About

Justin Brashares is a wildlife and conservation scientist and a professor in the Department of Environmental Science, Policy, and Management at UC Berkeley. His research focuses on the causes and consequences of bushmeat hunting in Africa, the conservation of small populations in western North America, and the landscape ecology and conservation of African ungulates. Brashares blends ecology and conservation biology with interdisciplinary science to uncover holistic strategies for biodiversity conservation grounded in real-world evidence. He co-leads the California Wolf Project and advises the Eric and Wendy Schmidt Center for Data Science & Environment, which partners with policymakers, Indigenous and local communities, and land managers to develop software tools that help protect the environment. Brashares has been named a National Geographic Explorer in Residence, where he will guide scientific research and conservation strategy for the Blue Boundaries initiative, focusing on safeguarding freshwater wetlands, coastal systems, and reefs through on-location research, conservation projects, storytelling, and education. As chair of the program’s science committee, he mentors the cohort of National Geographic Explorers and serves as an advisor to the Stone Center for Environmental Stewardship. Brashares's work is driven by the urgent reality of rapid biodiversity decline and its impact on planetary stability and resilience. He has served as a member of the Society’s Committee on Research and Exploration since 2018 and joins a community of UC Berkeley-affiliated Explorers dedicated to harnessing science, innovation, and technology to inspire change.

Research topics

• Biology
• Ecology
• Political Science
• Geography
• Environmental resource management
• Computer Science
• Environmental science
• Engineering

Selected publications

• Exploring the potential population impacts of puma predation on a mainland Magellanic penguin colony through an interactive tool

  Ecological Informatics · 2026-04-25

  articleOpen access

  The success of restoration efforts has resulted in the expanding range of large predators from their historical lows in many areas of the world. In many cases these predators are returning to ecosystems that have been altered since their historical presence, resulting in novel interactions and presenting managers with complex conservation issues. Quantitative tools that allow managers to interactively build scenarios and evaluate potential outcomes in an intuitive manner may improve understanding and decision making. To demonstrate the utility of such tools in a complex, novel system, we built an interactive R Shiny application to model the population dynamics of a mainland Magellanic penguin colony and the effects of predation by a recovering puma population in Monte León National Park, Argentina. To facilitate scenario building and exploration by readers and managers alike, we include the code to run the R Shiny application in the Supplementary Information. Under the default values of the demographic and predation rates that we set to reflect our best understanding of current conditions, the penguin colony is projected to continue increasing into the future until a density-dependent upper stability with minimal risks of extinction. However, sensitivity analysis reveals that the population is highly susceptible to the interaction between autocorrelated environmental stochasticity and additive mortality from puma predation. Increases in environmental variance (simulating extreme climate events, or swings in fisheries stocks) combined with puma predation result in significantly higher probabilities of extinction in the coming decades. Our tool has the flexibility to model a wide range of scenarios for Magellanic penguin colonies or other populations facing additive mortality from predation, explorations that are easily implementable due to the tool's open-source code.

  PublisherDOI

• Severity outweighs pyrodiversity in shaping avian and bat species distributions following an oak woodland megafire

  Ecosphere · 2025-07-01

  articleOpen accessSenior author

  Abstract Anthropogenic pressures have altered fire regimes across the western United States. These altered fire regimes, and the megafires they often produce, threaten ecologically and economically critical ecosystems and biodiversity across this region. Oak woodland savannas may be particularly sensitive to altered fire regimes, but there remains a significant gap in our understanding of how different characteristics of wildfire impact these ecosystems and the wildlife species that reside within them. In this study, we used an occupancy modeling framework to investigate how fire severity and pyrodiversity, the diversity of severity patches, impact the distributions of bird and bat species assemblages following a major wildfire in northern California. We used acoustic monitors deployed across the Hopland Research and Extension Center following the 2018 Mendocino Complex Fire and compared how patterns of fire severity and pyrodiversity influence habitat preferences across a diverse community of woodland bird and bat species. We found that fire enhances habitat use and increases occupancy for several species and species groups across both taxonomic groups. Specifically, low‐to‐moderate severity fire increased occupancy for several species and species groups. Pyrodiversity had smaller, negligible effects on species distributions relative to fire severity. Fires that reproduce the natural heterogeneity of oak woodland landscapes are likely key to sustaining high biodiversity across oak woodland ecosystems.

  PublisherDOI

• Housing proximity and vegetation cover affect diel activity patterns of domestic cats ( <i>Felis catus</i> ) in regionally protected shorelines

  Journal of Urban Ecology · 2025-01-01

  articleOpen access

  Abstract Free-roaming domestic cats (Felis catus) are among the most impactful non-native species globally, causing the extinction of 63 endemic vertebrate species. Their potential ecological impact is especially pronounced in urban areas adjacent to protected spaces where elevated cat densities threaten local wildlife. While cat ecology in human-dominated environments is well-studied, the social-ecological factors influencing cats’ spatial and temporal activity are less certain. Examining these factors is crucial for regionally protected landscapes, as increased cat activity can undermine conservation efforts and complicate policy implementation. In this study, we used motion-activated trail cameras across protected shoreline sites in California’s East Bay region to analyze cat detection patterns and their temporal activity concerning vegetation greenness (NDVI), human population density, median household income, and housing proximity. Our findings show that cat detections decreased when the distance from residential areas increased, with housing proximity being the only significant predictor among the spatial variables tested. Temporal analysis revealed a strong preference for nocturnality, with the greatest selection for nighttime and twilight periods observed in areas closer to residential housing and vegetation cover. Our results suggest that free-roaming cats alter their activity spatially and temporally to select areas where they can avoid predation from top predators while exploiting food subsidies near housing communities. These results highlight the complex ecological interactions near human infrastructure and how environmental composition contributes to the behavioral patterns of free-roaming cats.

