Further positive signs of life in Chernobyl
Scavenger activity verifies movement of nutritional resources, study suggests. Nick Carne reports.
There’s further evidence that wildlife is once again abundant in the Chernobyl Exclusion Zone (CEZ) in the Ukraine, three decades after the world’s most famous nuclear disaster.
A one-month study by a team from the University of Georgia, US, sighted 10 mammal and five bird species, including the rarely seen Eurasian otter.
"These animals were photographed while scavenging fish carcasses placed on the shoreline of rivers and canals in the CEZ," says ecologist James Beasley.
"We've seen evidence of a diversity of wildlife in the CEZ through our previous research, but this is the first time that we've seen white-tailed eagles, American mink and river otter on our cameras."
Lead investigator Peter Schlichting says previous studies have reported that scavenging activity can connect various food webs, but scientists weren't sure how this occurs.
In the new study, reported in the journal Food Webs, fish carcasses were placed at the edge of open waters at the Pripyat River and in nearby irrigation canals, mimicking the natural activity that occurs when currents transport dead fish carcasses to the shore.
Within a week, 98% had been consumed by scavengers.
"This is a high rate of scavenging, and given that all our carcasses were consumed by terrestrial or semi-aquatic species, it verifies that the movement of nutritional resources between aquatic and terrestrial ecosystems occurs more frequently than often recognised," Beasley says.
"We tend to think of fish and other aquatic animals as staying in the aquatic ecosystem. This research shows us that if a reasonable proportion of dead fish make it to shore, there is an entire group of terrestrial and semi-aquatic species that transfer those aquatic nutrients to the terrestrial landscape."
The team compared scavenger activity at the river with scavenger activity at the canals, evaluating parameters including the percentage of carcasses consumed and how quickly they were consumed; the number of species that showed up; and how frequently each species was detected.
Scavenger efficiency was higher in the river, because the limited shoreline cover increased the visibility of the fish carcasses, making them easier to find. However, as predicted, richness was higher in the canals.
"Many former agricultural areas within the CEZ were irrigated through the use of these small canals," Beasley said. "Most of them still hold water, but they are overgrown with vegetation that provides cover for wildlife, so they are used by a wider array of species."
The CEZ – also known as the Chernobyl Nuclear Power Plant Zone of Alienation – covers about 2600 square kilometres.