Variability in the functional role of Arctic charr Salvelinus alpinus as it relates to lake ecosystem characteristics

Woods, Pamela J.; Skúlason, Skúli; Snorrason, Sigurður S.; Kristjánsson, Bjarni K.; Ingimarsson, Finnur; Malmquist, Hilmar J.

doi:10.1007/s10641-013-0114-x

Cited by 8 publications

(20 citation statements)

References 51 publications

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“…2011, 2013a; Woods et al. 2013), but also reduce consumer–resource oscillations and thereby increase the stability of food webs in high-latitude lakes (Rooney et al. 2006).…”

Section: Discussionmentioning

confidence: 99%

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Lake size and fish diversity determine resource use and trophic position of a top predator in high‐latitude lakes

Eloranta

Kahilainen

Amundsen

et al. 2015

Ecology and Evolution

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Prey preference of top predators and energy flow across habitat boundaries are of fundamental importance for structure and function of aquatic and terrestrial ecosystems, as they may have strong effects on production, species diversity, and food-web stability. In lakes, littoral and pelagic food-web compartments are typically coupled and controlled by generalist fish top predators. However, the extent and determinants of such coupling remains a topical area of ecological research and is largely unknown in oligotrophic high-latitude lakes. We analyzed food-web structure and resource use by a generalist top predator, the Arctic charr Salvelinus alpinus (L.), in 17 oligotrophic subarctic lakes covering a marked gradient in size (0.5–1084 km2) and fish species richness (2–13 species). We expected top predators to shift from littoral to pelagic energy sources with increasing lake size, as the availability of pelagic prey resources and the competition for littoral prey are both likely to be higher in large lakes with multispecies fish communities. We also expected top predators to occupy a higher trophic position in lakes with greater fish species richness due to potential substitution of intermediate consumers (prey fish) and increased piscivory by top predators. Based on stable carbon and nitrogen isotope analyses, the mean reliance of Arctic charr on littoral energy sources showed a significant negative relationship with lake surface area, whereas the mean trophic position of Arctic charr, reflecting the lake food-chain length, increased with fish species richness. These results were supported by stomach contents data demonstrating a shift of Arctic charr from an invertebrate-dominated diet to piscivory on pelagic fish. Our study highlights that, because they determine the main energy source (littoral vs. pelagic) and the trophic position of generalist top predators, ecosystem size and fish diversity are particularly important factors influencing function and structure of food webs in high-latitude lakes.

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“…2011, 2013a; Woods et al. 2013), but also reduce consumer–resource oscillations and thereby increase the stability of food webs in high-latitude lakes (Rooney et al. 2006).…”

Section: Discussionmentioning

confidence: 99%

“…2003; Woods et al. 2013). Thus, high-latitude lakes containing Arctic charr offer an outstanding opportunity to study effects of ecosystem size, productivity, and disturbance on food-web structure and energy flow patterns in ecosystems with the same apex predator.…”

Section: Introductionmentioning

confidence: 99%

Lake size and fish diversity determine resource use and trophic position of a top predator in high‐latitude lakes

Eloranta

Kahilainen

Amundsen

et al. 2015

Ecology and Evolution

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“…Salmonids, especially, can form local populations across contrasting environments over a variety of geographical scales, and represent some of the best examples of diversification in freshwater fishes (Taylor, ; Keeley et al ., ; Vonlanthen et al ., ). Selection can operate to promote divergence among fish inhabiting the near shore, littoral versus off‐shore, open water habitats, that differ in resource composition and availability, and thermal regime (Clabaut et al ., ; McPhee, Noakes & Allendorf, ; Woods et al ., ). Indeed, specialization for benthic and pelagic food has frequently been proposed as a driving mechanism for many post‐glacial adaptive radiations (Vonlanthen et al ., ; McPhee et al ., ).…”

Section: Discussionmentioning

confidence: 99%

Polymorphism in lake trout in Great Bear Lake: intra-lake morphological diversification at two spatial scales

