Effects of Fire Suppression and Fuels Management on Rare Plants

Friday, October 21 at 1:00-2:40 pm, Fir Room

Session Description: California’s native flora, including rare plants, is widely assumed to be fire-adapted because fire has been a regular ecosystem disturbance process for millennia. Now that we are seeing dramatic effects of the Pyrocene period created by humans, there is a new urgency to understanding the roles played not just by fire in California ecosystems, but also the relatively recent syndromes of fuels reduction via prescribed burning and mechanical removal of biomass that serves as fuel; fire suppression tactics, including the wide firelines created by bulldozers and the aerial application of chemical fire retardant; and the challenges of post-fire restoration of landscapes, habitats and plant populations. We will examine these topics in this session, as well as taking a more nuanced look at the varied ways that plants adapt to fire through avoidance, resprouting, and long term seed banks dependent on fire cues for germination.

Session Chairs: Lusetta Sims (USDA Forest Service, Shasta-Trinity NF, Weaverville, CA, USA) and Julie Kierstead (USDA Forest Service, Regional Office, Vallejo, CA, USA)

22.1    A different kind of fuel modification: balancing fire safety and habitat

Alan Kaufmann (Laguna Canyon Foundation, Laguna Beach, CA, USA)

Throughout California, fire seasons are getting longer and fires are getting larger and more destructive. Combined with the increasing proximity of human-dominated and wild communities, these trends have created enormous pressure for land owners to manage vegetation along the wildland-urban interface, frequently with serious consequences to the habitat and its denizens, and sometimes in ways that actually make fire danger worse. Since 2015, Laguna Canyon has partnered with the City of Laguna Beach and others to develop and implement a fuel modification program in areas with high habitat value, comprising populations of protected species, including the threatened Big-leaved Crownbeard (Verbesina dissita). This program attempts to achieve fire safety goals while protecting, and in some cases enhancing, habitat value in the treatment area and adjacent wildlands. It uses hand crews under the direction and oversight of biologists to remove non-native plants first, then native plants only when necessary to reduce the remaining vegetative cover to 50%. Fire modeling predicts that this will reduce fireline intensity by at least 70%, giving residents more time to evacuate and firefighters more room to protect structures. This presentation will discuss the project rationale, treatment protocols, mitigation measures, challenges, and successes. Lessons learned include: hand crew fuel modification is expensive, but other methods can end up costing more in the long run; crew training and oversight is essential; this type of project provides lots of opportunities to educate the public about the importance of habitat and the value of native plants; protecting habitat values also protects aesthetic values; and a project is only as good as its maintenance.

22.2    California Vegetation Treatment Program: approaches for expediting wildfire resilience in sensitive natural communities and special-status plant habitat

Tammie Beyerl (Ascent Environmental, Sacramento, CA, USA), Hannah Weinberger (Ascent Environmental, Sacramento, CA, USA)

Decades of fire suppression and effects of climate change have contributed to the increase in wildfires annually since 2010, including recent catastrophic wind driven fires, often close to communities. The California Vegetation Treatment Program (CalVTP) Program Environmental Impact Report (PEIR) provides California Environmental Quality Act (CEQA) streamlining for the California Department of Forestry and Fire Protection (CAL FIRE) and other state and local agencies seeking to implement vegetation treatments to reduce wildfire risk and provides a framework for avoiding and minimizing impacts on special-status plants and sensitive natural communities while allowing for mitigation if significant impacts occur. CalVTP incorporates various activities such as mechanical or manual treatments, prescribed burning, herbivory, and herbicide application, which have potential to adversely affect plants and vegetation communities. The type and magnitude of impacts on botanical resources depend on various factors including the treatment activities implemented, species affected, as well as the time of year and location of treatments. Due to the geographic scope of CalVTP (approximately 20.3 million acres), nearly 2,200 special-status plant species and hundreds of sensitive natural communities, as well as riparian and oak woodland habitats and chaparral and coastal sage scrub vegetation types, were evaluated in the PEIR. Foundational to the CalVTP approach to avoiding, minimizing, and mitigating impacts to botanical resources are standard project requirements (SPRs) and mitigation measures that were developed in close coordination with agencies including the California Department of Fish and Wildlife, the California Coastal Commission, and the State Water Resources Control Board.

