Life Adapts to a Volcanic Landscape
Two thousand years after volcanic eruptions subsided, plants and animals still struggle to gain toeholds on this unforgiving lava field. Much of the world’s vegetation could not survive here at all. Environmental stresses created by scant soil and minimal moisture are compounded by highly porous cinders that are incapable of holding water near the ground surface where plants and other organisms can make ready use of it. Scarce at best—total average precipitation is between 15 to 20 inches per year—rainwater and snowmelt quickly slip down out of reach of the plants growing on cinder cones. Summer’s hot, dry winds rob moisture from all living things exposed to them. Whisking across leaves and needles the winds carry away moisture precious to plant tissues. On the side of a cinder cone, summer day temperatures at ground level can be more than 150°F.
The secret to survival here is adaptation. Most life forms cope by strategies of either resisting or evading the extremes of this semi-arid climate. To resist being robbed of moisture by winds and heat, a plant may feature very small leaves that minimize moisture loss. To evade heat, wind, and aridity, another plant may grow inside a crevice that provides life-giving shade and collects precious moisture and soil particles. Another plant may spend about 95 percent of the year dormant. It may rush through the germination, sprouting, leafing out, blooming, and fruiting stages and return to the dormancy of its seed stage in just two weeks. The dwarf buckwheat has adapted to life on porous cinders by evolving a root system that may spread out for up to 3 feet to support its aboveground part, which is a mere 4 inches high. This buckwheat only looks like a dwarf because you can not see its roots.
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