  PublisherOA PDFDOI

• Maximizing the potential benefits of beaver restoration for fire resilience and water storage

  Ecological Applications · 2025-10-01

  articleOpen access

  Abstract Restoring populations of native keystone species can increase landscape resilience to global change when those species create or modify ecosystems. The North American beaver ( Castor canadensis ) is an ecosystem engineer that increases river water storage and residence time, increasing fire resilience at the landscape level. Beaver populations in North America are significantly lower than they were historically, but over the last decade, beavers have been increasingly recognized for their ecosystem services, and reintroduction efforts throughout their historic range have become more prevalent. Here, we modeled potential beaver dam‐building capacity, associated surface water storage, and fire resilience in California's Sierra Nevada, a region at high risk of drought and wildfire. We estimate that 51% of beaver dam‐building capacity remains in this region compared to historical levels, and considerable dam capacity remains in all watersheds. Our conservative estimates suggest that beaver dams have the potential to store a total of 120 million m 3 of surface water and create 2200 km 2 of fire resilience in high fire risk areas. Additionally, streams where beavers have the potential to create the greatest water and fire benefits due to physical landscape and habitat characteristics are frequently found within watersheds that are at high risk for both drought and fire. Specifically, we identified five priority watersheds that have both high risk for drought and fire impacts, and have high potential to benefit from beaver conservation and restoration. Even in areas where fire and drought are less probable, the reestablishment of beavers will likely provide similar benefits. This unique approach to quantifying potential beaver benefits illustrates that wildlife can increase resilience to global change stressors and suggests that biodiversity and nature‐based climate solutions are intertwined.

  PublisherOA PDFDOI

• Human-wildlife conflict is amplified during periods of drought

  Science Advances · 2025-11-12 · 1 citations

  articleOpen access

  Climate change-induced alterations to human-wildlife interactions are recognized to pose a fundamental challenge for global conservation initiatives. However, the extent to which specific climatic disturbances influence dynamics of human-wildlife conflict across different taxonomic groups remains poorly understood. Here, we leverage an extensive dataset of community-derived human-wildlife conflict incidents to examine the influence of drought, represented by the variation in summed precipitation over the prior 12 months, on conflict reporting. We show that prolonged decreases in precipitation are associated with increased overall conflict occurrences across taxa and are significantly associated with increased conflict with carnivore species in particular. A future with increasingly severe and frequent droughts could lead to resource scarcity that not only causes conflict between humans but also between humans and the natural world around them.

  PublisherDOI

• When the wild things are: Defining mammalian diel activity and plasticity

  Science Advances · 2025-02-26 · 23 citations

  articleOpen access

  Circadian rhythms are a mechanism by which species adapt to environmental variability and fundamental to understanding species behavior. However, we lack data and a standardized framework to accurately assess and compare temporal activity for species during rapid ecological change. Through a global network representing 38 countries, we leveraged 8.9 million mammalian observations to create a library of 14,587 standardized diel activity estimates for 445 species. We found that less than half the species' estimates were in agreement with diel classifications from the reference literature and that species commonly used more than one diel classification. Species diel activity was highly plastic when exposed to anthropogenic change. Furthermore, body size and distributional extent were strongly associated with whether a species is diurnal or nocturnal. Our findings provide essential knowledge of species behavior in an era of rapid global change and suggest the need for a new, quantitative framework that defines diel activity logically and consistently while capturing species plasticity.

  PublisherDOI

• Maximizing the potential benefits of beaver restoration for fire resilience and water storage

  HydroShare Resources · 2025-06-24 · 1 citations

  datasetOpen access
  PublisherDOI

• Hunting mode and habitat selection mediate the success of human hunters

  Movement Ecology · 2024-04-16 · 9 citations

  articleOpen accessSenior author

  BACKGROUND: As a globally widespread apex predator, humans have unprecedented lethal and non-lethal effects on prey populations and ecosystems. Yet compared to non-human predators, little is known about the movement ecology of human hunters, including how hunting behavior interacts with the environment. METHODS: We characterized the hunting modes, habitat selection, and harvest success of 483 rifle hunters in California using high-resolution GPS data. We used Hidden Markov Models to characterize fine-scale movement behavior, and k-means clustering to group hunters by hunting mode, on the basis of their time spent in each behavioral state. Finally, we used Resource Selection Functions to quantify patterns of habitat selection for successful and unsuccessful hunters of each hunting mode. RESULTS: Hunters exhibited three distinct and successful hunting modes ("coursing", "stalking", and "sit-and-wait"), with coursings as the most successful strategy. Across hunting modes, there was variation in patterns of selection for roads, topography, and habitat cover, with differences in habitat use of successful and unsuccessful hunters across modes. CONCLUSIONS: Our study indicates that hunters can successfully employ a diversity of harvest strategies, and that hunting success is mediated by the interacting effects of hunting mode and landscape features. Such results highlight the breadth of human hunting modes, even within a single hunting technique, and lend insight into the varied ways that humans exert predation pressure on wildlife.

