effects of shoreline logging on the epilithic algal community in small canadian shield lakes with logged catchments
abstract
study area : coldwater lakes experimental watersheds area within the boreal-great lakes transition forest on the precambrian shield 200 km northwest of thunder bay and 70 km northwest of atikokan, northwestern ontario. lakes l26, l39 and l42. chlorophyll 'a' was used to index algal biomass ; carbon, nitrogen and phosphorus were used to measure nutritional status, and community characteristics were evaluated using areal densities of taxonomic classes. littoral zones were described using water turbulence index, littoral wind measurements, and mass measurements of epilithic material, etc. chlorophyll a, nutritional status and community characteristics of epilithic
algae in littoral zones of three small canadian shield lakes with logged
watersheds were assessed. sites were chosen with different shoreline
treatments, logged or unlogged shoreline forest, to estimate impacts of
shoreline logging on epilithic algal communities. all three lakes had logged
watersheds, and l42 and l39 had experienced some shoreline logging. no
shoreline logging had been done on l26, but two sites were used with
characteristics similar to logged and unlogged shoreline forest. chlorophyll a
(chi a) was used to index algal biomass; carbon (c), nitrogen (n) and
phosphorus (p) were used to measure nutritional status; and, community
characteristics were evaluated using areal densities of taxonomic classes.
littoral zones were described using a water turbulence index and littoral
wind measurements, mass measurements of epilithic material including
organic and inorganic components and changes in light (theoretical) and
tem perature (actual) environments following shoreline logging. the only
significant differences in measured variables were found at sites in l39, with
higher levels of total and organic material, chi a, c and n at the site with
logged shoreline forest. further, chlorophyceae, bacillariophyceae,
xanthophyceae and dinophyceae were higher and cyanophyceae were lower
in l39 a t the site with logged shoreline forest. no differences were found
between treatment sites in l42, or between sites in l26. differences found in
l39 may have been due more to inter-site variation than to shoreline logging.
overall, data did not show evidence of impacts to epilithic algal communities
or littoral environments from shoreline logging, however, results were not
conclusive given the preliminary nature and short time-span of the study.
collections
- retrospective theses [1604]