I am trained as an interdisciplinary evolutionary and macroecologist. My research uses metabolic scaling theory to motivate field studies and the compilation and analysis of large datasets to: i) uncover fundamental principles and general rules that govern the diversity of life, and ii) to use these “macroecological laws” as a framework to address practical issues in human and ecosystem health, conservation, and sustainability. I use equal parts theory and data to understand the energetics of life history, population dynamics, biogeography, and cities with practical implications for biodiversity conservation, environmental management, and sustainability. Recognizing the benefits of addressing questions at multiple levels of organization, I compliment field research with macroecological studies that seek to unify across levels and scales of analysis from individual resource allocation—to populations and communities—to the biosphere. 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. 

1) 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 M, where R is a trait of interest, M is size of organism, and R and are constants. Across species metabolic scaling theory predicts whole organism metabolic rates as ≈ ¾, biological times such as development and lifespan as ≈ ¼, and biological rates including heart rate and reproduction as ≈ -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). 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.

2) Sustaining isolated populations. The world’s habitats are becoming increasingly fragmented. However, we still lack general rules that predict the minimum constraints required for populations to persist. To address this shortcoming, we have developed a Constraint-based model of Dynamic Island Biogeography (C-DIB) to predict the emergence of populations and communities as “islands” cycle through time (Burger et al. 2019 Frontiers of Biogeography). This research links metabolic scaling theory with species distribution modeling to improve our understanding of the minimum constraints required to sustain viable populations. This research links the physical forces of dynamic “island” systems with constraints on animal space use and population densities. Uniquely, our model reveals the critical role of hysteresis – not only current system state, but also historical trajectory – in predicting different outcomes in populations and communities. Our C-DIB model applies to diverse taxa and systems and has implications for understanding biodiversity over paleo timescales to rapid land-use change such as fragmentation and urbanization. This research aims to generate new theoretical predictions and conservation targets of minimum viable areas to sustain populations in the face of changing landscapes and climate. This research is funded by the NSF 2020-2023 in collaboration with colleagues at the AMNH and City College of New York and UNAM in Mexico to study Madera sky island mountains in Mexico.

3) Scaling socio-ecological drivers of urban biodiversity. 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. I 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. 2020 TREE). Because these relationships often take linear and non-linear forms (Burger et al. 2020 submitted), 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.

4) Human macroecology and sustainability. I have been collaborating with a range of physical, biological, social, medical, and health scientists and engineers to develop an interdisciplinary research program we call human macroecology. This research bridges ecological theory and statistical analysis of large datasets to identify the unique biological, cultural, and technological innovations that have allowed human niche expansion, and how we can sustain the human system within global biophysical constraints. This research has highlighted core macroecological principles to guide sustainability (Burger et al. 2012 PLoS Biology), resource scarcity and macroeconomics (Brown et al. 2013 Ecol Engineering), food security (Hammond et al. 2015 BioScience) and the biogeography of hunter-gatherer resources and disease burdens (Burger & Fristoe 2018 PNAS). It has also revealed new insights into the challenges to sustainability posed by cultural evolution (Nekola et al. 2013 TREE), the rise of hyper-dense cities (Burger et al. 2017 Sci Rep), the energy-urban-demographic transition (Burger et al. 2019 BERQ; Burger 2019 BioScience), and emerging social and lifespan inequalities (Snyder-Mackler, Burger et al. 2020 Science).