Fire ecology and management in lowland riparian ecosystems of the Southwestern United States and Northern Mexico

Lowland riparian ecosystems, defined as those occurring at elevations at or below 5,000 feet (1,564 meters), constitute a small fraction of total land area in the southwestern United States and northern Mexico, yet they are extremely important to human livelihoods and biotic communities. In the hotter and drier conditions projected under ongoing climate change, riparian ecosystems are increasingly critical to the well-being of humans and wildlife. Riparian areas have been modified in various ways and to a large extent through human endeavor to utilize resources more predictably. These alterations often interfere with multiple and complex ecological processes, making riparian areas vulnerable to disturbance and change. Few naturally functioning riparian areas remain in the region, and those that do are imperiled by climate change, groundwater pumping, land use, and altered disturbance regimes. Some evidence suggests that fire regimes are changing in southwestern riparian zones; wildfires may be increasing in frequency and severity. This literature review summarizes and synthesizes the state of the knowledge of wildfire and prescribed fire effects on physical processes and vegetation, and postfire rehabilitation. Changing fire regimes are likely to have drastic and potentially irreversible effects on regional biodiversity and ecosystem function. However, options are available for managing riparian ecosystems that could make them more resilient to fire and climate change. This study is intended to inform management and identify gaps in systematically reviewed literature.