Burkle Lab — research themes

fire field work plant ID

ecological drivers of plant-pollinator biodiversity and ecosystem function across spatiotemporal scales

Disturbance is a key driver of biodiversity across spatiotemporal scales. However, natural disturbance regimes have been altered, and the severity of some disturbances is forecasted to increase with global change. Although ecologists have excelled at investigating how individual species and some local communities respond to disturbances, we lack a synthetic local understanding of how complex networks of species interactions recover from disturbances, especially at the large spatial scales most germane to conservation and management in naturally heterogeneous landscapes. In collaboration with Travis Belote (The Wilderness Society) and Jonathan Myers (Washington University), we are studying how spatial variation in the composition of plant and pollinator communities (beta-diversity), spatial variation in plant-pollinator interactions (interaction beta-diversity), and ecosystem services (pollination) respond to wildfire disturbance across a large- scale gradient of net primary productivity and regional biodiversity in the Northern Rockies Ecoregion of Montana. A major goal of this interdisciplinary collaboration is to enhance mechanistic understanding of community assembly, species interactions, and ecosystem services following disturbance in a biogeographically diverse but understudied region of critical conservation importance. We thank the Montana Forest Restoration Committee and the National Science Foundation for supporting this project.

flower strip bumble bee

evaluating native perennial flower strips for enhancing native bees and pollination services on farmlands

In collaboration with Casey Delphia and Kevin O'Neill (Montana State University), we are quantifying the benefit of native perennial flower strips on farms for pollinator conservation and pollination services to crops. The specific objectives of this project are to 1) determine the effects of flower strips on the abundance, diversity, and foraging behavior of native bees in crop fields; 2) determine the value of flower strips in improving crop pollination; 3) evaluate the potential of flower strips for native seed production and sales; and 4) execute a research-based outreach program to communicate our findings to producers, land managers, agricultural professionals, and the public. This project will provide valuable information on the biology and ecology of native bees on farmlands in general and in Montana specifically. Our long-term goals are to advance management strategies that support healthy, sustainable pollination systems in agriculture for ensuring food security and supporting environmental quality. We thank the Western Sustainable Agriculture Research and Education program for supporting this project.

portable volatile collection system

understanding the roles of plant volatiles in plant-pollinator interactions at a community scale and under climate change

In collaboration with Justin Runyon (Rocky Mountain Research Station, USFS), we are combining chemical ecology techniques and community network analyses to determine 1) the roles of floral and vegetative volatiles in community-level plant-pollinator interactions and 2) the effects of CO2 and drought on floral volatiles important for pollinator attraction and pollination services. We are growing differet forb species under elevated CO2 and drought conditions and will measure effects of these treatments on plant traits, volatiles, herbivory, and pollinator visitation. We thank the Forest Service for supporting this work which will also be used to motivate additional proposals and experiments.

christina herron-sweet knapweed

investigating multi-trophic interactions between invasive plants and insects to enhance native forage production on western rangeland

Healthy rangeland is important to livestock production, but the invasion of rangelands by non-native plant species threatens this economy. Biocontrol agents are commonly used to control these non-native plants, despite the potential for unexpected effects on complex interactions in the ecological community. In collaboration with Jane Mangold, Erik Lehnhoff, Jeff Littlefield, and Christina Herron-Sweet (Montana State University), we are investigating the effects of spotted knapweed (an aggressive non-native plant species) and its associated biological control agents on native plant community dynamics using a network approach to assess multi-trophic pollinator, herbivore and parasitoid interactions. This project will contribute to well-informed management decisions to enhance native forage production on rangelands.  We thank the Agriculture and Food Research Initiative for supporting this project and Christina's graduate work.

big sandy fort ellis

targeted grazing to reduce tillage in organic dryland systems: environmental, ecological, and economic assessment of reintegrating animal and crop production

This research project is large and interdisciplinary, involving animal husbandry practitioners, agricultural professionals, economists, and ecologists, among others.  In collaboration with Fabian Menalled, Kevin O'Neill, David Weaver, and Subodh Adhikari (Montana State University), our working group is  focused on understanding how sheep grazing on weeds in organic dryland agriculture influences interactions among beneficial insects, pest insects, and plants in a food web context. We thank the Organic Agriculture Research and Extension Initiative for supporting this research and Subodh's graduate work.

greenhouse

linking belowground and aboveground mutualistic interactions: soil mycorrhizae as mediators of plant-pollinator interactions

The goal of this research is to understand how different types of mycorrhizal fungi in the soil influence plant traits that are important for pollinator attraction.  Specifically, we have performed a greenhouse experiment manipulating six species of mycorrhizae in seven flowering plant species and are determining species-specific effects on plant growth and flowering.  This detailed study will form the foundation for field mesocosm experiments and future proposals.  This work is in collaboration with Cathy Zabinski (Montana State University).

carlinville claytonia

comparing historic and current plant-pollinator interactions to study global change effects

Although there is extensive research investigating how individual species of plants and animals are being affected by climate change and other anthropogenic forces, virtually nothing is known about how species interactions are being disrupted at the community level. In the late 1800's, the entomologist Charles Robertson meticulously documented all of the plant-pollinator interactions in the town of Carlinville, Illinois. We are recollecting these data and comparing historic interaction networks with those that persist today to understand how plant-pollinator interactions are changing over time as a function of climate change, invasive species, and land-use change. This work is in collaboration with Tiffany Knight (Washington University in St. Louis), Anny Chung (University of New Mexico - Albuquerque), and John Marlin (Illinois Natural History Survey).

★ Listen to podcasts of our research highlighted on Morning Edition of NPR here (2013) and here (2010).

★ Check out a very cool graphical visualization of wild bee losses from our study published in Scientific American.

Ryder Diaz wrote a piece, Reading Between the Grains, about our work using pollen from current and historic bee specimens to better understand changes in pollinator behavior over the last century.

gothic andrena

Other interests and research projects

  • effects of nitrogen enrichment on plants, pollinators, and their interactions. Rocky Mountain Biological Lab, Colorado.
  • plant fitness and pollinator health in agricultural systems, along urban-rural gradients
  • effects of invasive plants on pollinators
  • causes and consequences of native plant and pollinator diversity at different spatial scales
  • pollinator and plant responses to habitat modification, especially fire, grazing and fragmentation
  • establishment of bee species in newly restored habitats. Glades at Tyson Research Center, Missouri