Dissertation Research

Six-petaled Phlox drummondiiMy dissertation research explores the evolutionary and ecological significance of pentamerism (five-petaled) flowers. As angiosperms diversified, there was a reduction in petal number, and a tendency to fix on five petals throughout many lineages. I am testing whether this fixation for pentamerism is the result of adaptation or stabilizing selection in response to pollinators, or the result of evolutionary constraints.

Saltugilia splendens ssp. splendensMost of my research involves the Phlox family (Polemoniaceae), in which many species exhibit natural variation in petal number or inconstancy to the predominantly pentamerous phenotype. By examining the causes of this natural variation, I hope to answer questions about why many other plants are invariant with respect to petal number.

Currently, I am testing the following hypotheses:

  1. Saltugilia latimeriIs variation in petal number heritable and can increased or decreased petal number be selected for?
  2. Do environmental factors affect petal number?
  3. Do species with different pollination modes or self-pollinated species have varying degrees of inconstancy in petal number that might indicate shifting selection regimes?
  4. Do pollinators prefer a certain number of petals?
  5. Is there a fitness cost to increased inconstancy or to maintaining a constant phenotype?

Microcontroller-based Ecology

Ecological sensorA custom trigger for camera traps designed to film hummingbirds in high speed videoI have long been interested in home-brew electronics, and lately I have been applying this skill to ecological research.  I’ve collaborated with Alejandro Rico-Guevara in making a custom camera trap triggering system for filming hummingbirds in high speed video.  Our paper describing this system we built is now in review.  Currently I’m working with Timothy Moore to build and program low-cost ecological sensor networks.

Past Research

Invasion Demography of Centaurea stoebe

Invasive Centaurea stoebe growing in the Adirondack National ParkDuring my masters, I studied demographic heterogeneity of an emerging invasive plant species Centaurea stoebe in the Adirondack National Park and on Long Island in New York.  This plant is native to Europe and has become extremely invasive in the rangelands of the Western United States.  Although it was introduced to both the Western and Eastern US in the late 1800’s, it is less of a problem on the East Coast, and is often found only in disturbed sites or along roadways.  However, anecdotal evidence seems to suggest that its range is increasing in some of these areas.

I helped establish experiments to measure demography of C. stoebe at the landscape level to allow for modeling of population growth over large geographic areas and to determine whether factors such as disturbance and climate are allowing this species to begin invading new areas.  This work laid the foundation for the NSF grant DEB:1119891.

Fire Ecology in Midwestern Oak Savanna

A Picturesque view of Minnesota Oak Savanna at Cedar Creek Ecosystem Science ReserveI wrote my undergraduate thesis on fire scarring dynamics in the globally rare Midwestern oak savanna ecosystem. We compared contact fire scarring (caused by dead wood against a tree) and non-contact scarring over a variety of oak size classes at Cedar Creek Ecosystem Science Reserve in Minnesota, which has been burned periodically since 1964–one of the longest running prescribed burn programs in the nation.

Fire scare on a Bur Oak (Quercus macrocarpa) in Minnesota Oak Savanna
A contact scar on a Bur Oak

Contact scarring (which tends to be more severe) was more prevalent in areas of higher historical density prior to the prescribed burn program.  These can kill a tree and thus has demographic implications.  If initial fuel loads or fire residence times are high, mortality can outpace recruitment, nudging the system towards oak scrub or prairie instead of savanna over long periods of time.

We found that scarring can be minimized by burning when wind speeds are not low since the burn residence time decreases and contact scars become less likely.  This mimics natural fire conditions, but runs counter to what many burn managers do for safety reasons.  Therefore burn managers need to weigh safety against mimicking natural fire conditions and should avoid burning when wind speeds are very low.

Other Interests