The Warmest March: Soil Biota Response to an Extreme Warm Weather Event in the McMurdo Dry Valleys, Antarctica
Meredith D. Snyder, John E. Barrett, Mark R. Salvatore, Byron Adams, Peter Doran
As climate change influences species distribution and activity, it is important to monitor changes in the demography and abundance of sentinel taxa in harsh environments that are sensitive to extreme weather events. The cold and arid conditions of the Antarctic McMurdo Dry Valleys (MDV) limit soil communities to a few taxa of invertebrates, including 3 genera of nematodes: Scottnema; Eudorylaimus; and Plectus, which may be vulnerable to extreme and rapid freeze thaw cycles. The MDV experienced a record high temperature of 6.74°C on March 18th 2022, following organismal cryopreservation. We examined impacts of thaw within the Canada Stream Antarctic Specially Protected Area on soil biota abundance and demography by selecting sampling locations with remotely sensed data that experienced significant and nonsignificant changes in liquid surface water content. Invertebrate diversity and soil moisture were positively correlated (R2=0.50), with low abundance and diversity in dry soils (R2=0.86). Wetted soils had high mortality and fecundity of the endemic species Scottnema lindsayae, whereas mesophilic species showed no significant change. This study contributes to our knowledge of MDV invertebrate species distribution, community change, and how they respond to extreme weather events.
