title: More than a corridor: use of a main stem stream as supplemental foraging habitat by a brook trout metapopulation.
abstract: Coldwater fishes in streams, such as brook trout (Salvelinus fontinalis), typically are headwater specialists that occasionally expand distributions downstream to larger water bodies. It is unclear, however, whether larger streams function simply as dispersal corridors connecting headwater subpopulations, or as critical foraging habitat needed to sustain large mobile brook trout. Stable isotopes (δ(13)C and δ(15)N) and a hierarchical Bayesian mixing model analysis was used to identify brook trout that foraged in main stem versus headwater streams of the Shavers Fork watershed, West Virginia. Headwater subpopulations were composed of headwater and to a lesser extent main stem foraging individuals. However, there was a strong relationship between brook trout size and main stem prey contributions. The average brook trout foraging on headwater prey were limited to 126 mm standard length. This size was identified by mixing models as a point where productivity support switched from headwater to main stem dependency. These results, similar to other studies conducted in this watershed, support the hypothesis that productive main stem habitat maintain large brook trout and potentially facilitates dispersal among headwater subpopulations. Consequently, loss of supplementary main stem foraging habitats may explain loss of large, mobile fish and subsequent isolation of headwater subpopulations in other central Appalachian watersheds.
authors.affiliation: Division of Forestry and Natural Resources, West Virginia University, Morgantown, WV, 26506, USA. brockhunts@gmail.com.|Department of Fish, Wildlife and Conservation Ecology, New Mexico State University, 2980 South Espina Street, 132 Knox Hall, Las Cruces, NM, 88003, USA. brockhunts@gmail.com.
authors.forename: Brock M
authors.initials: BM
authors.lastname: Huntsman
authors.affiliation: Division of Forestry and Natural Resources, West Virginia University, Morgantown, WV, 26506, USA.
authors.forename: J Todd
authors.initials: JT
authors.lastname: Petty
authors.affiliation: Department of Geology and Geography, West Virginia University, Morgantown, WV, 26506, USA.
authors.forename: Shikha
authors.initials: S
authors.lastname: Sharma
authors.affiliation: Division of Forestry and Natural Resources, West Virginia University, Morgantown, WV, 26506, USA.
authors.forename: Eric R
authors.initials: ER
authors.lastname: Merriam
mesh_terms: D000818:Animals; D001061:Appalachian Region; D001499:Bayes Theorem; D017753:Ecosystem; D014337:Trout
keywords: Binary Patch-Matrix; Habitat supplementation; Metapopulations; River continuum concept; Riverscape