A multidecade experiment shows that fertilization by salmon carcasses enhanced tree growth in the riparian zone.

As they return to spawn and die in their natal streams, anadromous, semelparous fishes such as Pacific salmon import marine-derived nutrients to otherwise nutrient-poor freshwater and riparian ecosystems. Diverse organisms exploit this resource, and previous studies have indicated that riparian tree growth may be enhanced by such marine-derived nutrients. However, these studies were largely inferential and did not account for all factors affecting tree growth.

Effects of river restoration on riparian biodiversity in secondary channels of the Pite River, Sweden.

Between 1850 and 1970, rivers throughout Sweden were channelized to facilitate timber floating. Floatway structures were installed to streamline banks and disconnect flow to secondary channels, resulting in simplified channel morphologies and more homogenous flow regimes. In recent years, local authorities have begun to restore channelized rivers.

Restoration of rivers used for timber floating: effects on riparian plant diversity.

Fluvial processes such as flooding and sediment deposition play a crucial role in structuring riparian plant communities. In rivers throughout the world, these processes have been altered by channelization and other anthropogenic stresses. Yet despite increasing awareness of the need to restore natural flow regimes for the preservation of riparian biodiversity, few studies have examined the effects of river restoration on riparian ecosystems.

Salmon and alder as nitrogen sources to riparian forests in a boreal Alaskan watershed.

Anadromous Pacific salmon (Oncorhynchus spp.) transport marine-derived nitrogen (MDN) to the rivers in which they spawn. Isotopic analyses of riparian vegetation in a boreal Alaskan watershed indicate that trees and shrubs near spawning streams derive ~24-26% of their foliar nitrogen (N) from salmon.