PARENT SESSION
Organized Oral Session 33: Restoring and designing ecosystems for a crowded planet: Provision of ecosystem services or mere window dressing?
Organizer(s): ML Martinez and M Palmer
Wednesday, August 10, 1:30 PM - 5:00 PM, Meeting Room 510a, Level 5, Palais des congrès de Montréal
Restoring fire as a keystone process: Insights from the pine forests of arid North America.
Sisk, Thomas 1, Falk, Donald2, Savage, Melissa3, McCarthy, Patrick4, 1 Center for Environmental Sciences and Education, Flagstaff, AZ, USA2 Laboratory of Tree Ring Research, Tucson, AZ, USA3 University of California, Los Angeles, Los Angeles, CA, USA4 The Nature Conservancy, Santa Fe, NM
ABSTRACT- The exclusion of fire from long-needled pine ecosystems has led to the accumulation of biomass that fuels increasingly large crown fires across much of arid North America. This new fire regime contrasts with the frequent, low-intensity fire that typifies the paleoecological record across much of the region. Novel fire regimes, and the risks they pose, are the products of past attempts to engineer forest ecosystems. Throughout most of the 20th century, foresters traded old-growth forests, including the 'package' of ecosystem services benefiting people (e.g., the provision of clean water, erosion control, herbaceous productivity, and wildlife habitat) for two products – timber and livestock – that were thought to have overriding value for the increasing human population of the region. While producing short-term benefits, this management paradigm led to unanticipated ecosystem change, generating enormous costs associated with fire suppression, as well as the loss of life, property, and environmental quality. As a result, the restoration of natural fire regimes has garnered considerable political will and community support. However, formidable new challenges have emerged during the century of fire exclusion: fuel loads have increased, human communities have expanded into the forest, and nonindigenous species have dispersed widely. While restoration efforts strive to reverse the errors of the past, these new obstacles constrain management options. Furthermore, unfavorable economics associated with large-scale manipulations in forests that retain little marketable timber preclude widespread intervention to advance ecological objectives. Conversely, increasing demands for water, and the costs associated with watershed degradation, provide positive incentives for investment in restoration. We draw on cases studies from the southwestern USA and northern Mexico to develop a framework for assessing the likelihood of success in reestablishing natural fire regimes as a means to ecological restoration. We offer recommendations about how ecologists can respond to the challenge of engineering an intelligent transition to forest conditions that will support natural processes and, eventually, the return of the most-valued ecosystem services.
Key words: ecological processes, fire, restoration, ecosystem services