Oral Session - Fire in Landscapes - Day 1 Chair(s): Kashian, Daniel¹, ¹ Colorado State University, Fort Collins, CO
Thursday, April 1, 2004 8:00 AM - 9:40 AM Apollo Room 5

Landscape Transformations: Changes in Biodiversity and Ecosystem Functioning following the Ryan Fire of 2002. Lombardo, Keith^*,1, Kupfer, John¹, ¹ University of Arizona, Tucson, AZ, USA

ABSTRACT- The replacement of native flora with non-native species poses several serious threats to native landscapes. Among these threats are possible changes in biodiversity, species composition, and ecosystem functioning. In 1949, two non-native lovegrass species, Eragrostis lehmanniana and Eragrostis curvula were introduced to the Audubon Research Ranch of Elgin, Arizona. The subsequent establishment and spread of both species has led to differences between native and non-native grasslands in diversity, composition, and biogeochemical conditions. In addition, both lovegrass species have proven successful in re-establishing in recently burned areas, more so than native grasses of southeast Arizona. In May of 2002, the 38,000 acre Ryan Fire burned through the entire research area. This event provided the opportunity to examine the differences between non-native and native dominated grasslands, both before and after the fire. Comparison of pre- and post-fire results suggests that native and non-native grasslands are responding differently over time, at least in part, to the effects of wildfire. Further comparisons reveal that significant transformations are occurring in aboveground biomass, soil structure, species composition, and diversity. These alterations may be leading to changes in native fire regime characteristics including fire intensity and frequency.

KEY WORDS: fire, Lehmann Lovegrass, SE Arizona grasslands, ecosystem functions, biodiversity