The diversity of life in Antarctica is influenced by many factors, including its inhabitants, penguins and elephant seals. Researchers from the Free University of Amsterdam have found that these two groups of animals around their colonies promote biodiversity much more than previously thought. The secret of success: nitrogen-rich feces.
Antarctica is not as hostile a region as one could imagine. A large variety of different animal species have settled in this icy world and sometimes form huge clusters. Especially the different penguin species, the icons of Antarctica, form colonies of several thousand to millions of animals every spring. Elephant seals, the largest seals in the world, also conquer the beaches of the sub-Antarctic islands for mating every spring. Such quantities of animals also provide enormous amounts of feces, which is excreted daily. Stef Bokhorst from the Free University of Amsterdam (VUA) with colleagues has now found out that this has ecological consequences. “What we see is that the feces of seals and penguins partly evaporates as ammonia. The wind picks up the ammonia and blows it inland, where it gets back into the ground, providing nitrogen for plants that helps them live.”
The area that is fertilized in this way is up to 240 times the size of the colony. As a result, moss and lichens in particular find perfect conditions. These in turn make up the home of millions of small springtails and mites, small insects and spider-like species. “You can find millions of them per square meter in Antarctica. In the grassy landscapes of Europe and the USA, it is only 50 – 100,000 per square meter,” Bokhorst continues. This made identification difficult and lengthy. In the course of the studies, the scientists surprisingly discovered that it was not cold or water content that determines the diversity around a colony, but the number of animals in a colony. With this information, Bokhorst and his colleagues were able to create a map of biodiversity hotspots along the Antarctic Peninsula. However, this map is only a source and is based on the penguin data. The samples from the elephant seals were too small to be extrapolated. Nevertheless, initial statements can be made when using satellite data.
This data can now also be used to identify potential vulnerable areas. This is because climate change and invasive species threaten the flora and fauna of Antarctica. The small inhabitants around the colonies do not know many predators and the plant species have adapted in millions of years. But the rapidly changing conditions offer good conditions for introduced species. Just as penguin and seal colonies enrich the soil for the native flora, imported species could also find ideal conditions. This would also allow larger predators such as spiders and beetles to suddenly find a niche,” explains Stef Bokhorst. This is exactly the topic that the researchers now want to continue to devote themselves to and find out whether and how an invasion of this unique region can be prevented.
Source: Current Biology Biology, Cell Press
