This series on ConservationBytes.com takes a page out of our book Tropical Conservation Biology (Sodhi, Brook & Bradshaw) – therein we produced a series of ‘Spotlights’ describing the contributions of great thinkers to conservation science. Each highlight of a Conservation Scholar includes a small biography, a list of major scientific publications and a Q & A on the person’s particular area of expertise.
Our fourth Conservation Scholar is Mark Cochrane…
I am a Professor at the Geographic Information Science Center of Excellence at South Dakota State University and am jointly appointed with the Department of Biology and Microbiology and the Department of Geography. I conduct interdisciplinary work that combines remote sensing, ecology and other fields of study to provide a landscape perspective of the dynamic processes involved in land-cover change. I first became interested in ecology through coursework while I was completing my baccalaureate in Environmental Engineering at the Massachusetts Institute of Technology. I then spent a year working on a variety of research projects in Antarctica, furthering my interest in science. Having had enough of cold-weather environments, I chose to do my postgraduate research in the Brazilian Amazon and, in 1998, received a doctoral degree in Ecology from The Pennsylvania State University. I am among the world’s leading experts on wildfire in tropical ecosystems. I am renowned for documenting wildfire characteristics, behaviour and severe effects in tropical forests, as well as how current systems of human land-use foster wildfires. My research focuses on understanding spatial patterns, interactions and synergisms between the multiple physical and biological factors that affect ecosystems. Recently published work emphasizes human dimensions of land-cover change and the potential for sustainable development. My collaborative research with the Brazilian NGO IMAZON (The Amazon Institute of Man and the Environment) has been instrumental in the Brazilian government’s recent (2003) program to expand its national forest system in the Amazon to 50 million hectares. In my ongoing research programs, I continue to investigate the drivers and effects of disturbance regime changes resulting from various forms of forest degradation, including fire, fragmentation and logging.
- Cochrane M. A. (2001) Synergistic interactions between habitat fragmentation and fire in evergreen tropical forests. Conservation Biology 15, 1515-1521
- Cochrane M. A. (2003) Fire science for rainforests. Nature 421, 913-919
- Cochrane M. A., Alencar A., Schulze M. D., Souza C. M., Nepstad D. C., Lefebvre P. & Davidson E. A. (1999) Positive feedbacks in the fire dynamic of closed canopy tropical forests. Science 284, 1832-1835
- Cochrane M. A. & Laurance W. F. (2002) Fire as a large-scale edge effect in Amazonian forests. Journal of Tropical Ecology 18, 311-325
- Cochrane M. A. (2002) Spreading Like Wildfire – Tropical Forest Fires In Latin America And The Caribbean: Prevention, Assessment And Early Warning pp. 96. United Nations Environment Program, Regional Office for Latin America and the Caribbean
Questions and Answers
1. Are fires in tropical landscapes more frequent now than in the past?
Yes. Fires are much more prevalent in the tropics than in the past. The issues with fire in tropical landscapes do not centre on the presence of fire in these landscapes, but with the frequency with which they are burning. In many regions of the tropics, current land-use practices result in surviving forest fragments being subjected to fire so often that they are rapidly being degraded by a fire regime that they cannot withstand. Fire is the primary tool for clearing and maintaining agricultural land. Forests are slashed and allowed to dry before being burned to release their nutrients to the soils. Many lands are subsequently turned into pastures, which also are burnt frequently in order to keep trees from regrowing. Most land use is fire-dependent. Forests are also subjected to selective logging, which removes only the valuable trees and leaves the remaining forests susceptible to escaped fires. Having fire-dependent agriculture embedded in fire-susceptible forests quickly leads to forest fires. Once this occurs, the landscape is quickly converted from one of a few flammable islands (e.g., pastures) within a near fire-immune sea of vegetation (i.e., rain forests), to one where a fire at any location can permeate an entire region, forests and agricultural lands alike.
2. Will global climate change be important in altering future fire regimes?
Yes. Global climate change will likely result in important changes in regional fire regimes. Global climate models (GCMs) do not all agree on what the future climates will be like, but it is fairly certain that temperatures will increase substantially, especially in interior regions such as the upper Amazon. Most models show a concomitant increase in rainfall for these regions, but it is uncertain whether or not these increases will be enough to offset the drought stress from rising temperatures. Rainfall reductions from ongoing deforestation, however, will probably be greater than any projected increases due to global climate change, leading to a net increase in drought stress and fire behaviour, further stressing these important ecosystems.
3. How important are the adverse effects of fire on tropical biotas relative to other drivers such as habitat loss and land use change?
Fire is what integrates tropical landscapes. Habitat loss is primarily seen as a function of deforestation, but forest degradation through logging and fire causes substantial changes in forest structure and composition that affect habitability. The key aspect of wildfire is that once it has damaged a region’s forests, it effectively changes the ‘rules of the game’ for land management. What was once a highly fire-resistant ecosystem becomes a highly fire-susceptible forest. A positive feedback of increasing fire frequency, fire intensity and fire severity can become established. Instead of burning once every thousand years or more, these forests may burn once every 10 years or less. These forests cannot withstand such a fire regime and several fires can effectively deforest an area. As the landscape becomes more permeable to fire, even diligent landowners have difficulty protecting their lands from fires. Uncontrolled fires destroy large-investment, high-return perennial crops such as rubber tree, pepper and fruit plantations, making cattle ranching the most viable land use. Pasture grass is the most flammable land cover possible and only exacerbates a region’s fire problems.
4. Is there a theory in fire ecology, and if yes, what is it?
The short answer is no. To my knowledge there is no accepted theory underlying fire ecology.