Particulate organic contributions from forests and streams: debris isn't so bad

Abstract

It is clear that the input of "debris" from terrestrial plants falling into streams is one of the most significant processes occurring at the interface of terrestrial and stream ecosystems. Organic matter?leaves, twigs, branches, and whole trees?provides energy, nutrients, and structure to streams flowing through forests. A host of vertebrate and invertebrate animals has adapted to life in flowing waters and depends on leaves and wood for food and habitat. Accumulations of leaves and wood also create refuges from the extremes of drought and flood and modify the downstream movement of sediment.

Despite all that we know about the importance of organic matter in streams, all too often wood and leaves in streams have been viewed as a liability at worst and a nuisance at best. Even the terms we use to describe it debris, for example, ?suggest something cast off or discarded. Although excessive amounts of organic matter have negative impacts in streams, such as lowering dissolved oxygen, buildup of toxic substances, and blocking fish migration, most problems are local rather than symptomatic of a [an] underlying pathology. All of these reasons aside, the main reason for our aversion to wood and leaves in streams is far more basic: it just plain looks bad! But for diverse, productive invertebrates and fish, for preservation of natural sediment and water regimes, and for overall stream health, terrestrial plant debris is not only desirable but essential.

The task in this chapter is to outline what we know about the functions and values of leaves and wood in streams. In doing so we hope not only to dispel the common misconceptions that wood debris in streams is undesirable, but also to instill the concept of organic matter as an asset to be husbanded.

Citation

Dolloff, C. Andrew; Webster, Jackson R. 2000. Particulate organic contributions from forests and streams: debris isn''t so bad. In: Verry, Elon S.; Hornbeck, James W.; Dolloff, C. Andrew, eds. Riparian management in forests of the continental Eastern United States. Boca Raton, FL: Lewis Publishers, CRC Press LLC: 125-138.