Pamela E. Padgett
Research Plant Physiologist
USFS Pacific Southwest Research
Riverside, CA 92507
My primary research effort uses experimental studies to understand the interactions between lichens, plants, and plant communities and their environment, particularly air pollution and other human disturbances. Most of the studies are conducted under controlled conditions such as in greenhouses or growth chambers, or in research plots settings in the field. The scientific approach is to control the overall environment while changing one or two environmental characteristics in an effort to understand the cause and effect relationship between an environmental factor and a biological response. This approach has enabled us to separte the effects of individual air pollutants, for example ozone and nitric acid which typically co-occur. Or air pollution and drought stress, which have negative synergistic effects on plant physiology.
Secondary research efforts include understanding the effects of deposition of particulate pollutants on plants and plant communities. Particulates can cause both physical damage to plants such as coating surfaces and reducing light penetration to photosynthetic systems, or chemical damage by changing the nutrient balance within leaves. My research has also explored the changes in plant communities due to an initial catastrophic disturbance such as fire, and subsequent chronic disturbances due to nitrogen containing pollutants that shift the competative balance between native and exotic plant plant species. This work has major implications for critical habitat protection and restoration.
I maintain many active collaborations, both within the three branches of the Forest Service, State & Private, National Forest Systems and Research and Development, as well as interagency collaborations with the National Park Service, the US Geological Survey, and several state of California organizations and local groups. The overarching goal is to provide data and information to assist in the management of public lands and to encouraging the public to value their natural surroundings.
- University of California, Riverside, PhD Plant physiology, mineral nutrition, and nutrient metabolism, 1993
- Virginia Polytechnic Institute and State Univ., B.S. Agronomy, minor chemistry, 1987
- National Atmospheric Deposition Program, Member
Featured Publications & Products
- Padgett, PE. 2010. The effect of ambient ozone and humidity on the performance of nylon and Teflon filters used in ambient air monitoring filter-pack systems.
- Riddell, J.; Nash, T.H., III.; Padgett, P. 2010. Responses of the lichen Ramalina menziesii Tayl. to ozone fumigations.
- Fenn, M.E.; Sickman, J.O.; Bytnerowicz, A.; Clow, D.W.; Molotch, N.P.; Pleim, J.E.; Tonnesen, G.S.; Weathers, K.C.; Padgett, P.E.; Campbell., D.H. 2009. Methods for measuring atmospheric nitrogen deposition inputs in arid and montane ecosystems of western North America.
- Allen, Edith B.; Sirulnik, Abby G.; Egerton-Warburton, Louise; Kee, Sheila N.; Bytnerowicz, Andrzej; Padgett, Pamela E.; Temple, Patrick J.; Fenn, Mark E.; Poth, Mark A.; Meixner, Thomas. 2005. Air pollution and vegetation change in southern California coastal sage scrub: a comparison with chaparral and coniferous forest.
- Allen, Edith B.; Padgett, Pamela E.; Bytnerowicz, Andrzej; Minnich, Richard. 1998. Nitrogen deposition effects on coastal sage vegetation of southern California.
Publications & Products
- Bell, Michael D.; Sickman, James O.; Bytnerowicz, Andrzej; Padgett, Pamela E.; Allen, Edith B. 2014. Variation in isotopologues of atmospheric nitric acid in passively collected samples along an air pollution gradient in southern California.
- Jovan, Sarah, Dr.; Riddell, Jennifer; Padgett, Pamela E; Nash, Thomas, A. 2012. Eutrophic lichens respond to multiple forms of N: implications for critical levels and critical loads research.
- Riddell, J.; Padgett, P.E.; Nash, T., III. 2012. Physiological responses of lichens to factorial fumigations with nitric acid and ozone.
- Padgett, Pamela. 2011. Comprehensive assessment of deposition monitoring in Class I areas. A report to the Air Resources Management Director..
- Riddell, Jennifer; Jovan, Sarah, Dr.; Padgett, Pamela E.; Sweat, Ken. 2011. Tracking lichen community composition changes due to declining air quality over the last century: the Nash legacy in Southern California.
- Riddell, Jennifer; Jovan, S.; Padgett, Pamela; Sweat, K. 2011. Tracking lichen community composition changes due to declining air quality over the last century: the Nash legacy in southern California.
- Padgett, Pamela. 2009. Nitrogen deposition: the up and down side for production agriculture..