@article {KNZ001325,
	title = {Thresholds in macroinvertebrate biodiversity and stoichiometry across water-quality gradients in Central Plains (USA) streams},
	journal = {Journal of the North American Benthological Society},
	volume = {28},
	year = {2009},
	pages = {855 -868},
	abstract = {<p>N and P often limit primary and secondary production in ecosystems, but they also can cause eutrophication and negatively influence sensitive species above a certain level or threshold point. Aquatic biodiversity can have negative threshold relationships with water-quality variables at large scales, but the specific mechanism(s) driving these threshold relationships are not well established. We hypothesized that resource quality (i.e., C:P) might partly drive primary consumer (grazer and detritivore) richness thresholds by altering competitive interactions among species with differing resource demands, but might have less influence on predator richness. We estimated total N (TN), total P (TP), and turbidity thresholds for macroinvertebrate richness across trophic levels and feeding groups in Central Plains (USA) streams. We also determined if mean taxon body C:P of groups with diversity losses were negatively related to TP, a pattern that would suggest that eutrophic communities were dominated by a few species with high dietary P demands. Primary consumers were more sensitive to TN and TP (threshold mean  =  1.0 mg N/L and 0.06 mg P/L) than secondary consumers (threshold mean  =  0.09 mg P/L), a result supporting the resource quality hypothesis. Turbidity reduced richness regardless of feeding mode (threshold mean  =  4.7 NTU), a result suggesting that turbidity and nutrient thresholds were driven by different factors. The TP-richness threshold could be driven partially by changes in food quality because the mean body C:P of shredding and collector-gathering taxa declined as TP increased (threshold mean  =  0.07 and 0.75 mg P/L, respectively). Mean scraper C:P was not related to TP, a result indicating other factors might be responsible for the scraper richness threshold. Our results suggest that changes in resource quality could contribute to large-scale losses in biodiversity in nutrient-enriched lotic ecosystems. Within shredder and collector-gatherer macroinvertebrate feeding groups, P-rich food might allow faster growing taxa with high body P demands to out-compete slower growing taxa adapted to lower quality food resources. This pattern suggests that biotic integrity is directly linked to nutrients in streams and that toxicity, low dissolved O2, and increased turbidity might not be the only mechanisms leading to reductions in diversity as nutrient concentrations increase.</p>},
	keywords = {LTER-KNZ, bioassessment, breakpoints, eutrophication, nutrient criteria, Species richness, water quality},
	doi = {10.1899/08-113.1},
	url = {https://www.journals.uchicago.edu/doi/10.1899/08-113.1},
	author = {Evans-White, M.A. and W. K. Dodds and Huggins, D.G. and Baker, D.S.}
}
@article {KNZ001236,
	title = {Effects of grazing minnows (Phoxinus erythrogaster) and crayfish (Orconectes nais and O. neglectus) on stream ecosystem structure and function},
	journal = {Journal of the North American Benthological Society},
	volume = {27},
	year = {2008},
	pages = {772 -782},
	abstract = {<p>We compared the effects of 2 common grazers, southern redbelly dace (Phoxinus erythrogaster) and crayfish (Orconectes spp.), on ecosystem structure and function in experimental streams with pool and riffle habitats. Our goal was to identify potentially overlapping roles of these grazers in these systems. Measures of ecosystem structure included algal filament length, particulate organic matter (POM), densities of invertebrate taxa, and algal biomass. Ecosystem function was measured as gross primary productivity (GPP). Biomass-dependent effects of crayfish and dace on ecosystem properties were compared in autumn 2005 when mean water temperature was 12.9\&deg;C (range 7.6\&ndash;27.9\&deg;C). Increasing crayfish biomass did not influence ecosystem properties, but increasing dace biomass negatively affected algal filament length and chironomid abundance and positively affected chydorid abundance. Effects of moderately