Effect of natural drought cycle and climate change is restoration of the grasslands of centuries ago.By Moises Velasquez-Manoff Staff Writer of The Christian Science Monitor
Bandelier National Monument, N.M. - For 15 years, Craig Allen, a scientist with the US Geological Survey, has monitored a 2.7-acre plot here in northern New Mexico. During that time, he’s witnessed smaller tree species succeeding larger ones. He’s seen dry years, bark-beetle infestations, large-scale tree dieback, and finally, a shift toward grassland. To Dr. Allen, these changes tell a tale of combined human impacts – overgrazing, fire suppression, and climate change. And they underscore how human activity can amplify the effects of natural cycles to alter a landscape dramatically.
The American Southwest may be drying, one of the predicted consequences of human-induced global climate change. Less water in an already semiarid region will affect how, and for what, people use water. Allen also suspects that tree dieback here may be part of a worldwide phenomenon. As temperature extremes have inched higher in semiarid regions globally, forests have succumbed to heat stress.
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