Document: NAN-3-63-31

Urban sprawl in Colorado's front range: Consequences for carbon storage and productivity.

GOLUBIEWSKI, N.E.* and C.A.WESSMAN

University of Colorado, Boulder, CO 80309 USA ¹

Abstract:
Urbanization significantly modifies the surface of the earth and thereby alters the storage and fluxes of water, energy, and nutrients. This research considers how urban sprawl has altered the carbon storage, phenology, and aboveground net primary productivity (ANPP) in Colorado's Front Range. Specific research objectives include: How does the C-storage of urban, suburban, agricultural, and grassland areas compare? How does management alter the growing season and so affect the phenology of both managed and natural cover types? What are the integrated effects of urban, suburban, and agricultural environments on ANPP? In the first year of this study, cover-type specific values for C-storage (in both vegetation and soil), seasonal phenology, and ANPP were acquired from a combination of field measurements and existing data sets. Field data were collected in urban, suburban, and exurban sites. The ranges of ANPP and aboveground C-storage were estimated from biomass clips and allometric relationships. The range of belowground C-storage was estimated from soil cores acquired at each field site. Phenology was observed in the field as well as measured with light extinction instruments (LICOR line quantum sensors). These data were combined with existing data sets from grassland, agricultural, and riparian areas in order to create a regional database of C-storage, phenology, and ANPP by land-cover type. Significant differences existed among these cover types for each type of measurement. As in other studies of prairie systems, seasonal phenology and ANPP in managed systems differed markedly from natural systems. The balance of carbon stored in vegetation vs. soil varied among cover types. Moreover, the amount of C stored in suburban and urban areas did not reflect that of grassland and agricultural areas. Since land-cover change studies usually either ignore built-up areas or assume agriculture to be a proxy for suburban areas, these results revealed the importance of including the full range of land transformations for improved understanding of both C-storage and regional (if not global) land cover-change studies.

Keywords: land-use change, carbon storage, soil carbon, aboveground net primary productivity, seasonal phenology, urbanization

This abstract is being presented at: 10:30 AM in session:
CARBON STORAGE