My research involves field studies of behavior, life histories and biological interactions among stream-dwelling invertebrates, predatory fish and algal resources in streams of western Colorado near the Rocky Mountain Biological Laboratory (http://www.rmbl.org).   I am interested in the mechanisms, consequences and evolution of predator-prey, consumer-resource, and competitive interactions, and how they relate to environmental disturbance as a consequence of climate change.  Recent and ongoing studies include 1) existence of alternative community states of stream grazer communities (disturbance-tolerant vs disturbance-intolerant grazers) as a consequence of the disturbance regime, 2)  the influence of trade-offs between resistance/resilience to disturbance, vulnerability of grazers to predation and nutrients on the strength of top-down interactions, 3) effects of changing environmental conditions on the prevalence of mermithid parasites and the consequences for mayfly host populations, 4) effects of upstream range expansions of novel trout and stonefly predators on mayfly mortality, behavior and life history, 5) effects of increasing extreme hydrological events and warming stream water temperatures on the synchrony of metamorphosis and oviposition, fecundity and susceptibility of mayflies to parasites and predators, 6) development of an integrative demographic model to predict the interactive effects of multiple stressors on mayflies, 7) macroinvertebrates as indicators of impacts of human activities on stream habitat quality: integrating research, education and outreach, and 8) causes and consequences of proliferation of a native, nuisance diatom (Didymosphenia geminata) on otherwise pristine stream ecosystems.

Alternative community states of stream grazer communities as a consequence of the disturbance regime:

• Mayfly grazers and diatoms predominate in disturbance-prone streams
• Cased-caddisfly grazers, filamentous algae and moss predominate in less disturbed streams
• Variation in the hydrological and geomorphic disturbance regime can be used to predict those alternative community states

Trade-offs between resistance/resilience to disturbance, vulnerability of grazers to predation and nutrients on the strength of top-down interactions:

• Mayflies trade-off disturbance tolerance for greater vulnerability to predation
• Cased caddisflies are protected from predation, yet vulnerable to hydrologic and geomorphic disturbance
• Behavioral trophic cascades from trout – mayfly grazers – diatoms are suppressed by nutrient limitation in high-altitude streams
• Adding nutrients reduces the strength of grazer-algal interactions

Effects of changing environmental conditions on the prevalence of mermithid parasites and the consequences for mayfly host populations:

• Warming stream temperatures can create a mismatch between the availability of mayfly hosts for the infective stages of mermithid parasites, thereby explaining spatial and temporal variation in the prevalence of parasitism
• Parasite prevalence is not recruitment-limited, but instead may be a function of post recruitment processes affecting encounter rates between parasites and hosts
• Parasitized mayflies trade-off rates of resource consumption to reduce susceptibility to predation
• Parasites suppress host risk-taking behavior and decrease consumption by predators

 Effects of upstream range expansions of novel trout and stonefly predators on mayfly mortality, behavior and life history:

• Warming temperatures may favor brown trout typical of lower elevations, thereby changing the predation regime of mayfly grazers
• Proliferation of Didymo favors a species of predatory stonefly typical of lower elevations
• Changing predation regimes can affect the mortality (consumptive effects), behavior and life history of mayfly prey (non-consumptive effects)

Increasing extreme hydrological events and warming stream water temperatures affect the synchrony of metamorphosis and oviposition, fecundity and susceptibility of mayflies to parasites and predators:

• Floods and droughts affect the availability of large rocks protruding from the stream surface used by mayflies for oviposition
• Warming temperatures accelerates mayfly development and may lead to asynchrony in the timing of metamorphosis and oviposition
• Warmer temperatures can have indirect effects on mayflies by favoring predators or parasites

Macroinvertebrates as indicators of impacts on stream habitat quality: integrating research, education and outreach:

• Educating target groups about the theory and practice of biomonitoring streams
• Assessing the impacts of disturbances on stream habitat quality
• Baseline biomonitoring of invertebrates of streams vulnerable to degradation due to human activities
• Developing a long term database of stream invertebrate communities as a basis for understanding the relative importance of natural and human-induced disturbances in explaining population and community fluctuations

Causes and consequences of proliferation of a native, nuisance diatom (Didymosphenia geminata) on otherwise pristine stream ecosystems.