high biomasses of dace and crayfish were compared in spring 2006 when mean water temperature was 21.4\&deg;C (range 17.5\&ndash;29.9\&deg;C). Algal filament lengths were generally low relative to values obtained in autumn 2005 in both dace and crayfish treatments. In addition, algal filament length was shorter and chironomid density was lower in crayfish than in dace streams. The contrasting effects of dace and crayfish across sampling days, seasons, and habitats led us to hypothesize that physiological and behavioral traits of these species might limit the redundancy of their effects on ecosystems across broad spatial and temporal scales.</p>},
	keywords = {LTER-KNZ, context-dependent effects, experimental streams, foraging behavior, periphyton, physiology, Prairie stream, Primary production, Temperature},
	doi = {10.1899/07-136.1},
	url = {https://www.journals.uchicago.edu/doi/10.1899/07-136.1},
	author = {Bengtson, J.R. and Evans-White, M.A. and K. B. Gido}
}
@article {KNZ00866,
	title = {Ecosystem significance of crayfishes and central stonerollers in a tallgrass prairie stream: Functional differences between co-occurring omnivores},
	journal = {Journal of the North American Benthological Society},
	volume = {22},
	year = {2003},
	pages = {423 -441},
	abstract = {The ecosystem significance of crayfishes (Orconectes nais (Faxon) and O. neglectus (Faxon)) and central stoneroller minnows (Campostoma anomalum (Rafinesque)), was examined in a tallgrass prairie stream by estimating the trophic basis of production and consumption for each species. Annual ash-free dry mass production and production to biomass ratios of C. anomalum (260 mg m-2 y-1, 1.3) were lower than that of O. nais (719 mg m-2 y-1, 2.4) and O. neglectus (508 mg m-2 y-1, 2.1). Gut content analysis revealed no significant differences in the percentages of the various food items ingested by O. nais and O. neglectus, indicating they were functionally similar with respect to the types of organic matter processed in this system. We found a significant difference among seasons in the \% of invertebrates in C. anomalum guts (p = 0.0001) and the \% of algae in Orconectes spp. guts (p = 0.005), indicating the importance of measuring resource use throughout the growing season. Leaves contributed most to Orconectes spp. annual production (45\%) followed by animal matter (30\%), algae (19\%), and amorphous detritus (6\%). Algae contributed most to C. anomalum production (47\%) followed by amorphous detritus (30\%), animal matter (21\%), and leaves (2\%). Orconectes spp. consumed more leaf litter, filamentous green algae, and macroinvertebrates than C. anomalum, whereas C. anomalum consumed more diatoms. Crayfish and central stonerollers are both omnivores that function as important consumers and processors of algae and detritus in this tallgrass prairie stream, but each focuses on slightly different types of similar resources.},
	keywords = {LTER-KNZ, central stonerollers, Growth rate, gut contents, omnivory, Orconectes, secondary production},
	doi = {10.2307/1468272},
	author = {M. Evans-White and W. K. Dodds and M.R. Whiles}
}
@article {KNZ003,
	title = {A comparison of the trophic ecology of crayfish (Orconectes nais (Faxon) and Orconectes neglectus (Faxon)) and central stonerollers (Compostoma anomalum (Rafinesque)): omnivory in a tallgrass prairie stream},
	journal = {Hydrobiologia},
	volume = {462},
	year = {2001},
	pages = {131 -144},
	abstract = {Omnivorous fish, such as the central stoneroller minnow (Campostoma anomalum(Rafinesque)), and crayfish often play important roles in the trophic dynamics of streams. The trophic role of these two omnivores has not been compared within a system even though they both consume algae, detritus and invertebrates and often co-occur in streams in the Midwestern United States. Natural abundance of 15N and 13C isotopes and a whole stream 15N-labeled ammonium chloride release were used to compare the trophic ecology of the central stoneroller minnow (Campostoma anomalum (Rafinesque)) and two species of crayfish (Orconectes neglectus (Faxon) and Orconectes nais (Faxon)) in a tallgrass prairie stream. The δ15N and δ13C values of Orconectes spp. were more similar to coarse benthic