Research Program
Oak recruitment
In collaboration with Dr. Bruce Mahall and Dr. Frank Davis I am currently conducting research at the UC Sedgwick Reserve on factors limiting the establishment of oaks (Quercus lobata and Q. agrifolia). In a number of oak woodlands and savannas throughout the world stands are composed of large, old adults with few individuals in the smaller, younger classes, raising concerns that natural recruitment of the oaks may be insufficient to balance adult mortality. Past studies have demonstrated that oak seedling recruitment may be extremely limited in space and time as a result of many natural and anthropogenic factors operating independently or together. Our long-term program has been designed to achieve multiple objectives: to restore oak habitat, and to conduct a long-term ecological investigation that would improve our understanding of the role of cattle and other ecological factors in limiting or promoting establishment of oaks in large-scale, landscape-level environments. We have replicated large-scale planting experiments in four different years in oak savannas and woodlands over a program area of 200-ha.
In addition, Dr. Bruce Mahall, Dr. Shelly Cole, and I began studies of the physiology of coast live oak and valley oak seedlings in 2002 to examine the effects of annual summer drought on seedling survival and transition to the sapling stage. In summers of 2002–2006, we have measured water availability, rates of photosynthesis, and chlorophyll fluorescence characteristics of selected seedlings (planted in 1997–1998) and neighboring adults.
To characterize the understory vegetation and to examine effects of cattle grazing on the herbaceous vegetation of oak savannas and woodlands we established permanent sampling quadrats within our experimental areas in May 1996. In collaboration with Dr. Carla D’Antonio at UCSB, I am planning to examine the role of soil factors and historical land use in affecting the vegetation response to release from grazing across our paired grazed/ungrazed plots at Sedgwick Reserve.
Relevant publications and technical reports
- Tyler, C.M., D.C. Odion, and R.M. Callaway. 2007 (in press). Dynamics of woody species in the California grassland. Chapter 10, in Stromberg, M., Corbin, J. and C. D’Antonio, editors. Ecology and Management of California grasslands. University of California Press, Berkeley
- Tyler, C. M., F. W. Davis and B. E. Mahall. 2007 (in press). Influence of winter-spring livestock grazing on survival and growth of Quercus lobata and Q. agrifolia seedlings. In: ___ tech. coord. Proceedings of the sixth symposium on oak woodlands: Today's challenges, tomorrow's opportunities. Gen. Tech. Rep. PSW-GTR-___. Albany, CA: Pacific Southwest Research Station, USDA Forest Service
- Tyler, C. M., B. Kuhn, and F.W. Davis. 2006. Demography and recruitment limitations of three oak species in California. Quarterly Review of Biology 81:127-152.
- Mahall B., F. Davis, and C. Tyler. 2005. Final report of the Santa Barbara County Oak Restoration Program 1994-2005. Submitted to the Santa Barbara County Department of Planning and Development, Energy Division. 155pp.
- Tyler, C. M., B. E Mahall, F. W Davis, and M. Hall. 2002. Factors limiting recruitment in valley and coast live oak. In: Standiford, R.B., McCreary, D., Purcell, K.L., tech. coord. Proceedings of the fifth symposium on oak woodlands: Oaks in California's changing landscape. Gen. Tech. Rep. PSW-GTR-184. Albany, CA: Pacific Southwest Research Station, USDA Forest Service, pp 565-572.
- Callaway, R. M. and C. Tyler. 1999. Facilitation in rangelands: direct and indirect effects. Pp 197-202. Proceedings of the VI International Rangeland Congress, vol 1. People and rangelands: building the future. Townsville, Australia.
Chaparral and shrubland dynamics
My dissertation research focused on mechanisms controlling post-fire regeneration in chaparral plant communities. With Dr. Dennis Odion and others, I have been conducting ecological studies of the endangered Morro Bay manzanita, Arctostaphylos morroensis. I am currently interested in the application of such research for use in management and conservation of species in fire-prone systems.
Relevant publications and technical reports
- Tyler, C.M., D.C. Odion, and R.M. Callaway. 2007 (in press). Dynamics of woody species in the California grassland. Chapter 10, in Stromberg, M., Corbin, J. and C. D’Antonio, editors. Ecology and Management of California grasslands. University of California Press, Berkeley
- Tyler, C.M. and M. Borchert. 2003. Reproduction and growth of the chaparral geophyte, Zigadenus fremontii (Liliaceae), in relation to fire. Plant Ecology 165(11):11-20.
- Odion, D. and C. Tyler. 2002. Are long fire-free periods needed to maintain the endangered, fire-recruiting shrub Arctostaphylos morroensis (Ericaceae)? Conservation Ecology 6(2): 4.
- Tyler, C.M., D.C. Odion, D. Meade, and M. Moritz. 2000. Ecological studies of Morro Manzanita (Arctostaphylos morroensis): prescribed burning, seed ecology, and reproductive ecology. Report prepared for the California Department of Fish and Game, Species Conservation and Recovery Program. 38pp.
- Tyler, C.M., D.C. Odion, and D. Meade. 1998. Ecological studies of Morro Manzanita (Arctostaphylos morroensis): seed ecology and reproductive ecology. Report prepared for the California Department of Fish and Game, Species Conservation and Recovery Program. 30pp.
- Tyler, C.M. and D.C. Odion. 1996. Ecological studies of Morro Manzanita (Arctostaphylos morroensis). Report prepared for the California Department of Fish and Game, Endangered Plant Program. 46pp.
- Tyler, C.M. 1996. Relative importance of factors contributing to postfire seedling establishment in maritime chaparral. Ecology 77(7):2182-2195.
- Tyler, C.M. 1995. Factors contributing to postfire seedling establishment in chaparral: direct and indirect effects of fire. Journal of Ecology 83(6):1009-1020.
- Tyler, C.M. and C.M. D'Antonio. 1995. The effects of neighbors on the growth and survivorship of shrub seedlings following fire. Oecologia 102:255-264.
- D'Antonio, C.M., D.C. Odion and C.M. Tyler. 1993. Invasion of maritime chaparral by the alien succulent Carpobrotus edulis: the role of fire and herbivory. Oecologia 95:14-21.
