HR: 16:30h
AN: NB14D-05 INVITED     [Abstracts]
TI: Hierarchical influences on the biophysical properties of natural stream channels
AU: Stanfield, L W
EM: Les.Stanfield@mnr.gov.on.ca
AF: Jacques Whitford Environment Limited, 2781 Lancaster Road,, Ottawa, ON K1B 1A7 Canada
AU: * Kilgour, B
EM: bkilgour@jacqueswhitford.com
AF: Ontario Ministry of Natural Resources, RR 4, Picton, ON K0K 2T0 Canada
AB: In this paper we focus on how catchment and proximity effects influence the biophysical properties of streams and these conditions are modified by overall landuse in the catchment and site conditions. Biophysical data (fish, inverts, instream habitat, temperature and baseflow) were collected on wadable streams flowing into the Lake Ontario basin. A GIS application was developed to characterize the landscape conditions for each site. For each of 700 -1400 sites, biophysical and GIS data (drainage area, geology, landuse, slope, stream length, and climatic conditions) were summarized. We explored the relationship between slope and drainage area and two composite indices, one the baseflow index (BFI) combined geology and drainage potential and the other, percent impervious cover (PIC) provided a single metric of disturbance on the landscape. Multivariate approaches were used to develop models to relate each metric to landscape conditions, and PIC. Residuals of this analysis were related to local conditions to determine how much of the remaining variance was explained by these conditions. Our results indicate that several metrics demonstrate a threshold response to PIC and that local conditions have minimal capacity to mitigate these effects. Below the threshold several metrics demonstrated a linear response to PIC that enables predictions to be made of effects from development in a catchment. Instream habitat conditions were more important for some biota (e.g. brown trout) than others. We demonstrate how model results can be used to classify sites or stream segments based on predicted conditions and how results can be used to generate coarse population estimates
DE: 0400 Biogeosciences
SC: North American Benthological Society [NB]
MN: 2005 Joint Assembly