• Didymo proliferation is greater under high light conditions, and is suppressed by shade
• Didymo proliferation is greater in years with early spring snowmelt, lower peak flows and higher water temperatures, which are conditions becoming more common as the climate warms in high elevation systems
• Proliferation of Didymo causes a shift from mayfly-dominated to midge dominated benthic invertebrates, which provide lower caloric food for trout, thereby resulting in lower trout growth rates

We work in high elevation streams at one of the most beautiful places in the world, the Rocky Mountain Biological Laboratory (http://www.rmbl.org), which is situated in the West Elk Mountains near Crested Butte, Colorado.   Our sites include headwater snowmelt streams and spring-fed streams that are fishless, but contain predatory aquatic insects, and lake outlet streams and lower gradient streams that contain predatory brook trout. The favorite prey of aquatic insect predators and brook trout are mayflies of the genus Baetis, who lay their eggs under rocks in many of these high elevation streams.

Our methods include sampling invertebrates, fish and algae as well as physical, chemical attributes in the field, and experiments conducted in artificial streams (mesocosms and microcosms).

Research Publications (last 20 years)

Caudill, C. C. and B. L. Peckarsky.  2003.  Lack of appropriate behavioral or developmental responses by mayfly larvae to trout predators. Ecology 84:2133-2144. (pdf)

Dahl, J and B. L. Peckarsky. 2003.  Developmental responses to predation risk in morphologically defended mayflies.  Oecologia 137:188-194. (pdf)

Hughes, J. M., P. B. Mather, M. Hillyer, C. Cleary and B. L. Peckarsky. 2003. Genetic structure in a montane mayfly Baetis bicaudatus (Ephemeroptera: Baetidae), from the Rocky Mountains, Colorado.  Freshwater Biology 12:2149-2162. (pdf)

Dahl, J. and B. L. Peckarsky.  2003.  Does living in streams with fish involve a cost of induced morphological defenses?  Canadian Journal of Zoology 81:1825-1828. (pdf)

Macneale, K. H., B. L. Peckarsky, and G. E. Likens.  2004. Contradictory results from different methods for measuring direction of insect flight.  Freshwater Biology 49:1260-1268. (pdf)

McIntosh, A. R, B. L. Peckarsky, and B. W. Taylor.  2004. Predator-induced resource heterogeneity in a stream food web.  Ecology 85:2279-2290. (pdf)

McIntosh, A. R. and B. L. Peckarsky. 2004. Are mayfly anti-predator responses to fish odor proportional to risk?  Archiv für Hydrobiologie 160:145-151. (pdf)

Peckarsky B.L., J. M. Hughes, M. Hillyer, and A. C. Encalada. 2004.  Are populations of mayflies living in adjacent fish and fishless streams genetically distinct? Freshwater Biology 50: 42-51. (pdf)

Alvarez, M. and B. L. Peckarsky.  2005. How do grazers affect periphyton heterogeneity in streams? Oecologia 142: 576 – 587. (pdf)

Harper, M. P. and B. L. Peckarsky.  2005. Effects of pulsed and pressed disturbances on the benthic invertebrate community following a coal spill in a small stream in northeastern USA. Hydrobiologia 544:241-247. (pdf)

Macneale K. H., B. L. Peckarsky, and G. E. Likens.  2005.  Stable isotopes identify dispersal patterns of a stonefly.  Freshwater Biology 50:1117-1130. (pdf)

Harper, M. P. and B. L. Peckarsky.  2006.  Emergence cues of a mayfly in a high altitude stream ecosystem:  Implications for consequences of climate change.  Ecological Applications 16:612-621. (pdf)

Encalada, A. C. and B. L. Peckarsky. 2006. Selective oviposition by the mayfly Baetis bicaudatus. Oecologia 148:526-537. (pdf)

Encalada, A. C. and B. L. Peckarsky. 2007.  A comparative study of the cost of alternative mayfly oviposition behaviors.  Behavioral Ecology and Sociobiology 61:1437-1448. (pdf)

Peckarsky, B. L., B. L. Kerans, A. R. McIntosh and B. W. Taylor. 2008. Predator effects on prey population dynamics in open systems.  Oecologia 156:431-440. (pdf)

Wilcox, A, B. L. Peckarsky, B. W. Taylor and A. C. Encalada.  2008. Hydraulic and geomorphic effects on mayfly drift in high-gradient streams at moderate discharges. Ecohydrology 1:176-186. (pdf)

