SENTINELS OF CHANGE: WARMING SIGNALS IN MOUNTAIN LAKE COMMUNITIES OVER THE PAST 25 YEARS

As global temperatures rise, community assemblages in terrestrial, marine, and aquatic ecosystems are shifting, with warmer-adapted species becoming more prevalent while cooler-adapted species decline, a process known as thermophilization. Community thermal indices (CTIs) quantify the thermal affinities of entire communities and are key to forecasting future biodiversity patterns, allowing us to attribute species turnover to climate change and predict the influence of warming on ecosystem function. Our study aims to investigate the impact of environmental change on the thermophilization of zooplankton communities in montane lakes. Utilizing zooplankton diversity and environmental data from the Sierra Lakes Inventory Project (1995-2002) and the Eastern Sierra Nevada Mountain Lakes Long Term Monitoring Program (2013-present), we have determined the thermal affinities of zooplankton species, which range from 15°C for a large-bodied keystone grazer Daphnia melanica to 21°C for a small-bodied cladoceran, Scapholeberis mucronata. We then quantified the CTIs of zooplankton assemblages in Eastern Sierra Nevada lakes. We analyzed long-term shifts in zooplankton CTIs by comparing communities from 1995 to 2024 and assessed short-term differences by examining how CTIs varied with snowpack - an important determinant of water temperature in mountain lakes. Our project demonstrates how zooplankton in montane lakes are responsive to long- and short-term variations in temperature in an era of long-term warming and increased variation in snowpack. 

Presentation Preference: Poster

Primary Presenter: Meili Soriano, University of California, Irvine (sorianomeili0723@gmail.com)

Authors:

Meili Soriano, University of California, Irvine  (sorianomeili0723@gmail.com)

Jonathan Shurin, University of California, San Diego  (jshurin@ucsd.edu)

Celia Symons, University of California, Irvine  (csymons@uci.edu)