I am a currently a fourth year PhD candidate in the Biology Department at Stanford University, working both with the Stanford Center for Conservation Biology and the Natural Capital Project on understanding the impacts of human land use on biodiversity. My empirical work focuses principally on insect biodiversity in southern Costa Rica. In addition to this field work, I employ a variety of spatial modelling techniques to extrapolate local findings to regional and global patterns of diversity.

Prior to starting at Stanford, I obtained a Masters of Environmental Science from the Yale School of Forestry and Environmental Studies, where I worked with Dr. Os Schmitz to determine how New England old-field arthropod food webs varied along a suburban-forest gradient. I received my Bachelor of Science (in Ecology and Environmental Science) from the University of Delaware. While there I researched biological control of invasive weeds and restoration ecology with Dr. Judy Hough-Goldstein.

Academic Appointments

Honors & Awards

  • Graduate Research Fellow, National Science Foundation (2014-2019)

Professional Education

  • BS, University of Delaware, Ecology, Environmental Science (2013)
  • MESc, Yale School of Forestry and Environmental Studies (2015)

All Publications

  • Predator community composition is linked to soil carbon retention across a human land use gradient ECOLOGY Schmitz, O. J., Buchkowski, R. W., Smith, J. R., Telthorst, M., Rosenblatt, A. E. 2017; 98 (5): 1256-1265


    Soil carbon (C) storage is a major component of the carbon cycle. Consensus holds that soil C uptake and storage is regulated by plant-microbe-soil interactions. However, the contribution of animals in aboveground food webs to this process has been overlooked. Using insights from prior long-term experimentation in an old-field ecosystem and mathematical modeling, we predicted that the amount of soil C retention within a field should increase with the proportion of active hunting predators comprising the aboveground community of active hunting and sit-and-wait predators. This comes about because predators with different hunting modes have different cascading effects on plants. Our test of the prediction revealed that the composition of the arthropod predator community and associated cascading effects on the plant community explained 41% of variation in soil C retention among 15 old fields across a human land use gradient. We also evaluated the potential for several other candidate factors to explain variation in soil C retention among fields, independent of among-field variation in the predator community. These included live plant biomass, insect herbivore community composition, soil arthropod decomposer community composition, degree of land use development around the fields, field age, and soil texture. None of these candidate variables significantly explained soil C retention among the fields. The study offers a generalizable understanding of the pathways through which arthropod predator community composition can contribute to old-field ecosystem carbon storage. This insight helps support ongoing efforts to understand and manage the effects of anthropogenic land use change on soil C storage.

    View details for DOI 10.1002/ecy.1794/suppinfo

    View details for Web of Science ID 000400598500006

    View details for PubMedID 28273334

  • Cascading ecological effects of landscape moderated arthropod diversity OIKOS Smith, J. R., Schmitz, O. J. 2016; 125 (9): 1261-1272

    View details for DOI 10.1111/oik.02887

    View details for Web of Science ID 000382496000006

  • Spatially-explicit models of global tree density SCIENTIFIC DATA Glick, H. B., Bettigole, C., Maynard, D. S., Covey, K. R., Smith, J. R., Crowther, T. W. 2016; 3


    Remote sensing and geographic analysis of woody vegetation provide means of evaluating the distribution of natural resources, patterns of biodiversity and ecosystem structure, and socio-economic drivers of resource utilization. While these methods bring geographic datasets with global coverage into our day-to-day analytic spheres, many of the studies that rely on these strategies do not capitalize on the extensive collection of existing field data. We present the methods and maps associated with the first spatially-explicit models of global tree density, which relied on over 420,000 forest inventory field plots from around the world. This research is the result of a collaborative effort engaging over 20 scientists and institutions, and capitalizes on an array of analytical strategies. Our spatial data products offer precise estimates of the number of trees at global and biome scales, but should not be used for local-level estimation. At larger scales, these datasets can contribute valuable insight into resource management, ecological modelling efforts, and the quantification of ecosystem services.

