The California Department of Forestry and Fire Protection (Cal Fire) conducted a small, prescribed burn at Jasper Ridge Biological Preserve Monday morning. According to PHILIPPE COHEN, administrative director of the preserve, the burn went perfectly.
Cal Fire oversaw a small, prescribed burn at Jasper Ridge Monday morning. (Photos by Dan Quinn)
The burn was designed to test how climate change affects grassland restoration and probe whether wildfire can improve the ability of restored grasses to resist invasive species, particularly the widespread yellow star thistle.
The burn is part of a multi-year project supported by a National Science Foundation (NSF) grant received in 2009. The burn encompassed 1.2 acres of land that are part of the Jasper Ridge Global Change Experiment (JRGCE), which was launched in 1988 to illustrate how a typical California grassland ecosystem might respond to future global environmental changes.
The JRGCE uses grasslands as a model for understanding how ecosystems respond to such variables as elevated carbon dioxide, rising temperatures, increased nitrogen deposition and changing rainfall patterns. Grasslands are easily tended and have short life spans that allow for accelerated study. At Jasper Ridge, researchers control for those four aspects of climate change on land that has been broken into about 150 plots, each about nine square feet. Each plot represents a miniature complete ecosystem.
In July 2003, an accidental fire at Jasper Ridge opened the door to studies of the relationship among wildfire, climate change and ecosystems. The burn was accidental, but it affected an area perfectly suited to experimentation. About half of the JRGCE plots burned, meaning that all of the variables of climate change encompassed in the overall experiment were equally affected.
The significance of wildfires became clear the next spring when researchers observed the obvious differences in biomass production and plant distribution in each burned plot.
The NSF grant and burn take the JRGCE in a new direction. Researchers, led by staff scientist NONA CHIARIELLO and CHRIS FIELD, professor of biology and of environmental Earth system science, are moving beyond observation to apply their knowledge to the actual management of a grassland ecosystem.
“Many of the most challenging questions in environmental science involve the interaction of ecological processes with major disturbances like wildfire,” said Field. “We are very fortunate at Jasper Ridge that the combination of great infrastructure, the chance to collaborate with outstanding local fire agencies and excellent relationships with neighbors gives us the opportunity to conduct experiments that are innovative and important.”
Scientists from Stanford, the Carnegie Institution for Science, University of California-Berkeley, University of California-Santa Cruz and several other institutions are studying the site before, during and after the burn to maximize what can be learned about fire management under present and future conditions.
In many ways, the planning of the experiment was prescient. Regional climate change predictions for Northern California estimate a 90 percent increase in fire intensity and frequency, making it crucial that the relationship among fire, native grasslands and climate change be better understood.
Last year, the first year of the NSF-supported study, JRGCE researchers focused on the role of climate change in encouraging the replacement of naturalized grassland with native perennial grassland. In this—the second year—they are focusing on the role of wildfire in restoration. Next year, they will encourage the spread of yellow star thistle to test what effect climate change and restoration efforts have on invasion.
The yellow star thistle, first introduced to the United States in the 1800s, is native to the Mediterranean region. The plant grows quickly and aggressively crowds out native species. It is especially toxic to horses and is considered one of California’s most annoying weeds, having eliminated the native perennial bunchgrasses and annual forbs that thrived before the arrival of Europeans and their livestock.
The weed spread uninvited at Jasper Ridge, presenting another fortuitous opportunity for JRGCE researchers, who hope to better understand what characteristics apply to native species most likely to be successfully restored, given the realities of global climate change. They also hope to immediately offer insights into how Californians can best curb the invasion of yellow star thistle.