University of California, Irvine
BIO SCI - Center for Environmental Biology
Irvine, CA 92697-1450
office: 949-824-7151

email: skimball/at/uci.edu

Some of my research:

Traits influencing plant community composition

Penstemon hybrid zone: pollination, physiology, and fitness

Pollinators

Physiology

Reproductive Isolation

Restoration ecology at Carrizo Plain National Monument

Local ecology and geographic range limits

I am an evolutionary ecologist who studies how species’ traits interact with environmental conditions to determine population dynamics, range limits, and community composition.

Research Interests

Plant traits, such as water use efficiency, relative growth rate, temperature of maximum photosynthesis, timing of life history transitions, and flower color, can interact with environmental conditions to determine population dynamics. Such traits are shaped by natural selection. How do the traits of individual species interact with the environment to determine the outcomes of biotic interactions, influence population dynamics, and thus determine community composition? Answering this question is of fundamental importance to the field of ecology to establish links between functional biology, population demography, evolution, community ecology, and conservation biology, providing greater understanding of the maintenance of diversity. This question spans multiple scales, from carbon fixation and water loss at the cellular level to the assembly of entire communities of organisms. I am currently addressing this topic through a combination of field, greenhouse, and lab studies, including: (1) measuring phenotypic selection on physiological traits of species growing in multiple environments; (2) quantifying how plant traits influence trade-offs between competitive abilities and drought tolerance; and (3) understanding how shifts between facilitation and competition influence community composition depending on types of seed mixtures and maintenance techniques used in restoration.

I aim to advance ecological theory while simultaneously providing knowledge that may be used for the restoration and conservation of ecological communities.

Collaborators and Current Projects

Restoration of coastal sage scrub and native annual communities:
UCI's Center for Environmental Biology, under the direction of Diane Pataki, is collaborating with the Irvine Ranch Conservancy to conduct a restoration experiment at Loma Ridge. This collaboration addresses many research questions, but I am particularly interested in measuring interactions between the annuals and perennials, and understanding how plant traits influence community assembly.

Sonoran Desert winter annual community: Work with Amy Angert, Jennifer Gremer, Travis Huxman, and Larry Venable, focuses on a tradeoff between relative growth rate and water use efficiency. Such physiological traits relate to phenological differences among species, determine species’ responses to global change, and promote coexistence.

Range limits and hybridization: I worked with Diane Campbell to study how pollinator and physiological trait differences define the elevational range limits of two species that hybridize along an altitudinal gradient. I am continuing to investigate this hybrid system between Penstemon newberryi and P. davidsonii in the Sierra Nevada mountains of California.