Landscape Ecology

, Volume 22, Issue 3, pp 431–445

Simulating fire frequency and urban growth in southern California coastal shrublands, USA

  • Alexandra D. Syphard
  • Keith C. Clarke
  • Janet Franklin
Research Article

DOI: 10.1007/s10980-006-9025-y

Cite this article as:
Syphard, A.D., Clarke, K.C. & Franklin, J. Landscape Ecol (2007) 22: 431. doi:10.1007/s10980-006-9025-y

Abstract

Fire is an important natural disturbance in the Mediterranean-climate coastal shrublands of southern California. However, anthropogenic ignitions have increased fire frequency to the point that it threatens the persistence of some shrub species and favors the expansion of exotic annual grasses. Because human settlement is a primary driver of increased ignitions, we integrated a landscape model of disturbance and succession (LANDIS) with an urban growth model (UGM) to simulate the combined effects of urban development and high fire frequency on the distribution of coastal shrublands. We tested whether urban development would contribute to an expansion of the wildland-urban interface (WUI) and/or change in average fire return intervals and compared the relative impacts of direct habitat loss and altered fire regimes on functional vegetation types. We also evaluated two methods of integrating the simulation models. The development pattern predicted by the UGM was predominantly aggregated, which minimized the expansion of the WUI and increase in fire frequency, suggesting that fire risk may be higher at intermediate levels of urbanization due to the spatial arrangement of ignition sources and fuel. The comparison of model coupling methods illustrated how cumulative effects of repeated fires may occur gradually as urban development expands across the landscape. Coastal sage scrub species and resprouting chaparral were more susceptible to direct habitat loss, but increased fire frequency was more of a concern to obligate seeder species that germinate from a persistent seed bank. Simulating different scenarios of fire frequency and urban growth within one modeling framework can help managers locate areas of highest risk and determine which vegetation types are most vulnerable to direct habitat loss, altered fire regimes, or both.

Keywords

ChaparralCoastal sage scrubExotic grassFireLANDISLandscape modelModel couplingUrban growth modelWildland urban interface

Copyright information

© Springer Science+Business Media B.V. 2006

Authors and Affiliations

  • Alexandra D. Syphard
    • 1
    • 2
    • 4
  • Keith C. Clarke
    • 2
  • Janet Franklin
    • 3
  1. 1.Department of GeographySan Diego State UniversitySan DiegoUSA
  2. 2.Department of GeographyUniversity of CaliforniaSanta BarbaraUSA
  3. 3.Department of BiologySan Diego State UniversitySan DiegoUSA
  4. 4.Department of Forest Ecology & ManagementUniversity of Wisconsin–MadisonMadisonUSA