On Nov. 24 and Nov. 25 the Garden closes at 4 p.m. due to Las Noches de las Luminarias.
M.S., Northern Arizona University, 2011
• Plant physiological ecology
• Hydraulic architecture and morphology of plants; xylem cavitation
• Plant responses to water stress; drought-induced mortality mechanisms
• Plant histology
• Restoration ecology; establishment of common gardens and using them for research studies
• Climate change impacts on plant survival and potential restoration
I am a research technician in Dr. Hultine’s plant physiological and functional ecology lab. My work encompasses both field and lab duties to assist different researchers and their studies. These have included vegetation surveys, soil sampling, establishing common gardens of over 4000 trees, and various sampling and measurements for physiological studies. I am interested in the physiological responses to water stress. In particular, I investigate the hydrologic mechanisms plants perform to alleviate water stress, and how susceptible plants are to water stress. I have studied both inter- and intraspecific variations in xylem vulnerability to cavitation, and potential morphological differences such as vessel sizes. A better understanding of how inter-specific variations among populations along an elevation gradient in, for example, xylem cavitation, may help predict some potential climate change impacts on a species. Presently, my focal species include Fremont cottonwood and tamarisk tree species that have been collected along a 1500 meter elevation gradient and planted in common gardens.
Hultine KR, Dudley TL, Koepke DF, Bean DW, Glenn EP, Lambert AM. (2014). Patterns of herbivory-induced mortality of a dominant non-native tree/shrub (Tamarix spp.) in a southwestern US watershed. Biological Invasions 17: 1729–1742. Download Paper
Koepke DF, Kolb TE. (2013). Species variation in water relations and xylem vulnerability to cavitation at a forest-woodland ecotone. Forest Science 59(5): 524–535, DOI: 10.5849/forsci.12-053. Download Paper
Koepke DF, Kolb TE, Adams HD. (2010). Variation in woody plant mortality and dieback from severe drought among soils, plant groups, and species within a northern Arizona ecotone. Oecologia 163: 1079–1090, DOI: 10.1007/s00442-010-1671-8. Download Paper
Hultine KR, Koepke DF, Pockman WT, Fravolini A, Sperry JS, and Williams DG (2006) Influence of soil texture on hydraulic properties and water relations of a dominant warm-desert phreatophyte. Tree Physiology 26: 313–323. Download Paper
Fravolini A, Hultine KR, Koepke DF, Williams DG. (2003). Role of soil texture on mesquite water relations and response to summer precipitation. USDA Forest Service Proceedings RMRS-P-30: 125–129. Download Paper