Image courtesy of tiarescott via flickr
It is a testament to the disproportionate impact of global warming on certain ecosystems to see just how far Mongolia has managed to slide towards ecological collapse. John Bohannon's sobering account (sub. required) of the Lake Hovsgol project, which appears in the latest edition of the journal Science, offers little hope that Mongolia will be able to avoid a climate-induced catastrophe.
Clyde Goulden, a researcher from Philadelphia's Academy of Natural Sciences who is studying the ecology of Lake Hovsgol, notes that higher temperatures have already begun thawing the permafrost and disturbing the soil structure around the region's fragile trees. Mongolia has been hit especially hard by global warming, with temperatures rising, on average, twice as fast as the global average - winter temperatures have jumped 3.6°C over the last 60 years.
As he explained to Bohannon: "The grasslands are on the verge of ecological collapse. The environmental problems are closing in on two fronts at once." Dubbed the "blue pearl" for its pristine state, Lake Hovsgol, besieged on two fronts by harmful land-use patterns and the effects of global warming, risks tipping into an "alternative stable state":
"This transformation could be a one-way ticket. A long-standing question in ecology is whether communities of species can be tipped into "alternative stable states." The steppe grasslands, for example, have proved for millennia to be a robust solution to life in cold, dry Mongolia. But once widespread conversion to semidesert occurs, it might be virtually impossible to reverse, says Goulden. In the taiga, even a temporary loss of permafrost, combined with extreme drought and fires, might be a point of no return, he says. The theory of alternative stable states is a mainstay of modern ecology, says ecologist Peter Petraitis of the University of Pennsylvania. But despite decades of experiments, "it remains just that--a theory." What is needed is the intense study of a real-world system, he says."
Mongolia, unfortunately, might just provide that "real-world system"; the receding permafrost has left large areas of ground uncovered, accelerating soil warming and chipping away at the taiga forest. Spurred on by the region's wildfires, which have been steadily increasing over the last few years, and droughts, the region's remaining swaths of forest and grasslands risk being lost in a single summer - leaving behind a spare, "semidesertic" ecosystem.
Supported by a new NSF grant, Goulden and his colleagues in Mongolia will spend the next few years mapping Lake Hovsgol's permafrost, stream hydrology and plant species distribution; they also hope to construct more rigorous ecological models of global warming - using data from experiments examining the effects of temperature and plant cover on soil moisture and respiration.
Via ::Science: The Big Thaw Reaches Mongolia's Pristine North (magazine, sub. required)