Past Projects
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Geographic Distribution and Environmental Factors
Contributing to Genetic Variation in Mountain Pine Beetle Populations in Western North America In North America, millions of forest acres have been impacted by Dendroctonus ponderosae, the mountain pine beetle (MPB), which normally exists at low population sizes and serves a beneficial role in forest health. The MPB tends to target old, weak trees and by killing them, helps future forest regeneration. However, favorable environmental conditions can lead to exponential population growth, resulting in potential epidemic population outbreaks. Here, we use GIS data to 1) test the effects of host availability on genetic connectivity among populations, and 2) apply a correlational analysis to identify genetic markers associated with environmental differences across the geographic distribution of MPB. The goal is to understand populations connectivity, and to identify genetic markers that may predict important population metrics such as phenology and growth rate.
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Documenting Biodiversity in America's National Parks
Connecting people and nature, while preserving America’s land, is at the heart of the mission of the United States Department of the Interior. The National Park Service took a leading role in that mission beginning in 2007 by teaming up with iNaturalist and National Geographic Society to host national programs called BioBlitz that invited citizens into the parks to record observations of plants and animals. Although BioBlitzes have occurred for 10 years, the greatest surge of events came in 2016 in celebration of the National Park Service centennial. 126 national parks participated in 2016 and almost 6,500 species were documented by citizen scientists. (This is a poster about one of my internship projects with USGS.)
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Changes in Surface Fuels and Regeneration Following the
Mountain Pine Beetle Epidemic in Ponderosa Pine Forests Along the Colorado Front Range Over three million acres of Colorado’s forests have been affected by the mountain pine beetle (Dendroctonus ponderosae; MPB) epidemic since 1996. Although the epidemic has slowed, there is still cause for concern today. First, the many dead trees provide new surface fuels (dead wood on the ground) which could burn in wildfires. Also, future regeneration of ponderosa pine may be limited by the widespread mortality. Our research focused on how surface fuels and seedling density have changed in areas along the Colorado Front Range approximately 5 years following the MPB epidemic. We surveyed 3 sites which had experienced “high” MPB impacts and 3 with “low” MPB impacts; data had been previously collected on all sites in 2009-2011. We found that fine woody debris (FWD) increased significantly (8-10 times) in all sites by 2015 (p=<0.0001). Similarly, coarse woody debris (CWD) increased (p=0.0056) at all sites, but not to the extent of FWD. Density of small (< 6” (15.24 cm) tall) seedlings increased considerably, from 0 to 1 seedling/m2 in 2015, but there was no increase in larger seedlings (p=0.90). Although sites with both low and high MPB impacts showed similar increases in FWD and small seedlings, there was a trend for more CWD and fewer seedlings on high MPB sites after the epidemic. Overall, our results suggest that the MPB epidemic has not caused major changes in fuel loads and regeneration between high and low-impact sites during this 5 year time frame. However, we detected variation within sites which may be important to address with expanded survey efforts in future.
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