I am trained as an interdisciplinary macroecologist. My research combines theory with data from field studies and large datasets to: i) uncover fundamental principles of life history, behavior, ecology and biodiversity, and ii) to use these "macroecological laws” as a framework to address practical issues in human ecology, biodiversity conservation, equity and sustainability.

Some press research coverage: PLoS podcast, PLoS blog, Earth Times, Our Finite World, Business Insider, Phys.org, Sierra Club Canada, Ecology and Policy Blog of the British Ecological Society, Newswise, Scientific American blog, BioScience, Nautilus Magazine, New York Times, Nature Ecology and Evolution blog, Nature Sustainability, Duke Nicholas School Blog "Translational Ecology", Revista Endémico (en Español), Psychology Today, Inverse, Medicalexpress.com

My lab uses field and comparative studies to address basic questions related to social behavior, life history and population demography with implications for conservation and human ecology. I mostly study mammals, including humans, but other taxa too. Recognizing the benefits of addressing questions at multiple levels of biological organization, I compliment field research with macroecological and comparative studies that seek to unify across levels and scales of analysis from individual energy budgets—to population and community dynamics—to cities and the biosphere.

A central focus of my research is exploring biological metabolism (and energy broadly) as a common currency to study emergent properties and behaviors of complex biological and social systems across space and time scales. To that end, my interdisciplinary research pursues core scientific principles and currencies that transcend the physical, biological, and social sciences, making my research highly collaborative. Below are summaries of my primary areas of study.

Biological Scaling

Life is amazingly diverse, yet there are universal rules that emerge from fundamental biophysical constraints on all species. These are often characterized by scaling laws that can be derived mathematically and evaluated emperically in the field or data synthesis.

Toward a metabolic theory of life history. A major thrust of my research involves developing a metabolic theory of life history that applies across the diversity of life. Metabolism defines life and regulates energy allocation to the various components of growth, development, survival, and reproduction. Across organisms, biological rates and times generally scale as a power law, R=R_o M^b, where R is a trait of interest, M is size of organism, and R_o and b are constants. Across species metabolic scaling theory predicts whole organism metabolic rates as b ≈ ¾, biological times such as development and lifespan as b ≈ ¼, and biological rates including heart rate and reproduction as b ≈ -¼. Other behavioral, life history, population, spatial, and ecological characteristics scale with body size allowing theoretical predictions of parameter estimates that can be evaluated empirically. I am developing new extensions of metabolic theory that incorporate how mass-energy balance and demography constrain the allocation of biomass to the components of fitness: growth, survival, and reproduction (Burger et al. 2019 PNAS; Burger et al. 2021 Ecol Lett). This work has revealed general rules for life history tradeoffs that emerge from the universal biophysical constraints that act on all organisms. These rules are characterized by general equations that underscore the unity of life and provide a number of testable predictions at multiple levels of organization including individual resource allocation, the scaling of life history traits, population dynamics, demography, size distributions in ecosystems and trophic energetics (see Burger et al. 2021 Ecol Lett; Brown et al. 2022 Int Comp Biol).

Scaling approaches can be applied to lots of questions in biodiversity. For example, collaborating with three undergraduate students at UNC-Chapel Hill, we compiled a new comparative datasets of brain sizes for 1552 species (Burger, George, Jr. Leadbetter, and Shaikh - 2019 - J of Mammalogy). What's particularly interesting is that brain size scales sublinear to body size across all mammals and approximates ~0.75 power. So, humans don't have the largest absolute brain size or ratio of brain size to body size, but the largest brain size once accounting for deviations from this allometry. Interestingly, we still do not have an explanation for why the brain scales to the 3/4 power.

We are currently evaluating the life-history tradeoffs associated with brain size using metabolic scaling theory and data for thousands of species. We are seeking to uncover the general constraints and tradeoffs in brain size and pace of life histories that make up the extraordinary diversity of lifestyles in birds and mammals. I am also intersted in studying the scaling of other cognitive, morphological and life history traits.

'Sky Island' Biogeography & Conservation

Human Macroecology and Sustainability

In collaboration with my Ph.D. advisor, James H. Brown, and others in the Human Macroecology Group (see authors on papers) I have begun to explore the utility of a metabolic framework and macroecological approach to understand the evolutionary past and future trajectory of our own species. Despite being the most studied species on the planet, humans are not typically studied by ecologists the same way we study other organisms. This approach provides us with an appropriate means to quantify the flows of energy, materials, and information into, within, among and between human societies and the global environment from hunter-gatherers to urban dwellers. It also provides an explicit framework with mathematical predictions to compare and contrast the ecology of Homo sapiens to other organisms. Specifically, this work has outlined core ecological principles for sustainability science (Burger et al. 2012 PLoS Biol), the demography and energetics underpinning cummulative cultural evolution and innovation (Nekola et al. 2013 TREE; Burger 2018 Nature Sustainability), the scaling of energy use with economic growth across and within countries (Brown et al. 2014 Ecological Engineering), and emerging social and lifespan inequalities (Snyder-Mackler, Burger et al. 2020 Science).

Urban Biodiversity and the Importance of Scale

Despite rapid urbanization and growing cities, we lack a general framework to study global urban biodiversity across scales. Many ecological and evolutionary processes are affected by urbanization, but cities vary by orders of magnitude in both their size and degree of development. To quantify and manage urban biodiversity we must understand both how biodiversity scales with city size, and how ecological, evolutionary and socioeconomic drivers of biodiversity scale with city size. We have been developing macroecological approaches to quantify how environmental abiotic and biotic drivers as well as human cultural and socioeconomic drivers may act through ecological and evolutionary processes differently at different scales to influence patterns in urban biodiversity (Uchida et al. 2021 TREE). Because these relationships often take linear and non-linear forms, we have highlighted the need to describe the specific scaling relationships in evolutionary, ecological and social attributes. This includes deviations and potential inflection points where different management strategies may successfully conserve urban biodiversity.

To explore these knowledge gaps, I am collaborating broadly with natural and social scientists discussing to: 1) test global scaling relationships hypothesized in our new framework in Uchida et al. (2021) TREE; 2) provide insights from understudied regions (e.g., Latin America) on the interplay between physical, ecological, evolutionary and social factors that drive urban biodiversity; and, 3) explore human dimensions of urban biodiversity scaling, including biodiversity management, environmental justice and cross-scale functional arrangements of human settlements resulting in novel urban ecosystems; 4) the importance of scale in managing transnational cities.