Functional Feeding Groups: Shredders

Every fall, deciduous trees lose their leaves and some of them may fall into a stream. What happens to them? A community of organisms, called bacteria and microbes, inhabit a leaf and begin to break down the organic material, making it digestible for aquatic insects.

While this is happening, larger organisms such as caddisflies start to break down bigger sections of the leaves by eating the leaf and digesting it. The shredders play an important role in the ecosystem breaking down leaves and detritus, called Coarse Particulate Organic Matter (CPOM). This is often the first stage in decomposition of organic material from terrestrial resources (Barbour et al. 1999). The CPOM input and subsequent processing initiates the energetic dynamics in river systems, and will be discussed in later sections.