Resilience After the Flames By: Josie Lesage, Ph.D., Applied Ecologist
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n Southern California, where wildfires are a natural part of our ecosystem, many native plants have adaptations that allow them to recover after a burn without human intervention. But this may be changing as climate change, increased urban development, and the spread of invasive species lead to more frequent wildfires. As a result, humans may need to step in more often to help landscapes recover after fire. At Santa Barbara Botanic Garden, we’re working to better understand exactly where, how, and when to intervene in post-fire landscapes to make the greatest impact.
landscape is left looking like a moonscape, but that same fire also stimulates the seed bank and promotes resprouting of native species. In Southern California shrublands, wildflowers proliferate after fire while native shrubs recover by resprouting or germinating from the soil seed bank. As climate change, increased development, and the spread of invasive species lead to more frequent wildfires, we need to step in more often to help landscapes recover and maintain the benefits nature provides.
Fire is a major evolutionary force in our local habitats, and many of our local species are well adapted to the historical fire regime. A fire regime describes the seasonality, frequency, size, intensity, severity, and type of fire. These factors are important to consider when understanding fires, especially because different habitats have historically had different regimes. For example, in many shrubdominated chaparral habitats, infrequent but intense canopy fires are thought to be more common, while in oak woodland systems, low-intensity litter fires would be considered the norm. Following a typical high-intensity summer crown fire in chaparral, the
However, fire regimes are changing as more humans move into the wildland-urban interface, as invasive species spread into new areas, and as our climate changes. The fire return interval, or period between fires, has historically been between 30 to 100 years for chaparral ecosystems. However, with fires occurring more often, intervals shortening, and fire season extending on both ends — stretching into the earlier summer and later fall/winter — seed banks and resprouting are pushed to their limits. In systems where the fire regime has been radically changed, or where unadapted invasive species dominate, it may
Over 900 native plants of 18 species were planted to restore post-fire habitat above Lake Piru.
In restored versus unrestored plots, we’ll compare habitat quality, carbon sequestration, and soil nutrients over the next two years.
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Ironwood
