PARENT SESSION
Oral Session - Cross-Scale Landscape Analysis Chair(s): DiBari, John¹, ¹ Western Carolina University, Cullowhee, NC
Wednesday, March 31, 2004 10:00 AM - 12:00 PM Apollo Room 1

From patches to regions: Scaling biogeochemical patterns in soils of the Phoenix, AZ metropolitan region. ^*JENERETTE, DARREL and WU, JIANGUO , ¹ School of Life Sciences, Tempe, AZ, USA

ABSTRACT- How is within-patch heterogeneity related to regional patterns? How does regional heterogeneity affect sub-patch patterns? These questions are central to the science of spatial scaling. We address this problem for soil biogeochemical patterns in the Phoenix, AZ metropolitan region. Urban areas are particularly useful for studying scaling because they include both well-defined patches of land-cover and broad environmental gradients. Here we integrate the results of two intensive field soil surveys conducted in the Phoenix, AZ metropolitan region. In the spring of 2000 a synoptic survey of the entire region was conducted. This survey collected soil cores from 200 points in a spatially stratified dual density randomized design that covered an extant of 6,400 km². In conjunction with this regional dataset, in the spring of 2002 we surveyed six patches including mesic residential, agriculture, and native desert land-cover types. For each of these patch surveys we collected approximately 80 soil cores and information on topography and vegetation distributions. We report results from scaling analyses focusing on three important soil variables: bulk density, soil organic matter, and total nitrogen. Variability observed in the patch surveys was similar to the variability observed from the entire region. However, patterns at the patch level show strong site and patch type differences, while at the regional level these patch type differences are much weaker. Furthermore, correlations between variables and spatial autocorrelation for single variables are much stronger at the patch level than at the regional level. These differences in patterns have important implications for scaling patterns between patches and regions.

KEY WORDS: arid, biogeochemistry, terrestrial, scale, urban