The Harvest Begins

After five years of warming chambers, control plots, phenology counts, and watering, the PIRE Mongolia project all comes down to this: biomass measurements. And those measurements currently consume the Dalbay Camp.

As most regular readers of this blog should know, the PIRE Mongolia group studies the effects of climate and land use change in northern Mongolia. We warm our plots with chambers to increase temperature. We water our plots to increase rainfall. We cover our plots with other chambers to decrease rainfall. We fence our plots to keep grazers out and we open some fences in the fall to let grazers in. For five years, 82 little meter by half meter plots have all been subjected to varying degrees of “climate change” and grazing pressure.

And what have we found? Well, up to now, we’ve only collected data using what’s called non-destructive measurements. By counting the number of flowers in each plots, we can show how certain grasses and forbs react to climate manipulation, while others don’t really alter their numbers of flowers or their timing. By monitoring the soil temperature in the grazed plots, we could tell that grazers munch the plant litter that shades the soil and keeps it cool. But now the time for destruction has begun…

If we really want to understand how these types of climate manipulation might affect the community of plants that make up the Mongolian steppe, we need to understand how much biomass the plants produced after years of experiencing a different temperature. Every year, we’ve noted the type and number of plants growing in each plot, but that only tells part of the story. For example, the warmed plots could have lots of species, but maybe they aren’t all that big. Perhaps the warmer temperatures are an extra stress that prevents the plants from growing as large as they did previously. Or perhaps the drought treatment favors some of the grasses in the plots, allowing them to more effectively compete against the forbs and sedges, growing bigger and bigger. Or perhaps nothing happens at all. But to find out, we have to harvest all the plants, dry them, and weigh them.

This might sound like a simple task, but it’s actually quite difficult. Thursday, we began cutting the above-ground biomass (so stems and leaves, no roots) in every plot. Once cut, we sort the biomass by species, place it into little paper bags, and continue until the plot is a barren, brown meter by half meter square framed by the green vegetation surrounding it. Now, one of the gers is completely full of drying bags of vegetation, slowly taking over beds and preventing anyone from starting a fire, lest they accidentally set five years of experiment ablaze.

The warming experiment is not the only biomass action in Dalbay, however. Led by Dr. Bazartseren Boldgiv, chair of the Ecology Department at the National University of Mongolia and the chief Mongolian collaborator with the PIRE Mongolia project, a group of Mongolian students are harvesting two eight meter by eight meter plots of above-ground biomass. This effort is part of a global experiment to investigate the relationship between species richness and productivity (amount of above-ground biomass produced) in grasslands. This group has been diligently stapling paper bags every night, leaving bags out in the sun to dry, and quickly bringing them in from the rain.

While this work is important, the long days of uncomfortable and tedious work have taken a toll on camp life. The number of volleyball games has decreased, as have card games and groups going running. Now, the evenings seem mostly consumed with resting our backs in preparation for another long day ahead.

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