22.3    Reintroduction of the Ben Lomond wallflower (Erysimum teretifolium): experimental examination of the roles of soil disturbance, genetic factors, and habitat conditions in recovering an endangered plant endemic to the Santa Cruz Sandhills

Jodi M. McGraw (Jodi McGraw Consulting, Freedom, CA, USA), Justen Whittall (Santa Clara University, Santa Clara, CA, USA), Zachariah Jordan (Jodi McGraw Consulting, Freedom, CA, USA), Terris Kasteen (California Department of Fish and Wildlife, Santa Cruz, CA, USA), Alissa Wilson (Santa Clara University, Santa Clara, CA, USA) and Brody Sandel (Santa Clara University, Santa Clara, CA, USA)

Throughout California, species declines driven by anthropogenic factors necessitate efforts to re-establish extirpated populations and/or establish new populations to avert extinction. Successful (re-)introductions must address factors such as genetics, habitat conditions, and disturbance regimes, which will influence long-term population persistence. We explored these factors in an experimental reintroduction (2018-2020) of the state and federally endangered Ben Lomond wallflower (Erysimum teretifolium Brassicaceae) at the Bonny Doon Ecological Reserve (BDER), Santa Cruz County. We established wallflower through broadcast seeding, demonstrating the species’ ability to complete its entire life cycle in the eight sites, and by outplanting seedings, which experienced greater survivorship and reproduction than seeded plants due to their ‘head start’ in the greenhouse. There was no significant evidence of local adaptation, nor outbreeding depression in comparing the four genotypes of seedlings; however, hybrid crosses between Bonny Doon and non-Bonny Doon genotypes generally exhibited higher success, potentially reflecting heterosis: increased fitness from combining distinct genotypes. Among seeded plants, relative fitness was similar within the native-dominated silverleaf manzanita chaparral (sand chaparral) and maritime coast range ponderosa pine forest (sand parkland), though the latter features more fertile soils that support dense exotic plants, which reduce wallflower growth and survivorship in the absence of habitat treatments. Soil disturbance (“tilling”) increased wallflower growth, survivorship, and reproduction relative to just raking the soil, by loosening the soil and also initially reducing exotic plant competition in sand parkland. This research informed current efforts to expand wallflower populations by seeding the rare plant into areas burned or bull dozed during the 2020 wildfire, to compare fire and soil disturbance as future introduction treatments.

22.4    Response of Santa Cruz cypress to the CZU Lightening Complex Fire (2020) and the Martin Fire (2008)

Todd Lemein (United States Fish and Wildlife Service, Ventura, CA, USA), Jodi McGraw (Jodi McGraw Consulting, Freedom, CA, USA), Terris Kasteen (California Department of Fish and Wildlife, Santa Cruz, CA, USA)

The 2020 CZU Lightning Complex Fire burned 86,529 acres in the Santa Cruz Mountains, including four of the five populations of Santa Cruz cypress (Hesperocyparis abramsiana). Fire aides in opening cones of Santa Cruz cypress, releasing seed, and establishing an open canopy and bare mineral soil, which together should promote stand regeneration and survival. While the recent fire could promote populations of Santa Cruz cypress, several anthropogenic factors including alteration of the natural disturbance regime, exotic plants, drought, and climate change, create the potential for the fire to negatively impact the species. The US Fish and Wildlife Service funded a proposal to monitor the regeneration of the four burned populations, as well as to reassess the recovery of the fifth population that was burned in the 2008 Martin Fire. The first year of results collected in Spring 2022 will present a qualitative assessment of the effects of the 2020 fire and the initial progress of stand regeneration by examining Santa Cruz cypress distribution, abundance, population structure, and habitat conditions. A recensus of permanent plots established following the 2008 Martin Fire, which burned the fifth population, will also be presented to assess the longer-term effects of fire on that population. The results presented will be derived from data collected in the first year of a three year study.

22.5    Panel of Four Speakers

Tammie Beyerl (Ascent Environmental, Sacramento, CA, USA), Alan Kaufmann (Laguna Canyon Foundation, Laguna Beach, CA, USA), Todd Lemein (United States Fish and Wildlife Service, Ventura, CA, USA), Jodi M. McGraw (Jodi McGraw Consulting, Freedom, CA, USA)