SwePub - sökning: WFRF:(Koizumi K)

Numrering	Referens	Omslagsbild	Hitta
1.	2017 swepub:Mat__t
2.	Watz, Johan, 1977-, et al. (författare) Temperature-dependent competition between juvenile salmonids in small streams 2019 Ingår i: Freshwater Biology. - : Blackwell Publishing. - 0046-5070 .- 1365-2427. ; , s. 1534-1541 Tidskriftsartikel (refereegranskat)abstract Biotic interactions affect species distributions, and environmental factors that influence these interactions can play a key role when range shifts in response to environmental change are modelled. In a field experiment using enclosures, we studied the effects of the thermal habitat on intra- versus inter-specific competition of juvenile Dolly Varden Salvelinus malma and white-spotted charr Salvelinus leucomaenis, as measured by differences in specific growth rates during summer in allopatric and sympatric treatments. Previous laboratory experiments have shown mixed results regarding the importance of temperature-dependent competitive abilities as a main driver for spatial segregation in stream fishes, and no study so far has confirmed its existence in natural streams. Under natural conditions in areas where the two species occur in sympatry, Dolly Varden dominate spring-fed tributaries (cold, stable thermal regime), whereas both species often coexist in non-spring-fed tributaries (warm, unstable thermal regime). Enclosures (charr density = 6 per m2) were placed in non-spring-fed (10–14°C) and spring-fed (7–8°C) tributaries. In enclosures placed in non-spring-fed tributaries, Dolly Varden grew 0.81% per day in allopatry and had negative growth (−0.33% per day) in sympatry, whereas growth rates were similar in allopatry and sympatry in spring-fed tributaries (0.68 and 0.58% per day). White-spotted charr grew better in sympatry than in allopatry in both thermal habitats. In non-spring-fed tributaries, they grew 0.17 and 0.79% per day and in spring-fed tributaries 0.46 and 0.75% per day in allopatry and sympatry, respectively. The negative effect of inter-specific competition from white-spotted charr on Dolly Varden thus depended on the thermal habitat. However, there was no strong evidence of a temperature-dependent effect of intra- and inter-specific competition on white-spotted charr growth. Multiple factors may shape species distribution patterns, and we show that temperature may mediate competitive outcomes and thus coexistence in stream fish. These effects of temperature will be important to incorporate into mechanistic and dynamic species distribution models.

Watz, Johan, 1977-, et al. (författare)
Temperature-dependent competition between juvenile salmonids in small streams
2019
Ingår i: Freshwater Biology. - : Blackwell Publishing. - 0046-5070 .- 1365-2427. ; , s. 1534-1541
Tidskriftsartikel (refereegranskat)abstract
- Biotic interactions affect species distributions, and environmental factors that influence these interactions can play a key role when range shifts in response to environmental change are modelled. In a field experiment using enclosures, we studied the effects of the thermal habitat on intra- versus inter-specific competition of juvenile Dolly Varden Salvelinus malma and white-spotted charr Salvelinus leucomaenis, as measured by differences in specific growth rates during summer in allopatric and sympatric treatments. Previous laboratory experiments have shown mixed results regarding the importance of temperature-dependent competitive abilities as a main driver for spatial segregation in stream fishes, and no study so far has confirmed its existence in natural streams. Under natural conditions in areas where the two species occur in sympatry, Dolly Varden dominate spring-fed tributaries (cold, stable thermal regime), whereas both species often coexist in non-spring-fed tributaries (warm, unstable thermal regime). Enclosures (charr density = 6 per m2) were placed in non-spring-fed (10–14°C) and spring-fed (7–8°C) tributaries. In enclosures placed in non-spring-fed tributaries, Dolly Varden grew 0.81% per day in allopatry and had negative growth (−0.33% per day) in sympatry, whereas growth rates were similar in allopatry and sympatry in spring-fed tributaries (0.68 and 0.58% per day). White-spotted charr grew better in sympatry than in allopatry in both thermal habitats. In non-spring-fed tributaries, they grew 0.17 and 0.79% per day and in spring-fed tributaries 0.46 and 0.75% per day in allopatry and sympatry, respectively. The negative effect of inter-specific competition from white-spotted charr on Dolly Varden thus depended on the thermal habitat. However, there was no strong evidence of a temperature-dependent effect of intra- and inter-specific competition on white-spotted charr growth. Multiple factors may shape species distribution patterns, and we show that temperature may mediate competitive outcomes and thus coexistence in stream fish. These effects of temperature will be important to incorporate into mechanistic and dynamic species distribution models.

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