ZOOBENTHIC MACROINVERTBRATE COMMUNITY RESPONSES TO ICE BREAK UP IN SUBALPINE LAKE HABITATS OVER 15 YEARS

Winter conditions and ice dynamics govern lake ecosystem processes during the ice-free season in polar and temperate freshwater systems. Lake ice cover duration is increasingly variable and declining due to climate warming. As lake ice conditions change, the impacts of ice on lake benthic processes during subsequent ice-free seasons remain poorly documented despite the significance of these habitats to whole lake function. In this study, we examined the connections between ice off date, lake physical and chemical traits in the ice-free season, and zoobenthic macroinvertebrate diversity in a subalpine lake (Castle Lake, CA, USA). Zoobenthos were collected during three periods (early, mid, and late summer) from four nearshore-littoral and three profundal lake habitats over 15 years and identified to family. Ice off dates were highly variable, ranging from Julian days 51 to 178. We identified 30 families, dominated by 3 taxa (Chironomidae, Oligochaeta, Pisidium) during the sampling period, with richness ranging between 1 to 13 taxa. Preliminary analyses suggest zoobenthic diversity is highly variable across lake habitats across years and ice-out dates, supporting potential resiliency in community structure over space and time. Our results suggest dominant zoobenthic taxa have the capacity to withstand significant environmental variability under changing ice conditions.

Primary Presenter: Elizabeth Mast, University of Nevada, Reno (emast@nevada.unr.edu)

Authors:

Elizabeth Mast, Biology Department, University of Nevada, Reno AND Ecology, Evolution, and Conservation Biology, University of Nevada, Reno  (emast@nevada.unr.edu)

Sudeep Chandra, Biology Department, University of Nevada, Reno AND Global Water Center  (sudeep@unr.edu)

Joanna Blaszczak, Global Water Center AND Natural Resources and Environmental Science Department, University of Nevada, Reno  (jblaszczak@unr.edu)

Kenneth Nussear, Geography Department, University of Nevada, Reno  (knussear@unr.edu)

Erin Suenaga, Biology Department, University of Nevada, Reno AND Global Water Center  (esuenaga@unr.edu)

Facundo Scordo, Instituto Argentino de Oceanografía, Universidad Nacional del Sur (UNS)-CONICET, Bahía Blanca, Argentina  (scordo@agro.uba.ar)

Carina Seitz, Centro Regional Universitario Bariloche, Universidad Nacional del Comahue (UNCOMA)-CONICET, San Carlos de Bariloche, Argentina  (carina.seitz6@gmail.com)