The influence of urbanization and changes in hydrology on the trophic ecology of stream fishes
Currently, I am working with Jason Knouft in the Aquatic Ecology Laboratory at St. Louis University. One of the biggest threats to freshwater biodiversity is the anthropogenic alteration of natural flow regimes. I am investigating how changes in stream flow alter trophic complexity and resource heterogeneity for fish consumers (measured as 'isotopic niche breadth') using stable isotope analysis. I am working with data from fish assemblages and macroinvertebrates in the Meramec River watershed, which is located in southeastern Missouri. With this work I hope to increase our understanding of how human-induced alteration to freshwater systems alters important trophic interactions.
Currently, I am working with Jason Knouft in the Aquatic Ecology Laboratory at St. Louis University. One of the biggest threats to freshwater biodiversity is the anthropogenic alteration of natural flow regimes. I am investigating how changes in stream flow alter trophic complexity and resource heterogeneity for fish consumers (measured as 'isotopic niche breadth') using stable isotope analysis. I am working with data from fish assemblages and macroinvertebrates in the Meramec River watershed, which is located in southeastern Missouri. With this work I hope to increase our understanding of how human-induced alteration to freshwater systems alters important trophic interactions.
Titrating risk and reward to quantify the foraging cost of predation in coral reef communities
My research was part of the historic "Mission 31" at Aquarius Reef Base (ARB) at Conch Reef in the Florida Keys National Marine Sanctuary (FKNMS). Alongside Fabien Cousteau, Jacques Cousteau's grandson, a team of researchers lived underwater for 31 days, conducting experiments on the ocean floor. I am investigating how herbivorous reef fish make the trade-off between risk and reward by manipulating patch quality. We performed ‘behavioral titration’ experiments whereby food quality (i.e., density) was manipulated to determine the point at which foragers are willing to accept greater risk to receive a greater benefit. In this way, foragers should reveal a point of indifference between a low-reward/low-risk option and a high-reward/ high-risk option.
My research was part of the historic "Mission 31" at Aquarius Reef Base (ARB) at Conch Reef in the Florida Keys National Marine Sanctuary (FKNMS). Alongside Fabien Cousteau, Jacques Cousteau's grandson, a team of researchers lived underwater for 31 days, conducting experiments on the ocean floor. I am investigating how herbivorous reef fish make the trade-off between risk and reward by manipulating patch quality. We performed ‘behavioral titration’ experiments whereby food quality (i.e., density) was manipulated to determine the point at which foragers are willing to accept greater risk to receive a greater benefit. In this way, foragers should reveal a point of indifference between a low-reward/low-risk option and a high-reward/ high-risk option.
The effect of predator hunting mode and diel patterns in predation risk on herbivore feeding behavior
With the unique resources of Aquarius Reef Base (ARB) at Conch Reef in the Florida Keys National Marine Sanctuary (FKNMS), I am studying how crepuscular patterns of light availability, prey state (i.e., hunger) and predator functional traits (i.e., hunting mode) influence prey foraging behaviors. I directly alter the threat of predation using model predator decoys that I anchor to the reef in hunting poses for multiple short-term experiments. At increasing distances from decoys I place and film standardized assays of a palatable seagrass (Thallassia). By conducting these experiments at different times of day, using different predator models, I am addressing how responses to risk can change with context. Results suggest that prey state (i.e., hunger level) increases the amount of risk the prey are willing to accept. Furthermore, predator identity altered threat-sensitive responses of herbivores, with more threatening predators evoking greater responses by prey.
With the unique resources of Aquarius Reef Base (ARB) at Conch Reef in the Florida Keys National Marine Sanctuary (FKNMS), I am studying how crepuscular patterns of light availability, prey state (i.e., hunger) and predator functional traits (i.e., hunting mode) influence prey foraging behaviors. I directly alter the threat of predation using model predator decoys that I anchor to the reef in hunting poses for multiple short-term experiments. At increasing distances from decoys I place and film standardized assays of a palatable seagrass (Thallassia). By conducting these experiments at different times of day, using different predator models, I am addressing how responses to risk can change with context. Results suggest that prey state (i.e., hunger level) increases the amount of risk the prey are willing to accept. Furthermore, predator identity altered threat-sensitive responses of herbivores, with more threatening predators evoking greater responses by prey.
