Associations Between Iron Concentration and Productivity in Montane Streams of the Black Hills, South Dakota

Iron is an important micronutrient found in aquatic systems that can influence nutrient availability (e.g. phosphorus) and primary productivity. In streams, high iron concentrations often are associated with low pH as a result of acid mine drainage, which is known to affect fish and invertebrate communities. Streams in the Black Hills of South Dakota are generally circumneutral in pH, yet select streams exhibit high iron concentrations associated with natural iron deposits. In this study, we examined relationships among iron concentration, periphyton biomass, macroinvertebrate abundance, and fish assemblages in four Black Hills streams. The stream with the highest iron concentration (~5 mg Fe/L) had reduced periphyton biomass, invertebrate abundance, and fish biomass compared to the three streams with lower iron levels (0.1 to 0.6 mg Fe/L). Reduced stream productivity was attributed to indirect effects of ferric iron (Fe+++), owing to iron-hydroxide precipitation that influenced habitat quality (i.e. substrate and turbidity) and food availability (periphyton and invertebrates) for higher trophic levels (e.g. fish). Additionally, reduced primary and secondary production was associated with reduced standing stocks of salmonid fishes. Our findings suggested that naturally occurring iron deposits may constrain macroinvertebrate and fish production

Influence of Physiochemical and Watershed Characteristics on Mercury Concentration in Walleye, Sander vitreus, M.

Elevated mercury concentration has been documented in a variety of fish and is a growing concern for human consumption. Here, we explore the influence of physiochemical and watershed attributes on mercury concentration in walleye (Sander vitreus, M.) from natural, glacial lakes in South Dakota. Regression analysis showed that water quality attributes were poor predictors of walleye mercury concentration (R2 = 0.57, p = 0.13). In contrast, models based on watershed features (e.g., lake level changes, watershed slope, agricultural land, wetlands) and local habitat features (i.e., substrate composition, maximum lake depth) explained 81% (p = 0.001) and 80% (p = 0.002) of the variation in walleye mercury concentration. Using an information theoretic approach we evaluated hypotheses related to water quality, physical habitat and watershed features. The best model explaining variation in walleye mercury concentration included local habitat features (Wi = 0.991). These results show that physical habitat and watershed features were better predictors of walleye mercury concentration than water chemistry in glacial lakes of the Northern Great Plains

Pressures to Publish: Catalysts for the Loss of Scientific Writing Integrity?

Publishing research is the final step in the scientific process and is used as the primary means for disseminating research findings to the scientific community. Publishing can embody many personal motivations (e.g., gratification, seeing a finished product in print, desire to further science) for authors as well as professional benefits (e.g., promotion, tenure, future funding opportunities). As the scientific workforce and competition for jobs and funding increase, publishing productivity has become a driving factor for many authors, which may lead to writing practices that violate integrity. In this essay, we discuss writing actions that may be considered a violation of integrity in the context of traditional manuscript sections (introduction and discussion, methods, and results). We define “integrity” as consistency of actions that reflect honesty and truthfulness. Writing the introduction and discussion can be compared to an artistic creation because the rendition of the data may vary depending on the intentions and experience of the author. Some authors may be tempted to relate their research to a hot topic (e.g., climate change, model selection) in an attempt to increase publication success or maximize visibility in search engines, despite not having sufficient data to support their conclusions. Caution must be taken to not overextend the “story” beyond the bounds of the data. Modification of the methods and results sections contains the most extreme cases of scientific integrity violations (e.g., changing an alpha level, only presenting positive results, running numerous tests until desired outcome). Manipulation of methods or results is more difficult to detect by peer review. We believe that however destructive integrity violations may be, despite benefits to the author (e.g., accolades, publication, potential citations, promotion, etc.), the individual scientist should hold him- or herself accountable and to a high standard to avoid sacrificing integrity. Presión para publicar: catalizadores de la pérdida de integridad en la publicación científica Resume: La publicación es la etapa final del proceso científico y se utiliza como el medio principal para diseminar los hallazgos de una investigación. Para los autores, publicar puede implicar distintas motivaciones tanto personales (p.e. satisfacción, ver un producto final impreso, deseo de hacer más ciencia) como profesionales (p.e. promoción interna, basificación, oportunidades de financiamiento). A medida que se incrementa la fuerza laboral científica y la competencia por trabajo y financiamiento, la productividad en cuanto a las publicaciones se ha convertido en un factor determinante para muchos autores, lo cual puede dar pie a prácticas de publicación que comprometen la integridad. En este ensayo se discuten aquellas prácticas de publicación que se considera que comprometen la integridad en el contexto de las secciones habituales que conforman un artículo (introducción y discusión, métodos y resultados). Se define la integridad como la consistencia en acciones que reflejan honestidad y veracidad. Escribir la introducción y discusión se compara con una creación artística en cuanto a que la interpretación de los datos puede variar dependiendo de las intenciones y experiencia del autor. Algunos autores pueden estar tentados a relacionar su investigación a un tópico de actualidad (p.e. cambio climático, selección de modelos) en un intento por incrementar el éxito de la publicación y maximizar la posibilidad de ser encontrados mediante motores de búsqueda, a pesar de que no cuentan con suficientes datos como para apoyar sus conclusiones. Se debe tener cuidado para no extender la historia más allá de los límites que establecen los datos. La modificación de las secciones de métodos y resultados implica los casos más extremos de violaciones a la integridad (p.e. cambiar el nivel de alfa, presentar sólo resultados positivos, realizar numerosas pruebas hasta que salga el resultado esperado). La manipulación de los métodos o los resultados resulta particularmente difícil de detectar durante el proceso de revisión por pares. Creemos que no obstante lo destructivas que puedan ser las violaciones a la integridad y a pesar de los beneficios que obtengan los autores (p.e. premios, potencial de citación, promociones, etc.), el individuo científico debe mantener su sentido de responsabilidad y sus estándares en alto con el fin de evitar sacrificar su integridad

