Climate Change

Climate change affects nature’s dinner time: study

Moving out of nature's timing can mess up the food chain

By DTE Staff
Published: Thursday 26 April 2018
in the Netherlands, the Eurasian sparrow hawk has been late for dinner because its prey, the blue tit, has — over 16 years — arrived almost six days earlier than the hawk. Credit: allen watkin/Flickr

Timing is everything in nature. Bees have to be around and flowers have to bloom at the same time for pollination to work, and hawks need to migrate at the same time as their prey. But nature’s intricately timed dinner hour is being affected by global warming, often making hungry critters and those on the menu show up at much different times, says a new study.

A first-of-its-kind global mega analysis on the biological timing of 88 species that rely on another life form shows that on average species are moving out of sync by about six days a decade, although some pairs are actually moving closer together. 

The study in Monday’s Proceedings of the National Academy of Sciences gives a global look at a worsening timing problem. These changes in species' timing are considerably greater than they were before the 1980s, it said. 

In the Netherlands, the Eurasian sparrow hawk has been late for dinner because its prey, the blue tit, has—over 16 years—arrived almost six days earlier than the hawk. It’s most crucial in Washington state’s Lake Washington, where over the past 25 years, plant plankton are now blooming 34 days earlier than the zooplankton that eat them. That’s crucial because that’s messing with the bottom of the food chain. In Greenland, the plants are showing up three days earlier than the caribou, so more of the baby caribou are dying “because there wasn’t enough food,” says Heather Kharouba, lead author of the study and an ecologist at the University of Ottawa. 

The North Sea’s ecosystem has been wrecked likewise due to global warming. An analysis of half-a-century of data on the abundance of plankton shows that rising temperatures effect when these creatures breed. This further impacts the food chain.

The records of 66 plankton groups were seen to see their abundance with sea temperature changes. It was found that the timings of spring and autumn blooms of diatoms and dinoflagellates -- plankton that photosynthesise -- has stayed constant because these organisms use the changing lengths of the day as their cue to reproduce. But plankton higher up in the food chain (like copepods) have responded unfavourably: their larvae now appear two months late each year.

This is creating a serious mismatch between producers and consumers, as it means that animals near the top of the food chain, such as fish and seabirds, have less to eat, showed the study.

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