Publications
On Fire and Water: The Intersection of Wetlands and Burning Strategies in Managing the Anthropogenic Plant Communities of Yosemite National Park
Historical fire suppression and hydrological manipulation by the U.S. National Park Service (NPS) have significantly altered culturally significant plant communities in Yosemite National Park, compounding the effects of conifer encroachment on anthropogenic meadows. Research reveals that Native American tribes historically used periodic burning to maintain preferred plant communities, with wetlands playing a crucial cultural and ecological role. Ethnographic investigations show that wetland species were dominant among culturally important plants, and traditional burning practices adapted to seasonal water-table fluctuations in these environments. This study combines historical literature reviews, ethnographic accounts, and guidance from tribal elders to highlight the intersection of fire and water management in shaping culturally significant landscapes.
Safe harbor: translocating California red‐legged frogs to a climate refuge in Yosemite National Park
A successful translocation of California red-legged frogs (Rana draytonii) to Yosemite National Park demonstrates that climate refuges can serve as safe harbors for endangered species, even if marginally outside their historical range. The study challenged traditional restoration goals by prioritizing dynamic adaptation over literal historical baselines, addressing threats like drought, urbanization, and invasive predators, including American bullfrogs (Lithobates catesbeianus). Researchers combined ex situ conservation efforts—such as captive breeding and chytrid fungus inoculation studies at the San Francisco Zoo—with in situ translocation to establish a resilient population. The approach also highlighted the potential for low-cost egg-mass translocations in amphibians, offering a scalable model for biodiversity conservation amid rapid environmental change. This novel strategy not only advanced the species' recovery but also provided a framework for U.S. National Park Service to adopt flexible, forward-looking restoration methods in an era of climate uncertainty.
Wildfire-driven entry closures influence visitor displacement and spending to alternative park entrance corridors and gateway communities around Yosemite National Park
Wildfire-driven road closures at Yosemite National Park lead visitors to displace to nearby open entrance gates, significantly increasing attendance by about 50% and boosting need-based spending like gasoline. However, these displaced visitors do not contribute substantially to gateway communities through routine-based activities such as dining. The study analyzed county sales tax revenue during fire-related closures, revealing that economic impacts vary by spending category rather than visitor presence alone. While agencies could leverage this through-flux with targeted marketing and informational kiosks in gateway communities, current displacement patterns limit tourism-dependent economies' benefits.
Science and the evolving management of environmental hazards at Yosemite National Park
Yosemite National Park faces escalating environmental hazards, including wildland fires, tree mortality, extreme floods, and rockfalls/slides, which are increasingly severe due to climate change and development pressures. Research reveals that drought correlates with higher tree mortality rates, warmer precipitation advances peak streamflow, prolonged cold triggers rockfalls, and extended precipitation increases slides. These interconnected hazards pose significant risks given the park's high seasonal visitation. The study synthesizes administrative and environmental histories using archival records and long-term data to illustrate how science has evolved in guiding policy and management strategies over time.
Second-Entry Burns Reduce Mid-Canopy Fuels and Create Resilient Forest Structure in Yosemite National Park, California
Repeated burning in Yosemite National Park significantly reduces mid-canopy fuel loads and enhances forest resilience, biodiversity, and ecosystem health without further improvement after a second fire. Researchers analyzed long-term fire histories, LiDAR data, and topo-climatic datasets to assess how fire interactions with climate shape forest structure across elevation-driven gradients. They found that while tree density and mid-canopy strata cover decreased after two fires, subsequent burns did not alter these patterns further. This study provides critical insights for refining fire management prescriptions, balancing wildfire risk mitigation, and promoting ecosystem resilience in protected areas like Yosemite.
Feldspar recycling across magma mush bodies during the voluminous Half Dome and Cathedral Peak stages of the Tuolumne intrusive complex, Yosemite National Park, California, USA
Research reveals that the Tuolumne intrusive complex (TIC) in Yosemite National Park underwent significant feldspar recycling during its Half Dome and Cathedral Peak stages, indicating dynamic magma-mush interactions. The study found that contacts between major plutonic units are gradational zones up to 3 km thick, with distinct K-feldspar compositions in the equigranular Half Dome (eHD) and evidence of mixing between porphyritic Half Dome (pHD) and Cathedral Peak (CP) magmas. Plagioclase populations in eHD and CP suggest hybridization to form pHD, implying an evolving magmatic system with crystal-melt exchanges before final crystallization. Field mapping, petrographic analysis, and geochemical studies of feldspar populations provided these insights.
Long-Term Rodent Surveillance after Outbreak of Hantavirus Infection, Yosemite National Park, California, USA, 2012
A six-year rodent surveillance study in Yosemite National Park, California, found that deer mouse populations and hantavirus seroprevalence remained lower following a 2012 outbreak, though the latter difference was not statistically significant. The research, conducted by the California Department of Public Health, involved 17 trapping events across developed areas of Yosemite Valley and Tuolumne Meadows to monitor deer mouse (Peromyscus maniculatus) abundance and Sin Nombre orthohantavirus seroprevalence. The decline in rodent populations is likely attributed to intensified rodent exclusion efforts and reduced peridomestic habitat, suggesting that human interventions may influence both rodent dynamics and disease risk in high-traffic areas of national parks.
Opportunities and challenges for restoration of the Merced River through Yosemite Valley, Yosemite National Park, USA
A century of human disturbances along the Merced River in Yosemite National Park has created long-term consequences for riverine conditions, hindering natural recovery through passive restoration. Key findings indicate that reduced sediment influx—due to historical gravel mining and altered fluvial processes—and intensive visitor use have decoupled the river from its floodplain, damaged riparian zones, and distorted channel dynamics. Climate change may further amplify these challenges by both diminishing fluvial processes and increasing sediment export rates. The study integrates geomorphic, hydrological, and human-impact analyses to highlight the complex interplay of natural and anthropogenic factors shaping river restoration opportunities in this iconic landscape.
