Increasing land fragmentation, mostly caused by urban sprawl and “leap-frog’ developments, is a major concern in many rapidly growing metropolitan cities of the US. Land fragmentation affects biodiversity and ecosystem processes, as portions of the landscape become isolated without connecting corridors and this, in turn, can change ecological structure and function. This cross-site comparative study, a joint-collaboration of several LTER sites (i.e. Central Arizona-Phoenix, Sevilleta, Konza Prairie, Jornada Basin, and Shortgrass Steppe), takes a cross-site comparative approach to: (1) examine the land fragmentation patterns in some of the fastest growing southwestern cities of the US, and (2) understand the roles of urban population dynamics, water infrastructure, transportation networks, and annexation on land fragmentation.

Data used in this study are from the National Land Cover Dataset (NLCD) for the years 1992 and 2001, compiled from Landsat TM images. We reclassified the original NLCD land-use/cover classes of each research site into seven categories: developed (higher intensity), developed (lower intensity), agriculture/cultivated, forest, undeveloped/remnants, grass/shrubland, and water. We also quantified the fragmentation pattern through landscape metrics: Patch Density (PD), Interspersion and Juxtaposition Index (IJI), Contagion (CONTAG), Landscape Shape Index (LSI), Edge Density (ED), Shanon Density Index (SDI). We calculated these metrics for the individual research sites and then finally compared fragmentation patterns emerged across these sites. The results of this study will help understand the patterns and the processes of land fragmentation in the Southwestern United States.