Jennifer Balch

Introduction

 

We need to reassess the role of fire on Earth. At a global scale, we know very little about how fire influences ecosystem dynamics, and in turn, how ecosystem patterns and processes control the fire cycle. My research aims to understand the patterns and processes that underlie disturbance and ecosystem recovery, particularly how shifting fire regimes are reconfiguring tropical forests, encouraging non-native grass invasion, and affecting the global climate. My current and future research addresses the following major unsolved questions:

  • What is fire’s role in the Earth system? More specifically, how does fire contribute to global trends of climate warming and how does climate warming promote fire?
  • How are fire regimes altered by invasive species? Particularly, how is an invasive grass-fire cycle established and perpetuated?
  • How is the recent, unprecedented increase in human-initiated fires altering tropical-forest dynamics, and how has this increase in fire frequency changed carbon cycles and the recovery trajectory?


In addressing these questions, my research aims to explore global patterns of anthropogenic climate and land cover disruptions to help inform people about opportunities to curb and adapt to these changes.

Current Research interests and activities:

PYROGEOGRAPHY: UNDERSTANDING THE DISTRIBUTION AND DIVERSITY OF FIRE

Fire influences global ecosystem patterns and processes, including vegetation distribution and structure, the carbon cycle, and climate. Although humans and fire have always coexisted, our capacity to manage fire remains imperfect and may become more difficult in the future as climate change alters fire regimes. My work helps integrate knowledge about biomass burning across disciplines to form a new paradigm of 'pyrogeography' that outlines the pervasive influence of fire in the Earth system. This synthesis research explores the lineage of fire through time, fire’s role in influencing biome distribution, feedbacks with climate, and the complex human relationship with fire.  

THE INVASIVE GRASS-FIRE CYCLE IN FRONTIER LANDSCAPES

The introduction of invasive grass species coupled with alterations in fire behavior can create a novel grass-fire cycle. This cycle establishes when introduced grasses create more available fuel, which promotes fire. In turn, increased fire frequency or intensity can then favor continued expansion and growth of the invasive grass. It is hypothesized that such as invasive grass-fire cycle can initiate irreversible vegetation shifts in old and new frontier landscapes, such as the western U.S. and the Brazilian Amazon. My work aims to: 1) investigate how non-native grasses alter natural fire regimes from local to regional scales; and 2) determine the net carbon emissions associated with contemporary, anthropogenic grass-fire cycles.

INCREASING FIRE FREQUENCY IN THE AMAZON’S SEASONALLY DRY FORESTS

The tropics is a region marked by rapid landscape transformation and waves of frontier expansion that leave a patchwork of degraded and recovering forests amidst a matrix of human-dominated land uses. Fire is an integral tool in the transformation and management of these landscapes, as well as a pervasive threat to the longevity of tropical forests -- particularly during severe droughts. Moreover, the predominant source of ignitions is from human use -- or misuse -- of fire. Yet, our understanding of natural fire regimes and the consequences of human-altered fire frequencies in tropical forests is limited. Therefore, my work explores the effects of recurrent fire on Amazonian forest dynamics through a large-scale burn experiment.

Please see my website for further project details and links to my main collaborators.

Research Interests

  • fire ecology
  • Earth systems ecology
  • land use/landcover change
  • global change ecology
  • invasive species
  • tropical forest ecology

Education

  • Ph.D., School of Foresty and Environmental Studies, Yale University, 2008
  • A.B. with Honors, Department of Ecology and Evolutionary Biology, Princeton University, 1999

Courses Taught

  • GEOG 010
  • GEOG 497A
  • GEOG 510

Publications

Bowman, D.M.J.S., J.K. Balch, P. Artaxo, W.J. Bond, M.A. Cochrane, C.M. D’Antonio, R.S. DeFries, F.H. Johnston, J.E. Keeley, M.A. Krawchuk, C.A. Kull, M. Mack, M.A. Moritz, S.J. Pyne, C.I. Roos, A.C. Scott, N.S. Sodhi, T.W. Swetnam. In press. “The human dimension of fire regimes on Earth.” Journal of Biogeography.

Balch, J.K., D.C. Nepstad, L.M. Curran, P.M. Brando, O. Portela, P. Guilherme, J.D. Reuning-Scherer, and O. de Carvalho Jr. 2011. “Size, species, and fire characteristics predict tree and liana mortality from experimental burns in the Brazilian Amazon.” Forest Ecology & Management 261:68-77.

Balch, J.K., D.C. Nepstad, P.M. Brando, and A. Alencar. 2010. “Comment on ‘The Incidence of Fire in Amazonian Forests with Implications for REDD.’” Science 330:1627.

Bowman, D.M.J.S.*, J.K. Balch*, P. Artaxo, W.J. Bond, J.M. Carlson, M.A. Cochrane, C.M. D’Antonio, R.S. DeFries, J.C. Doyle, S.P. Harrison, F.H. Johnston, J.E. Keeley, M.A. Krawchuk, C.A. Kull, J.B. Marston, M.A. Moritz, I.C. Prentice, C.I. Roos, A.C. Scott, T.W. Swetnam, G.R. van der Werf, and S.J. Pyne. 2009. “Fire in the Earth system.” Science 324:481-484. *Authors contributed equally. (Selected for “Faculty of 1000 Biology” list of important articles.)

Balch, J.K., D.C. Nepstad, and L.M. Curran. 2009. “Pattern and process: Fire-initiated grass invasion at Amazon transitional forest edges.” Chapter 17 in Tropical Fire Ecology: Climate Change, Land Use and Ecosystem Dynamics (ed. Mark Cochrane). Springer/Praxis Publishing, UK.

Silveira, J.M., J. Barlow, A.V. Krusche, K.H. Orwin, J.K. Balch, and P. Moutinho. 2009. “Effects of experimental fires on litter decomposition in a seasonally dry Amazonian forest.” Journal of Tropical Ecology 25:657-663

Balch, J.K., D.C. Nepstad, P.M. Brando, L.M. Curran, O. Portela, O. Carvalho Jr., and P. Lefebvre. 2008.  “A negative fire feedback in a transitional forest of southeastern Amazonia.” Global Change Biology 14:2276-2287.

Rodríguez*, J.P., J.K. Balch*, and K.M Rodríguez-Clark. 2007. “Assessing extinction risk in the absence of species-level data: quantitative criteria for terrestrial ecosystems.” Biodiversity and Conservation 16:183-209. *Authors contributed equally.

Kennedy, C.M., J. Wilkinson, and J.K. Balch. 2003. “Conservation thresholds for land use planners.” The Environmental Law Institute, Washington, D.C.