Consequences of fire on California ecosystems

By Kathleen Wong, UC Natural Reserve System

When fires sweep across the landscape, they do much more than incinerate flammable items in their way. Flames cause chemical changes to soils, drive out animals, and expose areas to far more sun and rain than they once experienced. In some cases, a burn can be enough to shift not only erosion patterns but entire species assemblages. Yet fire can also serve as a source of renewal—triggering long-dormant seeds to sprout, or the appearance of plants not spotted in decades.

However, sorting out where these effects appear, and why, has been a tricky matter.

Then nine UC Natural Reserves burned in late summer of 2020. An estimated 21,000 acres of reserve and reserve-affiliated lands burned. The blazes consumed vehicles, incinerated towering trees, and even left one NRS staffer’s family homeless.

As painful as the fires have been for the NRS, their scope offers a prime opportunity to examine how fires affect a wide range of California’s natural habitats. The reserves that burned have different ecosystems, soils, and terrain, and experience different climate conditions. This enables scientists such as Becca Fenwick, with the NRS’s California Heartbeat Initiative, to observe how burn severity and environmental conditions shape ecosystem recovery from wildfire.