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Bridge under troubled water : Turbulence and niche partitioning in fish foraging

Pekcan-Hekim, Zeynep; Hellén, Noora; Härkönen, Laura; Nilsson, Anders LU ; Nurminen, Leena and Horppila, Jukka (2016) In Ecology and Evolution 6(24). p.8919-8930
Abstract

The coexistence of competing species relies on niche partitioning. Competitive exclusion is likely inevitable at high niche overlap, but such divide between competitors may be bridged if environmental circumstances displace competitor niches to enhance partitioning. Foraging-niche dimension can be influenced by environmental characteristics, and if competitors react differently to such conditions, coexistence can be facilitated. We here experimentally approach the partitioning effects of environmental conditions by evaluating the influence of water turbulence on foraging-niche responses in two competing fish species, Eurasian perch Perca fluviatilis and roach Rutilus rutilus, selecting from planktonic and benthic prey. In the absence of... (More)

The coexistence of competing species relies on niche partitioning. Competitive exclusion is likely inevitable at high niche overlap, but such divide between competitors may be bridged if environmental circumstances displace competitor niches to enhance partitioning. Foraging-niche dimension can be influenced by environmental characteristics, and if competitors react differently to such conditions, coexistence can be facilitated. We here experimentally approach the partitioning effects of environmental conditions by evaluating the influence of water turbulence on foraging-niche responses in two competing fish species, Eurasian perch Perca fluviatilis and roach Rutilus rutilus, selecting from planktonic and benthic prey. In the absence of turbulence, both fish species showed high selectivity for benthic chironomid larvae. R. rutilus fed almost exclusively on zoobenthos, whereas P. fluviatilis complemented the benthic diet with zooplankton (mainly copepods). In turbulent water, on the other hand, the foraging-niche widths of both R. rutilus and P. fluviatilis increased, while their diet overlap simultaneously decreased, caused by 20% of the R. rutilus individuals turning to planktonic (mainly bosminids) prey, and by P. fluviatilis increasing foraging on littoral/benthic food sources. We show that moderate physical disturbance of environments, such as turbulence, can enhance niche partitioning and thereby coexistence of competing foragers. Turbulence affects prey but not fish swimming capacities, with consequences for prey-specific distributions and encounter rates with fish of different foraging strategies (pause-travel P. fluviatilis and cruise R. rutilus). Water turbulence and prey community structure should hereby affect competitive interaction strengths among fish species, with consequences for coexistence probability as well as community and system compositions.

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author
organization
publishing date
type
Contribution to journal
publication status
published
subject
keywords
competition, diet choice, disturbance, feeding strategy, segregation
in
Ecology and Evolution
volume
6
issue
24
pages
12 pages
publisher
Wiley-Blackwell
external identifiers
  • scopus:85005896229
  • wos:000392063300024
ISSN
2045-7758
DOI
10.1002/ece3.2593
language
English
LU publication?
yes
id
0f498feb-44d9-4bb8-81af-94545b6d313b
date added to LUP
2017-01-11 14:25:28
date last changed
2017-09-18 11:36:02
@article{0f498feb-44d9-4bb8-81af-94545b6d313b,
  abstract     = {<p>The coexistence of competing species relies on niche partitioning. Competitive exclusion is likely inevitable at high niche overlap, but such divide between competitors may be bridged if environmental circumstances displace competitor niches to enhance partitioning. Foraging-niche dimension can be influenced by environmental characteristics, and if competitors react differently to such conditions, coexistence can be facilitated. We here experimentally approach the partitioning effects of environmental conditions by evaluating the influence of water turbulence on foraging-niche responses in two competing fish species, Eurasian perch Perca fluviatilis and roach Rutilus rutilus, selecting from planktonic and benthic prey. In the absence of turbulence, both fish species showed high selectivity for benthic chironomid larvae. R. rutilus fed almost exclusively on zoobenthos, whereas P. fluviatilis complemented the benthic diet with zooplankton (mainly copepods). In turbulent water, on the other hand, the foraging-niche widths of both R. rutilus and P. fluviatilis increased, while their diet overlap simultaneously decreased, caused by 20% of the R. rutilus individuals turning to planktonic (mainly bosminids) prey, and by P. fluviatilis increasing foraging on littoral/benthic food sources. We show that moderate physical disturbance of environments, such as turbulence, can enhance niche partitioning and thereby coexistence of competing foragers. Turbulence affects prey but not fish swimming capacities, with consequences for prey-specific distributions and encounter rates with fish of different foraging strategies (pause-travel P. fluviatilis and cruise R. rutilus). Water turbulence and prey community structure should hereby affect competitive interaction strengths among fish species, with consequences for coexistence probability as well as community and system compositions.</p>},
  author       = {Pekcan-Hekim, Zeynep and Hellén, Noora and Härkönen, Laura and Nilsson, Anders and Nurminen, Leena and Horppila, Jukka},
  issn         = {2045-7758},
  keyword      = {competition,diet choice,disturbance,feeding strategy,segregation},
  language     = {eng},
  month        = {12},
  number       = {24},
  pages        = {8919--8930},
  publisher    = {Wiley-Blackwell},
  series       = {Ecology and Evolution},
  title        = {Bridge under troubled water : Turbulence and niche partitioning in fish foraging},
  url          = {http://dx.doi.org/10.1002/ece3.2593},
  volume       = {6},
  year         = {2016},
}