Orrock, J. L, J. H. Grabowski, J. H. Pantele, S. D. Peacor, B. L. Peckarsky, E. L. Preisser, A. Sih and E. E. Werner. 2008. Consumptive and non-consumptive effects of predators on metacommunities of competing prey. Special Feature. Ecology 89:2426-2435. (pdf)

Peckarsky, B. L, D. A. Bolnick, L. M. Dill, J. H. Grabowski, B. Luttbeg, J. L. Orrock, S. D. Peacor, E. L. Preisser, O. J. Schmitz and G.C. Trussell.  2008. Revisiting the Classics: Considering non-consumptive effects in textbook examples of predator-prey interactions.  Special Feature. Ecology 89: 2416-2425. (pdf)

Schmitz, O. J., J. H. Grabowski, B. L. Peckarsky, E. L. Preisser, G. C. Trussell and J. R. Vonesh.  2008.  From individuals to ecosystem function: toward an integration of evolutionary and ecosystem ecology.  Special Feature. Ecology 89:2436-2445. (pdf)

Orrock, J. L., A. Sih, L. M. Dill, J. H. Grabowski, S. D. Peacor, B. L. Peckarsky, E. L. Preisser, J. R. Vonesh, and E. E. Werner. 2010. Predator effects in predator-free space:  The remote effects of predators on prey. Special Feature on the Ecology of Fear. The Open Ecology Journal 3:22 – 30.  (pdf)

Fuller, M. R. and B. L. Peckarsky.  2011.  Ecosystem engineering by beavers affects mayfly life histories. Freshwater Biology 56:959-979. (pdf)

Fuller, M. R. and B. L. Peckarsky.  2011. Does the morphology of beaver ponds alter downstream ecosystems? Hydrobiology 668 (1):35-48. (pdf)

Peckarsky, B. L., A. C. Encalada and A. R. McIntosh.  2011. Why do vulnerable mayflies thrive in trout streams? Feature Article in American Entomologist 57(3):152-164. (pdf)

Encalada, A. C. and B. L. Peckarsky. 2011. The influence of recruitment on within-generation population dynamics of a mayfly. Ecosphere 2(10):107.doi:10.1890/ES11-00103.1. (pdf)

Encalada, A. C. and B. L. Peckarsky. 2011. Large-scale manipulation of mayfly recruitment affects population size. Oecologia. DOI 10.1007/s00442-0112147-1. (pdf)

Encalada, A. C. and B. L. Peckarsky. 2012. Large-scale manipulation of mayfly recruitment affects population size. Oecologia 168:967-976. DOI 10.1007/s00442-0112147-1. (pdf)

Peacor, S. D., B. L. Peckarsky, G. C. Trussell, and J. R. Vonesh.  2013. Costs of predator-induced phenotypic plasticity: A graphical model for predicting the contribution of non-consumptive and consumptive effects of predators on prey. Oecologia 171:1-10. (pdf)

Alp, M., B. L. Peckarsky, S. Bernasconi and C. T. Robinson.  2013. Shifts in natural isotopic signatures of animals with complex life-cycles can complicate conclusions on cross-boundary trophic links. Aquatic Sciences 75:595-606. (pdf)

Àlvarez, M. and B. L. Peckarsky. 2013. The influence of moss on grazer assemblages in high altitude streams:food, refuge or both?. Freshwater Biology 58:1982-1994. (pdf)

Peckarsky, B. L., A. R. McIntosh, M. Alvarez, and J. M. Moslemi. 2013. Nutrient limitation controls the strength of behavioral trophic cascades in high elevation streams. Ecosphere 4(7):XX.(pdf)

Àlvarez, M. and B. L. Peckarsky. 2014. Cascading effects of predatory fish on the composition of benthic algae in high-altitude streams.  Oikos 123:120-127. DOI: 10.1111/j.1600-0706.2013.00397.x. (pdf)

Hernandez, S. and B. L. Peckarsky.  2014. Do stream mayflies exhibit trade-offs between food acquisition and predator avoidance behaviors? Freshwater Science 33:1-11. (pdf)

Peckarsky, B. L, A. R. McIntosh, S. C. Horn, A. Wilcox, K. McHugh, D. Booker, W. S. Brown, and M. Alvarez.  2014. Characterizing disturbance regimes of mountain streams. Freshwater Science 33:716-730. (pdf)

