Friday, August 10, 2007

PS 72-138: An integrated environmental analysis of dynamic interactions between landscapes and humans in the Colorado Front Range during the 19th and 20th centuries

Patrick S. Bourgeron, Hope C. Humphries, and Timothy R. Seastedt. University of Colorado at Boulder

The central goal of our project is to analyze the interactions between environmental and socio-economic dynamics in the Colorado Front Range, and to forecast the effects of these interactions on patterns of dynamic changes and ecological resilience across the urban-wildland/rural interface.  Four general questions are formulated:  (1) What are the mechanisms by which environmental and socio-economic dynamics interact to affect the adaptive cycles of socio-ecological systems (SES) in the study urban-wildland/rural interface?  (2) What are the mechanisms by which environmental and socio-economic attributes contribute to the resilience of SES in the study area?  (3) What conditions contribute to the loss of resilience of SES in the study area?  (4) What are the consequences of such loss of resilience for SES?  The analysis is conducted using a combination of narratives, simulation models of landscape change and land use within an environmental economic framework, a percolation model for understanding and predicting the dynamics of fire spread, and synthesis.  Results to date indicate that since 1860 there have been three major shifts in the structure and function of regional ecosystems in response to changes in climate variability, population increase, changing land use, and fire suppression.  Extreme droughts have combined with fuel loading increase (due to fire suppression) and land cover change (a function of land use change, such as exurban development) to alter landscape patterns and stand structure.  Changes in landscape patterns and stand structure in turn create a positive feedback to fuel loading accumulation and therefore likely influence the threshold behavior of fire intensity and size.  Changes in disturbance regimes alter the dynamic linkages between ecosystem structure and function resulting in progressive change in the Colorado Front Range stability landscape and steady erosion of ecological  resilience defined as the ability of landscape configuration to contain fire spread.