Reviewing controls of wetland water temperature change across scales and typologies

Abstract

Water temperature is crucial for aquatic ecosystem health, influencing physical and biochemical processes and determining the distribution of temperature-adapted organisms. Wetlands provide essential ecosystem services, including water quality improvement, yet their thermal regimes are understudied despite the critical role of water temperature in aquatic health. This review synthesizes 35 studies on water temperature controls in natural and constructed freshwater wetlands in predominantly midlatitude regions, published from 2000 to 2023. We identify key water temperature controls at landscape and wetland site-specific scales: landscape features including topography, geology, and land cover, and site factors including vegetation, hydroperiod, hydraulic conductivity, and wetland size. Regional climatic drivers of wetland water temperature are moderated by a site’s position on the landscape, groundwater inputs, and the water surface area-to-depth ratio. Vegetation can provide cooling through shading or contribute to thermal stratification by limiting water mixing. Wetland condition assessments used to assess the health and functionality of wetlands based on various biophysical and hydrological criteria offer insights into spatial influences on temperature change but tend to oversimplify these relationships. This highlights the need for refined typologies that conceptualize nested site-level controls within the broader landscape and account for temporal dynamics. Future research should focus on detailed investigations of thermal variations across wetland types and scales, with enhanced data resolution to support adaptive management amid climate change.