Habitat coupling is modified by dissolved organic carbon but not temperature in lake ecosystems

• Generalist predators play an essential role in lake ecosystems by linking spatially distinct habitats, a process known as habitat coupling. By eating a wide array of resources and moving between littoral and pelagic habitats, they link food webs and provide critical habitat stability. As climate change is expected to affect ecosystem stability, our attention should focus on how habitat coupling in these predator-stabilized systems is altered by climate change.Expected climate change effects in boreal regions are increases in temperature and dissolved organic carbon (DOC) concentrations. Therefore, we used stable isotopes and a space-for-time approach to examine the impact of DOC and temperature on resource use in a generalist predator, European perch (Perca fluviatilis), in 17 lakes in Sweden and Germany. We found that the impact of DOC on habitat coupling depended on fish ecotype, while both ecotypes showed increases in pelagic resource use, this will increase coupling by littoral fish, while decreasing coupling by pelagic fish. Though we found no direct effect of temperature on resource use, we did find that fish size, which decreases with warming, has an impact. We show that in the future, as fish size decreases and DOC increases, generalist predators will couple habitats less and have a more narrow dietary niche width. This shows that while perch will respond flexibly to changes in resource availability, stability may decrease in the process. 

Ämnesord

NATURVETENSKAP  -- Biologi -- Ekologi (hsv//swe)

NATURAL SCIENCES  -- Biological Sciences -- Ecology (hsv//eng)

Nyckelord

browning

climate change

niche width

perch

resource use

stable isotopes

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vet (ämneskategori)

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