%0 Journal Article %J Quarterly Review of Biology %D 2006 %T Demography and regeneration of oaks in the foothill woodlands of central California: a review of the scientific literature %A Tyler, C. M. %A Kuhn, W. %A Davis, F. W. %K oak woodland %K Quercus %K seedling establishment %X We review published studies on the demography and recruitment of California oak trees and focus on the widespread dominant species of the foothill woodlands, Quercus douglasii, Q. lobata, and Q. agrifolia, to ascertain the nature and strength of evidence for a decline in populations of these species. The vast majority of studies have been of short duration (less than three years), focused on the acorn and seedling life stages, and conducted at few locations within each species’ geographic range. We summarize the extensive body of research that has been conducted on the biological and physical factors that limit natural seedling recruitment of oaks. The oak “regeneration problem” has largely been inferred from current stand structure rather than by demographic analyses, which in part reflects the short-term nature of most oak research. When viewed over longer periods of time using field surveys or historical photos, the evidence for a regeneration problem in foothill oaks is mixed. Q. douglasii shows very limited seedling or sapling recruitment at present, but longer term studies do not suggest a decline in tree density, presumably because rare recruitment is sufficient to offset low rates of mortality of overstory individuals. Q. agrifolia appears to be stable or increasing in some areas, but decreasing in areas recently impacted by the disease Phytophthora ramorum. Evidence from the few available studies is more consistent in suggesting long-term declines in foothill populations of Q. lobata. Longterm monitoring, age structure analysis, and population models are needed to resolve the current uncertainty over the sustainability of oak woodlands in California. %B Quarterly Review of Biology %V 81 %P 127-152 %8 2006 %G eng %U http://www.journals.uchicago.edu/QRB/journal/issues/v81n2/810202/810202.web.pdf %0 Generic %D 2004 %T Santa Barbara County Oak Restoration Program. Yearly Progress Report for the Period July 2003 - June 2004 %A Mahall, B. E. %A Davis, F. W. %A Tyler, C. M. %I University of California Santa Barbara %8 July 14, 2004 %G eng %0 Generic %D 2003 %T Santa Barbara County Oak Restoration Program. Yearly Progress Report for the Period July 2002 - June 2003 %A Mahall, B. E. %A Davis, F. W. %A Tyler, C. M. %I University of California Santa Barbara %8 June 30, 2003 %G eng %0 Conference Paper %B Fifth Symposium on Oak Woodlands %D 2002 %T Factors limiting recruitment in valley and coast live oak %A Tyler, C. M. %A Mahall, B. E. %A Davis, F. W. %A Hall, M. %X The Santa Barbara County Oak Restoration Program was initiated in 1994 to determine the major factors limiting recruitment of valley oak (Quercus lobata) and coast live oak (Q. agrifolia). At Sedgwick Reserve in Santa Barbara County, California, we have replicated large-scale planting experiments in four different years to determine the effects of cattle and other ecological factors on oak seedling establishment in oak savannas and woodlands. In 33 large experimental plots (50 x 50 m) we planted acorns collected from Q. lobata and Q. agrifolia on the site. Fifteen of these large plots are controls, open to grazing, fifteen exclude cattle with the use of electric fence, and three are ungrazed in large ungrazed pastures. Within the plots, experimental treatments included: 1) protection from small mammals such as gophers and ground squirrels, 2) protection from large animals such as cattle, deer, and pigs, and 3) no protection from mammalian grazers. In winters 1997, 1998, 2000, and 2001, we planted approximately 1,000 acorns of each species. Results confirm that seed predation and herbivory by small mammals are a significant "bottleneck" to oak seedling recruitment on the landscape scale. Comparing results among years indicates that lack of late winter rainfall can significantly reduce oak emergence and establishment. Survivorship of protected acorns and seedlings is comparable in grazed and ungrazed areas. %B Fifth Symposium on Oak Woodlands %I USDA Forest Service %V General Technical Report PSW-GTR-184 %P 565-572 %8 2002 %G eng %U http://danr.ucop.edu/ihrmp/proceed/symproc50.html %0 Generic %D 2002 %T Santa Barbara County Oak Restoration Program. Yearly Progress Report for the Period July 2001 - June 2002 %A Mahall, B. E. %A Davis, F. W. %A Tyler, C. M. %I University of California Santa Barbara %8 June 30, 2002 %G eng %0 Generic %D 1999 %T Santa Barbara County Oak Restoration Program. Yearly Progress Report for the Period July 1998 - June 1999 %A Mahall, B. E. %A Davis, F. W. %A Tyler, C. M. %8 September 15, 19 %G eng %0 Journal Article %J Oecologia (Berlin) %D 1993 %T Invasion of Maritime Chaparral by the Introduced Succulent Carpobrotus-Edulis the Roles of Fire and Herbivory %A D'Antonio, C. M. %A Odion, D. C. %A Tyler, C. M. %K Aizoaceae Cervidae (Ecology Environmental Biology–Plant) (Ecology Environmental Biology–Animal) (Plant Physiology %K Biochemistry and Biophysics–Temperature) Plants Vascular plants Spermatophytes Angiosperms Dicots Animals Chordates Vertebrates Nonhuman vertebrates Mammals Nonhuman mammals Artiodactyls Deer Scat Seeds Temperature Herbivory Fire Seedling Mortality %X Invasion by the alien succulent, Carpobrotus edulis, has become a common occurrence after fire in maritime chaparral in coastal California, USA. We studied post-burn Carpobrotus establishment in chaparral that lacked Carpobrotus plants before the fire and compared seedbank and field populations in adjacent burned and unburned stands. Carpobrotus seeds were abundant in deer scat and in the soil before burning. Burning did not enhance germination: many seeds were apparently killed by fire and seed bank cores taken after fire revealed no germinable seeds. Laboratory tests showed that temperatures over 105.degree.C for five minutes killed Carpobrotus seeds. In a field experiment involving use of herbivore exclosures, we found that herbivory was an important source of mortality for seedlings in both burned and unburned chaparral. All seedlings, however, died outside of the burn regardless of the presence of cages. Establishment there is apparently limited by factors affecting plant physiology. In the burned area, seedlings that escaped herbivory grew very rapidly. Overall, it appears that herbivory limited seedling establishment in both burned and unburned sites but that the post-burn soil environment supported Carpobrotus growth in excess of herbivore use, thus promoting establishment. %B Oecologia (Berlin) %V 95 %P 14-21 %G eng