Use of Environmental DNA to Detect Grass Carp Spawning Events

The timing and location of spawning events are important data for managers seeking to control invasive grass carp populations. Ichthyoplankton tows for grass carp eggs and larvae can be used to detect spawning events; however, these samples can be highly debris-laden, and are expensive and laborious to process. An alternative method, environmental DNA (eDNA) technology, has proven effective in determining the presence of aquatic species. The objectives of this project were to assess the use of eDNA collections and quantitative eDNA analysis to assess the potential spawning of grass carp in five reservoir tributaries, and to compare those results to the more traditional method of ichthyoplankton tows. Grass carp eDNA was detected in 56% of sampling occasions and was detected in all five rivers. Concentrations of grass carp eDNA were orders of magnitude higher in June, corresponding to elevated discharge and egg presence. Grass carp environmental DNA flux (copies/h) was lower when no eggs were present and was higher when velocities and discharge increased and eggs were present. There was a positive relationship between grass carp eDNA flux and egg flux. Our results support the further development of eDNA analysis as a method to detect the spawning events of grass carp or other rheophilic spawners

Fish Assemblage Structure, Trophic Ecology, and Potential Effects of Invading Asian Carps in Three Missouri River Tributaries, South Dakota

Invasive species are spreading in aquatic systems at an unprecedented rate and have the potential to disrupt the structure and function of these systems. Two invasive species, Bighead Carp and Silver Carp (Asian carps), are spreading in the Mississippi River Basin and more recently into the Missouri River basin and tributaries. Asian carps exhibit fast population growth, are highly fecund, are plankton consumers and are known to cause negative impacts (e.g., decreased condition, decreased growth, altered composition) on native planktivores and plankton. Knowledge of Asian carp population structure and trophodynamics in newly invaded populations is necessary to understand invasion dynamics in general and to predict the impacts Asian carps may be having on the newly invaded community. We found that historically, assemblage structure of eastern South Dakota tributaries to the Missouri River (i.e., James, Vermillion, Big Sioux rivers) was persistent and displayed signs of biotic resistance. Silver carp population abundance increased each year of sampling (e.g., 2009-2012) comprising 45% of catches in 2012; however Bighead Carp did not follow this same pattern as catches remained minimal during this period. Additionally, the population of Silver Carp displayed erratic recruitment in that 91 % of catches were dominated by the 2010 year class. Distribution into eastern South Dakota tributaries was stopped by three substantial dams preventing further natural spread. Isotope analysis and diet analysis revealed that Silver Carp and Gizzard Shad overlapped trophically and the isotopic trophic niche of Emerald Shiner, which is usually pelagic, potentially moved to more benthic habitats and food sources as a result of Silver Carp presence. There were no perceived effects of Silver Carp on Bigmouth Buffalo however. With continued population increases of Silver Carp, the potential for competition for plankton resources becomes greater and trophic impacts may become more pronounced, especially for gizzard shad and emerald shiner. Invasive species are usually studied well after an introduction and colonization, unlike this study which began on the cusp of the northwestern United States invasion. This research and continued monitoring of this invasion can help to provide insights into invasion ecology (e.g., competition, phonotypic plasticity, biotic resistance), complex invasive species (e.g., opportunistic and adaptable), and potential impacts (e.g., nutrient cycling, trophic cascades) on the native community and ecosystem

