Abstract :
Dense growths of macrophytes in Canadian Shield lakes usually occupy areas comprising only 40% those of regions of allochthonous detritus accumulation. Because of this, allochthonous detritus may contribute more toward the standing crop of macroinvertebrates on a whole-lake basis even though the densities are often low. To investigate this possibility, comparisons were made of macroinvertebrate densities between both habitats within the littoral zones of 11 Canadian Shield lakes over a 2–3-year period. Allochthonous detritus was found to contribute more toward the total lake standing crop of littoral zoobenthos in over half of all comparisons. Modification in the amount of terrestrial vegetation supplied to lakes has the potential, therefore, to affect the amount of macroinvertebrates which are available to resident fishes.
