Climate change drives widespread shifts in lake thermal habitat

Abstract

Lake surfaces are warming worldwide, raising concerns about lake organism responses to thermal habitat changes. Species may cope with temperature increases by shifting their seasonality or their depth to track suitable thermal habitats, but these responses may be constrained by ecological interactions, life histories or limiting resources. Here we use 32 million temperature measurements from 139 lakes to quantify thermal habitat change (percentage of non-overlap) and assess how this change is exacerbated by potential habitat constraints. Long-term temperature change resulted in an average 6.2% non-overlap between thermal habitats in baseline (1978–1995) and recent (1996–2013) time periods, with non-overlap increasing to 19.4% on average when habitats were restricted by season and depth. Tropical lakes exhibited substantially higher thermal non-overlap compared with lakes at other latitudes. Lakes with high thermal habitat change coincided with those having numerous endemic species, suggesting that conservation actions should consider thermal habitat change to preserve lake biodiversity.

Anthropogenic climate change has altered lake state in the Sierra Nevada (California, USA)

“…The economy and resilience of California are linked to the Sierra Nevada snowpack and timing of melt; changes in seasonality therefore hold important implications for the state. Stable water column stratification affects not only nutrient status but also the concentration and spatial distribution of dissolved oxygen, food web organization, and water quality (e.g., Cohen et al, 2016;Kraemer et al, 2021;Smol, 2019). Changes in water column thermal stratification and nutrient cycling commence over abrupt transitions at June Lake, suggesting that rapid change as environmental thresholds are crossed is a hallmark of this ecosystem and perhaps others like it in the Sierra Nevada.…”

“…Changes in temperature likewise threaten high-altitude lakes in the Sierra Nevada, which provide valuable supporting, regulating, and cultural services for the region. Higher temperatures may promote early ice-off and an extended period of water column stratification in lakes, which affects thermal habitats and patterns of biodiversity (e.g., Kraemer et al, 2021).…”

Strong Warming Rates in the Surface and Bottom Layers of a Boreal Lake: Results From Approximately Six Decades of Measurements (1964–2020)

“…Given that, all lakes are land‐locked, these changes could be intensified by the projected changing climate under the future influence of anthropogenic stressors (Jane et al., 2021; Modabberi et al., 2020; Woolway et al., 2021). This could have deep implications for the lake ecological services (Kraemer et al., 2021; Pilla et al., 2020) and threaten both the quantity and quality of the most important sources of freshwater for humankind (Kraemer et al., 2015; Noori et al., 2018). Despite the global warming impact on the lakes, the rate of increase in the lake surface‐water temperature (LST) is not consistent with that in the lake deep‐water temperature (LDT).…”

Climate change and nutrient fluctuations interact to affect ecological networks in lakes

“…Human impacts, such as climate change and pollution, are reorganizing entire ecosystems by affecting the nature and strength of ecological interactions and thereby the composition of communities 1-4 . In fact, the global warming experienced by many lakes, particularly in the last decade, has shifted the balance of these delicate networks to an unstable situation in which slight increases in nutrient levels can trigger dramatic changes 5,6 . If the current rise in temperature continues, as predicted 6 , the dynamics of these communities are expected to destabilize 3,7,8 .…”