About

Bobbi Peckarsky is a professor in the Department of Entomology at the University of Wisconsin-Madison. Her 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. Her work focuses on the mechanisms, consequences, and evolution of predator-prey, consumer-resource, and competitive interactions, particularly in relation to environmental disturbances caused by climate change. Her ongoing studies include examining alternative community states of stream grazer communities as a result of disturbance regimes, the influence of trade-offs between resistance and resilience to disturbance, and the effects of changing environmental conditions on parasite prevalence and mayfly populations. She investigates how upstream range expansions of predators impact mayfly mortality and behavior, as well as how extreme hydrological events and warming stream temperatures affect the timing of metamorphosis, oviposition, and susceptibility to parasites and predators. Peckarsky also develops demographic models to predict the effects of multiple stressors on mayflies, and uses macroinvertebrates as indicators of stream habitat quality impacted by human activities. Her research is conducted in high elevation streams at the Rocky Mountain Biological Laboratory in Colorado, where she employs field sampling and experiments in artificial streams to understand ecological dynamics. Her work contributes to understanding the impacts of environmental disturbances on stream ecosystems, predator-prey interactions, and the proliferation of native nuisance species such as Didymo, with implications for conservation and biomonitoring.

Research topics

• Biology
• Ecology
• Zoology
• Fishery

Selected publications

• Consequences of nuisance algal blooms of <i>Didymosphenia geminata</i> on invertebrate communities in Rocky Mountain streams

  Freshwater Science · 2024-01-10 · 3 citations

  article
  PublisherDOI

• From Insects to Frogs, Egg–Juvenile Recruitment Can Have Persistent Effects on Population Sizes

  Annual Review of Ecology Evolution and Systematics · 2021 · 13 citations

  • Biology
  • Ecology
  • Zoology

  Understanding what regulates population sizes of organisms with complex life cycles is challenging because limits on population sizes can occur at any stage or transition. We extend a conceptual framework to explore whether numbers of successfully laid eggs determine densities of later stages in insects, fish, amphibians, and snails inhabiting marine, freshwater, or terrestrial habitats. Our review suggests novel hypotheses, which propose characteristics of species or environments that create spatial variation in egg densities and predict when such patterns are maintained throughout subsequent life-cycle stages. Existing data, although limited, suggest that persistent, strong associations between egg and subsequent juvenile densities are likely for species where suitable egg-laying habitat is in short supply. Those associations are weakened in some environments and for some species by density-dependent losses of eggs or hatchlings. Such cross-ecosystem comparisons are fundamental to generality in ecology but demand place-based understandings of species’ biology and natural history.

  PublisherOA PDFDOI

• Nonconsumptive effects of Brook Trout predators reduce secondary production of mayfly prey

  Freshwater Science · 2020 · 3 citations

  Senior authorCorresponding
  • Ecology
  • Biology
  • Fishery

  The nonconsumptive effects of predators on prey include behavioral, physiological, and life-history changes that reduce the risk of predation but have associated energetic or fitness costs to prey individuals and populations. Biologists have documented such changes for a wide array of predator–prey interactions in a variety of ecosystems; however, the energetic cost of nonconsumptive effects to prey populations has rarely been measured directly. Using a reach-scale manipulation of a naturally-fishless stream, we added chemical cues produced by live Brook Trout (Salvelinus fontinalis Mitchill, 1814) to simulate the presence of trout predation risk, and we quantified the impact of nonconsumptive effects on the secondary production of mayfly prey in the stream. The addition of trout chemical cues reduced the secondary production of larval Baetis mayflies in the treatment reach by 17% compared to an upstream, unmanipulated reference reach. This reduction was driven by smaller body size and earlier emergence of mayflies from the reach with added predator cues. The nonconsumptive effects of a predator can consequently reduce the flux of energy through a dominant stream invertebrate by altering individual life-history and development patterns. Furthermore, quantifying the population-level impact of nonconsumptive effects enables understanding the extent to which these widespread predator effects shape food-web dynamics and ecosystem processes.

  PublisherDOI

• Mayflies avoid sweets: fish skin mucus amino sugars stimulate predator avoidance behaviour of Baetis larvae

  Animal Behaviour · 2019-11-04 · 8 citations

  articleSenior author
  PublisherDOI

• Invertebrate Consumer–Resource Interactions

  Elsevier eBooks · 2017-01-01 · 15 citations

  book-chapter1st authorCorresponding
  PublisherDOI

• Appendix B. Images of apparatus used for field experiments.

  Figshare · 2016-01-01

  article1st authorCorresponding

  Images of apparatus used for field experiments.

