You are here:
ABSCISSA ASSESSMENT WITH ALGAE: A COMPARISON OF LOCAL AND LANDSCAPE IMPAIRMENT MEASURES FOR BIOLOGICAL ASSESSMENT USING BENTHIC DIATOMS
Citation:
Lane, C R. ABSCISSA ASSESSMENT WITH ALGAE: A COMPARISON OF LOCAL AND LANDSCAPE IMPAIRMENT MEASURES FOR BIOLOGICAL ASSESSMENT USING BENTHIC DIATOMS. Presented at North American Benthological Society, Vancouver, Canada, June 6-10, 2004.
Impact/Purpose:
The purpose of this research project is to provide methods, tools and guidance to Regions, States and Tribes to support the TMDL program. This research will investigate new measurement methods and models to link stressors to biological responses and will use existing data and knowledge to develop strategies to determine the causes of biological impairment in rivers and streams. Research will be performed across multiple spatial scales, site, subwatershed, watershed, basin, ecoregion and regional/state.
Description:
The development of rigorous biological assessments is dependent upon well-constructed abscissa, and various methods, both subjective and objective, exist to measure expected impairment at both the landscape and local scale. A new, landscape-scale method has recently been offered that allows for the combination of disparate factors into a single value (e.g., impervious surfaces, low-density residential, improved pasture, natural area): the Landscape Development Intensity index, or LDI. The LDI is calculated using GIS and published development coefficients, which are based on "emergy" calculations.
In this study, benthic diatoms from 70 isolated depressional herbaceous wetlands located throughout peninsular Florida were sampled along a gradient of human disturbance. Analyses were conducted at both the local and landscape scale to determine the efficacy of the LDI vis-a-vis locally measured physical and chemical variables of the water column and sediment (e.g., soil TP, water pH, specific conductivity). Multivariate analyses suggested that the LDI is reflective of benthic diatom community composition within isolated depressional wetlands, although individual variables measured on-site, such as specific conductivity or water total phosphorus, may be more strongly correlated.