The effect of acute and chronic predation risk on herbivore feeding behavior within a seascape context
The three dimensional structure of an ecosystem, often provided by living organisms such as trees and grasses, set the stage for where and how predator and prey interact. The term “landscape of fear” refers to the heterogeneous habitat created by terrain features that affect the probability of predator and prey encountering, an attack ensuing from that encounter and the probability that prey will escape. Across multiple reefs along the FKNMS with varying predator abundance, I am studying how landscape influences the predator-prey interaction. Our data suggest that important predator prey interactions may be altered as reef structural complexity is reduced by coral loss. Changes in structure could alter patterns of habitat use and foraging behavior. Such changes for large mobile herbivores, that are known to be important for their role in grazing and controlling algal overgrowth, may have important implications for benthic communities.
The three dimensional structure of an ecosystem, often provided by living organisms such as trees and grasses, set the stage for where and how predator and prey interact. The term “landscape of fear” refers to the heterogeneous habitat created by terrain features that affect the probability of predator and prey encountering, an attack ensuing from that encounter and the probability that prey will escape. Across multiple reefs along the FKNMS with varying predator abundance, I am studying how landscape influences the predator-prey interaction. Our data suggest that important predator prey interactions may be altered as reef structural complexity is reduced by coral loss. Changes in structure could alter patterns of habitat use and foraging behavior. Such changes for large mobile herbivores, that are known to be important for their role in grazing and controlling algal overgrowth, may have important implications for benthic communities.
Indirect effects of marine reserves on complex social and mating systems of important reef fishes
For many species securing large, high quality territories is important for feeding and reproduction. Many factors such as competition, habitat availability and male characteristics can influence a territory holder’s ability to establish and maintain a territory. The risk of predation is known to have an important influence on reproduction, however few have studied its effect on territoriality. I am studying territoriality in a haremic, polygynous species of reef herbivore, Sparisoma aurofrenatum, across eight reefs in the Florida Keys National Marine Sanctuary with varying predator biomass. Our work argues that coral loss and the resulting decline in structural complexity as well as declining predator abundances from overfishing could alter the territory dynamics and reproductive potential of important herbivore species.
For many species securing large, high quality territories is important for feeding and reproduction. Many factors such as competition, habitat availability and male characteristics can influence a territory holder’s ability to establish and maintain a territory. The risk of predation is known to have an important influence on reproduction, however few have studied its effect on territoriality. I am studying territoriality in a haremic, polygynous species of reef herbivore, Sparisoma aurofrenatum, across eight reefs in the Florida Keys National Marine Sanctuary with varying predator biomass. Our work argues that coral loss and the resulting decline in structural complexity as well as declining predator abundances from overfishing could alter the territory dynamics and reproductive potential of important herbivore species.
Using Stable Isotope Analysis (SIA) to understand the drivers of herbivore foraging
Food availability, competition, habitat complexity, and territorial damselfish shape foraging decisions of herbivorous coral reef fishes. However, relatively little is known about how predators affect herbivore diet selection. With this study I examined diets of two common reef herbivores, Sparisoma aurofrenatum and Acanthurus coeruleus in the Florida Keys, across sites of varying predator biomass. I used stable isotope analysis to understand the importance of predation risk relative to other known drivers of herbivore foraging decisions.I found that both predator and damselfish abundance impacted diet diversity in different ways for these two fishes, which may be linked to differences in sociality and group foraging. A. coeruleus is more likely to forage in schools potentially reducing predation risk and allowing them to overwhelm damselfishes and access their territories. Interestingly, damselfish abundance was positively correlated with predator biomass suggesting that predators may influence herbivore diets indirectly via altered densities or behavior of damselfishes. This work argues for more emphasis on the role of predation risk in affecting herbivore foraging in order to understand the implications of human-mediated predator removal and recovery in coral reef ecosystems.
Food availability, competition, habitat complexity, and territorial damselfish shape foraging decisions of herbivorous coral reef fishes. However, relatively little is known about how predators affect herbivore diet selection. With this study I examined diets of two common reef herbivores, Sparisoma aurofrenatum and Acanthurus coeruleus in the Florida Keys, across sites of varying predator biomass. I used stable isotope analysis to understand the importance of predation risk relative to other known drivers of herbivore foraging decisions.I found that both predator and damselfish abundance impacted diet diversity in different ways for these two fishes, which may be linked to differences in sociality and group foraging. A. coeruleus is more likely to forage in schools potentially reducing predation risk and allowing them to overwhelm damselfishes and access their territories. Interestingly, damselfish abundance was positively correlated with predator biomass suggesting that predators may influence herbivore diets indirectly via altered densities or behavior of damselfishes. This work argues for more emphasis on the role of predation risk in affecting herbivore foraging in order to understand the implications of human-mediated predator removal and recovery in coral reef ecosystems.