Households as ecological agents: Integrating household survey information in a spatially-explicit, dynamic urban watershed model. Neely L. Law, UNC-CH Morgan Grove, USDA Forest Service

Purpose Describe a survey and model that integrate social, physical and ecological data to understand the drivers/factors of hydroecologic change in an urban watershed

Introduction Urban watersheds –hybrid systems in which engineered systems superimposed on the natural system –ecosystems in which human actions exert direct or indirect control on ecosystem processes through the use and disposition of environmental resources

Change in flowpaths: forested to urban

Do people and place make a difference? Social differentiation affects distribution of capital and use of resources Link physical, ecological and social data to understand the drivers of ecological change in urban watersheds

Social area index for the Gwynns Falls watershed (Grove 1996).

Background Land use based simulation models aspatial human activity not considered Variation in lawn characteristics (scale at which they are run too coarse) –stratified by socioeconomic conditions? Social patterns and processes part of urban hydroecologic mosaic

Method of Integration Survey –data collection capturing social behavior and physical data Urban watershed model: RHESSys –analysis of integrated data

Survey Goals Global Analysis and modeling that integrates physical, ecological and sociocultural patterns and processes Specific Estimate nutrient and water flux from residential lawn care practices variation in practices model parameterization using RHESSys

Scale of research At what scale is the integration approached –patch subdivision or parcel Regional Hydro-Ecologic Simulation System model –spatially explicit hierarchical structure –spatial data processing and simulation model for water, carbon and nutrient flux

RHESSys Object Hierarchy

Aspatial Strata

Methods: Survey Household survey to link physical, ecological and social data –questionnaire and soil samples Survey focus on nutrient and water flux in urban watershed from lawn care maintenance practices –parameterize model –variation in lawn care practices

Survey Description 2 part survey design –Questionnaire lawn care practices lawn characteristics (grass species, % area) –Soil Samples soil sample analysis –bulk density, organic matter, chemistry Enroll participation of Master Gardeners

Survey Sample Geographic area of study –socioeconomic and hydrologic processes –subdivision Analytical unit: household stratified random sample of 2 study sites –Glyndon (0.8 km 2, n= 100) –Baisman Run (3.66 km 2, n=50)

Data Digital elevation model Parcel data (Maryland Property View) High resolution aerial photography Input to RHESSys: Regional Hydro- Ecologic Simulation System

Lessons to be Learned for Integrated Research Data –Scale to capture variability social and ecological variables patch redefined for urban watersheds –Availability require survey –scale and limited research area on fertilizer application –Tool(s) for spatial integration and scaling RHESSys