The lateral extent of the subsidy from an upland stream to riparian lycosid spiders

Type Article
Original languageEnglish
Pages (from-to)165-170
Number of pages6
JournalEcography
Volume28
Issue number2
Early online date14 Mar 2005
DOI
Publication statusPublished - Apr 2005
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Abstract

Adult aquatic insects emerging from streams can subsidize riparian food webs, but little is known of the spatial extent of these subsidies. Stable isotope (15N) enrichment of aquatic insects, principally a species of stonefly (Plecoptera: Leuctridae), emerging from an upland stream was used to trace the subsidy from the stream ecosystem to riparian spiders (Lycosidae). The downstream profile of spider δ15N correlated closely with that of adult stoneflies, indicating that they were deriving nutrition from aquatic sources. The contribution of adult aquatic insects to spider diets was determined using a two-source mixing model. Adult aquatic insects made up over 40% of spider diets adjacent to the stream, but