Reciprocal subsidies: dynamic interdependence between terrestrial and aquatic food webs.

Mutual trophic interactions between contiguous habitats have remained poorly understood despite their potential significance for community maintenance in ecological landscapes. In a deciduous forest and stream ecotone, aquatic insect emergence peaked around spring, when terrestrial invertebrate biomass was low. In contrast, terrestrial invertebrate input to the stream occurred primarily during summer, when aquatic invertebrate biomass was nearly at its lowest. Such reciprocal, across-habitat prey flux alternately subsidized both forest birds and stream fishes, accounting for 25.6% and 44.0% of the annual total energy budget of the bird and fish assemblages, respectively. Seasonal contrasts between allochthonous prey supply and in situ prey biomass determine the importance of reciprocal subsidies.

[1]  Shigeru Nakano,et al.  TERRESTRIAL–AQUATIC LINKAGES: RIPARIAN ARTHROPOD INPUTS ALTER TROPHIC CASCADES IN A STREAM FOOD WEB , 1999 .

[2]  F. Samson,et al.  Scale Perspectives on Avian Diversity in Western Riparian Ecosystems , 1994 .

[3]  Chris Cosner,et al.  How Habitat Edges Change Species Interactions , 1999, The American Naturalist.

[4]  M. Murakami,et al.  Species-specific bird functions in a forest-canopy food web , 2000, Proceedings of the Royal Society of London. Series B: Biological Sciences.

[5]  M. Wipfli Terrestrial invertebrates as salmonid prey and nitrogen sources in streams: contrasting old-growth and young-growth riparian forests in southeastern Alaska, U.S.A. , 1997 .

[6]  Donald L. DeAngelis,et al.  Energy flow, nutrient cycling, and ecosystem resilience. , 1980 .

[7]  S. C. Kendeigh Measurement of Bird Populations , 1944 .

[8]  William C. McComb,et al.  Streamside versus upslope breeding bird communities in the central Oregon coast range , 1992 .

[9]  L. Gray Response of Insectivorous Birds to Emerging Aquatic Insects in Riparian Habitats of a Tallgrass Prairie Stream , 1993 .

[10]  J. Lawton,et al.  Linking Species and Ecosystems , 1996 .

[11]  S. Fisher,et al.  Periphyton production in Fort River, Massachusetts , 1979 .

[12]  G. Minshall,et al.  The River Continuum Concept , 1980 .

[13]  Hirokazu Urabe,et al.  Linking microhabitat availability and local density of rainbow trout in low-gradient Japanese streams , 1999, Ecological Research.

[14]  Hirokazu Urabe,et al.  Selective foraging on terrestrial invertebrates by rainbow trout in a forested headwater stream in northern Japan , 1999, Ecological Research.

[15]  M. Murakami Foraging habitat shift in the narcissus flycatcher, Ficedulanarcissina, due to the response of herbivorous insects to the strengthening defenses of canopy trees , 1998, Ecological Research.

[16]  R. Naiman,et al.  The Ecology of Interfaces: Riparian Zones , 1997 .

[17]  Shigeru Nakano,et al.  Flexible niche partitioning via a foraging mode shift: a proposed mechanism for coexistence in stream‐dwelling charrs , 1999 .

[18]  S. Fisher,et al.  Secondary Production, Emergence, and Export of Aquatic Insects of a Sonoran Desert Stream , 1986 .

[19]  K. McCann,et al.  Food Web Stability: The Influence of Trophic Flows across Habitats , 1998, The American Naturalist.

[20]  H. Miyasaka,et al.  Effects of drift- and benthic-foraging fish on the drift dispersal of three species of mayfly nymphs in a Japanese stream , 1999, Oecologia.