Urban settlements
significantly impact ecosystem function by fragmenting and degrading natural
habitats, simplifying species composition, disrupting hydrological systems, and
modifying energy flows and nutrient cycles. Urban ecological scholars have
illustrated that human activities have a profound effect on ecosystem functions
at the landscape scale; however, little is known about the affect of localized
human activities as they affect the ecological processes. The aim of
this paper is to better understand how localized socio-demographics conditions,
and human activities along riparian corridors affect the biological condition
of stream systems. By examining land cover patterns at the riparian and
watershed scales, we assess the role of socio-demographic characteristics, and
human behaviors and preferences on macroinvertebrate
assemblages (measured as a Benthic Index of Biotic Integrity) in the Puget Sound lowland. Specifically, we address three
research questions: (1) what is the relationship between stated and observed
preference for riparian vegetation; (2) how do socio-demographics and human
preferences at the local scale affect in-stream conditions; and (3) what thresholds at the local scale regulate the
effects of human activities on in-stream conditions? We address these
questions in four steps. First, during the Fall of
2003 and 2004 we collected macroinvertebrate data
from 46 sites (7 streams) ranging from urban to rural in the Puget Sound lowland. Second, we administered a stated preference survey
to streamside residents during the Spring of 2004. Third,
we quantified the land cover conditions using Fragstats
spatial analysis software and a geographic information system. Finally, we
analyzed our data using parametric and non-parametric regression models. Our
results illustrate that revealed preference explains little to nothing about
stream conditions in urban areas, but has considerable explanatory value in
rural and urbanizing stream segments. In addition, our results suggest that
socio-ecological coupling may play a critical role in regulating ecosystem
functions at localized areas.