Heino, J. and B. L. Peckarsky. 2014.  Integrating behavioral, population and large-scale approaches for understanding stream insect communities.  Current Opinion in Insect Science 2:7-13. (pdf)

Alvarez, M., A. Landiera-Dabarca and B. L. Peckarsky. 2014. Origin and specificity of predatory fish cues detected by Baetis larvae (Ephemeroptera: Insecta).  Animal Behavior 96:141-149. (pdf)

Peckarsky B. L, A. R. McIntosh, M. Alvarez and J. M. Moslemi. 2015. Disturbance legacies and nutrient limitation influence interactions between grazers and algae in high elevation streams. Ecosphere 6(11):XXXX.(pdf)

Lund, J. O., S. A. Wissinger, and B. L. Peckarsky. 2016. Caddisfly behavioral responses to drying cues in temporary ponds: implications for effects of climate change. Freshwater Science 35(2):619-630. (pdf)

Landiera-Dabarca, A., Alvarez, M., and B. L. Peckarsky. 2019. Mayflies avoid sweets: fish skin mucus amino-sugars stimulate predator-avoidance behaviour of Baetis larvae.  Animal Behaviour 158:35-45. (pdf)

Koch, B. J., B. L. Peckarsky and R. O. Hall. 2020. Nonconsumptive effects of brook trout predators reduce secondary production of mayfly prey. Freshwater Science 39(3):549-558. (pdf)

Downes, B. A., B. L. Peckarsky, J. Lancaster, W. Boville, and M. Alp. 2021. (Invited review) From insects to frogs, egg-juvenile recruitment can have persistent effects on population sizes. Annual Review of Ecology, Evolution and Systematics 52:67-86. (pdf)

Teaching and Environmental Assessment Publications

Peckarsky, B. L., P. Fraissinet, M. A. Penton, and D. J. Conklin, Jr. 1990. Freshwater macroinvertebrates of Northeastern North America. Cornell University Press, Ithaca, NY.  442 pp.

Peckarsky, B. L. 1996. Predator-prey interactions. Chapter 20 (pp. 431-451) In: R. Hauer and G. Lamberti (eds.) Methods in Stream Ecology, Academic Press, NY.

Peckarsky, B. L. 1997. Macroinvertebrates as indicators of stream habitat degradation.  Pp. 37-40 in: Streamkeepers. Aquatic Insects as Biomonitors.  Xerces Society, Portland, OR. (pdf)

Peckarsky, B. L. 1998.The dual role of experiments in complex and dynamic natural systems.  pp. 311-423 in: Resetaritz, W. J. Jr. and J. Bernardo (eds).  Experimental Ecology. Issues and Perspectives. Oxford Univ. Press.

Anderson, C.R, B. L. Peckarsky, and S. A. Wissinger. 1999. Tinajas of southeastern Utah.  Invertebrate reproductive strategies and the habitat templet. pp. 791-810 in: Batzer, D. P, R.B. Rader, and S. A. Wissinger (eds.). Invertebrates in freshwater wetlands of North America. John Wiley & Sons, Inc, NY.(pdf)

Lytle, D. A. and B. L. Peckarsky. 2001. Spatial and temporal impacts of a diesel fuel spill on stream invertebrates. Freshwater Biology 46:1 – 12. (pdf)

Taylor, B. W, A. R. McIntosh and B. L. Peckarsky.  2001.  Sampling stream invertebrates using electroshocking techniques: implications for basic and applied research. Canadian Journal of Fisheries and Aquatic Science 58:1-9. (pdf)

Peckarsky, B. L.  2006.  Predator-prey interactions.  Chapter 24 In: R. Hauer and G. Lamberti (eds.) Methods in Stream Ecology, Academic Press, NY. Second edition. (pdf)

Peckarsky, B. L. J. D. Allan, A. R. McIntosh and B. W. Taylor.  2010.  Understanding the role of predation in open systems: the value of place-based research. Pages 185-206 In: Ian A. Billick and Mary V. Price, Editors.  The Ecology of Place.  University of Chicago Press. (pdf)

Peckarsky, B. L. and G. A. Lamberti. 2017. Invertebrate consumer – resource interactions. Chapter 18 In: F. R. Hauer and G. A. Lamberti (Eds.) Methods in Stream Ecology, Volume 1: Ecosystem Structure. Elsevier, Academic Press. ISBN: 9780124165588. (pdf)