organic matter (CBOM) and filamentous green algae than to invertebrates, fine benthic organic matter (FBOM), and periphyton. Values for δ15N and δ13C in C. anomalum were more similar to grazer and collector invertebrates and filamentous green algae than to FBOM and periphyton. Results from a 15N tracer release also indicated a portion of algae and/or invertebrates were a component of nitrogen assimilated in Orconectes spp. and C. anomalum diets. Gut contents of C. anomalum were also analyzed. In contrast to stable isotope data, amorphous detritus was a significant component of C. anomalum guts, followed by diatoms and filamentous green algae. A significant percentage of invertebrate material was found in C. anomalum guts sampled in the spring. Experiments were conducted in artificial streams to determine if Orconectes spp. and C. anomalum could reduce epilithic algal biomass in small streams. Algal biomass on clay tile substrata was decreased relative to controls in artificial stream channels containing O. neglectus (3.4 fold, p=0.0002), C. anomalum (2.1 fold, p=0.0012), and both species combined (3.0 fold, p=0.0003). Results indicate that Orconectes spp. are functioning more as algal and detrital processors than as predators in Kings Creek. Isotope and gut content data show that C. anomalum includes invertebrates as well as algae and detritus in its diet. Both species have the potential to affect algal biomass and are important omnivores in the stream food web.},
	keywords = {LTER-KNZ, food webs, gut analysis, Herbivory, omnivory, Stable isotopes},
	doi = {10.1023/A:1013182100150},
	author = {Evans-White, M.A. and W. K. Dodds and Gray, L. and Fritz, K.M.}
}
@mastersthesis {KNZ00733,
	title = {A comparison of the functional role of crayfishes and central stonerollers in a tallgrass prairie stream},
	volume = {MS Thesis},
	year = {2000},
	pages = {1 -96},
	school = {Kansas State University},
	type = {M.S. Thesis},
	address = {Manhattan, KS},
	keywords = {LTER-KNZ, tallgrass prairie},
	author = {Evans-White, M.A.}
}
@article {KNZ00731,
	title = {Quantification of the nitrogen cycle in a prairie stream},
	journal = {Ecosystems},
	volume = {3},
	year = {2000},
	pages = {574 -589},
	abstract = {Nitrogen (N) was added for 35 days in the form of 15NH4Cl to Kings Creek on Konza Prairie, Kansas. Standing stocks of N in key compartments (that is, nutrients, detritus, organisms) were quantified, and the amount of labeled N entering the compartments was analyzed. These data were used to calculate turnover and flux rates of N cycling through the food web, as well as nutrient transformation rates. Inorganic N pools turned over much more rapidly in the water column of this stream than in pelagic systems where comparable measurements have been made. As with other systems, the mass of ammonium was low but it was the key compartment mediating nutrient flux through the ecosystem, whereas dissolved organic N, the primary component of N flux through the system, is not actively cycled. Nitrification was also a significant flux of N in the stream, with rates in the water column and surface of benthos accounting for approximately 10\% of the total ammonium uptake. Primary consumers assimilated 67\% of the inorganic N that entered benthic algae and microbes. Predators acquired 23\% of the N that consumers obtained. Invertebrate collectors, omnivorous crayfish (Orconectes spp.), and invertebrate shredders dominated the N flux associated with primary consumers. Mass balance calculations indicated that at least 23\% of the 309 mg of 15N added during the 35 days of release was retained within the 210-m stream reach during the release. Overall, the rates of turnover of N in organisms and organic substrata were significantly greater when C:N was low. This ratio may be a surrogate for biological activity with regard to N flux in streams.},
	keywords = {LTER-KNZ, aquatic insects, C:N ratio, nitrogen cycle, nitrogen export, stream, Trophic structure},
	doi = {10.1007/s100210000050},
	author = {W. K. Dodds and Evans-White, M.A. and N.M. Gerlanc and Gray, L. and Gudder, D.A. and Kemp, M.J. and Lo{\textquoteright}pez, A.L. and Stagliano, D. and Strauss, E. and Tank, J.L. and M.R. Whiles and Wollheim, W.}
}
