Streamside tree cover: “aim for at least 50%”

Posted on May 26, 2009

Fallen leaves and bark are the main sources of energy for organisms inhabiting small forest streams.  However, in Australiathe historical effects of land clearing have converted large areas originally covered by Eucalyptus (e.g. river red gum) forest into pasture or cropland, and the removal of overstorey trees has led to a dramatic decrease in the amount of bottom detritus available to drive instream food webs.  Recent measurements suggest that adequate amounts of detritus are generated only where at least 50% of the original canopy cover is retained, a finding that may be useful as a rule of thumb for restoring cleared streams.

Reference: D. J. Reid, P. S. Lake, G. P. Quinn and P. Reich.  2008.   Association of reduced riparian vegetation cover in agricultural landscapes with coarse detritus dynamics in lowland streams. Marine and Freshwater Research 59,  998-1014.