In the unending quest for effective ways of adapting to climate change, it seems that musk ox and caribou may have some of the answers.
According to a study published this week, the large herbivores that inhabit Greenland and other regions in the far north can play an important role in maintaining biodiversity in a warming climate.
In the course of a 10-year Arctic field experiment, the Penn State biologist Eric Post found that the animals held back the growth of some plant species that would otherwise be likely to dominate the local ecosystem as temperatures rose.
Beginning in 2002, Dr. Post simulated a warmer environment in the remote community of Kangerlussuaq, Greenland, by building 8,600-square-foot ?warming chambers? ? cone-shaped hollow structures in which the animals were allowed to graze on the plants that grew under the new conditions.
The musk ox and caribou were excluded from separate areas of the same size that were also subjected to a rise in temperature of 1.5 to 3 degrees Celsius (2.7 to 5.4 degrees Fahrenheit), a level of warming that scientists project will occur over the next century.
Shrubs like willow and birch became more dominant as temperatures rose, shading other plants and producing leaf litter that cools the soil and reduces nutrients for competing species, thereby lowering species diversity.
But in the enclosures with grazing herbivores, those dominant species were largely kept in check, allowing the other plants to do better than they did in the areas from which the animals were excluded, Dr. Post found.
?In those areas where caribou and musk ox were able to graze freely, shrub responses to warming were muted, and species diversity within the plant community was maintained,? he wrote.
Dr. Post suggests that his research may have implications for other ecosystems. ?I think the relationships we see in Greenland would certainly apply to a wider variety of similarly generalist herbivores in other systems,? he wrote in an e-mail. ?One example may be moose, whose browsing can have huge effects on plant community composition, nutrient cycling rates and ecosystem function.?
He said the current decline of moose in northern Minnesota, for which scientists have not pinned down a cause, could thus have ?major consequences.?
Dr. Post?s paper adds yet another wrinkle to the debate over how climate change may affect biodiversity. A 2012 study published in the Proceedings of the National Academy of Sciences presented evidence from fossil records that rising temperatures have spurred an increase rather than a decline in biodiversity. Yet even emergent species won?t be able to keep up with the current rapid rate of climate change, meaning that the rate of extinctions will increase, it concluded.
The new study, published in the journal Proceedings of the Royal Society of London,? concluded that the animals may hold the key to the maintenance of plant diversity and therefore must be protected.
?What this experiment suggests is that factors that threaten the persistence of large herbivores may threaten the plant communities they exist in as well,? Dr. Post said.
?Conservation of these herbivores in the rapidly changing Arctic will require careful mediation of interacting stressors such as human exploitation, mineral extraction, and the direct effects of climate change,? he said.
kim zolciak kim zolciak travis pastrana quinton coples a.j. jenkins riley reiff david decastro
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