Data from: Species interactions, environmental gradients and body size shape population niche width ...

• Main Authors: Eloranta, Antti, Finstad, Anders, Sandlund, Odd, Knudsen, Rune, Kuparinen, Anna, Amundsen, Per-Arne
• Format: Dataset
• Language: English
• Published: Dryad 2021
• Subjects: FOS Biological sciences; Norway; Burbot; Finnmark; Lota lota; Northern Norway; Subarctic; lota
• Online Access: https://dx.doi.org/10.5061/dryad.gf1vhhmqz; https://datadryad.org/stash/dataset/doi:10.5061/dryad.gf1vhhmqz

Competition for shared resources is commonly assumed to restrict population-level niche width of coexisting species. However, the identity and abundance of coexisting species, the prevailing environmental conditions, and the individual body size may shape the effects of interspecific interactions on species’ niche width. Here we study the effects of inter- and intraspecific interactions, lake area and altitude, and fish body size on the trophic niche width and resource use of a generalist predator, the littoral-dwelling large, sparsely-rakered morph of European whitefish (Coregonus lavaretus; hereafter LSR whitefish). We use stable isotope, diet and survey fishing data from 14 subarctic lakes along an environmental gradient in northern Norway. The isotopic niche width of LSR whitefish showed a humped-shaped relationship with increasing relative abundance of sympatric competitors, suggesting widest population niche at intermediate intensity of interspecific interactions. The isotopic niche width of LSR ... : The 14 study lakes are relatively small (0.19–23.7 km2), dimictic and meso- or oligotrophic lakes situated along an altitude gradient (275–540 m a.s.l.) in the Finnmark region in northern Norway. The study area has very limited human activity and the catchment areas consist mainly of mountain birch forest and bogs. No major fishery or any stocking activity occur in the study lakes. Besides whitefish, perch, grayling and charr, some lakes have relatively scarce populations of burbot (Lota lota), brown trout (Salmo trutta), pike (Esox lucius), European minnow (Phoxinus phoxinus) and/or nine-spined stickleback (Pungitius pungitius). LSR whitefish is present in all study lakes, whereas six of the lakes host polymorphic whitefish populations having the additional presence of a small pelagic, densely-rakered (DR) and/or a small profundal, sparsely-rakered (SSR) whitefish morph (Siwertsson et al., 2013; Häkli et al., 2018). Survey fishing was conducted between 8th August and 17th September in 2005­–2009 using the ...