  DOI

• Caddisfly behavioral responses to drying cues in temporary ponds: implications for effects of climate change

  Freshwater Science · 2016-02-11 · 42 citations

  articleSenior authorCorresponding

  Aquatic organisms that live at high latitudes and elevations are especially vulnerable to climate-change-induced alterations in snowpack, snowmelt, and evaporation rates, all of which affect basin filling and drying dates. Extraordinarily early drying events in shallow ponds and wetlands at our study sites prompted us to conduct 2 mesocosm experiments to document how proximate cues of drying modify agonistic behaviors among larvae of the caddisfly, Asynarchus nigriculus. Larvae are mainly detritivores but can be extremely aggressive and engage in mob cannibalism, perhaps to obtain a dietary supplement that hastens escape from drying basins. In one experiment, we manipulated caddisfly density to simulate the effects of crowding during pond drying. In a 2nd experiment, we reduced water levels and manipulated a protein supplement that mimics the dietary benefits of cannibalism. We quantified the effects of those manipulations on aggressive behaviors that are precursors to cannibalism and on development time to pupation. Frequency and duration of agonistic encounters increased as a function of larval density and, independent of density, were higher in drying than nondrying treatments, especially in the absence of a protein supplement. Pupation occurred earlier in high- than low-density treatments and earlier with than without a protein supplement. In contrast, the timing of pupation was not accelerated in drying compared with nondrying treatments, which might reflect the extreme diel temperature fluctuations in drying ponds, hence suboptimal growth conditions. Our findings provide evidence that declining water levels and crowding serve as cues that enable caddisflies to adjust behavior and development in the face of habitat drying. Early drying events observed in recent years may exceed the limits of this flexibility and portend the demise of populations in temporary habitats that historically supported this species.

  PublisherDOI

• Appendix A. Detailed description of streams where surveys and experiments were conducted.

  Figshare · 2016-01-01

  datasetOpen access1st authorCorresponding

  Detailed description of streams where surveys and experiments were conducted.

  PublisherDOI

• Appendix B. Images of apparatus used for field experiments.

  Figshare · 2016-01-01

  datasetOpen access1st authorCorresponding

  Images of apparatus used for field experiments.

  PublisherDOI

• Disturbance legacies and nutrient limitation influence interactions between grazers and algae in high elevation streams

  Ecosphere · 2015-11-01 · 10 citations

  articleOpen access1st authorCorresponding

  Debate about control of interaction strength among species is fueled by variation in environmental contexts affecting food webs. We used extensive surveys and two field experiments to test the individual and interactive influences of variation in the assemblages and associated traits of grazers as shaped by the legacy of disturbance, nutrient limitation and the presence of top predators on the accrual of basal resources. We quantified hydrologic variation and streambed movement to describe the legacy of disturbance and sampled biota of 20 streams over five years in a high‐elevation catchment in Colorado, USA. Grazer assemblages switched from caddisfly‐dominated to mayfly‐dominated as disturbance increased. We manipulated the composition of grazer assemblages and the availability of nutrients (N and P) within flow‐through mesocosms assembled adjacent to 10 streams, and also deployed larger in‐stream channels manipulating the presence of top predators (brook trout) in five streams varying in disturbance regimes. In both experiments we compared the rate of accrual of benthic algae and the strength of grazer‐algal interactions among treatments. We observed no indirect effects of top predators on grazer mobility, grazer consumption of algae, or accrual of algal biomass (no trophic cascades). However, in both experiments accrual rates of algae yielded a unimodal pattern and grazer impacts on algae decreased with increasing disturbance, but only at ambient (limiting) nutrient conditions. When nutrients were amended in the mesocosm experiment, algal accrual was uniformly high and grazer impacts on algae were consistently low. Reduced algae accrual at high disturbance levels may be explained by direct effects of environmental harshness on algae, and at low disturbance by indirect effects on grazer traits (behaviors) rather than on grazer density. In more benign streams per capita and per unit biomass grazer impacts on algae were high and drift dispersal was low, both behaviors that reduced accrual of algae. We conclude that nutrient limitation and indirect effects of disturbance on accrual of algae mediated by grazer traits can be stronger than indirect effects of predators on algae, providing a new contribution to the debate about the influence of environmental context on the strength of food web interactions.

  PublisherOA PDFDOI

Recent grants

• Variation in the Strength of Cascading Trophic Interactions Across a Riverscape

  NSF · $350k · 2005–2010

Frequent coauthors

• Angus R. McIntosh

  University of Canterbury

  49 shared

• Gene E. Likens

  39 shared

• Stanley I. Dodson

  39 shared

• Brad W. Taylor

  North Carolina State University

  38 shared

• Robert Bohanen

  37 shared

• Grace Wyngaard

  37 shared

• John J. Magnuson

  University of Wisconsin–Madison

  37 shared

• John E. Havel

  Missouri State University

  37 shared

Education

• Ph.D., Entomology

  University of Wisconsin-Madison

  2005

• M.S., Entomology

  University of Wisconsin-Madison

  2001

• B.S., Entomology

  University of Wisconsin-Madison

  1999