Dryland responses to anthropogenic change: a biogeochemical perspective

Hugh Hanson seminar with Sasha C. Reed

Sasha C. Reed, U.S. Geological Survey

Dryland ecosystems represent our planet’s largest biome and are home to billions of people, yet,
our appreciation of their importance in global change feedbacks is still quite poor. While we
know arid and semiarid ecosystems can be affected by a host of anthropogenic changes – such as
climate change, increasing atmospheric CO2 concentrations, land use change, and nutrient
deposition – a synthetic understanding of the mechanisms and larger-scale consequences of this
change remain lacking. In this talk, I will use a biogeochemical lens to examine how dryland
plants and soil microbes are affecting and affected by environmental change. By considering the
cycles of carbon, nitrogen, and phosphorus both above- and belowground, I will ask questions
about how drylands work and how they are responding to our rapidly changing world. This will
include discussions about the fascinating biological soil crusts that help regulate dryland
function. We will cover topics such as temperature effects in warm biomes, the potential for
mass mortality events, and unexpected consequences of nitrogen deposition. I hope to leave you
with a biogeochemical appreciation for the importance and complicated connections of these
spectacular and dry ecosystems.

Wednesday, Oct. 19 | 1 - 2 p.m.
LSE 244
School of Life Sciences - E wing