Journal article
Mega-disturbances cause rapid decline of mature conifer forest habitat in California
Ecological applications, Vol.33(2), pp.1-19
03/01/2023
DOI: 10.1002/eap.2763
PMID: 36264047
Abstract
Mature forests provide important wildlife habitat and support critical ecosystem functions globally. Within the dry conifer forests of the western United States, past management and fire exclusion have contributed to forest conditions that are susceptible to increasingly severe wildfire and drought. We evaluated declines in conifer forest cover in the southern Sierra Nevada of California during a decade of record disturbance by using spatially comprehensive forest structure estimates, wildfire perimeter data, and the eDaRT forest disturbance tracking algorithm. Primarily due to the combination of wildfires, drought, and drought-associated beetle epidemics, 30% of the region's conifer forest extent transitioned to nonforest vegetation during 2011-2020. In total, 50% of mature forest habitat and 85% of high density mature forests either transitioned to lower density forest or nonforest vegetation types. California spotted owl protected activity centers (PAC) experienced greater canopy cover decline (49% of 2011 cover) than non-PAC areas (42% decline). Areas with high initial canopy cover and without tall trees were most vulnerable to canopy cover declines, likely explaining the disproportionate declines of mature forest habitat and within PACs. Drought and beetle attack caused greater cumulative declines than areas where drought and wildfire mortality overlapped, and both types of natural disturbance far outpaced declines attributable to mechanical activities. Drought mortality that disproportionately affects large conifers is particularly problematic to mature forest specialist species reliant on large trees. However, patches of degraded forests within wildfire perimeters were larger with greater core area than those outside burned areas, and remnant forest habitats were more fragmented within burned perimeters than those affected by drought and beetle mortality alone. The percentage of mature forest that survived and potentially benefited from lower severity wildfire increased over time as the total extent of mature forest declined. These areas provide some opportunity for improved resilience to future disturbances, but strategic management interventions are likely also necessary to mitigate worsening mega-disturbances. Remaining dry mature forest habitat in California may be susceptible to complete loss in the coming decades without a rapid transition from a conservation paradigm that attempts to maintain static conditions to one that manages for sustainable disturbance dynamics.
Details
- Title: Subtitle
- Mega-disturbances cause rapid decline of mature conifer forest habitat in California
- Creators
- Zachary L. L. Steel - University of California, BerkeleyGavin M. M. Jones - University of New MexicoBrandon M. M. Collins - Pacific Southwest Research StationRebecca Green - California Department of Parks and RecreationAlexander Koltunov - University of California, DavisKathryn L. L. Purcell - Pacific Southwest Research StationSarah C. C. Sawyer - Pacific Southwest Research StationMichele R. Slaton - Pacific Southwest Research StationScott L. L. Stephens - University of California, BerkeleyPeter Stine - Stine Wildland Resources Sci, Sacramento, CA USACraig Thompson - Pacific Southwest Research Station
- Resource Type
- Journal article
- Publication Details
- Ecological applications, Vol.33(2), pp.1-19
- DOI
- 10.1002/eap.2763
- PMID
- 36264047
- NLM abbreviation
- Ecol Appl
- ISSN
- 1051-0761
- eISSN
- 1939-5582
- Publisher
- Wiley
- Number of pages
- 19
- Grant note
- 8GG21823 / California Department of Forestry and Fire Protection
- Language
- English
- Date published
- 03/01/2023
- Academic Unit
- School of Earth, Environment, and Sustainability
- Record Identifier
- 9985219306202771
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