Shredders harder to find in the tropics

Posted on December 15, 2009

Leaf litter is a major source of nutrients and energy in stream ecosystems.  Invertebrates that shred this material (e.g., amphipods, isopods, caddisfly larvae) play a key role in introducing it to food chains in temperate regions, but there is less evidence of the importance of shredders in tropical streams.   In aHong Kongstream study there was no clear connection between litter leaf quality (toughness, nitrogen content) and the composition of colonizing communities.  However, in line with previous tropical studies, researchers found that specialist shredders made up only 1-6% of the invertebrate colonizers.  The low proportion may be due to the fact that the food quality of tropical plant species is highly variable, so that much litter  may be unpalatable or too tough for shredding invertebrates.

Reference:   Li, A.O., Ng, L.C.Y. & Dudgeon, D.  2009.   Effects of leaf toughness and nitrogen content on litter breakdown and macroinvertebrates in a tropical stream.   Aquatic Sciences 71, 80–93.