The overarching aim of our research program is to understand the implications of anthropogenic stressors (e.g. climate change, pollution, invasive species, and human encroachment) on behavioral and physiological responses that are necessary for individual and population level fitness in both keystone ecosystem engineers (e.g. prairie dogs) and wild-caught model organisms (e.g. Drosophila). To address these interdisciplinary questions, the research team utilizes both field and laboratory techniques, at multiple biological levels of organization. Our mission is to contribute to research that is important for improving environmental quality and conservation of keystone species and their habitats.
impact of multiple stressors on keystone mammalian species
Grasslands inhabit 26% of the world's land, however, most of the grasslands are now considered critically endangered due to fragmentation, suppression of fires, and transition into agricultural areas. Black-tailed prairie dogs are both a keystone species and ecosystem engineers native to these grasslands. They provide several ecosystem services to grassland ecosystems, such as regulating soil erosion and increasing plant biodiversity, to name a few. Black-tailed prairie dogs now inhabit approximately 2% of their historic range due to conversion of prairie to grassland, large scale poisoning, sylvatic plague, and climate change-induced drought. These population declines have led to an increase in desertification of semiarid grasslands and a loss of ecosystem services for grassland ecosystems. Therefore, conserving such an important keystone species is critical to the survival of vital grassland ecosystems. However, we know little about their reproductive physiology and behavior because they live and spend much of their time in burrows. Since prairie dogs live in socially complex, cooperative colonies, they are also an ideal system to monitor the impacts of multiple stressors on physiological and behavioral responses.
We use a variety of field and laboratory techniques to: 1) understand their basic reproductive biology and behaviors, 2) understand the long-term implications of plague and climate change on their reproduction, behaviors, and ability to rebound from these stressors, 3) measure predator abundance and its impact on long-term population sizes, 4) develop new conservation tools, and 4) test the efficacy of translocation methods.
We use a variety of field and laboratory techniques to: 1) understand their basic reproductive biology and behaviors, 2) understand the long-term implications of plague and climate change on their reproduction, behaviors, and ability to rebound from these stressors, 3) measure predator abundance and its impact on long-term population sizes, 4) develop new conservation tools, and 4) test the efficacy of translocation methods.
ecosystem-level studies
Impact of Black-tailed prairie dogs on biodiversity: We are collaborating with several other researchers from Colorado State University-Pueblo and U.S. Fish & Wildlife Service to determine the impact of Black-tailed prairie dogs on biodiversity in a grassland ecosystem.
Biomagnification of Pb in terrestrial ecosystems in Pueblo CO: Previous research has shown that areas within the city of Pueblo, Colorado have lead (Pb) levels higher than the Environmental Protection Agency's (EPA) 400 ppm benchmark for cleanup, due to pollution from past smelting activities. Therefore, the EPA added contaminated areas within the city of Pueblo to the Superfund National Priorities List in 2014, and cleanup efforts are currently underway. Despite our knowledge of Pb toxicity in humans, little is known regarding biomagnification of Pb in the food chain in terrestrial ecosystems. The broad objectives of this research is to determine whether Pb is biomagnifying in the terrestrial food chain at the Pueblo Superfund Site.
Biomagnification of Pb in terrestrial ecosystems in Pueblo CO: Previous research has shown that areas within the city of Pueblo, Colorado have lead (Pb) levels higher than the Environmental Protection Agency's (EPA) 400 ppm benchmark for cleanup, due to pollution from past smelting activities. Therefore, the EPA added contaminated areas within the city of Pueblo to the Superfund National Priorities List in 2014, and cleanup efforts are currently underway. Despite our knowledge of Pb toxicity in humans, little is known regarding biomagnification of Pb in the food chain in terrestrial ecosystems. The broad objectives of this research is to determine whether Pb is biomagnifying in the terrestrial food chain at the Pueblo Superfund Site.
using drosophila as a model for integrative behavioral ecotoxicology
Anthropogenic Pb pollution is ubiquitous in the environment due to past and current use. Pb exposure has been estimated to be responsible (or at least partially responsible) for population declines of several species. However, there has been little research on the implications of Pb exposure on behavioral and reproductive outcomes that may mediate a population's ability to persist in the face of this pollution. Drosophila is an ideal invertebrate model system to study behavioral and reproductive outcomes of Pb pollution because of the absence of ethical barriers, ease of sampling and manipulation, lower costs and technological tools available, and their complex reproductive system.
Our research team has previously used laboratory populations of Drosophila melanogaster to understand the reproductive behavioral impacts of Pb. We found that Drosophila readily accumulate Pb throughout their life, indicating that Drosophila are a suitable model system (Peterson et al. 2017, Chemosphere, 181:368-375). We found that developmental Pb exposure increased copulation duration and decreased fecundity at 500 uM PbAc (Peterson et al. 2019, Bulletin of Environmental Chemistry and Toxicology, 103:233-239). We also found that genetic variation plays a role in Pb susceptibility in these reproductive behaviors (Peterson et al. 2019, Bulletin of Environmental Chemistry and Toxicology, 103:233-239), indicating the importance of genetic variation on Pb susceptibility or resistance. We then found that Pb exposure induced asymmetrical assortative mating in Pb-treated females at 250 uM PbAc, but this is not mediated by differences in the courtship song, copulation duration and latency, or the sex pheromone profiles in males (Peterson et al. 2017, Current Zoology, 63:195-203). We currently collect wild populations of Drosophila pseudoobscura to continue this research and direct our research in the field with wildlife.
Our research team has previously used laboratory populations of Drosophila melanogaster to understand the reproductive behavioral impacts of Pb. We found that Drosophila readily accumulate Pb throughout their life, indicating that Drosophila are a suitable model system (Peterson et al. 2017, Chemosphere, 181:368-375). We found that developmental Pb exposure increased copulation duration and decreased fecundity at 500 uM PbAc (Peterson et al. 2019, Bulletin of Environmental Chemistry and Toxicology, 103:233-239). We also found that genetic variation plays a role in Pb susceptibility in these reproductive behaviors (Peterson et al. 2019, Bulletin of Environmental Chemistry and Toxicology, 103:233-239), indicating the importance of genetic variation on Pb susceptibility or resistance. We then found that Pb exposure induced asymmetrical assortative mating in Pb-treated females at 250 uM PbAc, but this is not mediated by differences in the courtship song, copulation duration and latency, or the sex pheromone profiles in males (Peterson et al. 2017, Current Zoology, 63:195-203). We currently collect wild populations of Drosophila pseudoobscura to continue this research and direct our research in the field with wildlife.