Large grazing animals revitalize a grassland in Europe
Scientists are learning more about the ecological function of large herbivores
Large grazing animals were reintroduced to grasslands in the Czech Republic in 2015. In the intervening years the grasslands, which had become dominated by tall, coarse grasses, have increased in ecological vibrancy, with a more diverse assemblage of native plant species. Even endangered species have increased where the herbivores have been reintroduced.
Scientists have been keeping tabs on the changes brought about by the grazers, publishing their findings this month in the peer reviewed journal Plant Ecology.
Overhunting, habitat loss, and other humans pressures have caused extinctions or near extinctions of large herbivores across Europe. Large native cattle no longer inhabit the Polish plains, and ibex are gone from Spain and France. The open spaces that these creatures inhabited no longer benefit from the ecological functions that they provided.
Large herbivores are functioning parts of ecosystems. In many cases they are considered keystone species, creatures that perform one of the vital tasks of an ecosystem. For generations, it was believed that livestock, both in Europe and North America, reproduced the ecological function of wild native herbivores. Whether they did or not has become moot with the development of factory farming in which grain and soy are grown then shipped to large-scale feeding lots. The cattle no longer graze.
Though folks recognize the importance of large grazing animals, there aren’t a great deal of studies on the results of when these animals are reintroduced to a wild area. That is why this recent study is so significant.
The study
The reintroduction took place about 20 miles northeast of Prague at the former Milovice Military Training Area, which had been an active military region throughout the 20th century until it was abandoned in the early 1990s following the crumbling of the Soviet Union. Some of the land was developed, but the core area was declared a Site of European Community Importance and later declared a National Nature Monument. Despite the declarations, the open space remained unmanaged, with disturbances by armored and offroad vehicles between 2009 and 2010.
Most of the Nature Monument is a semiarid temperate grassland. Temperate grasslands are non-forested lands that receive between 10 and 20 inches of rain a year. They are a rare find, particularly in Europe, as their naturally rich soils make them ideal for humans to raise their crops. The Nature Monument is home to jackals, gray wolves, deer, foxes, badgers, and wild boars.
The authors of the paper don’t say who performed the reintroduction, whether it was part of a rewilding project or if it was part of a Czech environmental program, but about a dozen of each of three species were translocated to the area: the Exmoor pony, a pony native to the British Isles that still roams free in some places there; semi-wild cattle; and European bison, which are the heaviest land animals in Europe. After their reintroduction, a semi-hands off approach was take with their care. People managing the reintroduction ensured the animals had water and a salt lick, but the animals received no supplemental feeding or medication, except in extreme cases.
What the scientists found
The researchers surveyed the areas where the animals grazed, comparing them to ungrazed areas, for four years. The thick grass diminished where the animals grazed, making way for flowering annuals. Overall, the grazed plots contained five to nine more species of plants than the ungrazed. (In all, the researchers kept track of 179 plant species for this study.) This obviously makes a better environment for pollinator species like butterflies and bees. The scientists surmise that the trampling by the large mammals disrupts the stronger species, the rough grass, and allows for a more diverse plant community.
The results were not immediate, taking six years, but after that time span the grazed plots had more endangered species than the ungrazed plots, including four rare sunflowers, two lotus, a member of the carnation family, and a rare wild rose.
As I mentioned above, not much other science has been done on large herbivore reintroduction, but the findings of this study coincide with an earlier finding. In a 2007 study of elk reintroduced to a grassland in northern California scientists found that the elk converted scrubland to grassland. They also significantly reduced the amount of nonnative grasses in the study area.
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