Chavarie

Howland

Harris

et al. 2014

Biol J Linn Soc Lond

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Great Bear Lake is the most northerly lake of its size and provides unique opportunities for intraspecific diversification. Despite increasing attention to intraspecific polymorphism, several knowledge gaps remain (e.g. determining the extent of intraspecific diversification in large relatively pristine lakes and at which spatial scale it can occur). We focused on geographical patterns of morphological differentiation within lake trout (Salvelinus namaycush) to describe two levels of intralake diversification in Great Bear Lake. We used a combination of geometric and traditional linear measurements to quantify differences in body shape, head shape, and fin and body lengths among 910 adult lake trout from the five distinct arms of Great Bear Lake. Although head and fin linear measurements discriminated the three common morphotypes at the whole‐lake level, inter‐arm variation in body shape was observed within each morphotype. A comparison of genetic and morphological distance matrices revealed the lack of an association between the two sets of data, although both comparisons revealed an association in the inter‐arm variation patterns among morphotypes, suggesting a phenotypically plastic response to distinct environments. The whole‐lake and inter‐arm morphological variation observed within lake trout demonstrates the importance of considering scale, especially across large lakes that exhibit marked complexity and a variety of freshwater habitats. © 2014 The Linnean Society of London, Biological Journal of the Linnean Society, 2014, 114, 109–125.

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“…The cannibals in the present investigation were larger during the young stages, contrary to what was reported by Sinnatamby et al (2013) from Lake Hazen, northern Canada. Sympatric speciation has been rendered possible for a number of species, especially salmonids such as char and whitefish (Coregonus lavaretus L.) (Thomassen et al 2011;Gowell et al 2012;Praebel et al 2013), and parallel divergence of forms diverging in body size should therefore be probable (Fraser et al 2008;Woods et al 2013). Maternal effects on egg size and resulting life history variation may also be a factor initiating genetic differentiation, eventually through mating preferences through prezygotic barriers by mate choice (Power et al 2009).…”

Section: Discussionmentioning

confidence: 99%

“…The governing mechanism underpinning each individual's life history and thus shaping the population structure is not known, but it may lie anywhere on a spectrum between complete genetic determination and environmentally, randomly induced phenotypic variation (Hindar et al1986;Gislason et al 1999;Woods et al 2013) or internal population dynamic cycles (Bystr€ om 2006;Svanb€ ack et al 2009;Roos & Persson 2013). A high degree of genetic determination in life history choice is suggested by some authors, but the evidence is still inconclusive (Gislason et al 1999;Janhunen et al 2010;Sinnatamby et al 2013).…”

Section: Introductionmentioning

confidence: 99%

Otolith size differences during early life of dwarf and cannibal Arctic char (Salvelinus alpinus)

Florø-Larsen

Finstad

Berg

et al. 2014

Ecology of Freshwater Fish

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In Arctic and alpine lakes, Arctic char [Salvelinus alpinus (L.)] often form two distinct morphs: invertebrate feeders ('dwarfs') and piscivores ('giant or cannibals'). Here, we test for early life history growth variation in dimorphic Arctic char as a proximate explanation for the observed life history variation between the two forms. Char were sampled in 11 alpine and Arctic Norwegian lakes. Dwarfs (defined as sexually mature char less than 15 cm long; N = 304) had a mean total length of 105 mm, whereas the typical cannibal (body length above 20 cm; N = 153) was 388 mm long. A positive correlation between egg size and otolith hatching ring were ascertained in a separate hatching experiment with brown trout (Salmo trutta) and it is assumed that this relationship also is valid for Arctic char, and otolith size was used as a proxy for length. Otolith hatching ring from Arctic char cannibals was larger (mean AE SD; 187 AE 24 lm) than those from dwarfs (mean AE SD; 164 AE 23 lm). There were only minor size differences between dwarfs and cannibals during the next three years, after which dwarfs usually matured. Two mutually nonexclusive, proximate explanations for the differentiation into separate morphs (dwarfs and cannibals) are therefore maternal effects and/or genetic based differentiation. The high catchability of large piscivorous char and low production in alpine and Arctic lake ecosystems may make these stocks particularly vulnerable to overexploitation.

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Variability in the functional role of Arctic charr Salvelinus alpinus as it relates to lake ecosystem characteristics

Cited by 8 publications

References 51 publications

Lake size and fish diversity determine resource use and trophic position of a top predator in high‐latitude lakes

Lake size and fish diversity determine resource use and trophic position of a top predator in high‐latitude lakes

Polymorphism in lake trout in Great Bear Lake: intra-lake morphological diversification at two spatial scales

Otolith size differences during early life of dwarf and cannibal Arctic char (Salvelinus alpinus)

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