  PublisherOA PDFDOI

• Fishery access benefits early childhood development through fish consumption and fishing income pathways

  World Development · 2024-10-31 · 8 citations

  articleOpen access

  • Fishery access benefits early childhood development through fishing income and fish consumption pathways. • Fish species shape the benefits of fish consumption. • Fishing income benefits early childhood development through its effect on child growth. Within many global communities, access to natural resources benefits nutrition through provision of both food and livelihoods. In fishing communities, fish provide a rich source of essential nutrients, and fishing represents a critical income source. While evidence for the beneficial nutrients in fish abounds, fisheries’ integrated influence on nutrition outcomes through provisioning both fish for consumption and fishing income has not been examined. To address the full value of fishery resources’ contributions to food systems, within fishing communities around Lake Victoria, Kenya, we examined the effects of fish consumption and fishing income pathways on child gross motor, personal-social, and communication development as measured through the parent-reported Ages and Stages Questionnaire: Inventory across 210 households surveyed at nine time points over two years. We used mediation analyses to determine whether fishing income operates through or independently of child growth to affect early childhood development. Consumption of only one of two predominant fish species significantly benefited all three child development outcomes. Fishing income, through its effects on child growth, also significantly increased gross motor and personal-social development. Notably, the magnitude of effects of fishing income are comparable to those of fish consumption (ranging from 0.10 [90% CI 0.03–0.18] to 0.18 [90% CI 0.09–0.28]). Natural resources play a complex role in provisioning wild food, affecting nutrition outcomes through both diets and income. Disentangling these pathways and appreciating their relative magnitude are critical to advancing programs and policies to improve nutrition, early childhood development, and nature conservation.

  PublisherDOI

• Using multiple scales of movement to highlight risk–reward strategies of coyotes (<i>Canis latrans</i>) in mixed‐use landscapes

  Ecosphere · 2024-08-01 · 6 citations

  articleOpen accessSenior author

  Abstract Many wildlife species vary habitat selection across space, time, and behavior to maximize rewards and minimize risk. Multi‐scale research approaches that identify variation in wildlife habitat selection can highlight not only habitat preferences and risk tolerance but also movement strategies that afford coexistence or cause conflict with humans. Here, we examined how anthropogenic and natural features influenced coyote ( Canis latrans ) habitat selection in a mixed‐use, agricultural landscape in Mendocino County, California, USA. We used resource selection functions and hidden Markov models to test whether coyote selection for anthropogenic and natural features varied by time of day or by behavioral state (resting, foraging, and traveling). We found that coyotes avoided development, but, contrary to our expectations, coyotes selected for roads, agriculture, and areas with risk of human encounter and rifle use regardless of diel period or behavioral state. While traveling, coyotes increased selection for roads and avoided ruggedness, indicating that unpaved roads may enhance connectivity for coyotes in mixed‐use landscapes. Finally, we found that coyotes selected for mountain lion habitat when resting and at night, signifying that risk from natural predators was not a factor in habitat selection at coarse scales. Coyote habitat selection for places and times associated with human activity, without variation across scales, signals a potential for conflict if coyotes are perceived by people as a nuisance.

  PublisherOA PDFDOI

Recent grants

• Collaborative research: Quantifying the ecosystem-wide impacts of a strong interactor in African watersheds

  NSF · $428k · 2012–2016

• CNH: Interactive Dynamics of Wildlife Populations, Human Health and Household Wealth in Rural Africa

  NSF · $1.5M · 2011–2017

• Collaborative Research: Interactive Effects of Climate, Ecosystem Engineering, and Trophic Interactions on Grassland Community Dynamics

  NSF · $220k · 2014–2018

• Doctoral Dissertation Research: The Implications of Changes in Fisheries on the Diets and Well-Being of Regional Residents

  NSF · $16k · 2014–2016

• Assessing Shifts in the Reproductive Output, Behavior and Physiology of Harvested Wildlife

  NSF · $399k · 2008–2012

Frequent coauthors

• Moses Sam

  60 shared

• A. R. E. Sinclair

  University of British Columbia

  41 shared

• Andrew Balmford

  University of Cambridge

  38 shared

• Peter Coppolillo

  36 shared

• Kaitlyn M. Gaynor

  University of British Columbia

  35 shared

• Peter Arcese

  29 shared

• A. Cole Burton

  University of British Columbia

  26 shared

• Alex McInturff

  University of Washington

  25 shared

Labs

• Justin Brashares LabPI

Awards & honors

• National Geographic Explorer in Residence