Reframing Native Knowledge, Co-Managing Native Landscapes: Ethnographic Data and Tribal Engagement at Yosemite National Park
A collaborative ethnographic database, comprising over 13,000 georeferenced entries from historical accounts and tribal oral histories, has been developed to document Native American land use and cultural significance within Yosemite National Park. This tool, already utilized by the National Park Service and tribal communities, facilitates the identification of culturally significant places and resources, fostering potential co-management opportunities. While the database offers a dynamic representation of cultural traditions, it also risks reinforcing hegemonic discourses. The study argues for critical engagement with these contradictions to meaningfully integrate Native voices into park management, serving as a model for broader conservation collaboration.
Rock strength properties of granitic rocks in Yosemite Valley, Yosemite National Park, California
A significant rock fall of 9,811 cubic meters from El Capitan's southeast face in Yosemite Valley on September 28, 2017, highlighted the need for detailed analysis of granitic rock strength properties. The study, conducted by Collins et al. (2020), focused on understanding the mechanical behavior of these rocks to assess their stability and potential hazards. Researchers employed a combination of field observations, laboratory tests, and numerical modeling to evaluate factors influencing rock fall events. Their findings provide critical insights for risk assessment and management in Yosemite National Park, where granitic rocks are prone to large-scale collapses due to geological and environmental stresses.
Soil Enzyme Activity and Soil Nutrients Jointly Influence Post-Fire Habitat Models in Mixed-Conifer Forests of Yosemite National Park, USA
In mixed-conifer forests of Yosemite National Park, soil enzyme activity and nutrient levels play a significant role in shaping species composition post-fire, often more so than topographic factors. A study analyzing 160 locations in the recently burned Yosemite Forest Dynamics Plot (YFDP) found that soil properties—including phosphatases and urease enzymes—defined habitat niches for 54.5% of species associations, compared to 45.4% defined by topography. Enzyme activity was particularly influential in explaining species abundance and basal area increment. While spatial factors explained more variation in stem abundance, mortality, and recruitment, the study underscores the need for a nuanced understanding of niche parameters beyond simple topographic data to fully grasp species habitat preferences.
The distribution of woody species in relation to climate and fire in Yosemite National Park, California, USA
A study on Yosemite National Park reveals that fire significantly influences the distribution of woody plant species, with 34% of models for these species showing improved accuracy when fire occurrence was included as a variable. Fire return interval and severity also enhanced predictions for 26% and 5% of species, respectively. The research analyzed 561 plots across the park, assessing climate factors like actual evapotranspiration (AET) and climatic water deficit alongside fire characteristics to map species distributions along a moisture gradient from cool-moist to hot-dry conditions. Findings underscore the importance of incorporating fire regimes into models for predicting species distribution changes in fire-prone ecosystems like those in western North America.
The changing anthropogenic diets of American black bears over the past century in Yosemite National Park
American black bears in Yosemite National Park now consume human foods at the same rate as they did over a century ago, despite a four-million-fold increase in annual park visitors. This significant reduction in anthropogenic diet reliance was achieved through targeted management strategies, including closing artificial feeding areas and implementing a $500,000 annual conflict mitigation program starting in 1999. Researchers analyzed carbon (δ¹³C) and nitrogen (δ¹⁵N) stable isotopes in bear tissues to track dietary shifts over time. The findings highlight the success of park management in curbing human-bear conflicts while maintaining ecological balance, offering a model for other protected areas.
Factors Associated with the Severity of Intersecting Fires in Yosemite National Park, California, USA
A study on Yosemite National Park's Illilouette Creek basin reveals that reburn fires tend to increase in severity, with high-severity burns often converting vegetation to montane chaparral. The research found no significant link between fire return interval and initial fire severity but identified associations with the number of years since the last burn, burning index, and previous fire severity. These factors interact to influence reburn severity, offering insights for ecosystem management. The study analyzed 28 fires larger than 40 ha from 1973 to 2011, providing a data-driven understanding of fire dynamics in this UNESCO World Heritage Site.
Climatic water deficit, tree species ranges, and climate change in Yosemite National Park
Research on Yosemite National Park reveals that projected increases in climatic water deficit (Deficit) due to climate change may significantly alter forest structure and composition. The study found a 23% increase in Deficit from present (1971–2000) to future projections (2020–49), with species like Pinus monticola and Tsuga mertensiana potentially facing disproportionate impacts. Using high-resolution spatial data, the study correlated tree species distributions with actual evapotranspiration (AET) and Deficit across a 2300-meter elevation gradient, showing that species differentiation intensifies under higher Deficit conditions. The research also highlights the importance of fine-scale soil and topographical data in improving vegetation-change projections in heterogeneous mountainous landscapes.
Fire regimes, forest change, and self‐organization in an old‐growth mixed‐conifer forest, Yosemite National Park, USA
A 2125-hectare old-growth mixed-conifer forest in Yosemite National Park exhibited frequent, low-severity fires with a median return interval of 10 years and an average burn extent of 115 hectares before Euro-American settlement. These fires created small canopy openings (<0.2 ha) and showed self-organizing behavior, with area burned increasing tenfold when an area had not been affected by the previous fire. Post-1905 fire suppression led to a significant increase in forest density, basal area, and a shift toward shade-tolerant, fire-intolerant species. The study suggests that restoring frequent, low-severity burns can mimic historical conditions, reducing surface fuels and creating small canopy openings characteristic of the reference forest.
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