Stream Animals & the Heterotrophic Food Chain

1. Stream Animals & the Heterotrophic Food Chain

2. Processing of Organic Matter • In fall, leaf debris from overhanging deciduous trees accumulates in the stream • Flowing water leaches the leaves soluble organic matter as dissolved organic matter (DOM) or fine particulate organic matter (FPOM) • The leaves remain as coarse particulate organic matter (CPOM)

3. Microbial Processing • The remaining leaf surface is colonized by bacteria (on FPOM) and fungi (on CPOM) • These microorganisms convert the cellulose and lignin into forms useable by invertebrates

4. Invertebrate Processing:1) Shredders • The shredders feed on the leaves and their resident microbes, and convert the CPOM into FPOM

5. Common Shredders • Craneflies(Diptera) • Caddisflies (Trichoptera) • Stone-Fly Nymphs (Plecoptera) • Crayfish

6. 2) Filtering and Gathering Collectors • FPOM carried down stream is acquired by the Filtering and Gathering Collectors, processed, and turned into DOM

7. Common Collectors • Blackflies(Diptera) • Fan and net spinning Caddisflies (Trichoptera) • Midges

8. 3) Scrapers, Piercers, & Gougers • Algae and mosses coating the surface or rocks is processed too • Scapers and Piercers feed on algae, while Gougers feed by burrowing into the trunks of fallen trees

9. Common Scrapers, Piercers, & Gougers Scrapers • Beetle Larvae (Coleoptera) • Mobile Caddisflies • Snails Piercers • Microcaddisflies Gougers • Fly Larvae (Diptera)

10. Invertebrate Predators • All the invertebrate organisms that process the leaves, algae, and wood are potential food for invertebrate predators • One common predator is the Hellgramite or Dobsonfly Larvae (Megaloptera)