OREGON STATE UNIVERSITY

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Research program overview

I am an animal ecologist with broad research interests, and the different components of my research program generally fall into two related areas. In the first, I investigate the behavioral, physiological, and ecological processes that influence the vital rates of animal populations. This work uses forest-dependent birds as a model group and examines how vital rates (e.g., nest success, juvenile survival) are influenced by land use and management activities. In the second area, I examine how natural (e.g., wildfire) and anthropogenic disturbances (e.g., timber harvest) are linked to population and community health parameters. This research is focused on native pollinators within managed forest ecosystems, and includes examining how native bees in managed forests interact with agricultural areas within mixed landscapes. In both areas, my work is grounded in basic and applied principles because of a recognition that organisms have evolved within a range of conditions, and their history must be understood to ensure that management actions result in conditions that are suitable for current-day populations to exist. I find that linking basic and applied science not only makes for stronger research, but it also helps to enhance the conservation implications of the work I undertake.

Influence of forest management on animal vital rates

Human-caused change to the environment has long been recognized as an important driver of habitat loss and degradation and, in turn, can lead to pronounced changes to natural communities. This is particularly true in forested ecosystems of the Pacific Northwest, where long-term and extensive population declines have been observed for a number of species that rely on specific forest successional stages during critical periods of the annual cycle.

 

Examples of recent and ongoing projects

  • Breeding ecology of the threatened Marbled Murrelet in coastal Oregon forests
  • Assessing the demographic response of woodpeckers to wildfire and management
  • Testing for forest herbicide effects on songbird vital rates
  • Interactive effects of temperature and herbicides on cavity-nesting bird reproduction
  • Quantifying use of intentionally created snags for cavity-nesting birds across 25 years

Ecology and conservation of native pollinators

Pollinators are responsible for fertilizing most of the world’s flowering plants and therefore play a pivotal role in natural and production systems. Despite some progress, most investigations of how land use has impacted pollinators and their ecosystem services have been restricted to agro-ecosystems and open field systems. In contrast, scant attention has been paid to pollinators in other natural habitats, including managed forests that may serve as source habitats and provide pollination services to adjacent agricultural lands.

 

Examples of recent and ongoing projects

  • Pollinator health as a function of management intensity within conifer forests
  • Evaluating the influence of forest biofuel removal on native bee communities
  • Assessing pollinator community composition across time in early-successional forests
  • Testing whether managed forests serve as source habitats for crop-pollinating bees
  • Development of a research agenda for pollinators in Pacific Northwest managed forests

Basic and applied aspects of stress hormones

Glucocorticoid hormones are common to all vertebrates and play a role in the regulation of several important processes including locomotor activity and energy metabolism. Corticosterone, the primary glucocorticoid in birds, is typically beneficial in the short term but can be costly under chronic levels. Therefore, corticosterone concentrations can provide information about the health and fitness prospects of an individual.

 

Examples of recent and ongoing projects

  • Evaluating the link between post-fledging survival and corticosterone
  • Using handicapping treatments to evaluate glucocorticoid-reproductive output links
  • Testing for parental alarm calls to invoke a corticosterone stress response in offspring
  • Assessing glucorticoid function changes as a function of altered brood size
  • Comparative ecology of the stress response in sympatric, ecologically similar swallows

Ecology and evolution of avian brood parasitism

Obligate avian brood parasitism occurs when a female brood parasite lays an egg into the nest of another species, and the host provides all parental care to the offspring of the brood parasite. Obligate brood parasitism is rare among birds and is limited to ~100 species in seven unique lineages. Because they are so different from other species, brood parasitic birds face unique challenges not experienced by species that raise their own offspring and therefore serve as an ideal group to test predictions from theory.

 

Examples of past projects

  • Assessing links between relatedness and begging in brood parasitic young
  • Evaluating adaptive differences in begging of brood parasites and their close relatives 
  • Quantifying the role of nestmate size on shaping begging behavior in brood parasites
  • Testing for community-wide host preferences by a generalist brood parasite
  • Use of stable isotopes to identify natal origins of the generalist Brown-headed Cowbird

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