    View details for DOI 10.1038/sdata.2016.69

    View details for Web of Science ID 000390229200002

    View details for PubMedID 27529613

    View details for PubMedCentralID PMC4986544

  • Mapping tree density at a global scale NATURE Crowther, T. W., Glick, H. B., Covey, K. R., Bettigole, C., Maynard, D. S., Thomas, S. M., Smith, J. R., Hintler, G., Duguid, M. C., Amatulli, G., Tuanmu, M., Jetz, W., Salas, C., Stam, C., Piotto, D., Tavani, R., Green, S., Bruce, G., Williams, S. J., Wiser, S. K., Huber, M. O., Hengeveld, G. M., Nabuurs, G., Tikhonova, E., Borchardt, P., Li, C., Powrie, L. W., Fischer, M., Hemp, A., Homeier, J., Cho, P., Vibrans, A. C., Umunay, P. M., Piao, S. L., Rowe, C. W., Ashton, M. S., Crane, P. R., Bradford, M. A. 2015; 525 (7568): 201-?


    The global extent and distribution of forest trees is central to our understanding of the terrestrial biosphere. We provide the first spatially continuous map of forest tree density at a global scale. This map reveals that the global number of trees is approximately 3.04 trillion, an order of magnitude higher than the previous estimate. Of these trees, approximately 1.39 trillion exist in tropical and subtropical forests, with 0.74 trillion in boreal regions and 0.61 trillion in temperate regions. Biome-level trends in tree density demonstrate the importance of climate and topography in controlling local tree densities at finer scales, as well as the overwhelming effect of humans across most of the world. Based on our projected tree densities, we estimate that over 15 billion trees are cut down each year, and the global number of trees has fallen by approximately 46% since the start of human civilization.

    View details for DOI 10.1038/nature14967

    View details for Web of Science ID 000360927400028

    View details for PubMedID 26331545

  • Untangling the fungal niche: the trait-based approach FRONTIERS IN MICROBIOLOGY Crowther, T. W., Maynard, D. S., Crowther, T. R., Peccia, J., Smith, J. R., Bradford, M. A. 2014; 5


    Fungi are prominent components of most terrestrial ecosystems, both in terms of biomass and ecosystem functioning, but the hyper-diverse nature of most communities has obscured the search for unifying principles governing community organization. In particular, unlike plants and animals, observational studies provide little evidence for the existence of niche processes in structuring fungal communities at broad spatial scales. This limits our capacity to predict how communities, and their functioning, vary across landscapes. We outline how a shift in focus, from taxonomy toward functional traits, might prove to be valuable in the search for general patterns in fungal ecology. We build on theoretical advances in plant and animal ecology to provide an empirical framework for a trait-based approach in fungal community ecology. Drawing upon specific characteristics of the fungal system, we highlight the significance of drought stress and combat in structuring free-living fungal communities. We propose a conceptual model to formalize how trade-offs between stress-tolerance and combative dominance are likely to organize communities across environmental gradients. Given that the survival of a fungus in a given environment is contingent on its ability to tolerate antagonistic competitors, measuring variation in combat trait expression along environmental gradients provides a means of elucidating realized, from fundamental niche spaces. We conclude that, using a trait-based understanding of how niche processes structure fungal communities across time and space, we can ultimately link communities with ecosystem functioning. Our trait-based framework highlights fundamental uncertainties that require testing in the fungal system, given their potential to uncover general mechanisms in fungal ecology.

    View details for DOI 10.3389/fmicb.2014.00579

    View details for Web of Science ID 000359187100001

    View details for PubMedID 25400630

    View details for PubMedCentralID PMC4215788

  • Impact of herbivory on mile-a-minute weed (Persicaria perfoliata) seed production and viability BIOLOGICAL CONTROL Smith, J. R., Hough-Goldstein, J. 2014; 76: 60-64
  • Potential Impact of Halyomorpha halys (Hemiptera: Pentatomidae) on Grape Production in the Finger Lakes Region of New York JOURNAL OF ENTOMOLOGICAL SCIENCE Smith, J. R., Hesler, S. P., Loeb, G. M. 2014; 49 (3): 290-303
  • Variable Seed Viability of Mile-a-Minute Weed (Devil's Tearthumb, Persicaria perfoliata) INVASIVE PLANT SCIENCE AND MANAGEMENT Smith, J. R., Hough-Goldstein, J., Lake, E. C. 2014; 7 (1): 107-112
  • Phototaxis, Host Cues, and Host-Plant Finding in a Monophagous Weevil, Rhinoncomimus latipes JOURNAL OF INSECT BEHAVIOR Smith, J. R., Hough-Goldstein, J. 2013; 26 (1): 109-119