutions fine enough to quantify spatial patterns in their distribution. We used global and local indicators of spatial autocorrelation (i.e., Moran&rsquo;s I) to quantify spatial patterns of adult and juvenile (&le;5 y of age) freshwater mussels across multiple scales based on survey data from 4 reaches (navigation pools 3, 5, 6, and 18) of the Upper Mississippi River, USA. Native mussel densities were sampled at a resolution of &sim;300 m and across distances ranging from 21 to 37 km, making these some of the most spatially extensive surveys conducted in a large river. Patch density and the degree and scale of patchiness varied by river reach, age group, and the scale of analysis. In all 4 pools, some patches of adults overlapped patches of juveniles, suggesting spatial and temporal persistence of adequate habitat. In pools 3 and 5, patches of juveniles were found where there were few adults, suggesting recent emergence of positive structuring mechanisms. Last, in pools 3, 5, and 6, some patches of adults were found where there were few juveniles, suggesting that negative structuring mechanisms may have replaced positive ones, leading to a lack of localized recruitment. Our results suggest that: 1) the detection of patches of freshwater mussels requires a multiscaled approach, 2) insights into the spatial and temporal dynamics of structuring mechanisms can be gained by conducting independent analyses of adults and juveniles, and 3) maps of patch distributions can be used to guide restoration and management actions and identify areas where mussels are most likely to influence ecosystem function.

Upper Misssissippi River

Annual variation in recruitment of freshwater mussels and its relationship with river discharge

Vital rates such as mortality, growth, and recruitment are important tools to evaluate the status of threatened populations and identify their vulnerabilities, leading to enhanced conservation strategies. Native freshwater mussels are a guild of largely sedentary, filter-feeding bivalves currently facing worldwide declines. Lack of recruitment has been identified as a major threat to mussel populations. A mussel bed in the Upper Mississippi River was sampled for 5&thinsp;years (2008&ndash;2012). A trend analysis showed a significant decline in the percentage of species with juvenile representatives. Species were grouped into equilibrium and periodic life history strategies to assess past recruitment. Residuals from catch-curve regressions quantified past year-class strength of both strategists and Amblema plicata over a 13-year period (1994&ndash;2006), and identified strong and weak year-classes. Generalized linear regression models containing July maximum discharge and April minimum discharge explained 64% of the variation in recruitment strength of A. plicata . The best model for the equilibrium strategists explained 86% of the variation in recruitment and contained the same variables as A. plicata, but also incorporated the 7-day minimum discharge. For the periodic strategists, the model containing the number of low-flow pulses and the mean duration of high-flow pulses explained 56% of the variation in recruitment strength. Understanding variation in recruitment dynamics of native mussels and its relationship to river discharge will be useful in designing effective management strategies to enhance conservation of this imperilled fauna.

Minnesota

Evaluation of the short term 12 hour toxicity of 3-trifluoromethyl-4-nitrophenol (TFM) to multiple life stages of Venustaconcha ellipsiformis and Epioblasma triquetra and its host fish ( Percina caprodes )

The present study evaluated the risk of 12-h exposures of the lampricide 3-trifluoromethyl-4-nitrophenol (TFM) to multiple life stages of the federally endangered snuffbox ( Epioblasma triquetra ) and its primary host fish the common logperch ( Percina caprodes ) as well as a surrogate to the snuffbox, the ellipse ( Venustaconcha ellipsiformis ). Life stages examined included free glochidia, 1-wk juveniles, and adults of the ellipse; free glochidia, glochidia on host fish, and 1-wk juveniles of the snuffbox; and adult logperch. Larval sea lampreys were also tested alongside adult ellipse and logperch for direct comparison. Survival exceeded 82% among all life stages in both mussel species at levels up to 1.8 times what would be applied during treatments, suggesting that routine sea lamprey control operations would not adversely affect mussels. However, substantial mortality of adult logperch was observed at TFM concentrations typically applied to streams, and loss of host fish could adversely affect snuffbox reproduction. In addition, TFM had no significant effect on the number of glochidia that metamorphosed on adult logperch. Although the snuffbox is not likely to be acutely affected from sea lamprey control operations, mitigation efforts to minimize impacts to the host fish should be considered.

Environmental Toxicology and Chemistry