DISTRIBUTION OF CRAYFISH SPECIES IN SELECT NORTH DAKOTA STREAMS

Crayfish have an integral role in aquatic ecosystems, serving as herbivores, predators, detritivores, and prey for fishes and other aquatic and terrestrial animals (Momot 1995, Taylor et al. 1996, Martin 1997). Many crayfish populations are currently declining as a result of habitat alteration (Taylor et al. 1996) and invasive predators (e.g., rusty crayfish Orconectes rusticus [Girard; Lodge et al. 2000]). Knowledge of crayfish distribution and biology in North America and specifically North Dakota is sparse or lacking (Taylor et al. 1996) and baseline information is necessary to identify effects of anthropogenic alterations. Early inventories documented 3 crayfish species in North Dakota: calico crayfish Orconectes immunis (Hagen), virile crayfish, O. virilis (Hagen), and devil crayfish, Cambarus diogenes Girard (Harris 1903, Crocker and Barr 1968, Hobbs 1989, Taylor et al. 1996); however an extensive statewide crayfish survey with site specific information has not been conducted. Additionally, the rusty crayfish is present in the surrounding states of Minnesota and South Dakota (Olden et al. 2006) and in southern Manitoba (Phillips et al. 2009). This invasive species has been known to displace native crayfishes (Hill and Lodge 1999) and cause severe ecological alterations that can affect fishes. The rusty crayfish can limit macrophyte growth which can remove habitat and alter nutrient cycles (Hill and Lodge 1999, Byron and Wilson 2001). Our objectives were to document presence and distribution of native and non-native crayfish species in central and western North Dakota

Associations Between Iron Concentration and Productivity in Montane Streams of the Black Hills, South Dakota

Iron is an important micronutrient found in aquatic systems that can influence nutrient availability (e.g. phosphorus) and primary productivity. In streams, high iron concentrations often are associated with low pH as a result of acid mine drainage, which is known to affect fish and invertebrate communities. Streams in the Black Hills of South Dakota are generally circumneutral in pH, yet select streams exhibit high iron concentrations associated with natural iron deposits. In this study, we examined relationships among iron concentration, periphyton biomass, macroinvertebrate abundance, and fish assemblages in four Black Hills streams. The stream with the highest iron concentration (~5 mg Fe/L) had reduced periphyton biomass, invertebrate abundance, and fish biomass compared to the three streams with lower iron levels (0.1 to 0.6 mg Fe/L). Reduced stream productivity was attributed to indirect effects of ferric iron (Fe+++), owing to iron-hydroxide precipitation that influenced habitat quality (i.e. substrate and turbidity) and food availability (periphyton and invertebrates) for higher trophic levels (e.g. fish). Additionally, reduced primary and secondary production was associated with reduced standing stocks of salmonid fishes. Our findings suggested that naturally occurring iron deposits may constrain macroinvertebrate and fish production

Adult and larval fish assemblages vary among small tributary mouths of Green Bay, Lake Michigan

Small tributaries of the Great Lakes serve as important habitat during critical life stages of many fish species, though temporal and spatial dynamics of the assemblage that uses these systems are seldom investigated. This study quantifies larval and adult fish assemblages captured by fyke net and light traps among small tributary mouths of Green Bay, Lake Michigan. Ten tributaries harbored a total of forty-five species representing seventeen families, with the most abundant including spottail shiner (Notropis hudsonius (Clinton 1824)) in adult assemblages and white sucker (Catostomus commersonii (Lacepde 1803)) in larval assemblages. Larval fish assemblage structures differed over five biweekly sampling events in May and June. Adult fish assemblage structures varied among tributaries but not among spring, summer, and fall samples. Larval and adult species assemblages at these rivermouths are likely influenced by hydrology, habitat structure, and species-specific ecology. Water movement may transport larvae into rivermouths, as larval assemblages were dominated by species that spawn in coastal habitats. Adult species richness varied with longitude, with the greatest diversity in tributaries on the west shore. This investigation of fish assemblages highlights the spatial and temporal variation that occurs in these systems and their role in shaping fish populations in Green Bay.The accepted manuscript in pdf format is listed with the files at the bottom of this page. The presentation of the authors' names and (or) special characters in the title of the manuscript may differ slightly between what is listed on this page and what is listed in the pdf file of the accepted manuscript; that in the pdf file of the accepted manuscript is what was submitted by the author