Image: Peter Macdiarmid / Staff via Getty Images
Seabird poop, or guano, has the power to nourish ecosystems, is worth millions of dollars, and leave a visual impression that can be seen from space.Now, scientists have scoured 14,000 years of poop from penguins, petrels, and shearwaters, preserved in the peatlands of the Falkland Islands, according to a study published on Friday in Science Advances. The idea was to gain insight into the possible correlations between climate changes and seabird ranges, as well as to assess the long-term effect of the birds on the land habitat.
The results suggest that seabird populations first exploded on this South Atlantic archipelago as the region was cooling some 5,000 years ago, which may indicate that current global warming will prompt the birds to seek colder refuges in the coming decades, once again.Because seabirds are “sentinels of global change,” according to the study, it is especially important to understand how climate and environmental shifts influence their behavior.“One of the main reasons why seabirds are so cool is because they are so sensitive to changes that are happening in the ocean, where they are getting their food from, and also the land where they are breeding or building their nests,” said Dulcinea Groff, who led the new research while pursuing a PhD at the University of Maine, in a call.“They are the canary in the coal mine,” noted Groff, who is now a postdoctoral research scientist at the University of Wyoming.Groff and her colleagues were able to peer back at ecological patterns that have played out over the past 14,000 years by examining a half-meter core of peat extracted from Surf Bay, East Falkland.The first 9,000 years of that record reveal an absence of seabirds, but circumstances abruptly changed when the birds established a toe-hold 5,000 years ago. The rich guano pooped by seabirds over these millennia fueled the growth of tussac (Poa flabellata) grass, a plant that creates an “unusually high-resolution record capable of recording abrupt changes,” the study notes.
As a result, the peat core contains a detailed picture of charcoal, pollen, bird poop, and many other insights into the ecological history of Surf Bay.“One of the things that I love about paleoecology is that we have to use all these forensic techniques,” said Jacquelyn Gill, an associate professor of paleoecology and plant ecology at the University of Maine and co-author on the study, in a call.“There’s just a lot of indirect indicators that we’re using to create these records from the past because we can’t actually go out and observe what’s happening over these thousands of years of time,” Gill added.While it’s not possible to directly link the establishment of seabird colonies to regional cooling in the Falklands—seabird migration patterns are driven by a bevy of complex factors—the islands likely acted as a “cold-climate refugium,” according to the study. Given that climate change has amplified environmental shifts at higher latitudes, near the poles, it’s possible that the birds may soon uproot and look for cooler havens once more.“Our conservation strategies often focus on protecting a place where species are found now, and that means they are not very robust to climate change,” Gill said. “If those birds were to move out of those protected areas, the places they move into are not necessarily going to be protected right away, or at all.”A loss of seabirds in the Falklands would not only affect the future of the birds, but also the tussac grass ecosystems that their poops have helped nourish for thousands of years. These grasslands are already under stress as a result of human activity in recent centuries, which has inspired local grassland restoration projects.
“If seabirds do go away, or find a more suitable habitat, that could also have implications for what they are thinking about for the tussac grass restoration,” Groff said.Seabirds are also important to the Falklands ecotourism industry; people travel from all around the world to the archipelago to catch a glimpse of the penguins and other birds. Considering the ecological, economic, and cultural value of these seabirds, Groff hopes that there will be “a lot of international collaboration” on conservation strategies to protect these sentinel species—and the ecosystems and communities that rely on them.“A warming South Atlantic casts doubt over the future of the Falkland Islands as a long-term seabird breeding hot spot,” Groff’s team warn in the study. “Our work suggests that as the Southern Ocean continues to warm in the coming decades, the Falkland Islands seabird communities may undergo abrupt turnover or collapse, which could happen on the order of decades.”