Stream inflows to lake deltas: A tributary junction that provides a unique habitat in lakes

1. Tributary junctions in stream networks provide unique habitats within fluvial networks by contributing differently sized sediment and organic materials, providing temperature refuge, and other conditions distinct from the receiving stream. These same attributes at tributaries entering lakes (inflow streams) support special, within-lake locations that are used by several organisms at some times of year, which we call lake deltas. 2. Here we consider the evidence of these lake deltas as a special environment in terms of their physical, chemical, and biological characteristics. There are several potential contributions from tributary streams, and much of the emphasis has been on resource subsidies to lakes, but other factors may also contribute to the uniqueness of lake deltas. 3. The degree to which these deltas provide productivity and biodiversity hotspots is not well known, but we present evidence in support of this assertion. We also offer suggestions for a suite of hypotheses that can be tested. These junctions may also provide an excellent model system for testing the consequences of resource subsidies (organic matter, invertebrates) to recipient communities from small to mid-sized streams. 4. Consolidation of these ideas will allow testing for the uniqueness of these lake delta habitats and the mechanisms responsible, and perhaps promote greater efforts at protecting processes that sustain these areas in lakes.

Automated summary

Tributary junctions in stream networks provide unique habitats within fluvial networks, and support special within-lake locations that may influence lake productivity and biodiversity.