Complex ecological effects of urbanization in arid ecosystems
Urban landscapes cover less than five percent of Earth’s land surface but are home to more than half of humanity and affect airsheds that extend tens to hundreds of kilometers past their borders. Combined with manipulative experiments, gradients within and across cities can be used as living laboratories to explore complex, sometimes bidirectional interactions between people and the ecosystems that support us.
Sharon J. Hall, associate professor in ASU's School of Life Sciences, will discuss research conducted as a part of the Central Arizona–Phoenix Long-Term Ecological Research project (CAP LTER). Hall's research group investigates the direct and indirect effects of urbanization on plants, soils, and people.
"Our interdisciplinary studies have yielded numerous ecological surprises," explained Hall. "Deserts appear to be 'nitrogen saturated' ecosystems during most years; atypical microbial domains contribute to nitrogen cycling processes; and rates of nitrogen deposition are lower than expected in Phoenix with a large contribution from NH3. Our work in managed ecosystems have also yielded unexpected findings: Both protected open space parks and desert yards within the city appear to be 'domesticated,' exhibiting characteristics similar to both native desert and residential grassy lawns; and emerging water-wise landscapes converted from former turfgrass cause changes in human behavior that may contribute to large, hidden pools of nitrate beneath the soil surface."
Hall's upcoming presentation, part of the Science and Mathematics Colloquium Series, is funded and organized by the Faculty of Science and Mathematics, College of Integrative Sciences and Arts, at ASU's Polytechnic campus.