PARENT SESSION
Oral Session - Landscape Models to Predict Future Landscape Change - Day 1 Chair(s): Neale, Anne¹, ¹ Landscape Ecology Branch, Las Vegas, NV
Wednesday, March 31, 2004 10:00 AM - 12:00 PM Apollo Room 5

Modeling alternate scenarios of urban growth on habitat fragmentation in southern California. ^*SYPHARD, ALEXANDRA D. ^1,2, CLARKE, KEITH C. ² and FRANKLIN, JANET ³, ¹ San Diego State University, San Diego, CA, USA² University of California, Santa Barbara, Santa Barbara, CA, USA³ San Diego State University, San Diego , CA, USA

ABSTRACT- Land use/land cover change is the most important factor affecting ecological systems due to habitat loss and fragmentation and their interaction with other components of global change, such as biological invasions of non-native species. In southern California, population growth and economic expansion are the primary drivers of land use change, and the population is expected to double in 40 years. Although directly adjacent to the nation′s second largest metropolitan area, the Santa Monica Mountains National Recreation Area (SMMNRA) remains mostly undeveloped, with 50 percent of the area protected as parkland. A cellular automaton (CA) model was calibrated using historical growth patterns in the region, and used to forecast three scenarios of urban growth in the SMMNRA from 2000 – 2050, with development prohibited beyond 25%, 30%, and 60% slope. Habitat fragmentation was assessed using several landscape metrics, then compared to results from a simpler urban growth model developed for the same region. Urban area is predicted to increase from 11% of the landscape in 2000 to 26%, 35%, and 47% in 2050, respectively, for the three slope scenarios. In 2000, the majority of vegetation constituted one large, interconnected patch. With development prohibited beyond 25% and 30% slope, this patch will become increasingly perforated, but should stay intact. However, if growth is permitted up to 60% slope, the patch breaks apart, initiating a behavioral phase change affecting all other landscape metrics. General growth patterns predicted by the simpler model resembled those generated by the CA, but the CA model produced more patches and edge in the landscape.

KEY WORDS: Habitat fragmentation, Urban growth, Landscape model, Cellular automata, Southern California